Alabama 811 | Know What's Below.

Waiting to See What Happens

| February 28, 2011 @ 3:32 am | 5 Replies

Tornado watches cover a wide area early on this Monday morning, all the way from Ohio to Arkansas, including the western third of Tennessee and much of Arkansas.

One tornado warning in Ohio right now, along with two severe thunderstorm warnings in Indiana and one in Arkansas.

Thunderstorms are raging across a wide area, from western new York and Pennsylvania through much of Ohio, Indiana, southern Illinois, and Missouri.  Other strong storms were over southwestern Arkansas and northeastern Louisiana. This line segment is approaching northwestern Louisiana right now, moving eastward at about 40 mph.

There is a 1002 millibar low over northwestern Arkansas. This low holds the key to significant severe weather over North and Central Alabama today, as Dr. Tim pointed out in his 1:45 post. (see below) If it intensifies and moves more eastward across Tennessee, winds to the southeast of it will be “backed” meaning they will be more southerly and southeasterly than southwesterly. This imparts more low level spin to the atmosphere and could spell big trouble for places like Nashville and North Alabama north of a line from Muscle Shoals to Cullman to Gadsden.

The SPC folks seem to think so. Here is their convective outlook for today, which has much of North Alabama in the Moderate Risk category and the rest of the state in a Slight Risk, their standard risk category.

Temperatures are too warm over Alabama for 3 a.m. on the last day of February. It is 70F at Jasper, 71F at Tuscaloosa and 69F at Birmingham. It is 75F at Starkville MS. Instabilities are in the 500 j/kg2 range over much of Mississippi and northwestern Alabama, but a significant cap is in place across the region, acting as a lid on the atmosphere.

A few very light showers are ongoing across Alabama at this hour, mainly around Cullman and Decatur, with sprinkles from Birmingham down to Selma. Winds are out of the south, averaging 10-20 mph, with gusts to 25 mph.

For now, the forecast seems to be on track. We will be watching developments to the west. I would anticipate tornado watches for much of Central and North Alabama by midmorning. Damaging winds of 70 mph or greater will be the main threat along with 1 inch or greater hail, with a chance for tornadoes.

The SPC has the 15% tornado probability line down to about Red Bay to Nauvoo to Warrior to Springville to Ragland to Jacksonville line. This is the probability that there will be a tornado within 25 miles of any location in that area. The 10% probability extends down to a line from Millport to Moores Bridge to Bessemer to Childersburg to Woodland in Randolph County. They show the significant tornado potential as far south as Sulligent to Berry to Birmingham to Pell City and Oxford.

So, as Dr. Tim said, have a reliable source of weather information with you at all times today and check current conditions frequently. The key to being ready when severe weather threatens is information and knowing what you will do if a warning is issued. We will have frequent up to th eminute information here, and any time there is a tornado warning in the ABC3340 DMA, continuous long form coverage with James, Jason and Ashley B.

Category: Alabama's Weather, Severe Weather

About the Author ()

Bill Murray is the President of The Weather Factory. He is the site's official weather historian and a weekend forecaster. He also anchors the site's severe weather coverage. Bill Murray is the proud holder of National Weather Association Digital Seal #0001 @wxhistorian

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