Tag Archives: Dr. Jeff Masters

Dr. Jeff Masters on The Drought

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Historic 2012 U.S. drought continues to expand and intensify
Posted by: Dr. Jeff Masters, 2:01 PM GMT on July 20, 2012 +11

The great U.S. drought of 2012 continues to accelerate, and grew larger and more intense over the past week, said NOAA in their weekly U.S. Drought Monitor report issued Thursday, July 19. The area of the contiguous U.S. covered by drought expanded from 61% to 64%, and the area covered by severe or greater drought jumped from 37% to 42%. These are truly historic levels of drought, exceeded only during the great Dust Bowl drought of the 1930s and a severe drought in the mid-1950s. If we make the reasonable assumption that the current area covered by drought is representative of what the average for the entire month of July will be (based on the latest drought forecast from NOAA’s Climate Prediction Center), the July 2012 drought is second only to the great Dust Bowl drought of July 1934 in terms of the area of the contiguous U.S. covered by moderate or greater drought. The five months with the greatest percent area in moderate or greater drought, since 1895, now look like this:

1) Jul 1934, 80%
2) Jul 2012, 64%
3) Dec 1939, 60%
4) Jul 1954, 60%
5) Dec 1956, 58%

If we consider the area of the contiguous U.S. covered by severe or greater drought, July 2012 ranks in 5th place:

1) Jul 1934, 63%
2) Sep 1954, 50%
3) Dec 1956, 43%
4) Aug 1936, 43%
5) Jul 2012, 42%


Figure 1. The twice-monthly U.S. Drought Outlook, updated on Thursday, July 19, predicts that drought will continue through October over most of the U.S., and expand to the north and northeast. Image credit: NOAA Climate Prediction Center.

The drought forecast: not encouraging
In their twice-monthly drought outlook, released on Thursday, NOAA’s Climate Prediction Center had this to say about the drought: The combination of heat and dryness has severely reduced the quality and quantity of the corn and soybean crop, with 38 percent of the corn and 30 percent of the soybeans rated as poor or very poor as of July 15 by NASS/USDA. Some states, such as Kentucky, Missouri, and Indiana, had over 70 percent of their corn adversely rated. Unfortunately, drought is expected to develop, persist, or intensify across these areas, and temperatures are likely to average above normal. Some widely-scattered relief may come in the form of cold front passages or organized thunderstorm clusters (MCSs), but widespread relief for much of the area is not expected. Unfortunately, the self-perpetuation of regional drought conditions, with very dry soils and very limited evapotranspiration, tends to inhibit widespread development of or weaken existing thunderstorm complexes. It would require a dramatic shift in the weather pattern to provide significant relief to this drought, and most tools and models do not forecast this. Unfortunately, all indicators (short and medium-term, August, and August-October) favor above normal temperatures. With much of the Plains already in drought, above normal temperatures expected into the fall, and a dry short-term and 30-day forecast, the drought should persist, with some possible development in the northern Plains.

One bright spot: drought conditions are expected to improve over the Southwest U.S. over the next few weeks, as the annual summer monsoon peaks and brings heavy rains. The Southeast U.S. has seen some improvement over the past week, due to an upper-level low pressure system that has brought heavy rains. The potential for a landfalling tropical storm to bring drought-busting rains during the August – September – October peak of hurricane season led NOAA to predict possible improvement in drought conditions over the Southeast U.S.


Figure 2. The U.S. has seen twelve weather-related disasters costing at least $15 billion since 1980, according to NOAA’s National Climatic Data Center. Two of the top three most expensive disasters have been droughts. The drought of 2012 could well make it three out of four. “It might be a $50 billion event for the economy as it blends into everything over the next four quarters,” said Michael Swanson, agricultural economist at Wells Fargo & Co. in Minneapolis, the largest commercial agriculture lender. Only three $50 billion weather disasters have hit the U.S. since 1980.

The Atlantic is quiet
There are no tropical cyclone threat areas in the Atlantic to discuss. The models are showing formation of an extratropical cyclone along an old frontal boundary over 1,000 miles off the Northeast U.S. coast on Tuesday, and it is possible such a storm could acquire tropical characteristics and get a name. Such a storm would not be a threat to any land areas. There is an unusual amount of dry, sinking air over the tropical Atlantic and Caribbean that is squashing development of tropical waves coming off the coast of Africa, so it doesn’t look too likely that the U.S. will get something it really needs–a big, wet Category 1 hurricane that sloshes ashore over the Gulf Coast, stalling over the Midwest, bringing copious drought-busting rains.

And the Heat Goes On

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The June 2012 U.S. heat wave: one of the greatest in recorded history
Posted by: Dr. Jeff Masters, 7:34 PM GMT on July 03, 2012 +35

Intense heat continues to bake a large portion of the U.S. this Tuesday, with portions of 17 states under heat advisories for dangerously high temperatures. The heat is particularly dangerous for the 1.4 million people still without power and air conditioning due to Friday’s incredible derecho event, which is now being blamed for 23 deaths. The ongoing heat wave is one of the most intense and widespread in U.S. history, according to wunderground’s weather historian, Christopher C. Burt. In his Sunday post, The Amazing June Heat Wave of 2012 Part 2: The Midwest and Southeast June 28-30, Mr. Burt documents that eighteen of the 298 locations (6%) that he follows closely because of their long period of record and representation of U.S. climate broke or tied their all-time heat records during the past week, and that “this is especially extraordinary since they have occurred in June rather than July or August when 95% of the previous all-time heat records have been set for this part of the country.” The only year with more all-time heat records than 2012 is 1936, when 61 cities of the 298 locations (20%) set all-time heat records. The summer of 1936 was the hottest summer in U.S. history, and July 1936 was the hottest month in U.S. history.

According to wunderground analysis of the National Climatic Data Center (NCDC) extremes database, during June 2012, 11% of the country’s 777 weather stations with a period of record of a century or more broke or tied all-time heat records for the month of June. Only 1936 (13% of June records broken or tied) and 1988 (12.5%) had a greater number of all-time monthly June records. I expect when NCDC releases their analysis of the June 2012 weather next week, they will rank the month as one of the top five hottest Junes in U.S. history.


Figure 1. Across the entire Continental U.S., 72% of the land area was classified as being in dry or drought conditions as of June 26, 2012. Conditions are not expected to improve much over the summer: the NOAA Climate Prediction Center’s latest drought outlook shows much of the U.S. in persistent drought conditions, with very few areas improving. The rains brought by Tropical Storm Debby did help out Florida and Georgia, however. Image credit: NOAA Environmental Visualization Laboratory.

The forecast: hot and dry
July is traditionally the hottest month of the year, and July 2012 is likely to set more all-time heat records. The latest predictions from the GFS and ECMWF models show that a ridge of high pressure and dry conditions will dominate the weather over about 80 – 90% of the country during the next two weeks, except for the Pacific Northwest and New England. This will bring wicked hot conditions to most of the nation, but no all-time heat records are likely to fall. However, around July 11, a sharp ridge of high pressure is expected to build in over the Western U.S., bringing the potential for crazy-hot conditions capable of toppling all-time heat records in many western states.

The intense heat and lack of rain, combined with soils that dried out early in the year due to lack of snowfall, have led to widespread areas of moderate to extreme drought over much of the nation’s grain growing regions, from Kansas to Indiana. The USDA is reporting steadily deteriorating crop conditions for corn and soybeans, and it is likely that a multi-billion dollar drought disaster is underway in the Midwest.

The wunderground Extremes page has an interactive map that allows one to look at the records for the 298 U.S. cities that Mr. Burt tracks. Click on the “Wunderground U.S. Records” button to see them.

Quiet in the Atlantic
There are no threat areas to discuss in the Atlantic, and none of the reliable computer models are developing a tropical cyclone over the next seven days.

Have a great 4th of July holiday, everyone, and I’ll be back Thursday with a new post.

Jeff Masters

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Dr. Jeff Masters on Extreme Heat, Etc.

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Extreme storms and extreme heat hit the U.S.
Posted by: Dr. Jeff Masters, 5:50 PM GMT on June 30, 2012 +36

A violent line of organized severe thunderstorms called a derecho swept across the U.S. from Illinois to Virginia on Friday, damaging houses, toppling trees, bringing down power lines. The storms killed six people in Virginia, two in New Jersey, and one in Maryland, and left at least 3.4 million people without power. The thunderstorms in a derecho (from the Spanish phrase for “straight ahead”) create violent winds that blow in a straight line. The traditional definition of a derecho is a thunderstorm complex that produces a damaging wind swath of at least 240 miles (about 400 km), featuring a concentrated area of thunderstorm wind gusts exceeding 58 mph (93 km/hr.) A warm weather phenomenon, derechos occur mostly in summer, especially June and July in the Northern Hemisphere. They can occur at any time of the year and occur as frequently at night as in the daylight hours. As seen on our wundermap with the “go back in time” feature turned on, Friday’s derecho began near Chicago in the early afternoon, then marched east-southeast, peaking in intensity over Virginia and Washington D.C. on Friday evening. The derecho was unusually intense due to the extreme heat, which helped create an unstable atmosphere with plenty of energy to fuel severe thunderstorms.


Figure 1. Radar image from our wundermap with the “go back in time” feature turned on for 11 pm EDT Friday June 29, 2012, showing the derecho over Washington D.C. and Baltimore. Click on the “hour” button above the wundermap to advance the time by one hour to watch the progress of the derecho across the country.


Figure 2. NOAA’s Storm Prediction Center (SPC) logged 871 reports of damaging winds on Friday. Twenty one of these reports were for winds over 80 mph. The highest wind gust was in Oswego, Illinois: 92 mph.


Figure 3. A dramatic change in the weather in Buckeye land: the temperature at Ohio State University in Columbus, Ohio dropped from 97°F to 68° after passage of Friday’s derecho. The storm brought a wind gust of 82 mph to campus, and 0.86″ of rain.

Historic heat wave topples Dust Bowl-era extreme heat records
A historic heat wave on a scale and intensity not seen in the U.S. since the great heat waves of the 1930s Dust Bowl era set new all-time heat records for at least ten major cities Friday. According to wunderground’s weather historian Christopher C. Burt, fifteen of the 303 major cities he maintains records for on the wunderground extremes page have set all-time heat records in the past four days. The only year with more all-time heat records is 1936, when 61 cities set all-time heat records. In 2011, which had the 2nd warmest summer in U.S. history, only ten of the 303 cities set all-time heat records during the entire summer. With the the hottest month of the year (July) still to come, 2012 threatens to rival the great Dust Bowl summer of 1936 for extreme heat.

All-time records for any date tied or broken on Friday:

109° Nashville, TN (old record 107° 7/28/1952
109° Columbia, SC (old record 107° on two previous occasions)
109° Cairo, IL (old record 106° on 8/9/1930)
108° Paducah, KY (ties same on 7/17/1942
106° Chattanooga, TN (ties same on 7/28/1952)
105° Raleigh, NC (ties same on 8/21/2007 and 8/18/1988)
105° Greenville, SC (old record 104° 8/10/2007 although 106° was recorded by the Signal Service in July 1887)
104° Charlotte, NC (ties same on 8/9 and 10/2007 and 9/6/1954)
102° Bristol, TN (ties same on 7/28/1952-this site now known as `Tri-State Airport’)
109° Athens, GA. This is just 1° shy of the Georgia state record for June of 110° set at Warrenton in 1959.

All-time state June heat records set Friday:

113° Smyrna, TN (old record 110° in Etowah in June 1936)
109° Cairo, IL (old record 108° in Palestine in June 1954)

Also of note: Atlanta, GA hit 104° (its all-time June record), and just 1° shy of its all-time record of 105° set on 7/17/1980. The forecast for Atlanta on Saturday calls for a high of 105°F, which would tie for the hottest day in the city’s history.

Wunderground’s weather historian Christopher C. Burt has a new post called The Amazing June Heat Wave of 2012 Part 1: The West and Plains June 23 – 27 summarizing the early portion of this week’s historic heat wave. He plans to make a follow-up post on Sunday summarizing the records set on Friday and Saturday.

Relatively quiet in the Atlantic
An area of heavy thunderstorms, associated with an upper level low pressure system, has developed in the Gulf of Mexico along the Texas coast. This disturbance will probably move ashore over Texas before development into a tropical depression can occur, and NHC is giving it a 0% chance of development. The tropical wave approaching the Lesser Antilles (Invest 97L) has dissipated due to dry air, and is no longer a threat. None of the reliable computer models are developing anything during the next seven days.

Jeff Masters

from:    http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2141

Hurricane Carlotta Targetting Mexico

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Hurricane Carlotta bears down on Mexico’s Pacific coast
Posted by: JeffMasters, 4:10 PM GMT on June 15, 2012 +32
Hurricane Carlotta has steadily intensified today as it heads northwest towards the Mexican coast east of Acapulco. Recent satellite loops show a well-organized storm with a prominent eye, solid eyewall with cold cloud-tops, and good low-level spiral banding. Carlotta may be undergoing rapid intensification, thanks to favorable sea surface temperatures near 30°C (86°F) and moderate wind shear of 10 – 20 knots. A hurricane hunter mission is en-route, and will arrive at the storm near 2pm EDT on Friday to see how strong Carlotta has become. Carlotta’s rain bands have already moved over the coast of Mexico a few hundred miles east of Acapulco, as seen on Puerto Ánoel radar.


Figure 1. Morning satellite image of Carlotta.


Figure 2. Morning radar image of Carlotta from the Puerto Ánoel radar.

Forecast for Carlotta
Carlotta is likely to continue to strengthen as it approaches the western coast of Mexico east of Acapulco. As a large portion of the hurricane’s circulation moves over the mountains of Mexico on Saturday morning, steady weakening should occur. Heavy rains from Carlotta will be the storm’s main threat, and these rains will steadily progress westwards along the coast, arriving at Acapulco by Saturday morning. With rainfall amounts of 6 – 10 inches possible along the track of Carlotta, the potential for dangerous flash flooding and mudslide will be a concern all along the coast affected by Carlotta.

The Atlantic is quiet
There are no threat areas to discuss in the Atlantic today. The GFS model is predicting that some of the moisture and energy from Carlotta could move into the Gulf of Mexico next week and form a tropical disturbance capable of becoming a tropical depression, but this solution is unlikely.

Jeff Masters

from:    http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2121

Dr. Jeff Masters on Hurricanes & Tropical Storms

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Today is my last day in Ponte Vedra Beach, Florida, where 700 of the world’s hurricane experts are gathered to attend the 30th Conference on Hurricanes and Tropical Meteorology of the American Meteorological Society. It’s been a great week of learning and catching up with old friends, and I present below a few final summaries of talks I attended.

Impact of Tropical Cyclones on drought alleviation in the Atlantic and Gulf Coasts
Dr. Pat Fitzpatrick of the Stennis Space Center in Mississippi discussed how landfalling tropical storms and hurricanes can alleviate drought. The biggest winner tends to be the Southeast U.S. states of Florida, Georgia, South Carolina, and North Carolina, where about 20% – 50% of all droughts between 1960 – 2009 were busted by a landfalling tropical storm or hurricane. It is uncommon for Texas to see a drought busted; less than 10% of all Texas droughts have been ended by a hurricane or tropical storm. This occurs because the Southeast U.S. can receive heavy rains from hurricanes moving up the East Coast, or moving through the Gulf of Mexico, while relatively few storms track over Texas. Over the course of a year, hurricanes and tropical storms contribute 15 – 20% of rain along the Gulf Coast, and 3 – 16% along the East Coast. The length of a drought does not seem to affect whether a drought can be ended by a hurricane or not. Hurricanes have been able to end both short (< 3 month) and long (> 12 month droughts) equally well.


Figure 1. Example of a drought-busting tropical storm. Moderate drought (Palmer Drought Severity Index, PDSI, ≤ –2.0) was present in 52 percent of the Florida, Georgia, South Carolina, and North Carolina climate divisions in May 2006. The percentage decreased to 29 percent after Tropical Storm Alberto passed through on June 11 – 15, 2006. Image credit: U.S. Drought Monitor.


Figure 2. Rainfall in inches from the passage of Tropical Storm Alberto in 2006. Image credit: NOAA/HPC.

According to the U.S. drought monitor, over 90% of the area of Florida, Georgia, South Carolina, and North Carolina are currently in moderate to exceptional drought. There is 1 – 2 inches of rain coming to much of the region over the next few days, but that will not be enough to bust the drought. Based on Dr. Fitzpatrick’s research, there is a 20% – 50% chance that the drought will be broken by a tropical storm or hurricane. The first storm on the list in 2012 is Alberto again; let’s hope we get another Alberto this year that imitates the 2006 version of Alberto.

Patterns of rapid intensification
Peter Yaukey of the University of New Orleans studied patterns of hurricane rapid intensification in the Atlantic from 1950 – 2009. The Gulf of Mexico and Caribbean saw the most rapid intensification events, and the Northeast Atlantic the fewest. Interestingly, he found that rapid intensification events did not peak in September, but tended to be more common in June and July. Hurricane are less likely to intensify in the late afternoon and early evening (near 00 UTC), and more likely to intensify just after midnight, at 06 UTC.

Jeff Masters

from:    http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2076

Quiet Hurricane Season Expected

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fr/Dr. Jeff Masters:

CSU: expect a quiet 2012 Atlantic hurricane season; EF-3 tornado confirmed in Texas
Posted by: JeffMasters, 2:47 PM GMT on April 05, 2012 +29
Expect one of the quietest Atlantic hurricane seasons since 1995 this year, say the hurricane forecasting team of Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU) in their latest seasonal forecast issued April 4. They call for an Atlantic hurricane season with below-average activity: 10 named storms, 4 hurricanes, and 2 intense hurricanes. An average season has 10 – 11 named storms, 6 hurricanes, and 2 intense hurricanes. The 2012 forecast calls for a below-average chance of a major hurricane hitting the U.S., both along the East Coast (24% chance, 31% chance is average) and the Gulf Coast (24% chance, 30% chance is average). The Caribbean is forecast to have a 34% chance of seeing at least one major hurricane (42% is average.) Four years with similar pre-season March atmospheric and oceanic conditions were selected as “analogue” years that the 2012 hurricane season may resemble: 2009, 2001, 1965, and 1957. These years all had neutral to El Niño conditions during hurricane season. The average activity for these years was 9.5 named storms, 4.8 hurricanes, and 2.3 major hurricanes.


Figure 1. Departure of sea surface temperature (SST) from average for April 5, 2012, as computed by NOAA’s NESDISbranch. SSTs in the hurricane Main Development Region (red box) were near average to below-average.

Why the forecast of a quiet season?
The CSU team cited two main reasons why this may be a quieter than average hurricane season:

1) La Niña has weakened rapidly over the tropical Eastern Pacific over the past month, and is expected to be gone by the end of April. In its wake, El Niño conditions may develop in time for the August – September – October peak of hurricane season. If El Niño conditions are present this fall, this will likely bring about a quiet Atlantic hurricane season due to increased upper-level winds over the tropical Atlantic creating wind shear that will tend to tear storms apart. The CSU team is leaning towards putting their trust in the ECMWF model, which is predicting that a weak El Niño event will be in place by fall.

2) Sea surface temperatures (SSTs) in the Main Development Region (MDR) for hurricanes from the Caribbean to the coast of Africa between 10°N and 20°N were near average to below average in March 2012. Virtually all African waves originate in the MDR, and these African waves account for 85% of all Atlantic major hurricanes and 60% of all named storms. When SSTs in the MDR are much above average during hurricane season, a very active season typically results (if there is no El Niño event present.) Conversely, when MDR SSTs are cooler than average, a below-average Atlantic hurricane season is more likely. This year’s SSTs in the MDR are among the coolest we’ve seen since our current active hurricane period began in 1995. The cool temperatures are largely due to strong surface winds that blew during the winter over the tropical Atlantic in response to the positive phase of the North Atlantic Oscillation (NAO.) The strong winds stirred up the water, bringing up cooler waters from the depths.

How good are the April forecasts?
The forecasters are using a new statistical model developed last year for making April forecasts, so we don’t have a long enough track record to judge how good the new model is. The new model correctly predicted a more active than average season for last year, though called for more activity than was actually observed. However, April forecasts of hurricane season activity are low-skill, since they must deal with the so-called “predictability barrier.” April is the time of year when the El Niño/La Niña phenomenon commonly undergoes a rapid change from one state to another, making it difficult to predict whether we will have El Niño, La Niña, or neutral conditions in place for the coming hurricane season. Correctly predicting this is key, since if El Niño, conditions are present this fall, this will likely bring about a quiet Atlantic hurricane season due to increased upper-level winds over the tropical Atlantic creating wind shear that will tend to tear storms apart.

CSU maintains an Excel spreadsheet of their forecast errors ( expressed as a mathematical correlation coefficient, where positive means a skilled forecast, and negative means they did worse than climatology) for their their April forecasts. For now, these April forecasts should simply be viewed as an interesting research effort that has the potential to make skillful forecasts. The next CSU forecast, due by June 1, is the one worth paying attention to. Their early June forecasts have shown considerable skill over the years.

to read more, go to:    http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2067

Jeff Master on Hot Times In March

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Summer in March, 2012 draws to a close
Posted by: JeffMasters, 4:54 PM GMT on March 23, 2012 +21
The most incredible spring heat wave in U.S. and Canadian recorded history is finally drawing to a close today, after a ten-day stretch of unprecedented record-smashing intensity. Since record keeping began in the late 1800s, there have never been so many spring temperature records broken, and by such a large margin. Airports in fifteen different states have set all-time records for March warmth, which is truly extraordinary considering that the records were set in the middle of the month, instead of the end of the month. The 29.2°C (85°F) measured at Western Head, Nova Scotia yesterday was the third warmest temperature ever recorded in Canada in March, according to Environement Canada and weather records researcher Maximiliano Herrera (top two records: 31.1°C at Alberini Beaver Creek BC on March 29th 1926, and 29.4°C in 1921 at Wallaceburg.) Michigan’s all-time record for March warmth was toppled on Wednesday, when the mercury hit 90°F at Lapeer. The previous record, 89° at Lapeer in 1910, was matched at three stations yesterday–Ypsilanti, Dearborn, and Lapeer. The duration, areal size, and intensity of the Summer in March, 2012 heat wave are simply off-scale, and the event ranks as one of North America’s most extraordinary weather events in recorded history. Such a historic event is difficult to summarize, and in today’s post I will offer just a few of the most notable highlights.


Figure 1. Clear skies over the Eastern U.S. caused by a blocking ridge of high pressure on March 21, 2012, are apparent in this visible satellite image. The comma-shaped cloud pattern over the Central U.S. is associated with a “cut-off” low pressure system. This low is moving over the Eastern U.S. today through Saturday, and will bring an end to “Summer in March” over the U.S. and Canada. Image credit: NOAA’s Environmental Visualization Lab, and modified by Andrew Freedman of Climate Central.

Low temperatures beating previous high temperature records for the date
I’ve never seen a case where the low temperature for the date beat the previous record high. This happened on at least four occasions during “Summer in March, 2012”:

The low temperature at Marquette, Michigan hit 52° on March 21, which was 3° warmer than the previous record high for the date.

The low at Mt. Washington, NH on March 21 (44°) beat the previous record high for the date (43°.)

The low temperature for International Falls, Minnesota on March 20 bottomed out at 60°F, tying the previous record high for the date.

The low temperature in Rochester, Minnesota on March 18 was 62°F, which beat the previous record high for the date of 60°.

Breaking all-time April records for warmth in March
Not only did many locations in Canada set records for their all-time warmest March day during “Summer in March, 2012”, a number also broke their record for warmest April day:

St. John, New Brunswick hit 27.2°C (81°F) on March 21. Previous March record: 17.5°C on March 21, 1994. April record: 22.8°C.

Halifax, Nova Scotia hit 27.2°C (81°F) yesterday. Previous March record: 25.8° set the previous day. April record: 26.3°C, set on April 30, 2004.

Kejimkujik Park, Nova Scotia hit 27.9°C on March 21. Previous March record: 22.5°C on March 30, 1986. April record: 25°C on April 27, 1990.

Breaking daily temperature records by more than 30°F
It is exceptionally rare for a weather station with a 50+ year period of record to break a daily temperature record by more than 10°F. During “Summer in March, 2012”, beating daily records by 10° – 20°F was commonplace, and many records were smashed by over 20°. Two stations broke records by more than 30°F, which is truly surreal. Western Head, Nova Scotia hit 29.2°C (85°F), yesterday, breaking their previous record for the date (10.6°C in 1969) by 18.6°C (33°F.) Yesterday’s high temperature was 24°C (44°F) above average. Pellston, Michigan in the Northern Lower Peninsula–dubbed “Michigan’s Icebox”, since it frequently records the coldest temperatures in the state–hit 85° on March 21. This broke the previous record for the date (53° in 2007) by 32°, and was an absurd 48°F above average.

Breaking daily temperature records nine consecutive days or more
It is extremely rare for stations with a 50+ year period of record to break a daily high temperature record for seven or more days in a row. The longest such streak of consecutive high temperature records at International Falls, Minnesota, was a 5-day period March 3 – 7, 2000. The city has tied or broken their high temperature for the date ten consecutive days, as of yesterday. This streak will likely end today, as the high is predicted to be 60 – 65, and the record high for the date is 66. Chicago, Illinois has tied or broken their daily high temperature record the past nine days in a row. This ties the nine-day streak of record highs set on August 26 – September 3, 1953. Other cites that have set daily high temperature records the past nine days in a row include Fort Wayne and South Bend, Indiana. Numerous cities have broken high temperature records on seven consecutive days during “Summer in March, 2012”, including Gaylord, Pellston, and Traverse City in Michigan.


Figure 2. All-time high temperature records set in March 2012 for the U.S. The grey icons show locations where the March record was broken on multiple days. Image taken from wunderground’s new record extremes page, using data from NOAA’s National Climatic Data Center.

The big picture: the impacts of “Summer in March, 2012”
I’ve always said living in Michigan would be much more bearable if we could just get rid of March. March weather here is always horrible, with brutal cold, high winds, damaging ice storms, heavy snow, interminable cloudy stretches with no sun, all interspersed with a few teasing warm spells. Well, this year, I got my wish. This March, we started with twelve days of April weather, followed by ten days of June and July weather, with nine days of May weather predicted to round out the month. This has been a huge benefit to the economy–vastly reduced heating costs, no snow removal bills, and far fewer traffic accidents due to icy roads. However, there is major downside to the “Summer in March, 2012” heat wave. The growing season is now in full swing, five weeks early. A damaging freeze that will severely impact the fruit industry and other sensitive plants is very likely. Indeed, the forecast calls for lows in the upper 20s in the cherry-growing region of Michigan near Traverse City on Monday night. The exceptional March warmth has also melted all the snow in the northern U.S. and southern Canada, drying out the soils and setting the stage for a much warmer than average summer, and an increased chance of damaging drought conditions. The early loss of snowpack will also likely cause very low flow rates in the major rivers in late summer and early fall, reducing the amount of water needed for irrigation of crops. Low flows may also cause problems for navigation, limiting commercial barge traffic on Midwest rivers.

Links
Andrew Freedman of Climate Central interviewed a number of climate scientists who are experts in studying the link between extreme weather events and climate change for his post, Global Warming May Have Fueled March Heat Wave Odds.

Wunderground’s weather historian Christopher C. Burt will be posting a more comprehensive summary of the “Summer in March, 2012” heat wave this weekend.

Have a great weekend, everyone, and I’ll be back Monday with a new post. I expect I’ll be hard at work this weekend, mowing my lawn for the first time ever in March!

Jeff Masters

Jeff Masters on Possibility of Tornadoes 3/2

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The winter of 2012 blew out like a lion yesterday, with a massive Leap Day storm that pounded the Midwest with deadly tornadoes and heavy snow. A violent EF-4 tornado with 180 mph winds tore through Harrisburg, Illinois at 4:56 am CST yesterday morning, killing six, injuring approximately 100, and damaging 200 homes and 25 businesses. The tornado cut a path seven miles long and 250 yards wide across the town, according to the NWS damage survey. Another person was killed in southwest Missouri near Buffalo when am EF-2 tornado ripped through a mobile home park late Wednesday night. Twelve others were injured in the mobile home park. Four additional deaths occurred due to tornadoes in Cassville, MO, Smithville, TN, and Monterey, TN yesterday, bringing the death toll of the two-day severe weather outbreak to eleven. An EF-2 tornado also plowed through downtown Branson, Missouri yesterday morning, injuring 33 people. The tornado blew out or cracked windows in 219 of the hotel rooms in the 12-story/295 room Hilton Branson Convention Center, and extensively damaged three of Branson’s 50 plus theaters–Americana Theater, Branson Variety Theater and Dick Clarks’ American Bandstand Theater. The Branson Landing on Lake Taneycomo and the Veterans Memorial Museum were also heavily damaged. An NWS storm survey found the tornado was 400 yards wide and carved a path 22 miles long. An EF-2 tornado also hit the small town of Harveyville, Kansas (population 275), twenty miles southwest of Topeka, at 9:03 pm Wednesday night. The tornado destroyed 40 – 60% of the structures and injured twelve, three critically. Overall, damage from the two-day tornado outbreak will run in the hundreds of millions of dollars, and could add up to be the first billion-dollar weather disaster of 2012 in the U.S.


Figure 1. Damage in Branson, Missouri after yesterday’s tornado. Image credit: BransonRecovery Facebook page.

Yesterday’s tornado outbreak’s place in history
Yesterday was the deadliest day for U.S. tornadoes since May 24, 2011, when 18 people died in a Midwest tornado outbreak–part of the five-day outbreak that brought the deadliest U.S. tornado since 1947, the May 22, 2011 Joplin, Missouri tornado, which killed 158 people and injured 1150. The preliminary tornado total from February 28 – 29 of 2012 is 30, making it the largest February tornado outbreak since February 17 – 18, 2008, when 31 twisters touched down. Yesterday’s Harrisburg, Illinois tornado was the deadliest February tornado since the February 10, 2009 EF-4 twisterthat struck Southern Oklahoma near Ardmore, killing eight. The deadliest February tornado in recorded history occurred on February 21, 1971, when an F-4 tornado ripped a 202-mile path through Mississippi, killing 58 people.


Figure 2. By analyzing both the rotational velocity of the storm systems (the spinning of tornadoes has high rotational velocity compared to the surrounding storms) and presence of hail, scientists at the NOAA National Severe Storms Laboratory have developed a product that approximates the track of tornadoes, shown here for the February 29, 2012 storms. Image credit: NOAA Environmental Visualization Laboratory.

Violent tornadoes in February: a rarity
Violent February tornadoes are rare in February. The Tornado History Project lists eighteen EF-4 and one EF-5 tornadoes in the U.S. during the month of February since 1950–an average of one violent February tornado every three years. Part of the reason for this is the lack of warm, unstable air so early in the year. However, this year’s unusually mild winter has led to ocean temperatures across the Gulf of Mexico that are approximately 1°C above average–among the top ten warmest values on record, going back to the 1800s. Averaged over the month of February, the highest sea surface temperatures on record in the Gulf between 20 – 30°N, 85 – 95°W occurred in 2002, when the waters were 1.34°C above average. Yesterday’s tornado outbreak was fueled, in part, by high instability created by unusually warm, moist air flowing north from the Gulf of Mexico due to the high water temperatures there.

Heavy snow hits Upper Midwest
The same storm system also brought the heaviest snows of the winter to portions of the Upper Midwest, which has received scant snowfall this winter. Widespread heavy snow fell in northern Wisconsin, where Mincqua recorded 18 inches. South Dakota, Central Minnesota, and Michigan’s Upper Peninsula also received snow amounts in excess of a foot. The storm also brought moderate snows to Northern New England, with southern Vermont receiving more than 8 inches. The latest NOAA Storm Summary has detailed storm total accumulation info.


Figure 3. Snowfall amounts for the 3-day period ending at 7 am local time Thursday, March 1, 2012. Image credit: NOAA Southern Region Headquarters.

New tornado outbreak likely on Friday
The storm system that brought yesterday’s tornadoes and snow has moved into Canada and New England, and the threat of severe weather is minimal today in the Midwest. However, a new storm system is expected to form over Missouri early Friday and track northeastward, unleashing a new tornado outbreak over Tennessee, Kentucky, Alabama, Mississippi, Indiana, and Ohio. NOAA’s Storm Prediction Center has placed this region in their “Moderate Risk” area for severe weather Friday, and is warning of the possibility of long-track significant tornadoes. Consult ourSevere Weather Page and Interactive Tornado Page to follow the storms.


Figure 4. NOAA’s Storm Prediction Center has placed much of Tennessee, Kentucky, and portions of surrounding states in their “Moderate Risk” area for severe weather on Friday. This is one level below the highest level of alert, “High Risk.”

Portlight disaster relief charity responds to the Harrisburg, Illinois tornado
Portlight is sending people into the Harrisburg, IL, area at this time in response to the tornado disaster there. They will be assessing needs there and surrounding areas. As usual, they will be focusing efforts on the un-served, under-served and forgotten. Please visit the Portlight Disaster Relief blog to learn more. Donations are always welcome!

Jeff Masters

from:    http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2042

Dr. Jeff Masters on Climatic Warming

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Posted by: JeffMasters, 2:53 PM GMT on February 10, 2012 +30
Last week, I blogged about how wintertime minimum temperatures in the U.S. have risen so much in recent decades, that the United States Department of Agriculture (USDA) had to update their Plant Hardiness Zone Map for gardeners for the first time since 1990. The Plant Hardiness Zone Map is the standard by which gardeners and growers can determine which plants are most likely to thrive at a location. I got to looking at the new zone map for Ann Arbor, Michigan, where I live, and saw how we’ve shifted one 5-degree Fahrenheit half-zone warmer. Ann Arbor used to be in Zone 5, but is now solidly in the warmer Zone 6. This got me to wondering, what sort of plants in Zone 6, until now rare or unknown in Ann Arbor, might migrate northwards in coming decades into the city? Then, with a sudden chill, I contemplated a truly awful possibility: The Ohio Buckeye Tree.


Figure 1. Comparison of the 1990 and 2012 USDA Plant Hardiness Zone Maps. Image credit: USDA and Arbor Day Foundation.

Buckeyes in Ann Arbor? The Horror!
For those of you unfamiliar the the buckeye tree, it is the emblem of Ohio State University. The Buckeyes of Ohio State have one of the most fierce rivalries in sports with that “school up north”, the University of Michigan. As someone who spent twelve years of my life as a student at the University of Michigan, the thought of Buckeye trees in Ann Arbor is not one I care to contemplate. But the USDA Forest Service has published a Climate Change Tree Atlas which predicts that the Ohio Buckeye Tree can be expected to march northwards and infest Ann Arbor with a warming climate. I can only sadly predict that to stem the invasion, non-ecologically-minded University of Michigan students will unleash genetically engineered wolverines that eat buckeye seeds.


Figure 2. Potential changes in the mean center of distribution of the Ohio Buckeye tree. The green oval shows the current center of the range of the Buckeye Tree, well to the south of Ann Arbor. In a scenario where humans emit relatively low amounts of heat-trapping gases like carbon dioxide (light blue oval), the Buckeye Tree edges into Southern Michigan, and marches into Ann Arbor under the medium and high scenarios for emissions (other ovals.) Image credit: USDA Forest Service Climate Change Tree Atlas.

Libyan snowstorm triggered major Saharan dust storm
On February 6, a rare snow storm hit North Africa, bringing 2 – 3 inches of snow to Tripoli, Libya. It was the first snow in Tripoli since at least 2005, and may be the heaviest snow the Libyan capital has seen since February 6, 1956. The storm responsible for the North African snow also had strong winds that kicked up a tremendous amount of dust over Algeria during the week. This dust became suspended in a flow of air moving to the southwest, and is now over the Atlantic Ocean.


Figure 3. Dust storm on February 7, 2012, off the coast of West Africa, spawned by a storm that brought snow to North Africa on February 6. Note the beautiful vorticies shed by the Cape Verde Islands, showing that the air is flowing northeast to southwest. The red squares mark where fires are burning in West Africa. Image credit: NASA.

Have a great weekend, everyone, and I’ll be back Monday with a new post.

Jeff Masters

Dr. Jeff Masters on January Weather & Records

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Posted by: JeffMasters, 2:25 PM GMT on February 08, 2012 +21
It wasn’t the warmest January in U.S. history, but it sure didn’t seem like winter last month–the contiguous U.S. experienced its fourth warmest January on record, and the winter period December 2011 – January 2012 was also the fourth warmest in the 117-year record, reported NOAA’s National Climatic Data Center yesterday. The percent area of the U.S. experiencing extremes in warm maximum temperatures was 56 percent–the second highest value on record. Thirteen of the 550 major U.S. cities with automated airport weather stations broke or tied all-time records for their hottest January temperature:

Craig, CO 82°F
Bakersfield, CA 82°F
Alexandria, LA 83°F
Duluth, MN 48°F
Minot, ND 61°F
Mitchell, SD 68°F
Fargo, ND 55°F
Jamestown, ND 56°F
Huron, SD 65°F
Aberdeen, SD 63°F
Iron Mountain, MI 52°F
Alma, GA 83°F
Omaha, NE 69°F

However, extremely cold air settled in over Alaska in January, and several cities in Alaska had their coldest average January temperatures on record: Nome (-16.6 degrees F), Bethel (-17.3 degrees F), McGrath (-28.5 degrees F), and Bettles (-35.6 degrees F).


Figure 1. State-by-state rankings of temperatures for January 2012. Nine states had top-ten warmest Januarys on record, while no states had below-average temperatures in January. Records go back to 1895. Image credit: NOAA’s National Climatic Data Center.

28th driest January for the contiguous U.S.
The first week of January was almost precipitation-free across the entire contiguous U.S., but a series of storms over Texas, the Ohio Valley, and the Pacific Northwest later in the month boosted precipitation totals enough to make January 2012 the 28th driest in the 118-year period of record. Remarkably, Texas had its 30th wettest January on record, and was the 2nd wettest state during the month. Texas also had a very wet December, their 19th wettest December. It is very rare for Texas to receive so much precipitation during a La Niña winter. Texas had not experienced two consecutive months with above-average precipitation since January – February 2010, during the last El Niño event.


Figure 2. State-by-state rankings of precipitation for January 2012. Three states had top-ten driest Januarys on record, while no states had a top-ten wettest January. Records go back to 1895. Image credit: NOAA’s National Climatic Data Center.

3rd least-snowy January
According to the Rutgers Global Snow Lab, the average U.S. snow extent during January was the 3rd smallest January snow cover extent in the 46-year period of record. The National Weather Service sends out a daily “Weather and Almanac” product for several hundred major U.S. cities that we make available on underground. The February 6 statistics for those cities that reported measurable snow this winter show that only fifteen cities in the lower 48 states reported above-average snowfall as of February 6, and 155 had received below-average snowfall.


Figure 3. The new “Blue Marble” image of Earth on January 4, 2012, as seen by the VIIRS instrument on the new Suomi NPP satellite. The U.S. and Canada are virtually snow-free and cloud-free, which is extremely rare for a January day. The lack of snow in the mountains of the Western U.S. is particularly unusual. I doubt one could find a January day this cloud-free with so little snow on the ground throughout the entire satellite record, going back to the early 1960s. NOAA’sAdvanced Hydrologic Prediction Service shows that only one state–Washington–had areas where precipitation accumulated more than 0.25″ on January 4, 2012, which is an extraordinary occurrence for a January day. Image credit:NASA.

Drought expands in January
According to the U.S. Drought Monitor, as of January 31st, 2012, about 3.3 percent of the contiguous U.S. was experiencing the worst category of drought–called D4 or exceptional drought–about the same as the beginning of the month. However, the percent area of the U.S. experiencing drought of any severity increased from 32 percent at the beginning of January to 38 percent at the end of the month. Most of the drought expansion occurred across the Upper Midwest and the western states.

2nd most January tornadoes on record
With 95 preliminary tornado reports, January 2012 is likely to end up with the 2nd most January tornadoes since 1950 (the record is 218, set in January 1999.)

from:    http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2031