The SPC is forecasting ...severe thunderstorms expected over parts of the lower mississippi valley today.... Please read the latest public statement about this event.
| Categorical Graphic |
|---|
|
| Probabilistic Tornado Graphic |
 |
 |
| Probabilistic Damaging Wind Graphic |
 |
 |
| Probabilistic Large Hail Graphic |
 |
 |
SPC AC 020601 DAY 1 CONVECTIVE OUTLOOK RESENT 1 NWS STORM PREDICTION CENTER NORMAN OK 0101 AM CDT FRI MAY 02 2008 VALID 021200Z - 031200Z ...THERE IS A MDT RISK OF SVR TSTMS FROM EXTREME NRN LA...TO CNTRL IL... ...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN TX TO THE SRN GREAT LAKES... ...POTENTIAL FOR SIGNIFICANT SEVERE WEATHER ACROSS THE MS VALLEY TODAY... STRONGEST BELT OF MID LEVEL FLOW...H5 TO 90KT...WILL ROTATE AROUND THE BASE OF A VERY STRONG TROUGH INTO MO LATER THIS MORNING AS UPPER LOW PIVOTS SWD AND DEEPENS OVER SCNTRL NEB. THIS DEEPENING PROCESS WILL ENCOURAGE STRENGTHENING OF LLJ ACROSS THE LOWER-MID MS VALLEY REGION WHERE MOISTURE/INSTABILITY RECOVERY WILL CONTINUE AHEAD OF COLD FRONT. EARLY THIS MORNING A SQUALL LINE WAS BEGINNING TO ORGANIZE ALONG SHARP COLD FRONT FROM ERN KS...SWWD INTO CNTRL OK. THIS ACTIVITY SHOULD CONTINUE TO EVOLVE DURING THE PRE-DAWN HOURS AS IT IS SHUNTED SEWD TO A POSITION ROUGHLY FROM WRN MO...SWWD INTO NERN TX BY 02/12Z. ALTHOUGH A SQUALL LINE WILL CERTAINLY BE WELL ORGANIZED AT THE BEGINNING OF THE PERIOD...IT APPEARS DEEP LAYER SHEAR WILL BE MORE THAN ADEQUATE FOR MAINTAINING DISCRETE EMBEDDED SUPERCELL STRUCTURES ALONG THE FORCED LINE. LARGE HAIL AND DAMAGING WINDS SHOULD BE THE PRIMARY SEVERE THREATS WITH THIS FRONTAL BAND...HOWEVER ISOLATED TORNADOES COULD DEVELOP WHERE SUPERCELL STRUCTURES ARE OBSERVED. LATE EVENING MODEL GUIDANCE ALSO SUGGESTS PRE-FRONTAL CONVECTION MAY ACTUALLY DEVELOP WITHIN WARM ADVECTION ZONE FROM NRN LA...NWD INTO SERN MO BY SUNRISE. THERE IS SOME REASON TO QUESTION THIS SCENARIO GIVEN THE INHIBITION NOTED ON 00Z SOUNDINGS ACROSS THIS REGION. HOWEVER...SUSTAINED LIFT DURING THE EARLY MORNING HOURS DOES GIVE CREDENCE TO THIS POSSIBILITY. IF CONVECTION DOES NOT BREAK OUT AHEAD OF MAIN COLD FRONT THEN BOUNDARY LAYER MOISTURE/INSTABILITY RECOVERY WILL BE MUCH GREATER ACROSS AR INTO MO/IL AHEAD OF WIND SHIFT. THIS WILL RESULT IN A MUCH MORE BUOYANT AIRMASS FOR POTENTIALLY TORNADIC SUPERCELL DEVELOPMENT. FORECAST SOUNDINGS ACROSS THIS REGION CERTAINLY FAVOR MULTIPLE CONVECTIVE MODES GIVEN THE STRONG COLD FRONT AND THE POSSIBILITY FOR PRE-FRONTAL STORMS WITHIN THE WARM ADVECTION ZONE. GREATEST THREAT FOR DAMAGING TORNADOES SHOULD OCCUR ALONG AN AXIS FROM SRN AR INTO SRN IL...ESPECIALLY IF BOUNDARY LAYER AIRMASS DESTABILIZES AS EXPECTED. OTHERWISE...DAMAGING WINDS AND HAIL SHOULD ACCOMPANY SEVERE SQUALL LINE AS IT PROGRESSES EWD INTO THE LOWER OH/TN VALLEY REGION LATE. FARTHER NORTH...DEEP SFC LOW SHOULD LIFT NWD ACROSS IA INTO EXTREME SERN MN BY EARLY AFTERNOON. A NARROW WEDGE OF ENHANCED SFC HEATING ACROSS IA APPEARS POSSIBLE BY LATE MORNING. IF THIS OCCURS THEN BOUNDARY LAYER INSTABILITY...SBCAPE TO 1000 J/KG...WILL BECOME SUPPORTIVE OF SUPERCELL STRUCTURES WITHIN STRONGLY SHEARED/FORCED ENVIRONMENT. IF THIS EVOLVES AS MODELS SEEM TO SUGGEST THEN A NARROW AXIS FROM NWRN IL INTO NRN IA AND PERHAPS EXTREME SERN MN WILL HAVE AN INCREASED RISK OF ISOLATED TORNADOES. ..DARROW/CROSBIE.. 05/02/2008 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z