Twin States Weather Blog

Severe Weather Outbreak Likely...

**1:21 PM: EDITED TIMING OF SEVERE WEATHER**

* Warm, moist air will continue north out of the Gulf of Mexico tonight and tomorrow. As this is occurring, a deep trough will spin up and deepen a surface low in the Plains. Extremely favorable wind shear and ample instability will set the stage for an outbreak of severe thunderstorms and tornadoes tomorrow.

* In my opinion, the key to the severity of this event involves sunshine. If the sun comes out tomorrow morning, we could see a memorable tornado outbreak across Mississippi and Alabama. If the sun does not come out at all, we will still see severe weather, but the magnitude of the event would not be as great.

* The Storm Prediction Center has outlooked all of our area under a Moderate Risk for severe weather. We are also under a 45% "hatched" area, this is very rare and indicates that the SPC believes this could be a rather significant outbreak of severe weather and tornadoes.

* Here are some excerpts from the SPC's discussion:

MS/AL
MAXIMIZED SFC HEATING WILL COINCIDE WITH OPTIMAL VERTICAL SHEAR AND
INCREASING LOW LEVEL MOISTURE TO MAXIMIZE RISK FOR SVR
HAIL...WIND...AND IN PARTICULAR...SIGNIFICANT TORNADOES.  ALTHOUGH
MIDLEVEL LAPSE RATES MAY REMAIN AOB 7 DEG C/KM...SFC DEW POINTS
SHOULD INCREASE INTO 60S F ALONG AND S OF MARINE FRONT.  THIS WILL
SUPPORT POCKETS OF MLCAPES 500-1000 J/KG...WHERE BREAKS IN CLOUD
COVER OCCUR BEHIND EARLY-PERIOD PRECIP ASSOCIATED WITH STRONG WAA
REGIME.  THIS WILL BE SUITABLE FOR TORNADIC SUPERCELLS AND BOWING
LINE SEGMENTS IN ENVIRONMENT CHARACTERIZED BY LARGE LOW LEVEL
HODOGRAPHS -- 0-1 KM SRH AOA 300 J/KG -- AND 0-6 KM SHEAR EXCEEDING
60 KT.  A FEW LONG-LIVED AND LONG-TRACK SUPERCELLS ARE POSSIBLE
GIVEN STRENGTH OF DEEP-LAYER KINEMATIC PROFILES AND RAPID NEWD
SPREAD OF FAVORABLE INFLOW-LAYER MOISTURE.

* Let's talk specifics:

When: This is complex...A first round of elevated thunderstorms will affect us overnight, between midnight at 6 am...The main threat with those is hail, and most of them will stay below severe limits.

The more substantial threat arrives between roughly 10:00 am and 6:00 pm tomorrow. That's when we will see the possibility of tornadoes.

Where: Area-wide (Although I do think the greatest threat could very well evolve in Alabama)

Primary Threat: Tornadoes and Damaging Winds

What To Do: Stay close to a good source of weather information tomorrow morning...Be sure your NOAA weather radio is functioning properly, and discuss your plan of action in the event of a tornado warning with your family ahead of time.

* We will have more on the threat of severe weather through the day today and tonight...

Labels: Severe Weather

posted by WTOK Weather Staff @ 11:48 AM