Saturday, April 14, 2012

Update on Severe Thunderstorm/Tornado Outbreak for Later Today & Tonight...

A significant outbreak of severe thunderstorms and tornadoes is still expected today and into tonight. The main questions right now are where and when storms will initiate, and what the primary threats will be in a given area and time.

First, as an overview (and this has not changed from my previous post earlier this morning) severe storms including large hail, damaging winds and tornadoes are possible later today and tonight anywhere within the yellow shaded area on this image:

The relative risk of severe weather will increase within the red and lavender colored areas, where the potential for very large hail (greater than 2 inches in diameter), damaging winds in excess of 70 mph and strong to violent tornadoes (some of a long track duration) are possible. 

Thunderstorms are beginning to break out over southwest and west-central Kansas into the Oklahoma panhandle at this hour: well as over central Nebraska:

This acitivty is gradually gaining intensity, but is not particularly well organized at this point.  I would not be surprised to start seeing severe thunderstorm warnings from this activity soon, mainly for hail.  Furthermore, I would expect this activity to become better organized with increasing severe weather potential, including tornadoes, by midday and into this afternoon.

During the afternoon and into this evening, the wind profile will increase throughout the lower and middle atmosphere such that a pronounced threat of tornadoes will develop, some of which could become strong or violent and have a long track.  This threat is highest within the lavender and purple shaded areas with the black hatching as shown on this image:

This threat will initially include the cities of Grand Island, Hastings, Concordia, Salina, Hutchinson, Great Bend, Wichita and Woodward, and will spread East to include Lincoln, Norfolk, Topeka, Emporia, Enid, Ponca City and Oklahoma City by very late afternoon or most likely this evening.

If you live in these or surrounding areas, please pay very close attention to the weather today.  This is a potentially dangerous, life threatening situation for the indicated areas.

Further East Later This Evening and Tonight:
Some question remains as to whether storms will remain discrete with high tornado potential as the activity continues Eastward late this evening and into tonight.  A cold front may catch up with the dryline such that storms form into more of a solid line toward Midnight.  If this takes place, the tornado threat (while not zero) would diminish, and the damaging wind threat would increase.  

Folks living toward the Eastern edges of the severe weather threat area from the above images should treat this as a potential tornado situation for tonight until we can be more confident as to how this aspect of the situation will unfold.  This would include the cities of Omaha, Kansas City and Tulsa.

Even if storms do form into a solid line with lesser tornado potential by tonight, the threat of damaging straight line winds could become quite pronounced (i.e., gusts greater than 70 mph possible over a large area, which could cause significant damage and disrupt power supplies, etc).

It will be very important for folks, especially in the Eastern part of the severe weather outlook area, to have a way to receive severe weather warnings overnight tonight.  See this post for some tips and suggestions.

Make Sure to Be Prepared and Stay Up to Date:
If you live across any of the threat areas described above, please pay attention to the weather today.  Listen to NOAA Weather Radio, local media or another trusted source for later information and warnings.  Make sure that you've re-stocked your severe weather safety kit and have identified your best sheltering option ahead of time, that way you can take quick action when the time comes.

Please check back on the blog throughout the day for updates.  Once storms develop, be sure to also follow my facebook and/or twitter feeds for more frequent updates on specific storm threats as they happen!

If you enjoy reading the blog, please click on the icons below to "Like" my facebook page and/or follow me on twitter. You'll find posts at these locations that aren't always on the blog, especially during rapidly changing weather situations...

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