Saturday, March 31, 2012

Plains Severe Weather Outbreak Possible Monday


Tornado kicking-up dust. Courtesy of Photos.cmo
By Dan DePodwin, Meteorologist
Mar 31, 2012; 3:45 PM ET
As the calendar turns to April, severe weather season begins to ramp up in the Plains, especially in Tornado Alley. AccuWeather.com meteorologists are monitoring the potential for an outbreak of severe thunderstorms beginning late Monday afternoon from Texas to Kansas.
The potent storm system currently bringing rain and mountain snow to the West will push eastward this weekend and emerge on the eastern side of the Rockies Monday morning.
Meanwhile, a strong flow of hot air across the Plains will allow temperatures to soar to the 90-degree mark for the first time this year in many places. The combination of unusually warm, moist air and a strong disturbance has the potential to produce significant severe weather beginning late Monday afternoon.
Although this potential outbreak is still a few days away, AccuWeather.com meteorologists are focusing on an area from central Texas to southern Kansas as the focal point for damaging storms.
Thunderstorms should erupt late Monday afternoon across the southern Plains and rumble north and east overnight.
Cities that could be impacted include Abilene and Dallas, Texas, Oklahoma City, Okla., and Wichita, Kan.
The atmospheric set-up looks conducive for all types of severe weather including damaging winds, hail, and tornadoes. In addition, torrential downpours and frequent lightning will accompany these storms.
After Monday night, the severe weather threat may spread eastward into the Southeast and Tennessee Valley.
The forecast for this potential severe weather outbreak will no doubt be tweaked over the weekend, so be sure to stay tuned to AccuWeather.com for the latest.

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Real-time imagery from GOES-East and GOES-West Satellites in full color

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Tennessee Valley Hail, Drenching Downpours Today


Lightning streaks across the sky. Photo courtesy of Photos.com
By Dan DePodwin, Meteorologist
Mar 31, 2012; 11:30 AM ET
A day after powerful thunderstorms rumbled through the Ohio Valley, more strong to severe thunderstorms are expected to develop late this afternoon and evening across the Tennessee Valley and Southeast.
Parts of this region had bouts of heavy thunderstorms yesterday. Although the storm system that brought those downpours is moving off the Carolina coast, a trailing disturbance threatens to bring more storms today.
While a widespread severe weather outbreak is not expected, some storms could produce large, damaging hail.
Although gusty winds and tornadoes are not likely, an isolated strong wind gust or twister is not completely out of the question. Stay tuned to AccuWeather.com throughout the day for the latest updates.
Residents in close proximity to the southern border of Tennessee should keep an eye to the sky this afternoon and evening for threatening weather. Cities that could get storms include Memphis and Chattanooga, Tenn., Tupelo, Miss., and Birmingham, Ala.
 

Storms will develop this afternoon and evening and can produce large hail.
As temperatures fall later this evening after sunset, the severe threat will diminish. However, leftover thunderstorms could still produce torrential downpours overnight.
These downpours can lead to localized flooding and ponding on roadways. Visibility will also be significantly reduced. Never drive through a flooded roadway.
As with any thunderstorm, lightning will also be a threat. If you hear thunder, be sure to take shelter inside and wait until the storm passes.

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AccuWeather.com - WeatherMatrix | Awesome Lightning Photos, Videos from Pennsylvania

Mar 31, 2012; 9:44 AM ET
Pennsylvania was lucky enough to get some decent lightning (for late March!) last night and some of the Pennsylvania Storm Chasers on Facebook scored some excellent pics & video. The highlight was this video by Edward Ramolt, where he caught lightning striking a couple hundred feet away on his iPod in Pittsburgh (click to play):


Ron Shawley also got some great shots from Chickaree Mountain up above Johnstown:
He also got several shots of "ground-to-cloud" lightning (upwards striking) from the local power plant:
I was barely awake for the 9:30 storms, which popped up suddenly, so all I got was this quick video of a cloud-to-cloud strike (with birds - that's a new one), which is slowed down to 1/4 speed here:
All told, about 8.700 lightning strikes hit the ground in and around the state yesterday evening:
All quite impressive considering that storms were forming while temperatures were in the 40s (midnight temps shown)!
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Quick Shot of Northeast Snow Sunday Night


Picture of snow covering a flower courtesy of Photos.com

Mar 31, 2012; 8:32 AM ET
Despite the incredible warmth that surged across much of the East throughout the month of March, a little taste of winter will return on Sunday night.
A quick shot of snow will fall across northern sections of New England and southern Maine where the air will be just cold enough to produce frozen precipitation.
In areas farther south, snow will mix with rain as the air will be slightly warmer.
A fast-moving clipper system will race from southern Ontario into the mid-Atlantic on Sunday afternoon and night. As the storm pushes eastward, cooler air will be drawn in and precipitation will fall as snow.
Since the snow will be falling at night, the opportunity exists for at least some small accumulations. If the snow would have been falling during the day, the strong late March and early April sun would have made it difficult for much accumulation to occur.
Residents in northern New England who will be traveling on Sunday night should do so with caution and watch out for any slick spots that develop on roadways.
The snow will be quick to end as the storm system races off the coast and into the Atlantic Ocean.
Beyond Sunday night, chances for a little snow will continue through next week.
According to Expert Senior Meteorologist Alex Sosnowski, "a dip in the jet stream will continue to send bouts of chilly air and spotty snow into the Northeast through next week."

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Friday, March 30, 2012

Dr. Jeff Masters' WunderBlog : Great Lakes ice cover down 71% since 1973 : Weather Underground


Published: 1:08 PM GMT on March 30, 2012
Ice cover on North America's Great Lakes--Superior, Michigan, Huron, Ontario, and Erie--has declined 71% since 1973, says a new study published in the Journal of Climate by researchers at NOAA's Great Lakes Environmental Research Laboratory. The biggest loser of ice during the 1973 - 2010 time period was Lake Ontario, which saw an 88% decline in ice cover. During the same time period, Superior lost 79% of its ice, Michigan lost 77%, Huron lost 62%, and Erie lost 50%. The loss of ice is due to warming of the lake waters. Winter air temperatures over the lower Great Lake increased by about 2.7°F (1.5°C) from 1973 - 2010, and by 4 - 5°F (2.3 - 2.7°C) over the northern Lakes, including Lake Superior. Lake Superior's summer surface water temperature warmed 4.5°F (2.5°C) over the period 1979 - 2006 (Austin and Colman 2007). During the same period, Lake Michigan warmed by about 3.3°F (1.7°C), Lake Huron by 4.3°F (2.4°C), and Lake Erie showed almost no warming. The amount of warming of the waters in Lakes Superior, Huron, and Michigan is higher than one might expect, because of a process called the ice-albedo feedback: when ice melts, it exposes darker water, which absorbs more sunlight, warming the water, forcing even more ice to melt. This sort of vicious cycle is also responsible for the recent extreme loss of Arctic sea ice. The increase in temperature of the lakes could be due to a combination of global warming and natural cycles, the researchers said. They noted a pronounced 4-year and 8-year oscillation in ice coverage, which could be caused by the El Ninño/La Niña and Arctic Oscillation (AO), respectively.

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Figure 1. A tale of two winters: Lake Superior was choked with ice at the end of the winter of 2008 - 2009 (top), but was virtually ice-free at the end of the winter of 2011 - 2012 (bottom.) Image credit: NASA.

The consequences of Great Lakes ice loss
Ice coverage on the Great Lakes was just 5% this past winter, the second lowest on record, behind 2002. The lack of Great Lakes ice this winter probably added a few degrees of warmth to the unprecedented "Summer in March" conditions observed in Michigan last week--an event the National Weather Service in Detroit called "perhaps the most anomalous weather event in Michigan since climate records began 130 years ago." We can anticipate that areas surrounding the Great Lakes will see an increased incidence of warm spring weather due to decreased ice cover on the lakes.

The loss of Great Lakes ice has allowed much more water to evaporate in winter, resulting in heavier lake effect snow near the shore, and lower lake levels. Lower water levels have had a significant impact on the Great Lakes economy. Over 200 million tons of cargo are shipped every year through the Great Lakes. Since 1998, when water levels took a severe drop, commercial ships were forced to light-load their vessels. For every inch of clearance that these oceangoing vessels lost because of low water levels, $11,000 - $22,000 in profits were lost per day. Hydropower plants have also been affected by low water levels; several New York and Michigan plants were run at reduced capacity, forcing them to buy higher priced energy from other sources, and passing on the higher costs to consumers. The large loss of ice is also likely to accelerate shoreline erosion because of the increase in open water, and promote more algal blooms. It is uncertain if the Great Lake water levels will continue to fall as the climate warms, since the region is expected to see an increase in precipitation over the coming decades. In Michigan, annual precipitation increased by about 14% between 1895 - 2011, according to theNational Climatic Data Center.


Figure 2. Great Lakes ice coverage for the period December 4 - March 5, from the winter of 1980 - 1981 through 2011 - 2012. The winter of 2011 - 2012 had the second lowest ice coverage on record, just 5%. Only 2001 - 2002 (4.5%) had lower ice cover. The median ice coverage between 1980 - 2011 was about 19%. Image credit: Environment Canada.


Figure 3. Water levels on Lake Superior between 1860 and February 2012. Since the late 1990s, water levels have seen a steep decline, due to the loss of ice cover allowing more evaporation. Image credit: NOAA/GLERL.

References
Austin, J. A., and S. Colman, 2007, "Lake Superior summer water temperatures are increasing more rapidly than regional air temperatures: A positive ice-albedo feedback," Geophys. Res. Lett., 34, L06604, doi:10.1029/2006GL029021.

Wang, J., X. Bai, H. Hu, A.H. Clites, M.C. Colton, and B.M. Lofgren, 2012, "Temporal and spatial variability of Great Lakes ice cover, 1973-2010," Journal of Climate 25(4):1318-1329 (DOI:10.1175/2011JCLI4066.1)

Have a great weekend, everyone! I'll be back by Monday at the latest with a new post, and may post some weather humor on Sunday (April Fools Day), as well.

Jeff Masters

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Warmth to fuel mid-U.S. t-storms; Chicago temps surge Sunday

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AccuWeather.com - Outdoor - Huge 'Solar Tornado' Twists Across Sun's Surface in New Video

Mar 29, 2012; 9:52 AM ET
NASA's Solar Dynamics Observatory spacecraft observed a "tornado" as wide as five Earths raging on the sun's surface on Sept. 25, 2011. This sequence of photos follows the tornado over 2 1/2 hours.

Credit: NASA/SDO/AIA/Aberystwyth University/Li/Morgan/Leonard
A NASA spacecraft has captured video of a massive solar "tornado" five times wider than the Earth twisting its way across the surface of the sun.
NASA's Solar Dynamics Observatory (SDO) looked on as the huge, swirling storm raged on Sept. 25, 2011, spinning solar gas at speeds up to 186,000 mph (300,000 kph), researchers said. Here on Earth, tornado wind speeds top out at around 300 mph (483 kph). 
"This is perhaps the first time that such a huge solar tornado is filmed by an imager," Xing Li of Aberystwyth University in Wales, who analyzed the SDO footage, said in a statement. "Previously, much smaller solar tornadoes were found by the [NASA/European Space Agency] SOHO satellite. But they were not filmed."
Li and other researchers will present a movie of the tornado Thursday (March 29) at the 2012 National Astronomy Meeting in Manchester, the United Kingdom.
SDO's instruments saw gases as hot as 3.6 million degrees Fahrenheit (2 million degrees Celsius) rise from a dense solar structure called a prominence, then travel about 124,000 miles (200,000 kilometers) along a spiral path into the upper solar atmosphere, researchers said.  
Unlike Earth's tornados, which are driven by wind, solar twisters are shaped by our star's powerful magnetic field. They often occur in concert with violent explosions of solar plasma known as coronal mass ejections, or CMEs. Some researchers think the tornados may help trigger CMEs, which can streak through space at several million miles per hour.
CMEs that hit Earth can wreak havoc on our planet, causing temporary disruptions in GPS signals, radio communications and power grids. They also typically supercharge the dazzling light shows near Earth's poles known as the northern and southern lights.
The $850 million SDO spacecraft, which launched in February 2010, is the first in a fleet of NASA efforts to study our sun. The probe's five-year mission is the cornerstone of a NASA science program called Living with a Star, which aims to help researchers better understand aspects of the sun-Earth system that affect our lives and society.
The sun is currently in an active period of its 11-year weather cycle. The current cycle is known as Solar Cycle 24 and will peak in 2013.
Follow SPACE.com for the latest in space science and exploration news on Twitter@Spacedotcom and on Facebook.
Copyright 2012 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
By: SPACE.com Staff



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AccuWeather.com - Joe Lundberg | At Least Two More Very Warm Surges Ahead


Mar 30, 2012; 10:05 AM ET
Friday, 11:30 a.m.
March will go down in the record books as one of the warmest ever. No doubt it will absolutely smash monthly records in a lot of places, particularly across the Midwest and northern Plains. Places such as Sioux Falls, Des Moines, Minneapolis and Chicago are all more than 16 degrees above normal for the month, with only two more days to go into the books. That's an average of 16 degrees per day! How wild is that?
Records have been destroyed all over the place: the most 80-degree days in March in Chicago and the warmest ever in March in Caribou, Maine. Record highs have been set in Florida, up and down the East Coast, as well as in the Great Lakes, the Ohio Valley, the Tennessee Valley, the Plains and the Rockies.
And we're not done seeing records get erased. At least two more warm surges are left in this pattern before we can put a little sanity back in the pattern. The first of these is already blossoming over the Rockies, where it will challenge a record in Denver this afternoon with sunshine. By tomorrow, they should pretty easily beat their existing record, and I suspect many more places over the eastern Rockies and out onto the Plains will do the same. Look at the GFS ensemble projected anomalies for tomorrow:
Keep in mind that is the composite average of many individual ensemble runs, so in extreme events, those extremes may be tempered by some lower individual members. This means it could be even farther above normal in more places that what that image is suggesting!
This warm surge will quickly cross the Mississippi Valley into the Midwest on Sunday, even leaking into the western Ohio Valley. Little of this warmth will reach the Northeast, though even there at least one day will get pretty warm next week, probably Tuesday, and perhaps even Wednesday until a cold front passes.
That front is tied to a strong upper-level trough that will crash onto the West Coast tomorrow into tomorrow night:
By Wednesday, that same trough will push a cold front to the East Coast. While that is happening, the cooldown spreading out of the West and through the Rockies onto the Plains early in the week will give way to yet another fast-building upper level ridge:
And that means still another surge of very warm air coming out of the Rockies and into the central northern Plains. Look at the projected anomalies for Thursday:
This warmth will again progress downstream on Good Friday into the Ohio Valley, and it will slowly warm heading into Easter weekend in the East, though not to the extent the Plains and eastern Rockies will get to experience.
We'll have to wait until the following week to see more definitive signs of a pulling back from this very warm pattern across the country. Until then, many parts of the country will continue to run weeks ahead of normal as far as temperatures are concerned.

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AccuWeather.com - Meteo Madness | Two Snow Shots in the Northeast. Hail Storms Ohio Valley


Mar 30, 2012; 8:00 AM ET
I don't have a lot of time today because we are saying goodbye to my Ken Reeves this afternoon. I think the images say for themselves what is going to happen the next couple of days. Just watch the storms in the Ohio Valley, as they could produce big hail today.
Thanks again to everyone for the support this week during this difficult time here at AccuWeather. 

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Spotty Severe Storms in Texas, Oklahoma, Kansas


By , Expert Senior Meteorologist
Mar 30, 2012; 12:48 PM ET
There is the risk of spotty severe thunderstorms over portions of the south-central Plains late today into tonight.
While conditions for producing thunderstorms in the area from central Texas to south-central Kansas are marginal, any thunderstorms that get going could quickly become severe.
The main risk with the storms will be frequent lightning strikes, large hail and flash flooding. However, if and once the storms get to the stage of producing hail of golf-ball size or larger, they can just as easily produce localized damaging wind gusts and even an isolated tornado.
Much of the day and the night in the region will be free of storms. In addition, since this is not likely to be a broad sweeping area of severe weather, most places may escape unscathed.
Temperatures and humidity levels will reach the point of making the atmosphere unstable. As a dry push of air known as the dry line drifts eastward, it could be enough to set off a few big storms.
People will want to keep tabs on a potential severe weather outbreak for early next week over part of the same area. As a storm swings in from California, it could initiate powerful thunderstorms in portions of western and central Texas, Oklahoma and Kansas, sometime during the period from Sunday night into Monday night. Details will follow over the weekend.
Meanwhile, the Ohio Valley will be targeted by a zone of severe thunderstorms into this evening.

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Rounds of Snow to Continue for Northeast


By , Expert Senior Meteorologist
Mar 30, 2012; 12:45 PM ET
A dip in the jet stream will continue to send bouts of chilly air and spotty snow into the Northeast through next week.
After a narrow zone of snow affects areas from upstate New York to southern New England tonight, a second swath of snow will aim for areas farther north Sunday night into early Monday.
The snow will attempt to reach areas missed by tonight's snow, with perhaps a slight overlap.
The overall pattern will continue to funnel near-average temperatures into the Northeast through next week, after an incredibly warm month as a whole.
Additional spotty rain and wet snow showers can occur on a couple of occasions into the Easter weekend. Most of the snow showers will tend to occur over the higher ground from northern Pennsylvania to southern Ontario.
It is possible the jet stream may relax and flatten enough to allow more warming and a break in chilly precipitation by Easter Sunday. However, since that is more than a week away, the timing of the break, if it occurs, is questionable.

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Heavy Rain and Flash Flooding in Fiji


Floodwaters rise on the main shopping street of Nandi, Fiji, Thursday, Jan. 26, 2012. (AP Photo/Pita Ligaiula)
By Eric Leister, Meteorologist
Mar 30, 2012; 9:20 AM ET
A tropical low pressure brought widespread flooding to parts of Fiji from Thursday night into Friday. The hardest hit areas were on the western side of the main island Viti Levu where the town of Nandi has been cut off from other parts of the island.
Nandi, home to Fiji's International Airport, received over 11 inches of rain since Thursday, with rain still falling across the area on Friday night. The slow movement of the tropical low will result in a continuing threat for locally heavy rainfall through the weekend and possibly into early next week.
The heavy rainfall caused most flights to and from the International Airport to be canceled on Friday, while hundreds of people were forced from their homes and many stranded on rooftops.
The National Disaster Management Office says the water levels from this flooding event are higher than the flooding in January which was responsible for 11 deaths.
Other local communities have been cut off by raging flood waters as rivers overflowed their banks, forcing most schools to close on Friday.
No deaths have been reported thus far; however, life-threatening flooding will be possible through the weekend.

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Colorado Fire May Spread with High Winds, Warmth


In this aerial photograph, smoke rises from the Lower North Fork Wildfire as it burns near the foothills community of Conifer, Colo., southwest of Denver on Tuesday, March 27, 2012. (AP Photo/David Zalubowski)
By , Meteorologist
Mar 30, 2012; 8:48 AM ET
High winds, warmth and low humidity will make the battle against the Lower North Forks Wildfire more difficult for fire fighters this weekend.
The gusty winds will continue to whip the area today, threatening to spread the blaze, which is burning near Conifer, Colo., about 20 miles southwest of Denver.
The wildfire has charred nearly 4,100 acres of the foothills of the Front Range. As of early Friday, the fire was approximately 45 percent contained.
Hundreds of firefighters were frantically trying to gain control of the blaze before the high winds, warmth and low humidity pose the biggest risk of the fire spreading this weekend.
According to the Denver Post, two people have been killed by the fire and one woman is missing.
More than two dozen homes have already been damaged or destroyed.
Winds, Record Warmth, Low Humidity Pose High Fire Danger
Warm, southwesterly winds will become very strong over the weekend as a storm pushes across the interior West.
According to Expert Senior Meteorologist Alex Sosnowski, "Winds can get cranking there Friday with temperatures will spike over the weekend, so the danger factor could really increase."
Gusts of more than 40 mph from the south and southwest can occur late today and Saturday.
"Winds of this magnitude can rapidly fan the flames or carry burning embers to unburned locations," Sosnowski added.
The highest wind gusts, surpassing 60 mph, are anticipated on Sunday and Monday.
High temperatures will challenge record highs across the region through the weekend, adding to the dangers. Humidity will also be very low, so there will be tinder-dry fuel for the fire to feed on.

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Typhoon Pakhar Aims Rain, Wind towards Vietnam


Typhoon Pakhar showing an impressive cloud swirl on Friday, March 30, 2012. Southern Vietnam is to the left (west).(NRLMRY/MTSAT-2 image)
By , Senior Meteorologist
Mar 30, 2012; 7:54 AM ET
An unusual late-March tropical cyclone will send torrential rain and strong winds ashore in Vietnam over the weekend.
Tropical Storm Pakhar, which took shape over the southern South China Sea Thursday, could landfall in southern Vietnam by Saturday night or Sunday.
Excessive rain and flooding is possible over a wide area along and north of Pakhar's direct path. Damaging winds will be possible as well.
Friday, the center of Tropical Storm Pakhar was within about 300, or 480 km, east-southeast of Ho Chi Minh City, according to the Joint Typhoon Warning Center. At the time, highest sustained winds were 75 mph, or 120 km/h, with storm movement towards the west at about 3 mph.
A stretch of coast east of Ho Chi Minh City will be at greatest risk of a storm landfall, as shown by forecast tools available to AccuWeather.com
Flooding rainfall to at least 12 inches, or 30 cm, will be possible near the storm's track, but also northward along the coast to Nha Trang or even Qui Nhon.
Any widespread heavy falls of rain would be unusual, as March into April marks the latter part of the yearly dry season in southern Vietnam. For instance, normal monthly rainfall in March is less than 2 inches, or 50 mm. April is also normally a rather dry month along the coast, but can bring increasing rainfall inland.
The western North Pacific Ocean tropical basin is the most prolific in terms of number of named storms each year. However, March and April are within the seasonal lull in tropical cyclones.
On average, a named storm happens about once ever three years in March. April storm frequency is about two-fold that of March.
Meteorologist Eric Leister contributed to this story.

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Snow for New York State, Part of New England


There is a chance that a bit of snow could coat the grass and flowers springing up in the coming days in part of the Northeast. (Photos.com image)
By , Expert Senior Meteorologist
Mar 30, 2012; 7:08 AM ET
Big temperature swings are no stranger to March and neither is snow following unusual warmth in the Northeast.
Mother Nature will try to sneak some snow in before the end of the month over portions of the mid-Atlantic that experienced temperatures 30 degrees above normal last week.
A storm working to produce severe thunderstorms over the Ohio Valley today will bring a dash of snow to part of the Great Lakes, northern mid-Atlantic and New England during the first part of the weekend.
Today over northern Michigan, some wet snow will try to mix in.
Farther east tonight into the first thing Saturday, up to few inches of snow can fall on non-paved surfaces of upstate New York into the Berkshires of western Massachusetts and northwestern Connecticut because the air will have a few more roots and will avoid the sun's energy,
Across upstate New York, the bulk of the snow is likely to be bounded by the Thruway and the Southern Tier Expressway in central and eastern areas.
Wet snow can mix in as far south as the mountains of the northern tier of Pennsylvania, the Poconos and the hills of northwestern New Jersey and as far east as Boston.
Most paved surfaces are warm this time of the year and especially so due to the unusual conditions during much of the late winter and March. As a result, most of the snow will melt as it falls on paved surfaces, even at night. However, where the snow comes down hard enough and in areas shaded from the sun during the day, there can be some slush for a time.
Some snow has been already falling on portions of New England this week. Bangor, Maine, received a couple of inches of snow from Wednesday afternoon into the early morning hours today. For the New England city, it was already the second snow event of the week. The event this Saturday is likely to slide south of Maine and most of New Hampshire, Vermont and northern upstate New York.
Much of the middle part of the nation will continue to bask in unusual warmth over the next couple of weeks. Interestingly, there will be a tendency for a dip in the jet stream to linger or keep showing up in the Northeast during that time.
As a result, another system may drop across northern upstate New York and northern and central New England with a dose of snow late Sunday into early Monday.
Yet another bout of cold air and perhaps snow showers could affect portions of the Northeast over the Easter weekend.

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Severe Weather to Rattle Ohio Valley


By Matt Alto, Meteorologist
Mar 30, 2012; 4:10 AM ET
Locally severe thunderstorms will affect the Ohio Valley today into this evening.
As of the morning rush hour, the storms have only produced a few instances of pea-sized hail. However, the storms will turn more violent moving into the Ohio Valley as the day progresses.
The thunderstorms will strengthen this afternoon along the cold front as it slices into building warmth and surging moist air.
The storms will eventually morph into a squall line that will progress northwest to southeast throughout the afternoon and into the first half of the night.
Locations from Indiana and western Kentucky eastward into Ohio and portions of West Virginia will be at the greatest risk for severe storms today. This includes the cities of Indianapolis, Louisville, Cincinnati and Columbus.
A few strong storms will skirt southern lower Michigan, southwestern Ontario and the Erie lake shore area.
With very cold air aloft, the primary threat with the strongest storms will be large hail the size of golf balls or greater.
Damaging wind gusts greater than 60 mph will also be possible as gusty winds aloft are transported to the ground in some of the storms. These gusts would be enough to bring down tree limbs and cause brief and spotty power outages.
Although a few isolated tornadoes cannot be ruled-out, the overall tornado threat looks to be rather minimal.
As is the case with all thunderstorms, lightning can strike without warning. When you hear thunder, seek shelter indoors. If you cannot get to your home, business or store, remain in your vehicle.
These storms will also cause hazardous driving conditions on the interstates across the region, including Interstates 65, 70, 71 and 75. Motorists are likely to encounter brief periods of heavy, blinding rain.
Rather stormy weather may be in store for the afternoon rush around Dayton, Cincinnati and Louisville.
The threat for strong storms will continue even after the sun sets this afternoon as the storm system races towards the mid-Atlantic.
Locations from southwestern Pennsylvania, southern Ohio, northern West Virginia and eastern Kentucky are be in line for the potential for severe storms after dark. This includes the cities of Pittsburgh, Charleston and London.
The threat for damaging storms will diminish throughout the course of the night as the storms approach the Appalachians. Meanwhile on the northern fringe of this system, wintry precipitation will fall across parts of upstate New York and southern New England.
Check back with AccuWeather.com throughout the day for the latest on the severe weather threatening the Ohio Valley.

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Thursday, March 29, 2012

Weather Extremes : The Historic Anomalous Temperature Event of March 2012 : Weather Underground

Posted by: weatherhistorian, 9:27 PM GMT on March 23, 2012
The Historic Anomalous Temperature Event of March 2012

What is probably the most extraordinary anomalous heat event in U.S. (and portions of Canada) history has finally begun to slacken at the time of this writing (March 23rd). Never before has such an extended period of temperatures so far above normal been recorded. Here is a summary of some of the statistics so far. To quote what Weather Bureau officials stated in March 1910, "Never since the Weather Bureau was established has there been such an early opening of spring." That event in 1910 has been surpassed this month as the most intense such in our nation's history. As the Caribou, Maine NWS office posted on March 22nd: “TO PUT THINGS IN PERSPECTIVE...THIS WAS A ONCE IN A LIFETIME WARM SPELL FOR MARCH...AND NOT JUST HERE BUT ACROSS MUCH OF THE NORTHERN TIER OF THE U.S.”



A stubborn omega pattern that persisted for almost three weeks across the nation was the cause of the anomalous warmth. Graphic from NWS Milwaukee office.

All-time March Monthly Heat Records Broken

Below is a list of some of the monthly records broken at a selection of sites with long periods of record.

NORTH DAKOTA

Bismarck 81° 3/16 (ties old record several occasions)

SOUTH DAKOTA

Pierre 88° 3/18 (old record 87° several occasions)

A reading of 94° was reported from Winner on 3/18. This is the warmest reading recorded during the heat wave at any location, but short of the South Dakota March record of 96° set at Tyndall in March 1943.

MINNESOTA

Int’l Falls 79° 3/18 (old record 73° on 3/31/1963)





Minnesota’s normally substantial March snow pack completely disappeared over the course of just two weeks from March 8-22. Map graphic from NWS Duluth office.

WISCONSIN

Madison 83° 3/21 (old record 82° several occasions)

Milwaukee 84° 3/21 (old record 83° on 3/20/2012)

Green Bay 82° 3/21 (ties old record on 3/29/1910)

A temperature of 88° may have been recorded at a COOP site near Waupaca on 3/18. If verified this would beat the existing state record for March heat of 86° recorded at Prairie du Chien and Dodge on 3/29/1986.

ILLINOIS

Chicago fell short 1° of record (88° 3/31/1986) with 87° on 3/21

MICHIGAN

Saginaw 87° 3/21 (old record 83° 3/24/1910)


Detroit 86° 3/22 (old record 82° 3/28/1945)

Flint 86° 3/21 (old record 83° 3/22/1938)

Traverse City 87° 3/21 (old record 82° 3/29/1910)

Grand Rapids 87° 3/21 (old record 82° 3/29/1910)

Lansing 86° 3/21 (old record 82° 3/24/1910)

Marquette 81° 3/21 (old record 71° 3/8/2000)

*Marquette’s record heat anomaly is almost beyond belief as can be read in this report. Their 47” snow pack on March 5th melted away to nothing in just two short weeks.

Muskegon 82° 3/21 (old record 80° 3/31/1981)

Sault Ste. Marie 83° 3/21 (old record 75° 3/28/1946)

Alpena 87° 3/21 (old record 80° 3/8/2000)

NOTE: Basically, every site in Michigan broke their March heat record during this event. The list of cities is too long to include all herein. The state record for March was broken at Lapeer on 3/21 when a reading of 90° was measured (previous record was 89°, also at Lapeer in 1910).

INDIANA

Fort Wayne 87° 3/21 (old record 3/24/1910)

South Bend 85° 3/21 (ties 3/31/1981)

OHIO

Cleveland 83° 3/21 (ties old record set in 3/28/1945)

Akron 83° 3/22 (old record 82° 3/24/1910)

Mansfield 84° 3/22 (old record 82° 3/30/1986)

Toledo 85° 3/21 (old record 83° 3/24/1910)

Columbus 85° 3/22 (old record 82° 3/24/1910)

Dayton 86° 3/21 (old record date unknown)

NEW YORK

Buffalo 82° 3/21 (old record 81° 3/28/1945)

VERMONT

Springfield reached 83° on 3/22. One degree short of the state March heat record.

There may have been other records set in Vermont but the NWS historical records for Vermont are practically non-existent. Curiously, Vermont is one of the, if not THE most difficult state in the U.S. to find extreme weather records. Data in this regard only exists for Burlington (which did not break its March heat record—81° on 3/21 and 3/22). The only source for Vermont weather records is David Ludlum’s ‘The Vermont Weather Book’ published in 1985 by the Vermont Historical Society. In this book 84° is listed as the state March heat record (at Bennington 3/29, 1945 and Burlington March 29, 1946—also recorded on March 31, 1998 after the publication of Dr. Ludlum’s book). Perhaps somebody could make this a worthy project! The ‘Northeast Regional Climate Center’ has no climate summaries available for specific stations (aside from a handful of major cities), unlike all the other regional climate centers.

NEW HAMPSHIRE

Berlin 80° 3/22 (tied with 3/30/1998)

First Connecticut Lake 77° 3/22 (old record 73° date NA)

Like Vermont, New Hampshire is very difficult to research extreme weather records. However, the famous heat day of March 31, 1998 probably stands clear of most records yet measured so far this March at any location. For instance, it was 89° at Concord, Durham, and Greenland on that day.

MAINE

Caribou 75° 3/21 (old record 73° 3/30/1998)

Houlton 79° 3/21 (old record 72° 3/30/1998)

Bangor 84° 3/22 (old record 79° 3/29/1946)

CANADA

Historical weather records for March heat were smashed over a large portion of eastern Canada. Here are a few of the highlights:

Ottawa, Ontario 27.4°C (81.3F°) 3/21 (old record 26.7°C/80.1°F 3/29/1946

Windsor, Ontario 27.0° (80.6F°) 3/21 (old record 26.6°C/79.9°F 3/28/1945)

Kapuskasing, Ontario 26.2°C (79.2F°) 3/20 (old record 19.4°C/66.9° 3/25/1945)

Winnipeg, Manitoba 24.0°C (75.2°F) 3/19 (old record 23.3°C/73.9°F 3/27/1946)

Montreal, Quebec 25.8°C (78.4F°) 3/21 (old record 25.6°C/78.1°F 3/28/1945)

Quebec City, Quebec 18.3°C (64.9F°) 3/21 (old record 17.8°C/64.0°F 3/30/1962)

St. John, New Brunswick 27.2°C (81.0F°) 3/21 (old record 16.8°C/62.2°F 3/29/1999)

Halifax, Nova Scotia 27.2°C (81.0°F) 3/22 (old record 25.6°C/78.1°F 3/31/1998)

At St. John this March record was warmer than their all-time April monthly heat record!

Western Head, Nova Scotia recorded 29.2°C (84.6°F) on 3/22, the warmest temperature ever recorded in March in Nova Scotia and the 3rd warmest March temperature on record for all of Canada. It surpassed its previous daily record high of 10.6°C (51.1°F) by an astonishing 18.6°C (33.5°F)!

Temperature Anomalies and Duration of Heat Wave

Impressive as all the specific temperature records broken listed above may be, it was the persistence of the record warmth and the amazing departures from normal seasonal temperatures that were the most notable aspect of this heat event.

International Falls, Minnesota broke or tied its daily record maximum temperatures for an amazing 10 consecutive days from March 13-22. This is the longest such stretch at a site with 100 years of record that I am aware of. The previous record length was at Tulsa, Oklahoma with a 9-day consecutive stretch of daily record highs June 2-10, 1911. The old Tulsa record was also matched by Chicago, Illinois where daily high records were broken or tied from March 14-22:



Note all the record warm daily lows. This is another remarkable aspect of the March heat event, not just in Chicago but everywhere else in the affected region as well. Table from NWS Chicago office.

Fort Wayne and South Bend, Indiana also broke their daily high records for 9 consecutive days. The departure from normal was simply astounding. On March 21st Traverse City, Michigan averaged 42° above normal with a daily high/low of 87°/62°. That date’s average is 42°/23°. The low temperature of 62° was 4° warmer than the previous record dailyhigh temperature! Other examples of the daily lows breaking or tying their previous record daily highs are listed inposted on March 22.

Pelston, Michigan seems to have taken the cake so far as having the single most anomalous departure from normal of any site during the heat wave when it was 44° above average on March 21st.

The other extraordinary element of the heat event is that it began during the first half of the month of March. Virtually every weather station from the Dakotas to New England in the northern third of the nation recorded their warmest temperatures for so early in the season ever measured. Madison, Wisconsin recorded 82° on March 15th, a full two weeks earlier than its previous first 80° reading (March 29, 1910). Since records at Madison began in 1869 there have only been 10 days with 80°+ temperatures during March. Of those, 5 of them occurred this March! This is comparable to the cool July of 2009 when Madison had just seven 80°+ days and a high of 82° that month. It reached 83° in Madison this March.

In another week or so we will be able to look at the monthly March data for the U.S. and begin to tally the list of all the cities that have recorded their warmest March on record. It is bound to be an impressive list. Here is how the nation has fared for the 30 days ending on March 22 so far:



Christopher C. Burt
Weather Historian


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Dr. Jeff Masters' WunderBlog : February 2012 the globe's 22nd warmest; record Hawaii hailstone confirmed : Weather Underground

By Dr. Jeff Masters

Published: 2:09 PM GMT on March 28, 2012
February 2012 was the globe's 22nd warmest February on record, according to the National Oceanic and Atmospheric Administration's National Climatic Data Center (NCDC). Global temperatures were the 15th warmest on record according to NASA. It was the coolest February since 1994, and the coolest month, relative to average, since January 2008. The relatively cool temperatures were due, in part, to the on-going La Niña event in the Eastern Pacific, which has brought a large amount of cool water to the surface. February 2012 global land temperatures were the 37th warmest on record, and ocean temperatures were the 12th warmest on record. Global satellite-measured temperatures for the lowest 8 km of the atmosphere were colder than average, the 7th or 13th coldest in the 34-year record, according to Remote Sensing Systemsand the University of Alabama Huntsville (UAH). February temperatures in the stratosphere were the coldest on record. We expect cold temperatures there due to the greenhouse effect and to destruction of ozone due to CFC pollution. Snow cover during February varied dramatically depending on which hemisphere you were in. Eurasia had its third largest snow cover extent in the 46-year period of record, while North America had its fourth lowest. As seen in Figure 1, much of North America and Siberia were much warmer than average, while Europe was considerably colder than average. Wunderground's weather historian, Christopher C. Burt, has a comprehensive post on the notable weather events of February in hisFebruary 2012 Global Weather Extremes Summary.


Figure 1. Departure of temperature from average for February 2012. Image credit: National Climatic Data Center (NCDC) .

La Niña weakens, almost gone
A borderline weak La Niña event continues in the equatorial Pacific, where sea surface temperatures were approximately 0.5°C below average during February and the the first half of March. NOAA's Climate Prediction Center forecasts that La Niña will be gone by the end of April. The majority of the El Niño computer models predict neutral conditions for this fall, during the August - September - October peak of hurricane season, though 32% of the models predict an El Niño will develop. El Niño conditions tend to decrease Atlantic hurricane activity, by increasing wind shear over the tropical Atlantic.

February Arctic sea ice extent fifth lowest on record
Arctic sea ice extent was at its fifth lowest extent on record in February, according to the National Snow and Ice Data Center. Continuing the pattern established in January, conditions differed greatly between the Atlantic and Pacific sides of the Arctic. On the Atlantic side, especially in the Barents Sea, air temperatures were higher than average and ice extent was unusually low. February ice extent for the Barents Sea was the lowest in the satellite record, due to air temperatures that ranged from 4 - 8°C (7 - 14°F) above average at the 925 mb level (about 3000 feet above sea level). In contrast, on the Pacific side, February ice extent in the Bering Sea was the second highest in the satellite record, paired with air temperatures that were 3 to 5 degrees Celsius (5 to 9 degrees Fahrenheit) below average at the 925 mb level. Satellite sea ice records date back to 1979.


Figure 2. Record-setting hailstone from the Hawaii 'supercell' thunderstorm that hit the Hawaiian island of Oahu on March 9, 2012. Image credit: NOAA/National Weather Service.

Huge hailstone sets Hawaii record
A hailstone with the diameter of roughly that of a grapefruit that hit Oahu on March 9, 2012, has been confirmed as the largest hailstone on record for the state of Hawaii, according to NOAA. The record-setting hailstone was dropped by a “supercell” thunderstorm on the windward side of Oahu. There were numerous reports of hail with diameters of 2 to 3 inches and greater. Hail the size of a penny (diameter of 3/4 inch) or quarter (diameter of one inch) has been reported in Hawaii only eight times since records began, and there is no record of hail larger than 1 inch in diameter. Hail the size of golf balls and baseballs can only form within intense thunderstorms called supercells. These supercells need warm, moist air to rise into progressively colder, drier air, as well as winds changing direction and increasing speed with increasing height off the ground. For both sets of conditions to exist at the same time in Hawaii is extremely rare, but that did occur on March 9. Conditions that day were ideal for a supercell to form, and the storm looked very much like supercell thunderstorms common in the Central U.S. during spring. Supercells can also produce tornadoes, another rarity in Hawaii. The same hail-producing supercell produced a confirmed EF-0 tornado with winds of 60-70 mph in Lanikai and Enchanted Lakes on Oahu.

Jeff Masters

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