TC Chapala, Yemen, & Texas Flooding

Posted on November 1, 2015 by marcia

Category 4 Chapala On Its Way to Yemen; Texas Gasping after More Record Rain

By: Bob Henson and Jeff Masters , 5:30 PM GMT on October 31, 2015

Figure 1. Tropical Cyclone Chapala as seen from the International Space Station at sunset on Halloween evening, October 31, 2015. At the time, Chapala was a Category 4 storm with 135 mph winds. The coast of Oman/Yemen is visible at the bottom of the image. Image credit: Commander Scott Kelly.

Figure 2. Tropical Cyclone Chapala as seen by the MODIS instrument on NASA’s Terra satellite on Saturday morning, October 31, 2015. At the time, Chapala was a Category 4 storm with 135 mph winds. Image credit: NASA.

The forecast for Chapala
The biggest change since Friday is a southward departure in Chapala’s track. The cyclone is now heading due west and should continue on that bearing for the next couple of days, with a slight curve to the west-northwest as it approaches Yemen on Monday night. Chapala’s healthy structure may keep dry air at bay for some time, but eventually the cyclone should weaken as it near the Arabian Peninsula and ingests greater amounts of parched desert air. The Joint Typhoon Warning Center brings Chapala onshore in the high tropical-storm-strength range, with sustained winds possibly close to hurricane strength.

Figure 3. Three tropical cyclones are known to have made landfall on the southern coast of Oman and Yemen betwen 1891 and the beginning of modern satellite records (1990). Two of these reached northeast Yemen, in May 1959 and May 1960. Both were rated as “severe cyclonic storms” prior to landfall (solid line), meaning their top 3-minute average wind speeds were at least 48 knots (55 mph). Image credit: Courtesy Dr. Mrutyunjay Mohapatra, Head, Cyclone Warning Division and Regional Specialised Meteorological Centre, India Meteorological Department.

According to NOAA’s Historical Hurricanes tool, there have only been six major Category 3 or stronger tropical cyclones recorded in the Arabian Sea (though accurate satellite records go back to just 1990.) The Arabian Sea doesn’t get many tropical cyclones since it is small; furthermore, the Southwest Monsoon keeps the tropical cyclone season short, with a short season that lasts from May to early June before the monsoon arrives, then another short season in late October through November after the monsoon has departed. Strong Arabian Sea storms are rare due to high wind shear and copious dry air from the deserts of the Middle East, with just two Category 4 or 5 storms ever recorded–Gonu in 2007 and Phet in 2010. Both cyclones hit Oman after weakening below Category 4 strength.

Landfalling cyclones are even more rare in Yemen. The only one in the post-1990 satellite database is Tropical Depression Three of 2008 (also known as the 2008 Yemen Cyclone), which came on the heels of heavy rains from another storm and resulted in disastrous flooding. According to EM-DAT, the international disaster database, that storm killed 90 people and did $400 million in damage, making it the second worst natural disaster in Yemen’s history, behind a June 13, 1996 flood (thanks go to wunderground member TropicalAnalystwx13 for alerting us to this fact.) The India Meteorological Department maintains a database of tropical cyclones in the region going back to 1891 that shows two cyclonic storms reaching the Yemen coast in 1960 and 1961 (see Figure 3).

Figure 4. The port of Al Mukalla. Image credit: Roo72/Wikimedia Commons.

Figure 5. Topography of Yemen. Image credit: Sadalmelik/Wikimedia Commons.

Chapala’s southward track will make it only the second tropical cyclone recorded near the mouth of the Gulf of Aden, which is crossed by roughly 400 ships a week. The adjustment in Chapala’s track could have major implications for Yemen, as it brings the center closer to the 980-year-old settlement of Al Mukalla (also known as Mukalla), a busy port and Yemen’s fifth-largest city (population around 300,000). If Chapala were to pass just south of Al Mukalla, the sharp angle of approach to the coast would accentuate any storm surge. Yemen has been in the grip of a civil war since March, so any landfall near this populated area could intersect with the conflict in hard-to-predict ways. According to an October 30 article from Reuters, ten of Yemen’s 22 governorates were assessed as being in an emergency food situation in June, one step below famine on a five-point scale. The assessment has not been updated since then, partly because experts have not managed to get sufficient access to survey the situation. About a third of the country’s population, or 7.6 million people urgently require food aid, the The U.N. World Food Programme said (thanks go to wunderground member barbamz for alerting us to this article.)

As it moves ashore, Chapala will slam into steep mountains near the coast, boosting its potential to dump several years’ worth of rain in just a day or two (see Figure 6). The annual average rainfall in Yemen is less than 2” along the immediate coast and less than 5” inland, except along higher terrain, where it can approach 10”. Any landfall near Al Mukalla could result in serious urban flooding (the city straddles a canal that extends to the coast from the adjacent mountainsides).

Figure 6. The 5-day rainfall forecast from the 2 am EDT Saturday, October 31, 2015 run of the HWRF model called for some truly stunning rainfall amounts in the parched desert regions of eastern Yemen: over two feet! Image credit: NOAA/EMC.

Rain-weary Texans deal with another deluge
Yet another round of epic downpours struck the heart of Texas from Friday into Saturday. The focus on Friday morning was the HIll Country and the adjacent San Antonio and Austin metro areas, which suffered through record rain and destructive flooding back in May. The air traffic control center at Austin’s Bergstrom International Airport has been shut down after being inundated with six inches of water on Friday. A Houston center is handling its duties until a temporary facility arrives on Monday. Bergstrom received 5.76” of rain in just one hour, as part of a phenomenal calendar-day total of 14.99” on Friday. That’s more than the site had ever recorded in any prior 14-day period! (Records at Bergstrom go back to 1942. Thanks to Nick Wiltgen at weather.com for this statistic.). The total also came within a hair (0.067%) of reaching the city’s all-time 24-hour record of 15.00”, set at Camp Mabry on September 9, 1921, in association with a Category 1 hurricane that caused severe flooding in the San Antonio area. Further south, Brownsville had its second wettest October day in 128 years of recordkeeping, with 6.55” on Friday beaten only by 9.09” on October 4, 1996, in association with Tropical Storm Josephine. The absence of a tropical cyclone makes this event across central and south Texas all the more remarkable.

Figure 7. Jim Richardson and his wife Jeannette look on as the Blanco River recedes after the flash flood in Wimberly, Texas Friday, Oct. 30, 2015. A fast-moving storm packing heavy rain and destructive winds overwhelmed rivers and prompted evacuations Friday in the same area of Central Texas that saw devastating spring floods. Image credit: Ricardo Brazziell/Austin American-Statesman via AP.

Figure 8. Estimated rainfall between 7:00 am CDT Friday, October 30, and Saturday, October 31. Image credit: NOAA Advanced Hydrologic Prediction Service.

A subsequent round of heavy thunderstorms moved into southeast Texas overnight and into Saturday morning, causing widespread flooding in the Houston area, as well as scattered wind damage perhaps associated with one or more tornadoes. With light rain hanging on at noon CDT Saturday, Houston’s Hobby Airport had received 6.50” for the day, bringing its monthly total to 14.24”. Hobby will fall short of the Houston area’s wettest October on record, 17.64” in 1949, a total largely goosed by a Category 2 hurricane early that month. The front edge of this sprawling area of heavy thunderstorms is now approaching southeast Louisiana, which has also been hammered by heavy rain in October. Baton Rouge had received 10.85” for the month as of Friday, and New Orleans 8.88”. NOAA’s Weather Prediction Center is calling for as much as 5-6” of rain over the area today into Sunday. Baton Rouge has an outside chance of scoring its wettest October on record (17.64”, from 1949; records go back to 1889), as does the Louis Armstrong New Orleans International Airport (13.20” in 1985, in association with Hurricane Juan; records go back to 1946).

Dallas-Fort Worth International Airport racked up another 2.25” from Friday through 11:00 am CDT Saturday. The airport has now recorded 48.92” for the year, making 2015 the sixth wettest year since DFW-area records began in 1898. One of the most reliable U.S. impacts from El Niño is increased cold-season rainfall from Texas to Florida. Given the strong El Niño influence already at hand, DFW has a good chance over the next two months of topping 53.54” (1991) to score its wettest year on record. In fact, it could happen quite soon: WPC is projecting 2” to 5” of rain across central North Texas late next week, as another strong Pacific upper-level storm carves its way into the western U.S. That storm will give the Pacific Northwest a seasonally heavy drenching this weekend, and it may leave the first significant accumulation of the season along the snow-starved Sierra Nevada on Monday and Tuesday–perhaps as much as a foot on the highest peaks. A winter storm watch has been hoisted for the region, but we’re guessing most residents will be elated rather than spooked by this October 31 development. Have a great Halloween weekend, everyone!

Bob Henson and Jeff Masters

from: http://www.wunderground.com/blog/JeffMasters/category-4-chapala-on-its-way-to-yemen-texas-gasping-after-more-recor

Hurricane Joaquin Heads Towards the East Coast

Posted on September 30, 2015 by marcia

Hurricane Warnings for the Bahamas From Joaquin; Threat to U.S. East Coast Grows

By: Jeff Masters and Bob Henson , 3:38 PM GMT on September 30, 2015

Joaquin is now a hurricane, and Hurricane Warnings are up for the Central Bahama Islands as the slowly intensifying storm moves southwest at 6 mph. An Air Force hurricane hunter aircraft made two penetrations of Joaquin’s center on Wednesday morning, and found top surface winds of 80 mph, a central pressure of 971 mb, and a huge 54-mile diameter eye with a fully closed eyewall. Joaquin continues to battle high wind shear of 20 knots due to strong upper-level winds out of the north-northwest, but this wind shear had fallen by about 5 knots since Tuesday morning. Water vapor satellite loops show that a large area of dry air lay to the northwest of Joaquin, and the strong wind shear was driving this dry air into Joaquin’s core, keeping intensification slow. Visible and infrared satellite loops show that Joaquin has developed a large Central Dense Overcast (CDO) of high cirrus clouds over the center, characteristic of intensifying storms, and the hurricane’s large eye was beginning to be apparent. Upper level winds analyses from the University of Wisconsin show that the hurricane has developed an impressive upper-level outflow channel to the southeast, which is supporting the intensification process. Ocean temperatures in the region are near 30°C (86°F)–the warmest seen there since record keeping began in 1880.

Figure 1. Latest satellite image of Joaquin.

The U.S. outlook for Joaquin
A hurricane watch could be required for portions of the U.S. East Coast as early as Thursday night. The forecast for Joaquin is very complex, and the confidence in both the intensity and track forecast for the storm is low. Joaquin is trapped to the south of a high pressure system whose clockwise flow will push the cyclone very slowly to the southwest or west-southwest at about 3 – 6 mph. As the storm progresses to the southwest, the strong upper-level winds out of the north currently bringing high wind shear of 20 knots will gradually decrease, continuing to allow Joaquin to strengthen. The 8 am EDT Wednesday run of the SHIPS model predicted that wind shear over Joaquin would fall to the moderate range, 10 – 20 knots, on Thursday and Friday. These conditions should allow Joaquin to intensify to a Category 2 hurricane by Thursday. As Joaquin progresses to the west, the storm will also increasingly “feel” the steering influence of a strong upper-level trough of low pressure situated over the Eastern United States on Friday, and begin to turn north. These winds may also open up another upper-level outflow channel to the northwest of Joaquin on Friday, potentially allowing the storm to intensify to Category 3 strength. However, as Joaquin gets closer to this trough, its winds will bring high wind shear of 20+ knots, likely halting the intensification process and causing weakening by Sunday.

Figure 2. Our two top models for forecasting hurricane tracks, both run at 8 pm EDT Tuesday September 29, 2015 (00Z Wednesday) , came up with two very different solutions for the path of Joaquin. The GFS model showed Joaquin making landfall in Virginia, while the European model took the storm to the northeast out to sea without hitting the U.S. Image credit: wundermap with the “Model Data” layer turned on.

Figure 3. The ensemble runs of our two top models for forecasting hurricane tracks, both run at 8 pm EDT Tuesday September 29, 2015 (00Z Wednesday). The 50 members of the European model ensemble (top) and the 20 members of the GFS model ensemble (bottom) both had numerous model runs that took Joaquin into U.S. East Coast, and ones that missed the U.S. coast entirely. Ensemble runs take the operational version of the model and run it at lower resolution with slightly different initial conditions, to generate an “ensemble” of possible forecasts. The operation high-resolution (and presumably best-guess) forecast for the models is shown in red. The European model ensemble had four members that tracked the movement of Joaquin exceptionally well during the previous 12 hours; three of those four members had tracks for Joaquin that missed the U.S., and one that hit the coast near New York City. Image taken from a custom software package used by TWC.

The big trend from the 00Z Wednesday (8 pm EDT Tuesday) suite of computer model guidance was a marked convergence toward a landfall in the vicinity of North Carolina or Virginia. The 00Z HWRF and GFDL models were joined by the 00Z GFS in hooking Joaquin toward the northwest on Friday and accelerating the hurricane into the coast between Cape Hatteras, NC, and the Delmarva Peninsula as a significant hurricane on Saturday/Sunday. The high-resolution HWRF and GFDL output showed central pressures in the 940-950 mb range at landfall, with wind speeds on par with a Category 2 hurricane. The 00Z UKMET solution angled more north-northwestward, with Joaquin arriving near the southern end of the Delmarva and scraping up the coast into eastern New Jersey and New York. Among the major dynamical models, only the European (ECMWF) model remained adamant that Joaquin would head to sea well before reaching the southeast U.S., although its 00Z track was a bit west of previous runs. The leftward hook prominently featured in the other models is being driven by the increasingly negative tilt (NW-to-SE) to the upper trough deepening over the eastern U.S. late this week. The models are projecting that this trough would pull in Joaquin on its northeast side, in much the same way that a strong upper-level low did with Hurricane/Superstorm Sandy in 2012. However, in Joaquin’s case, the process would unfold a couple of hundred miles to the south. The ECMWF run shows a very similar upper-level pattern to the other models, but the timing of the trough’s interaction with Joaquin and with Invest 90L is such that the hurricane is shunted to sea instead of being tucked into the northeast side of the trough. 90L was centered at 8 am EDT Wednesday about 1000 miles east-northeast of Joaquin. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave 90L 2-day and 5-day odds of development of 40% and 70%, respectively.

Figure 4. Model track guidance initialized at 12Z Wednesday (8 am EDT) shows a continued clustering of model solutions toward North Carolina and the mid-Atlantic. This early-track guidance uses 12Z data on Joaquin to update the previous model runs from 06Z. This map does not include the ECMWF model, whose 00Z operational run took Joaquin out to sea. Image credit: Levi Cowan, tropicaltidbits.com.

Back in 2012, the ECMWF model caught on to the leftward hook of Sandy’s track several days before other models. The ECMWF’s high overall skill means we cannot entirely discount its out-to-sea forecast for Joaquin just yet. At the same time, the strong consistency among other leading models in projecting a NC/mid-Atlantic landfall cannot be ignored. We can gain more perspective on this scenario by looking at the ECMWF and GFS ensemble output from 00Z Wednesday. In each ensemble, the model is run a number of times for the same situation, but with the starting conditions varied slightly to represent the uncertainty in our starting-point observations of the atmosphere. The ECMWF and GFS ensembles from 00Z Wednesday are much more similar in flavor than you might expect from looking at their single operational runs. Both models have a majority of ensemble members heading for North Carolina and the mid-Atlantic, with a few outliers heading to sea.

If Wednesday’s 12Z (8 am EDT) models continue to zero in on a NC/VA landfall, and especially if the ECMWF comes more fully around, then this solution will become a more high-confidence forecast. The NHC has been nudging its “cone of uncertainty” toward the left, still splitting the difference between the ECMWF and other solutions while acknowledging the westward trend. The entire U.S. coast from the Outer Banks of NC to southern New England was located in the 5-day cone issued at 11 am EDT Wednesday and valid at 2 am EDT Monday. Even if NHC moves more fully toward the NC/mid-Atlantic scenario, we can still expect to see a large swath of coastline remaining in the “cone” as we get closer to Joaquin’s eventual landfall.

Potential impacts from Joaquin
Apart from the remaining uncertainty about a U.S. landfall, Joaquin is now poised to bring hurricane-force conditions into or very close to the southeastern Bahamas. WIth luck, these islands will remain on the weaker left-hand side of Joaquin. If the hurricane makes a sharp turn to the north on Friday as predicted, the effects should be considerably less on the northwestern Bahamas.

It is relatively rare for a hurricane to make a Sandy-like left hook into the U.S. East Coast. Such a track was unprecedented for New Jersey in hurricane annals, and even in the NC/VA area, it is uncommon enough that the likely effects would be both unusual and high-impact. The closest analogue from recent years is 2003’s Hurricane Isabel. After a much longer life as a Cape Verde system and a Category 4 hurricane from the Central Atlantic (briefly a Category 5), Isabel angled sharply northwestward and made landfall on North Carolina’s Outer Banks as a strong Category 2 hurricane. Isabel then continued on a fairly direct track to western Pennsylvania as it weakened. Isabel’s trajectory brought huge surf to the coast from North Carolina to New Jersey, with a major storm surge pushing into the Chesapeake Bay and nearby waterways, plus widespread impacts from high wind and heavy rain. Joaquin is not as large or long-lived a storm as Isabel, but if it moved slightly to the north of Isabel’s path, its track could be even more favorable for a Chesapeake surge. Hurricane-force winds would be another factor to contend with, especially just north of Joaquin’s track during and just after landfall. Storm surge expert Dr. Hal Needham of LSU has a detailed look at the potential for storm surge from Joaquin along the U.S. East Coast in his Wednesday morning blog post, Widespread Storm Surge Event to Impact U.S. Atlantic Coast.

One very worrisome aspect of Joaquin is the torrential rains that it could bring from the Carolinas to the Northeast and perhaps even New England. Heavy rains and scattered flash flooding have already occurred in parts of these areas over the last 24 hours, as a preexisting front is overtopped by near-record amounts of water vapor streaming over the region ahead of the trough that will help steer Joaquin. The hurricane itself, arriving after several days of antecedent rainfall, has the potential to produce truly historic rainfall totals. This morning’s 7-day outlook from the NOAA Weather Prediction Center, which goes with the NC/mid-Atlantic scenario, shows widespread 5-10″ amounts from North Carolina to southern New England. Model output suggests that localized 7-day totals of 10-20″ or more are not out of the question, depending on Joaquin’s exact track. We’ll have more on the ongoing and potential flood risk in our afternoon post.

Figure 5. Projected 7-day rainfall amounts from 12Z Wednesday, September 30, to 12Z October 7. Image credit: NOAA Weather Prediction Center.

We’ll have a new post this afternoon.

Jeff Masters and Bob Henson

from: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=3131

Typhoon Noul & 1st Atlantic Invest

Posted on May 7, 2015 by marcia

Atlantic’s First Invest of the 2015, 90L, Organizing Over the Bahamas

By: Jeff Masters and Bob Henson , 3:50 PM GMT on May 06, 2015

2015: May 6
2014: June 4
2013: May 18
2012: February 5
2011: March 10
2010: May 24
2009: May 18
2008: May 31
2007: May 8
2006: June 10

Figure 1. Latest satellite image of Invest 90L.

Satellite loops show heavy thunderstorms between the Southeast coast of Florida and the Northwest Bahamas in association with 90L increased on Wednesday morning, but there was no evidence of an organized surface circulation trying to form. Long-range radar out of Melbourne, Florida showed no low-level spiral bands trying to form, and the activity was not well-organized. Wind shear was a moderate to high 15 – 25 knots. Water vapor satellite loops show a large area of dry air to the west of 90L over Florida and the Gulf of Mexico, and this dry air is retarding development, thanks to strong upper-level winds out of the west driving the dry air into the core of 90L. Ocean temperatures were near 26°C (79°F), which is about 1.7°C (3°F) above average for this time of year, and just at the limit of where a tropical storm can form. The Hurricane Hunter mission scheduled for Wednesday afternoon was cancelled, and has be re-scheduled for Thursday afternoon, if necessary.

Figure 2. Wind forecast for Saturday, May 9, 2015 at 11 am EDT made by the 00Z Wednesday run of the European model. The model is predicting a subtropical depression to be off the coast of the Southeast U.S.

Forecast for 90L
The 8 am EDT run of the SHIPS model predicted that wind shear over 90L would fall to the moderate range, 10 – 20 knots, on Thursday and Friday, which should allow 90L to approach subtropical depression status by Friday at the latest. Phase space diagrams from Florida State University from Wednesday morning’s 06Z run of the GFS model support the idea that this system could be a subtropical or tropical system by Friday. Ocean temperatures fall to about 25°C (77°F) in the waters off of the North Carolina coast, so the farther north the storm wanders, the tougher time it will have developing tropical characteristics–though if the storm manages to find a sweet spot over the core of the warm Gulf Stream current, it has better odds of development. Steering currents are weak over the waters off the Southeast U.S. coast, so expect a slow and erratic motion for 90L. The Wednesday morning 00Z runs of our two top models for predicting tropical cyclones tracks, the European and GFS models, both showed the system making landfall this weekend, with the GFS model predicting landfall in South Carolina on Saturday, and the European model taking the storm ashore in North Carolina on Sunday. Beginning on Friday, coastal regions of both of these states can expect heavy rains and high surf causing rip currents and coastal erosion. Note that the west side of 90L will be weaker and drier, due to the dry air to the west of the storm, and the heaviest rains and stongest winds of 90L will be on the east side of the storm, over North Carolina. In their 8 am EDT Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day odds of development of 60%, respectively.

Wunderblogger Steve Gregory has a more detailed look at the meteorology of 90L in his Wednesday afternoon post.

Figure 3. Latest projected track of Typhoon Noul from the Joint Typhoon Warning Center (JTWC); a time of 9:00 p.m. JST Wednesday is 1200 GMT or 8 am EDT.

Typhoon Noul posing an increased threat to northern Philippines
After dumping more than 10 inches of rain at Yap International Airport, Category 1 Typhoon Noul is on its way toward the northern Philippines. Noel is gradually intensifying, with sustained winds of 90 mph reported at 8 am EDT (1200 GMT) Wednesday. Satellite loops show that the storm’s center is obscured by central dense overcast, but microwave data obtained by satellite shows that an open eye is already present. Noel is well structured and passing over warm waters, with only weak to moderate wind shear, so continued strengthening into a Category 4 storm is expected. Noel will encounter a trough as it approaches the Philippines, which may force the storm to recurve before making landfall there. However, model guidance has been trending westward, albeit with some uncertainty, and the official Joint Typhoon Warning Center track (see Figure 3) now brings Noul ashore along the northeast coast of Luzon, the largest and northernmost island of the Philippines. Noel is expected to peak in intensity just a few hours before approaching Luzon, with sustained winds of 105 knots (120 mph) projected by the JTWC near landfall. The northeast part of Luzon is mountainous, which could increase the risk for very heavy rains as Noul moves onshore or nearby, although a grazing landfall would put most of Luzon on the weaker western side of the circulation. Noul will be referred to as Dodong in the Philippines’ naming system.

Another tropical system, Invest 93W, is organizing to the east, and is likely to develop late this wee. It is too soon to know what its chances are of affecting the Philippines or Japan next week.

An exceptionally busy early portion of typhoon season
Noul’s formation date of May 3 marks the second earliest appearance on record for the Northwest Pacific’s sixth named storm of the year, according to statistics of the Japan Meteorological Agency’s database from 1951 – 2015 maintained by Digital Typhoon. The average is 1.8 storms before May 8. The record is held by 1971, when the sixth named storm of the year (Babe) formed on May 3, six hours earlier than Noul’s formation time. Noul will be the second tropical cyclone to affect the Philippines so far in 2015. The first was Tropical Storm Maysak, which hit the Philippines exceptionally early in the season–during Easter weekend, April 4 – 5. Fortunately, Maysak was weakening rapidly as it made landfall, and no deaths or significant damage were reported (though four people were injured after huge waves generated by Maysak hit them while they were taking selfies along the shoreline of Dipaculao town in Aurora province on April 4.)

Jeff Masters and Bob Henson

from: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2975

Thanksgiving Nor-Easter

Posted on November 25, 2014 by marcia

Unwelcome Nor’easter Poised to Snarl Wednesday Travel

By: Dr. Jeff Masters , 2:44 PM GMT on November 25, 2014

After basking in record warm temperatures in the 60s and 70s on Monday, the Northeast U.S. is bracing for a Wednesday winter onslaught, as a significant Nor’easter will bring heavy snows to the roads at the same time that millions of people hit the roads in advance of the Thanksgiving holiday. The unwelcome storm will form off the coast of South Carolina Tuesday night and track north-northeastward, parallel to the coast, on Wednesday. Snow will begin in the Southern Appalachians late Tuesday night and spread northeastwards on Wednesday. Areas to the east of the I-95 corridor will start off with heavy rain, but the rain will transition to wet, heavy snow on Wednesday afternoon as cold air spills southwards along the coast. Little or no accumulation is likely in Washington D.C., which hit a pleasant 74°F on Monday. The story is different, though, in Philadelphia, where a Winter Storm Watch for 2 – 3 inches of snow was posted on Monday–even as the temperature rose to a record high for the date of 72°F. Higher snowfall amounts of 4 – 8″ are possible in New York City, which also experienced a record high on Monday–64°F at Kennedy Airport. Boston will also be severely impacted beginning late Wednesday afternoon, with snows of 4 – 6″ possible. Portland, Maine, which hit a record 63°F on Monday, is under a Winter Storm Watch for 4 – 8″ of snow. The heaviest snows will come Wednesday afternoon into Wednesday evening in the big cities, and may take some time to accumulate on the roads due to stored heat from the warm temperatures of the past few days. Traveling earlier in the day Wednesday is definitely recommended if you have the flexibility, as road conditions will steadily deteriorate through the afternoon into evening. The worst conditions will be experienced inland from the coast, where widespread snow amounts of 6 – 12 inches are likely along a swath from Northeast Pennsylvania and Northwest New Jersey into Maine, including Hartford, Connecticut and central Massachusetts cities like Worcester. As usual with a storm of this nature, small changes in the forecast track of the system can cause large changes in the amount of snowfall near the coast, so stay tuned to the latest forecasts.

Figure 1. Snowfall forecast for the New York City area made on Tuesday morning, November 25, 2014. Image credit: NWS New York City.

Figure 2. Snowfall forecast for the Boston area made on Tuesday morning, November 25, 2014. Image credit: NWS Boston.

Figure 3. Snowfall forecast for the Philadelphia area made on Tuesday morning, November 25, 2014. Image credit: NWS Philadelphia.

Air travel will be heavily impacted
Heavy rains will cause flight delays at the large airports of the Northeast beginning Wednesday morning, and these delays will increase on Wednesday afternoon as the snow flies. All of the major airlines are allowing people to change their tickets for free at the airports expected to be affected by Wednesday’s storm; here is one such list of cities from United:

Albany, NY (ALB)
Allentown, PA (ABE)
Atlantic City, NJ (ACY)
Baltimore, MD (BWI)
Bangor, ME (BGR)
Boston, MA (BOS)
Buffalo, NY (BUF)
Burlington, VT (BTV)
Harrisburg, PA (MDT)
Hartford, CT (BDL)
Manchester, NH (MHT)
New York/Newark, NJ (EWR – Liberty)
New York, NY (JFK)
New York, NY (LGA – LaGuardia)
Philadelphia, PA (PHL)
Portland, ME (PWM)
Providence, RI (PVD)
Rochester, NY (ROC)
Syracuse, NY (SYR)
Washington, DC (DCA – National)
Washington, DC (IAD – Dulles)
White Plains, NY (HPN)
Wilkes-Barre/Scranton, PA (AVP)

from: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2867

On Jet Stream Buffalo Snow 11/19

Posted on November 20, 2014 by marcia

Buffalo Belted With Five Feet of Snow; Is Jet Stream Weirdness to Blame?

By: Dr. Jeff Masters , 4:30 PM GMT on November 19, 2014

America’s remarkable mid-November Arctic blast continued Wednesday morning, with hundreds of daily record low temperatures falling again. Charlotte, North Carolina bottomed out at 14°F, the coldest temperature ever measured so early in the season, and January-like cold brought temperatures 15 – 35°F below average to most of the eastern half of the country. Hardest hit by the unseasonably early Arctic outbreak was Buffalo, New York, where a record lake effect snowstorm was being blamed for at least five deaths. Three of the deaths were from heart attacks, one from a traffic accident, and one was a 46-year old man who was found dead in his stranded car. Up to five feet of snow fell along the south and east sides of the city in the 24 hours ending at 10 pm EST Tuesday, thanks to an intense band of heavy lake effect snow coming off of Lake Erie. The extreme snow band was very narrow; in the 24 hours when Lancaster on the city’s east side was pummeled with 60″ of snow, the Buffalo Airport, just six miles to the northwest, received only 3.9″. Extreme atmospheric instability due to relatively warm waters in the lake were responsible for the intensity of the storm; water temperatures were 47°F at the Environment Canada Port Colborne buoy at the east end of Lake Erie on Tuesday. A state of emergency has been declared in Erie County, New York, which includes Buffalo, and the National Guard has been called out to help dig people out. Thankfully, the band of heavy snow responsible for the extreme accumulations shifted northwards out of the city on Wednesday morning, and only minor accumulations will occur during the remainder of Wednesday. On Thursday morning, though, a new lake effect snowstorm will set up. The NWS in Buffalo is forecasting that while this storm will not be quite as intense, up to two feet of additional snow could fall in the same regions that received up to five feet of snow already this week.

Figure 1. A lake effect snow storm brought five feet of snow to Lancaster, New York on November 18, 2014. Image credit: Melinda Stoldt, via Facebook.

Figure 2. Radar loop of an intense lake effect snow band affecting the Buffalo, New York region between 6:36 – 9:07 am EST November 19, 2014. The band, which had been nearly stationary over South Buffalo for over 24 hours, is seen finally lifting northwards out of the city, thanks to a wind shift caused by an approaching trough of low pressure.

Most extreme Lake Erie snowstorm on record?
According to wunderground’s weather historian Christopher C. Burt, yesterday’s snowfall totals near Buffalo may challenge the official 24-hour snowfall record for the state of New York. The State Climate Extremes Committee (SCEC) lists the official record 24-hour snowfall for the state of New York as 49.0” on November 14 – 15, 1900. As of 10 pm EST Tuesday, at least five suburbs of Buffalo on its south and east sides had beaten this mark, recording 51 – 60″ of snow in 24 hours. The champions were was Lancaster and Gardenville, with 60″ of snow in 24 hours. It is yet not clear if any of these reports will be worthy of official status, recognized by the SCEC. Mr. Burt notes, though, that the SCEC is rife with errors and probably should not be taken too seriously. Much greater 24-hour totals have been reported from various observers/sources over the years at multiple locations in New York. The greatest unofficial 24-hour total he is aware of is 68” at Adams, NY on Jan. 9, 1976. Also, 77” fell in Montague Township in 24 hours on Jan. 11 – 12, 1997. This value was discounted by the SCEC as a result of a small technicality due to one too many snow board measurements being taken (7 instead of 6). However, the figure itself was accepted as accurate, but not official since the observer made a small error in the timing of his snow accumulation measurements. Note that all of these record 24-hour snowfalls came in Lake Ontario’s lake effect snow band, where higher terrain helps lift the air streaming off the lake to extract more snow. In Mr. Burt’s words, “So far as Lake Erie events, I think this week’s event one will go down as the most extreme on record.

Figure 3. MODIS satellite image of the lake effect snowstorm over Lake Erie on Tuesday afternoon, November 18, 2014. Strong updrafts due to relatively warm lake waters of 47°F created a towering line of clouds that cast a shadow to their north. Image credit: NASA.

Buffalo’s worst snowstorm: January 1977
This week’s storm did not significantly affect the mid through northern portions of metro Buffalo, including downtown, which is typical for a Lake Erie lake effect snowstorm–the heaviest snow falls south of the city. However, back in January 1977, a 5-day blizzard hit all of Western New York, including Buffalo. The combination of blowing snow, wind and Arctic temperatures resulted in hundreds of people being stranded in their cars. Because of constant whiteout conditions and life threatening wind chills, as well as the fact that nobody had cell phones back then to communicate in an emergency, 29 people lost their lives. Many were asphyxiated in their cars or froze to death from exposure.

Mr. Burt documents the history of lake effect snowstorms in his 2013 post, Lake Effect Snow Totals and Historical Perspective.

Is the jet stream getting weird?
This week’s intense cold blast is being triggered by an unusually extreme jet stream pattern, featuring a sharp ridge of high pressure along the U.S. West Coast and a deep trough of low pressure diving to the south over the Central United States. This configuration allows cold air to spill out of the Arctic behind the trough into the Central U.S., and be replaced by anomalously warm air flowing northwards along the West Coast of the U.S. deep into the Arctic. This extreme jet stream pattern is due, in part, to the influence of Super Typhoon Nuri, which caused a ripple effect on the jet stream after the typhoon became one of the most powerful extratropical storms ever recorded in the waters to the west of Alaska eleven days ago. However, we’ve seen an unusual number of extreme jet stream patterns like this in the past fifteen years, which happens to coincide with the period of time we’ve been observing record loss of summertime Arctic sea ice and record retreat of springtime snow cover in the Arctic. Could it be that these changes in the Arctic are causing the wacky jet stream behavior of recent years? That’s the theory being advanced by a number of prominent climate scientists. I’ve written extensively about the topic, and my most recent post on the subject was in April, California Drought/Polar Vortex Jet Stream Pattern Linked to Global Warming. A updated story that I wrote for the just-published December issue of Scientific American discusses the theory and its detractors, and you can read it on-line for $6 (or buy a copy at the news stand.) My conclusion in the article: If Arctic changes are truly to blame for wacky jet stream behavior, losing the remaining 50 percent of the Arctic sea-ice coverage between now and 2030 will bring even greater antics. If the Arctic is not involved, that is worrisome as well—because that means jet stream changes are due to an unknown mechanism, leaving us with no idea how the jet stream will respond as climate change progresses. Thus, my forecast for the next 15 years: expect the unprecedented.

Video 1. A time-lapse view of Lake Erie from Buffalo, New York during the lake-effect snow storm of November 18, 2014. Note the rising motion of the clouds, showing the extreme instability of the atmosphere due to relatively warm waters at the surface (47°F at the Environment Canada Port Colborne buoy at the east end of Lake Erie.)

from: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2863

Dr. Masters’ Tropical Watch

Posted on September 6, 2014 by marcia

Norbert Hits Category 3; Three Minor Atlantic Threat Areas to Watch

By: Jeff Masters , 4:13 PM GMT on September 06, 2014

Hurricane Norbert put on an unexpected burst of rapid intensification overnight, topping out as a Category 3 storm with 120 mph winds at 5 am EDT Saturday. Norbert continues to chug parallel and just offshore from the coast of Mexico’s Baja Peninsula, bringing heavy rain and tropical storm-force winds to the coast. Satellite loops on Saturday morning showed that Norbert had a small eye and some very impressive eyewall thunderstorms with cold cloud tops. However, the storm is starting to weaken, thanks to cooler ocean temperatures near 27°C (81 °F), and drier air. The models all show the core of the hurricane remaining just offshore as it moves northwest parallel to the Baja Peninsula over the next three days, so heavy rains of 3 – 6″ causing flash flooding will be the primary threat from Norbert to Baja. The counter-clockwise flow of air around the hurricane is pulling moisture from the remnants of Tropical Storm Dolly and from the tropical Eastern Pacific northwards into Northern Mexico and the Southern Arizona, and this moisture will be capable of causing flooding rains in those regions.

Norbert’s intensification into a Category 3 storm gives the Eastern Pacific seven major hurricanes so far this year. With the season typically only 2/3 over by September 9, we have a decent chance of tying or beating the record of ten intense hurricanes in a season, set in 1992 (this tally includes hurricanes in the Central Pacific.) The 2014 tally for the Eastern Pacific currently stands at 14 named storms, 10 hurricanes, and 7 intense hurricanes. An average Eastern Pacific hurricane season sees 15 named storms, 8 hurricanes, and 3 intense hurricanes during the entire year. The records for total number of named storms, hurricanes, and intense hurricanes were all set in 1992, with 28 named storms, 16 hurricanes, and 10 intense hurricanes (with the Central Pacific tallies included.)

Figure 1. Hurricane Norbert near Mexico’s Baja Peninsula at 10:30 am EDT September 6, 2014. At the time, Norbert was a Category 3 storm with 115 mph winds. Image credit: NASA/GSFC.

Figure 2. Predicted seven-day precipitation amounts for the period ending on Saturday, September 13 show a large area of 3+ inches are expected over Southeast U.S., thanks to a weak tropical disturbance. A region of 2+” of rain is expected over Southern Arizona due to the flow of moist air northwards caused by Hurricane Norbert’s circulation. Image credit: NOAA/HPC.

Southeast U.S. disturbance bringing heavy rains
A weak area of low pressure near the coast of Georgia is bringing heavy rain showers to the Southeast U.S. coast and adjacent waters, but this this activity is very disorganized. The disturbance will bring heavy rains in excess of three inches to the coast over the next few days as the low drifts northeastward. After that time, the low will likely merge with a frontal zone over the ocean and head out to sea. In their 8 am EDT Saturday Tropical Weather Outlook, NHC gave the system 2-day and 5-day odd of development odds of 0% and 10%, respectively.

Tropical Wave 90L
A tropical wave (90L) located a few hundred miles west of the Cape Verde Islands is headed west to west-northwest at about 15 mph. Satellite images show 90L has plenty of spin, but little heavy thunderstorm activity. Though Sea Surface Temperatures are fairly warm, 27.5°C (82°F), and wind shear is low, 90L is embedded in a very dry air mass that is expected to get dryer as the storm progresses westwards. None of our three reliable computer models for predicting tropical storm formation predicts development of 90L over the next five days. In their 8 am EDT Saturday Tropical Weather Outlook, NHC gave the system 2-day and 5-day odd of development odds of 10%. The wave should arrive in the northern Lesser Antilles Islands by Wednesday night.

New African Tropical Wave
Following on the heels of 90L will be a new tropical wave that is expected to push off the coast of Africa on Sunday night or Monday morning, bringing heavy rain showers and gusty winds to the Cape Verde Islands on Monday and Tuesday. All three of our three reliable computer models for predicting tropical storm formation show development of the new wave by Wednesday. The new wave will see similar conditions to 90L, though, and will struggle with dry air and moderate wind shear. In their 8 am EDT Saturday Tropical Weather Outlook, NHC gave the system 2-day and 5-day odd of development odds of 0% and 30%, respectively. The wave should take a more northwesterly track then 90L, and not threaten the Lesser Antilles Islands.

from: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2788

Dr. Masters on Tropical Storms

Posted on August 26, 2014 by marcia

Cristobal a Hurricane; Little Change to 97L

By: Dr. Jeff Masters , 12:25 PM GMT on August 26, 2014

It doesn’t look much like hurricane, but the Hurricane Hunters measured surface winds around 75 mph on Monday evening and Tuesday morning in Hurricane Cristobal, making it the third hurricane of the 2014 Atlantic hurricane season. These missions proved the value of hurricane hunter flights, since there is no way that we would have known Cristobal was a hurricane based on satellite data. The storm is stretched out in a long line of heavy thunderstorms, has no eye or low-level spiral bands, and is giving early August’s Hurricane Bertha some stiff competition for ugliest Atlantic hurricane of the century. Along with Hurricane Arthur and Hurricane Bertha, Cristobal gives us three Atlantic hurricanes so far this year, exceeding the entire 2013 Atlantic hurricane season total. The second (and final) hurricane of the 2013 season (Ingrid) did not arrive until September 14. On average, the third hurricane of the Atlantic season arrives on September 9, and the third named storm of the year on August 13. The last time the first three named storms in the Atlantic became hurricanes was in 1983, when Alicia, Barry and Chantal all became hurricanes (if we exclude 1992, when an unnamed subtropical storm formed prior to the arrival of Hurricanes Andrew, Bonnie, and Charley.) Cristobal continues to dump heavy rains over the Central and Southeast Bahamas and Turks and Caicos Islands as the storm heads northeastwards out to sea. Satellite loops show that Cristobal is struggling with wind shear, with a center of circulation partially exposed to view, and all the heavy thunderstorms pushed to the south and east sides of the center. The only land area at risk from Cristobal is Bermuda, and the 5 am EDT Tuesday Wind Probability Forecast from NHC gave that island a 27% chance of experiencing tropical storm force winds of 39+ mph. The GOES-14 satellite is in rapid-scan mode over Cristobal on Tuesday, and you can access an impressive 1-minute resolution satellite loop of the storm from the NOAA/RAMMB website.

Figure 1. MODIS true-color image showing Tropical Storm Cristobal’s intense thunderstorms stretching from the Southeast Bahamas to Bermuda at 2 pm EDT on August 25, 2014. At the time, Cristobal had top winds of 60 mph. Image credit: NASA.

Little change to 97L headed towards the Lesser Antilles
A tropical wave (Invest 97L) was near 13°N, 47°W on Tuesday morning, about 900 miles east of the Lesser Antilles Islands, and was headed west to west-northwest at about 15 mph. Satellite loops show the wave has changed little since Monday, and has a modest amount of spin but only a small amount of heavy thunderstorms. Water vapor satellite images and the Saharan Air Layer analysis show that 97L is located in a dry environment, which is keeping development slow. Wind shear was a moderate 10 – 20 knots, which should allow some slow development. Sea Surface Temperatures are near 27.5°C, which is warm enough to allow some slow development. The wave should arrive in the Lesser Antilles Islands by Friday and be near Puerto Rico on Saturday, according to the Tuesday morning runs of the GFS model. None of the three reliable computer models for predicting tropical storm formation predict 97L will develop over the next five days. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC gave 97L 2-day and 5-day development odds of 0% and 20%, respectively. These odds are 10% lower than their previous advisory, and NHC has stopped running their suite of models on 97L.

New tropical wave coming off coast of Africa this weekend
A large and powerful tropical wave will move off the coast of Africa on Friday evening, and the GFS model has been very aggressive in recent runs about developing this wave into a tropical storm within a day of its emergence. The other reliable models for tropical cyclone genesis, the European and UKMET models, have not been developing this wave right away. Residents of the Cape Verde Islands should anticipate the possibility of heavy rain and strong winds on Saturday as the wave moves west at 10 – 15 mph across the islands. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC gave 97L 2-day and 5-day development odds of 0% and 30%, respectively.

The Gulf of Mexico is worth watching
In the Gulf of Mexico, heavy thunderstorm activity has diminished since Monday along a weak cold front stretching from South Florida to the Louisiana coastal waters. Some models show a weak area of low pressure developing along this front and moving westwards over Texas by Friday, and we should keep an eye on this region for development.

Figure 2. MODIS true-color image of Hurricane Marie in the Eastern Pacific taken at approximately 18:15 UTC (2:15 pm EDT) on August 25, 2014. At the time, Marie was a Category 4 storm with 145 mph winds. Image credit: NASA.

Powerful Hurricane Marie generating huge waves in Eastern Pacific
The Eastern Pacific’s Hurricane Marie had weakened to a Category 2 storm with 105 mph winds on Tuesday morning, but was still generating huge swells that were bringing large waves to the coasts of Southern California and Mexico’s Baja Peninsula. At 5 am EDT on Tuesday, Marie’s tropical storm-force winds covered a huge area of ocean, up to 275 miles from the center, and 12-foot high seas extended up to 550 miles from the center. A High Surf Advisory is in effect for Los Angeles, where waves of 10 – 15 feet will potentially cause structural damage to piers and beachside property as well as significant beach erosion. The powerful surf will be accompanied by strong rip currents and long-shore currents, making for very hazardous swimming and surfing conditions through Thursday. Satellite loops on Tuesday morning showed a steady degradation of Marie’s cloud pattern, with the eyewall cloud tops warming and the areal coverage of the strongest thunderstorms decreasing. The storm is headed to the northwest over cooler waters and into drier air, and will not affect any land areas.

You can see a spectacular loop of infrared satellite images of Marie as it intensified into a Category 5 storm on Sunday at the CIMSS University of Wisconsin.

from: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2776

Record Drought in California

Posted on May 15, 2014 by marcia

Record May Heat, Drought, and Fires Scorch California

By: Dr. Jeff Masters , 2:21 PM GMT on May 15, 2014

Record May heat sent temperatures soaring above 100° in much of Southern California on Wednesday, and fierce Santa Ana winds fanned fires that scorched at least 9,000 acres in San Diego County, forcing thousands to evacuate. For the second consecutive day, the Los Angeles Airport set a record for the hottest May temperature since record keeping began in 1944. Wednesday’s 96° beat the record set on Tuesday of 93°. Other all-time May record heat was recorded at Camarillo (102°) and Oxnard (102°) on Wednesday. In Downtown Los Angeles, the mercury hit 99° on Wednesday, falling short of the all-time May record is 103° set on May 25, 1896. More record heat is forecast on Thursday, and hot offshore Santa Ana winds will bring extreme fire danger.

Figure 1. A firenado in Fallbrook, California at old Highway 395 and Interstate 15 on May 14, 2014. Image credit: Jena Rents via Twitter.

Figure 2. True-color MODIS satellite image of fires burning in Southern California and Northern Mexico on Wednesday afternoon, May 14, 2014. Image credit: NASA.

100% of California in severe to exceptional drought
Today’s U.S. Drought Monitor report showed grim news for California: 100% of the state is now in severe or higher drought, up from 96% the previous week. Though just 25% of California is classified as being in the highest level of drought, “Exceptional”, Erin McCarthy at the Wall Street Journal estimates that farms comprising 53% of California’s $44.7 billion market value lie in the Exceptional drought area. Averaged state-wide, the Palmer Drought Severity Index during April 2014 was the second worst on record, behind 1977. For the 12-month period ending in April, drought conditions in California for 2013 – 2014 were also the second most severe on record, slightly below the 2008 – 2009 drought. To break the drought, most of the state needs 9 – 15″ or precipitation to fall in one month. This amounts to more than a half-year’s worth of precipitation for most of the state.

Figure 3. The May 13, 2014 U.S. Drought Monitor showed 100% of California in severe or higher drought, with 25% of the state in the highest level of drought, “Exceptional.” Image credit: U.S. Drought Monitor.

California’s rainy season is over
The California October through April rainy season is now over. Between October 2013 and April 2014, the state received 10.44″ of precipitation, which is just 51% of average for the period, and the third lowest such total on record. Going back to 1895, the record low mark was set in 1976 – 1977, when the state got just 34% of its average rainy season precipitation. California typically receives less than 10% of its annual precipitation between May and September, and the coming hot and dry summer in combination with a severely depleted Sierra snowpack will cause a severe fire season and significant agricultural damages. The fifth and final snow survey of the season on May 1 found that the statewide snowpack’s water content–which normally provides about a third of the water for California’s farms and cities–was only 18% of average for the date. Already, the 2014 drought has cost the state at least $3.6 billion in agricultural damages, the California Farm Water Coalition estimates. CAL FIRE recently announced it had hired 125 additional firefighters to help address the increased fire threat due to drought conditions.

from: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2679

Jeff Masters on California Drought

Posted on February 2, 2014 by marcia

California’s Sierra Snowpack Only 12% of Average, a Record Low

By Dr. Jeff Masters

Published: 4:32 PM GMT on January 31, 2014

California’s first significant snow storm of 2014 hit the Sierras on Wednesday and Thursday, dumping up to 2 feet of snow, with a melted water equivalent of up to two inches. However, this modest snowstorm was not enough to keep the Sierra snowpack from recording its lowest snow amounts in more than 50 years of record keeping during Thursday’s Sierra Snow Survey. The survey found a snow pack that was only 12% of normal for this time of year. Until Thursday, the lowest statewide snowpack measurement at this time of year was 21% of average, in 1991 and 1963, according to the Los Angeles Times. Since snowpack in the Sierras forms a crucial source of water for California, the dismal snow survey results are a huge concern.

Figure 1. Frank Gehrke, chief of the California Cooperative Snow Survey Program for the Department of Water Resources, walks leaves a snow covered meadow after the second snow survey of the year near Echo Summit, Calif., Thursday, Jan. 30, 2014. Despite the overnight snow storm the survey showed the snow depth at 12.4 inches with a water content of only 1.4 inches for this location at this time of the year. Gehrke said that while the recent snow fall will help, it is not enough to impact the water supply.(AP Photo)

The forecast: little drought relief in sight
One of the most persistent and intense ridges of high pressure ever recorded in North America has been anchored over the West Coast since December 2012. While the ridge has occasionally broken down and allowed low pressure systems to leak though, these storms have mostly brought spotty and meager precipitation to California, resulting in California’s driest year on record during 2013. January 2014 could well be its driest January on record. The ridge inevitably builds back after each storm, clamping down on any moisture reaching the state. Since rain-bearing low pressure systems tend to travel along the axis of the jet stream, these storms are being carried along the axis of the ridge, well to the north of California and into Southeast Alaska, leaving California exceptionally dry. The latest runs of the GFS and European models show that the ridge is now building back, and it appears likely that California will see no significant precipitation until at least February 7. A weak upper level low will move along the coast on Sunday and spread some light rain along the immediate coast, but this precipitation will generally be less than 0.25″–too little to have any significant impact on the drought. The ridge will not be as intense when it builds back, though, which gives me some hope that a low pressure system will be able to break the ridge by mid-February and bring the most significant rains of the winter rainy season to California.

Figure 2. One of the key water supply reservoirs for Central California, Lake Oroville, as seen on January 20, 2014. Image credit: California Department of Water Resources.

Worst California drought in 500 years?
UC Berkeley paleoclimatologist B. Lynn Ingram, author of “The West Without Water: What Past Floods, Droughts, and Other Climatic Clues Tell Us About Tomorrow”, said in an interview, “this could potentially be the driest water year in 500 years.” Her research on tree rings shows that California has not experienced such an extreme drought since 1580. “If you go back thousands of years, you see that droughts can go on for years if not decades, and there were some dry periods that lasted over a century, like during the Medieval period and the middle Holocene. The 20th century was unusually mild here, in the sense that the droughts weren’t as severe as in the past. It was a wetter century, and a lot of our development has been based on that.” It’s no wonder, then, that the overall agricultural impact of the drought could reach $1 billion this year, according to the Fresno-based Westlands Water District.

California’s drought woes are part of an on-going 14-year Western U.S. drought that began in 2000, and peaked between 2000 – 2004. A 2012 study titled, Reduction in carbon uptake during turn of the century drought in western North America, found that the 2000 – 2004 drought was the most severe Western North America event of its kind since the last mega drought over 800 years ago, during the years 1146 – 1151. The paper analyzed the latest generation of climate models used for the 2013 IPCC report, which project that the weather conditions that spawned the 2000 – 2004 drought will be the new normal in the Western U.S. by 2030, and will be considered extremely wet by the year 2100. If these dire predictions of a coming “megadrought” are anywhere close to correct, it will be extremely challenging for the Southwest U.S. to support a growing population in the coming decades.

Megadroughts in the Western U.S. can develop from natural causes, as well, and the current pattern of cooler than average ocean temperatures in the Eastern Pacific and warmer than average ocean temperatures in the Atlantic increase the odds of drought conditions like the ones we have seen during the current megadrought. Edward Cook, director of the Tree Ring Laboratory at Columbia University’s Lamont-Doherty Earth Observatory in Palisades, N.Y., said at a presentation last month at the American Geophysical Union meeting that tree ring data show that the area of the West that was affected by severe drought in the Medieval period was much higher and much longer than the current drought. It is “indeed pretty scary,” Cook said. “One lasted 29 years. One lasted 28 years. They span the entire continental United States.” Two megadroughts in the Sierra Nevada of California lasted between 100 and 200 years. Bobby Magill at Climate Center has more on Dr. Cook’s presentation in a post, Is the West’s Dry Spell Really a Megadrought?

Figure 3. Normalized precipitation over Western North America (five-year mean) from 22 climate models used to formulate the 2013 IPCC report, as summarized by Schwalm et al., 2012, Reduction in carbon uptake during turn of the century drought in western North America. The horizontal line marks the precipitation level of the 2000 – 2004 drought, the worst of the past 800 years. Droughts of this intensity are predicted to be the new normal by 2030, and will be considered an outlier of extreme wetness by 2100. The paper states: “This impending drydown of western North America is consistent with present trends in snowpack decline as well as expected in-creases in aridity and extreme climate events,including drought, and is driven by anthropogenically forced increases in temperature with coincident increases in evapotranspiration and decreases in soil moisture. Although regional precipitation patterns are difficult to forecast, climate models tend to underestimate the extent and severity of drought relative to available observations. As such, actual reductions in precipitation may be greater than shown. Forecasted precipitation patterns are consistent with a probable twenty-first century megadrought.” Image credit: Schwalm et al., 2012, Reduction in carbon uptake during turn of the century drought in western North America, Nature Geoscience 5, 551-555, Published online 29 JULY 2012, DOI: 10.1038/NGEO1529, www.nature.com/naturegeoscience.

Related posts
Unprecedented Cut in Colorado River Flow Ordered, Due to Drought, my August 2013 post.

Lessons from 2012: Droughts, not Hurricanes, are the Greater Danger, my November 2012 post.

How Two Reservoirs Have Become Billboards For What Climate Change Is Doing To The American West, August 12, 2013 climateprogress.org post by Tom Kenworthy.

Scientists Predicted A Decade Ago Arctic Ice Loss Would Worsen Western Droughts. Is That Happening Already?, June 2013 post by Joe Romm at climateprogress.org.

Twenty Cities At Risk of Water Shortages, August 14, 2013 wunderground news post by Nick Wiltgen

‪If There’s Global Warming…Why Is It So Cold?‬
It’s been top-ten coldest January on record in the Upper Midwest, and much colder than average over much of the Eastern U.S. However, the that isn’t the case over other portions of the globe, including the Western U.S. and Alaska. Wunderground’s weather historian Christopher C. Burt analyzes the situation in his latest post, How Cold has this January been in the U.S.? He concludes, “this January’s average temperature nationally has probably been close to normal since the western half of the nation has been almost as much above average as the eastern half was below average. The only region that will most likely have experienced a TOP 10 coldest January will be the Upper Midwest.” In the U.S., only four stations set all-time low minimum temperature records in January, compared to 34 that set all-time high maximum temperature records. I’ve been monitoring global temperatures this month, and it appears likely that January will rank between the 5th and 15th warmest January since record keeping began in 1880. Of particular note were the amazingly warm January temperatures in the Balkans. According to weather record researcher Maximiliano Herrera, “over 90% of all stations in the Balkans from Slovenia to Croatia to Bosnia to Serbia To Montenegro to Kosovo etc., have DESTROYED their previous record of warmest January ever (many locations have 100 – 200 years of data.) In many cases the monthly temperatures were 7 – 9°C (13 – 16°F) above average, and the new records were 3 – 4°C above the previous record. This is for THOUSANDS of stations, almost all of them. In Slovenia, for example, Mount Kredarica is the only station in the whole country not to have set its warmest January on record.”

Video 1. ‪If There’s Global Warming … Why Is It So Cold?‬ The latest video from climate videographer Peter Sinclair on the Yale Climate Forum website demonstrates that while it was a very cold January in the Midwest, this has been counterbalanced by record warmth over the Western U.S. and Alaska, caused by an unusually extreme kink in the jet stream.

Links
Another Unexpected Disaster That Was Well Forecast. Based in Atlanta, TWC’s Bryan Norcross concludes that “WARM GROUND + VERY COLD AIR + SNOW + WORKDAY = CHAOS. If the decision-makers understood the formula above, this information should have been sufficient to trigger a proper response.”

Jon Stewart Lays Into Georgia’s Snowpocalypse

from: http://www.wunderground.com/blog/JeffMasters/article.html?entrynum=2624

2013 Heat Records

Posted on January 20, 2014 by marcia

Nine Nations or Territories Set All-Time Heat Records in 2013

By: Dr. Jeff Masters, 2:43 PM GMT on January 20, 2014

+23

It was another notable year for all-time heat records in 2013, with six nations and three territories tying or setting records for hottest temperature on record. No nations set an all-time cold record in 2013. For comparison, five countries and two territories set all-time hottest temperature records in 2012, and the most all-time national heat records in a year was twenty nations and one territory in 2010. Since 2010, 45 nations or territories have set or tied all-time heat records, but only one nation has set an all-time cold temperature record. Since each of those years ranked as one of the top eleven warmest years in Earth’s history, and 2010 was the warmest year on record, this sort of disparity in national heat and cold records is to be expected. Most nations do not maintain official databases of extreme temperature records, the national temperature records I report here are in many cases not official. I use as my source for international weather records Maximiliano Herrera, one of the world’s top climatologists, who maintains a comprehensive list of extreme temperature records for every nation in the world on his website. If you reproduce this list of extremes, please cite Maximiliano Herrera as the primary source of the weather records. Wunderground’s weather historian Christopher C. Burt maintains a database of these national heat and cold records, for 235 nations and territories, on wunderground.com’s extremes page.

Figure 1. A moose takes a dip to cool off in a backyard pool in this photo taken in Big Lake, Alaska on June 17, 2013, by Lonea Moore McGowen (Courtesy KTUU-TV.) Bentalit Lodge, Alaska hit 36.7°C (98°F) on June 17, tying the mark set in Richardson on 15 June 1969 for hottest undisputed temperature in Alaska history. The official heat record for Alaska remains the 100°F registered at Fort Yukon on June 27, 1915. However, there are questions concerning this figure as outlined by our weather historian, Christopher C. Burt.

New all-time national heat records set in 2013

Heard and McDonald Islands (uninhabited territory of Australia) set a new all-time heat record of 26.1°C (79°F) at Split Bay on 1 March. Previous record: 21.6°C set at the same station in April 1992.

Ghana tied its all time highest temperature record with 43.0°C (109.4°F) at Navrongo on 6 March; the same value had also been recorded on 25 February 2010 and 19 April 2010 at the same location.

The United States tied its highest undisputed temperature at the Furnace Creek Visitors Center, Death Valley California, with 53.9°C (129°F) on 30 June. The only higher temperatures ever recorded on the planet occurred in Death Valley on July 10, 12, and 13, 1913, when readings of 134°F, 130°F, and 131°F were recorded. These 100-year-old official hottest temperatures in Earth’s history have many doubters, though, including Mr. Burt, who noted in a 2010 blog post that “The record has been scrutinized perhaps more than any other in the United States. I don’t have much more to add to the debate aside from my belief it is most likely not a valid reading when one looks at all the evidence.

St. Pierre et Miquelon, a French territory off the coast of Newfoundland, Canada, set its all time highest temperature record with 28.3°C (82.9°F) at the St. Pierre Airport on 6 July. Previous record: 28.0°C at St. Pierre town in August 1876 and August 1935.

Greenland, a territory of Denmark, set a new all time highest temperature with 25.9°C (78.6°F) at Maniitsoq Airport on 30 July. Previous record: 25.5°C at Kangerlussuaq on 27 July 1990. There is a claimed 30.1°C measurement at Ivigtut on 23 June 1915, but this is almost certainly a mistake, since the reading doesn’t fit at all with the hourly data of that day, and the station in over a century has never recorded any temperature above 24°C.

Austria set a new national record of highest temperature with 39.9°C (103.8°F) at Dellach im Drautal on 3 August, which beat the old record of 39.7°C set at the same location on 27 July 1983. The 3 August 2013 record was beaten again on 8 August 2013, with a 40.5°C (104.9°F) reading recorded at Bad Deutsch-Altenburg.

Slovenia also set a new all time heat record on 8 August, with 40.8°C at Cerklje Ob krki. Previous record: 40.6°C set at Crnomelj on 5 July 1950.

Japan set a new all-time heat record with 41.0°C (105.8°F) at Shimanto on 12 August. Previous record: 40.9°C at Tajimi and at Kumagaya on 16 August 2007.

Comoros tied its national record of highest temperature at the Hahaya Int. Airport with 35.6°C (96.1°F) on 19 November; the same value was recorded at the former Moroni Airport (its location looks to have been very close of the current international airport) on 31 December 1960.

Figure 2. The official Furnace Creek, Death Valley maximum recording thermometer for the maximum temperature measured on June 30th, 2013. The 129.2°F (54.0°C) reading was the highest June temperature ever measured on Earth. Photo courtesy of Death Valley National Park and NWS-Las Vegas. Note, though, since only whole Fahrenheit figures are official in the U.S., the value was registered as 129°F.

Notable global heat and cold records set in 2013
Hottest temperature in the world in 2013: 53.9°C (129°F) at Death Valley, California, June 30
Coldest temperature in the world in 2013: -81.7°C (-115°F) at Dome A, Antarctica, July 31
Hottest temperature in the Southern Hemisphere: 49.6°C (121.3°F) at Moomba Aero, Australia, January 12
Coldest temperature in the Northern Hemisphere: -64.2°C (-83.6°F) at Summit GEO, Greenland, March 4

Number of major world stations which set their all time highest temperature in 2013: 389
Number of major world stations which set their all time lowest temperature in 2013: 12

On 27 February, 2013, a new February all-time heat record for the Northern Hemisphere was set with 44.5°C (112.1°F) at Abu Na’ Ama (Sudan). Previous record: 44.4°C with two former record holders: Kayes in Mali, and Kiffa in Mauritania.

A day for the history books: European heat wave of 8 August 2013
An incredible heat wave over Central Europe on 8 August 2013 was a day for the history books of world climatology, with two nations and three world capitals setting all-time heat records on the same day. Dozens of stations in six European countries also set all-time heat records that day. The three capitals that set new all-time heat records on 8 August:

Vienna, Austria reached 39.5°C (103.1°F), beating the previous city record of 38.9°C which was recorded in July 1957.

Bratislava, Slovakia reached 39.4°C (102.9°F), beating the previous city record of 38.9°C set in July 2007.

Ljubljana, Slovenia reached as high as 40.2°C (104.4°F), beating for the FIFTH TIME IN SIX DAYS the old record of 38.0°C set in June 1935. This is particularly amazing, since the city has about 150 years of data. This is the sequence:

3 August 38.3°C
4 August 38.4°C
6 August 38.6°C
7 August 39.5°C
8 August 40.2°C

One other world capital set an all-time heat record in 2013: Bangkok, Thailand, which reached 40.1°C (104.2°F) in the Metropolis Station on 26 March, beating the previous record of 40.0°C set in April 1979 and April 2012.

A big thanks goes to Maximiliano Herrera for providing the information in this post.

from: http://www.wunderground.com/blog/JeffMasters/show.html

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