The SPC is forecasting ...severe thunderstorms expected over parts of the lower mississippi river valley and arklatex vicinity this afternoon and tonight.... Please read the latest public statement about this event.
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SPC AC 231629 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1129 AM CDT FRI APR 23 2010 VALID 231630Z - 241200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS THE ARKLATEX AND LOWER MS RIVER VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL/SOUTHERN PLAINS TO THE LOWER/MIDDLE MS RIVER VALLEY... ...ARKLATEX TO MID-SOUTH/LOWER MS RIVER VALLEY THIS AFTERNOON AND EVENING... WATER VAPOR LOOPS SHOW A LARGE UPPER TROUGH/BASAL UPPER JET STREAK ACROSS THE SOUTHERN ROCKIES/NORTHERN MEXICO...WITH SEVERAL LOW AMPLITUDE DISTURBANCES AIDING STRONG/SEVERE TSTM DEVELOPMENT ACROSS THE ARKLATEX TO LOWER MS RIVER VALLEY THIS AFTERNOON. SUCH DEVELOPMENT SHOULD CONTINUE TO INCREASE/EXPAND EAST-NORTHEASTWARD THROUGH THE AFTERNOON...WITH AN INCREASINGLY MOIST BOUNDARY LAYER AND AMPLE DEEP LAYER/LOW LEVEL SHEAR WELL-SUPPORTIVE OF SUPERCELLS CAPABLE OF TORNADOES...A FEW OF WHICH COULD BE STRONG. REFERENCE TORNADO WATCH 79 AND ASSOCIATED/SUBSEQUENT MESOSCALE DISCUSSIONS FOR THE LATEST DETAILS. ...NEB/KS/MO THIS AFTERNOON... MODEL GUIDANCE IS IN AGREEMENT THAT A NARROW AXIS OF A MODERATE INSTABILITY WILL DEVELOP THIS AFTERNOON ALONG/AHEAD OF COLD FRONT FROM CENTRAL/SOUTHEAST NEB INTO EASTERN KS AND WESTERN MO. SUFFICIENT SURFACE HEATING AND DYNAMIC COOLING ALOFT WILL HELP TO ERODE THE CAP AND LEAD TO THE DEVELOPMENT OF SCATTERED THUNDERSTORMS BY MID/LATE AFTERNOON. ORIENTATION OF DEEP-SHEAR VECTOR NORMAL TO THE BOUNDARY SUGGEST THE DISCRETE STORM INITIATION IS LIKELY...WITH SUFFICIENT LOW LEVEL SHEAR FOR A RISK OF A FEW TORNADOES TODAY. OTHERWISE...SUPERCELLS CAPABLE OF VERY LARGE HAIL AND DAMAGING WINDS ARE EXPECTED FOR SEVERAL HOURS THIS EVENING. ...CENTRAL HIGH PLAINS THIS AFTERNOON... WEST OF THE LOWER/MIDDLE MO RIVER VALLEY...OTHER LOW-TOPPED STRONG/SEVERE TSTMS MAY DEVELOP ON THE PERIPHERY OF THE DRY SLOT AND IN VICINITY OF THE NEARLY VERTICALLY STACKED CYCLONE ACROSS THE CENTRAL HIGH PLAINS. SEVERE HAIL AND ISOLATED TORNADOES WILL BE POSSIBLE. ...EAST TX/SOUTHEAST OK TO ARKLATEX TONIGHT... THE MAIN SOUTHERN STREAM SHORTWAVE TROUGH /WITH ATTENDANT 100+ KT UPPER JET STREAK/ CURRENTLY OVER THE SOUTHERN ROCKIES/NORTHERN MEXICO IS FORECAST TO BECOME MORE NEUTRAL TO NEGATIVELY TILTED AND PIVOT INTO TX/OK LATE TONIGHT. THIS IS LIKELY TO RESULT IN THE RAPID DEVELOPMENT OF INTENSE THUNDERSTORMS ALONG THE DRYLINE/OVERTAKING COLD FRONT ACROSS EAST TX/SOUTHEAST OK TO THE ADJACENT ARKLATEX TONIGHT...WITH STORMS RACING EASTWARD TOWARD THE LOWER MS VALLEY EARLY SATURDAY MORNING. LARGE HAIL...DAMAGING WINDS...AND TORNADOES WILL ALL BE POSSIBLE WITH THESE STORMS. THIS ACTIVITY WILL LIKELY BE THE START OF ANOTHER VERY ACTIVE SEVERE WEATHER DAY ACROSS THE LOWER MS RIVER VALLEY ON SATURDAY. ..GUYER/GRAMS.. 04/23/2010 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z