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Posted at 2:05 PM ET, 03/ 3/2011

Active U.S. spring severe weather season likely

By Jason Samenow
Tornado. Source: NOAA.

The predictions of several independent long-range forecast outlets support a very busy severe weather season across the middle portion of the U.S. from east of the Rockies to near the East Coast. This means an enhanced risk of thunderstorms capable of producing damaging winds, large hail, and tornadoes.

In its spring outlook issued this morning, State College, Pa.-based AccuWeather warned severe weather would be "more active than normal."

"The zone of greatest concern for above-normal severe thunderstorm activity this spring ... lies from Arkansas and Missouri into Tennessee and Kentucky, areas that have been targeted already by several severe outbreaks the last week of February," wrote AccuWeather.

While NOAA's Climate Prediction Center [CPC] does not issue a spring thunderstorm outlook, its 90-day temperature outlook would suggest the kind of elevated north to south temperature contrast necessary to fuel big storms in the transition zone.

As Paul Yeager, weather blogger for America Online, described:

[CPC's] forecast for March through May calls for temperatures that are likely to be warmer than average in the southern part of the country and cooler than average in the northern part of the country. Thus, the contrast will be more intense than in a typical year.

Yeager also noted the 2011 severe weather season is off to a fast start:

Through Monday, there have been about 800 preliminary reports of damage from severe weather in 2011, more than 2.5 times greater than the number through the first two months of 2010. January and February 2010 generated 307 reports, including just one February tornado.

Meteorologist Dave Tolleris, who forecasts for commercial purposes, released his spring outlook yesterday - headlining his Powerpoint presentation: "Much above normal severe weather season." Similar to NOAA's CPC, Tolleris is generally forecasting colder than normal temperatures across the northern tier of the U.S. and persistently warm temperatures relative to average across the Deep South. AccuWeather's spring temperature forecast shows the same general pattern.

AccuWeather's spring temperature forecast.

So there is strong agreement in the temperature pattern predicted by both commercial and government outlets. This is a reflection of the La Nina pattern expected to persist through the Spring, even if its intensity wanes as some computer models suggest.

During La Nina, a strong northern jet stream brings reinforcing shots of cold air to the northwest and north central portions of the U.S. while a ridge of subtropical high pressure to the southeast pumps warm air over the South. And it's the places caught in the middle that have a heightened risk of severe thunderstorms.

Will the heightened risk of severe storms extend to the mid-Atlantic and D.C. metro region, which, from the look of things, seem to be a bit south and east of the biggest temperature contrast and storm dynamics?

Ken Reeves, Director of Forecasting Operations at AccuWeather, told me: "...the dynamics [supporting the enhanced risk of severe weather in the middle Mississippi Valley and into portions of the Tennessee and Ohio Valleys] will change and the reasons for the higher risks farther west will not necessarily translate eastward, especially the farther east you go. I currently do not see any stand out factors that point to a higher or lower likelihood for severe weather around Washington D.C."

While some of the best dynamics for storms characteristically pass to the mid-Atlantic's west and northwest during La Nina, the warm, unstable air ahead of such systems can still fuel big storms here. For example, several severe weather outbreaks occurred in the spring of 2008, the last La Nina event.

See these posts recapping storms from 2008:

Inside the Suffolk, Va. Tornado
Recap: June 4 Severe Weather Outbreak
Severe Storms Strike Again

We'll take a closer look at the La Nina/severe weather link in the mid-Atlantic in a future data-driven post...

By Jason Samenow  | March 3, 2011; 2:05 PM ET
Categories:  Latest, Long-range outlooks, Thunderstorms, U.S. Weather  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: Was this winter really that windy in Washington?
Next: PM Update: Friday temps inch upward


Any snow enthusiasts out there who could turn to spring thunderstorms (hopefully not severe) as a source of enjoyment? Regret the season transitioned earlier than some of you snow lovers would have liked...

Posted by: Camden-CapitalWeatherGang | March 3, 2011 3:23 PM | Report abuse

i enjoy thunderstorms (as well as hail, heat waves and, yes, the occasional hurricane) - but i'm more particular about WHEN they come than i am with snow. i'll happily take a snow storm any time - since they happen so rarely. but, with t-storms, i'd rather have them all happen before the pool opens or after it closes, when i'm not golfing, when i'm not at an outdoor happy hour, or playing tennis or hiking - as i dislike having the important plans altered by t-storms.... so, before scheduling any t-storm this summer, please check with me. thanks.

jason, CWG,
you said the la nina pattern is expected to continue through spring, albeit w/waning intensity. is there any way of knowing whether next winter will be el nino or la nina?

Posted by: walter-in-fallschurch | March 3, 2011 4:09 PM | Report abuse

Oh my. I don't know what to do!! With the economy, democrats run amok, the situation in the Arab world, etc., I don't know if my nerves can stand all this upcoming severe weather. Can anyone advise me?

Posted by: rpcv84 | March 3, 2011 4:33 PM | Report abuse

Don't worry, folks.

If the sources of these forecasts are any indication of their accuracy, our area will have a normal, semi-calm spring, with just enough rain and sun to put us in a good mood for fun and adventure.

Posted by: jismquiff | March 3, 2011 5:06 PM | Report abuse

I like thunderstorms almost as much as snow. they really get my blood pumping:)

Posted by: snowlover31 | March 3, 2011 6:02 PM | Report abuse

My adrenalin pumps when I here there is going to be severe weather in all seasons. I'm pumped about the later part of spring and summer. Hopefully we get strong to severe thunderstorms with hail, damagingwinds, and tornadoes. Hopefully this happens later in the spring and summer months.

Posted by: weatherfreak1994 | March 3, 2011 6:24 PM | Report abuse


Nobody has any real idea what the ENSO phase will be next winter. If I had to guess, weak La Nina or neutral.

Posted by: Jason-CapitalWeatherGang | March 3, 2011 7:41 PM | Report abuse

I like thunderstorms almost as much as snow. they really get my blood pumping:)

Posted by: snowlover31 | March 3, 2011 6:02
You must be a woman. Any man would correctly write that a hot blonde in stilettos and a tight mini gets the blood and more pumping - not a thunderstorm or snow...

Posted by: rpcv84 | March 3, 2011 7:43 PM | Report abuse

Oh goody. I'll have to fly right over those thunderstorms in May on my way to Dallas. Guess I'll put in the order now for the tranquilizers.

Posted by: electromd1 | March 3, 2011 8:09 PM | Report abuse

@rpcv84 i dont find your comment very ammusing.
but you have a point.

Posted by: snowlover31 | March 4, 2011 6:29 AM | Report abuse

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