| Categorical Graphic |
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| Probabilistic Tornado Graphic |
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| Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
| Probabilistic Damaging Wind Graphic |
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| Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
| Probabilistic Large Hail Graphic |
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| Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
SPC AC 111251 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0751 AM CDT SAT AUG 11 2012 VALID 111300Z - 121200Z ...NO SVR TSTM AREAS FORECAST... AN UPPER LOW OVER LOWER MI/ONTARIO WILL CONTINUE TO AFFECT THE NORTHEAST STATES TODAY...WHILE A PROGRESSIVE SHORTWAVE TROUGH OVER THE NORTHERN ROCKIES TURNS SOUTHEAST AND AFFECTS THE CENTRAL HIGH PLAINS. WHILE THE THREAT OF ORGANIZED SEVERE STORMS APPEARS RATHER LOW TODAY...SEVERAL AREAS MAY SEE LOCALLY STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING. ...NORTHEAST... MORNING VISIBLE SATELLITE IMAGERY SHOWS FEWER CLOUDS OVER THE NORTHEAST STATES TODAY COMPARED TO YESTERDAY. THIS WILL INCREASE THE LIKELIHOOD OF AT LEAST POCKETS OF STRONGER DAYTIME HEATING AND DESTABILIZATION. MODEL SOUNDINGS FOR LATER TODAY SUGGEST EARLY AFTERNOON MLCAPE VALUES OVER 1000 J/KG FROM CENTRAL/EASTERN NY INTO WESTERN NEW ENGLAND. SCATTERED THUNDERSTORMS WILL LIKELY FORM ALONG THIS CORRIDOR AS A MID LEVEL SHORTWAVE TROUGH OVER SOUTHEAST OH APPROACHES THE REGION. MID LEVEL LAPSE RATES ARE MARGINAL FOR ROBUST UPDRAFTS. HOWEVER...SUFFICIENT DEEP LAYER EFFECTIVE SHEAR AND SOME DRY AIR ALOFT MAY POSE A RISK OF A LOCALLY GUSTY OR DAMAGING WIND GUSTS IN THE STRONGEST STORMS. SMALL HAIL MAY ALSO OCCUR OVER PARTS OF NY WHERE SLIGHTLY COOLER MID LEVEL TEMPERATURES ARE EXPECTED. ...VA/CAROLINAS... 12Z RAOBS SHOW SUBSTANTIAL MOISTURE IN PLACE ACROSS MUCH OF THE SOUTHEAST STATES INCLUDING SC/NC/VA. BROKEN CLOUDS WILL SLOW THE DAYTIME HEATING PROCESS...BUT MODERATE INSTABILITY SHOULD DEVELOP BY MID/LATE AFTERNOON WITH MLCAPE VALUES AROUND 2000 J/KG. FORCING FOR ASCENT WILL BE RATHER WEAK...PROVIDING UNCERTAINTY REGARDING COVERAGE/INTENSITY OF STORMS. HOWEVER...RATHER STRONG LOW/MID LEVEL FLOW SUGGESTS SOME RISK OF GUSTY/DAMAGING WINDS IN THE STRONGER CELLS TODAY. CLOUD TRENDS WILL BE MONITORED THROUGH THE MORNING FOR GREATER DESTABILIZATION THAN CURRENTLY EXPECTED WHICH COULD WARRANT AN UPGRADE TO SLIGHT RISK. ...CENTRAL HIGH PLAINS... A RATHER STRONG AND PROGRESSIVE SHORTWAVE TROUGH OVER THE NORTHERN ROCKIES IS FORECAST TO TRACK SOUTHEASTWARD AND AFFECT THE CENTRAL HIGH PLAINS LATER TODAY. STRONG HEATING WILL OCCUR AHEAD OF THIS FEATURE OVER PARTS OF SD/NEB/KS AND EASTERN CO...RESULTING IN STEEP LOW LEVEL LAPSE RATES. LOW LEVEL MOISTURE WILL BE SOMEWHAT LIMITED WITH AFTERNOON SURFACE DEWPOINTS LIKELY TO REMAIN IN THE 50S. HIGH-BASED THUNDERSTORMS ARE EXPECTED TO FORM OVER PARTS OF EASTERN WY/CO DURING THE AFTERNOON AND SPREAD INTO WESTERN SD/NEB/KS DURING THE EVENING. MODEL SOLUTIONS ARE BECOMING MORE AGGRESSIVE WITH THUNDERSTORM COVERAGE OVER THIS REGION. IF THIS TREND IS CORRECT...THE THREAT OF COLD POOL DEVELOPMENT AND A MORE ORGANIZED THREAT OF DAMAGING WINDS MAY ALSO MATERIALIZE. THIS AREA WILL ALSO BE MONITORED IN LATER OUTLOOKS FOR POSSIBLE UPGRADE. ...SWRN AZ/SERN CA... SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP TODAY OVER THE MOUNTAINS OF SOUTHEAST AZ. RATHER STRONG EASTERLY FLOW ALOFT MAY HELP A FEW OF THESE STORMS TO PROPAGATE WESTWARD INTO THE LOWER DESERTS AFTER DARK. LOCALLY DAMAGING WINDS WOULD BE THE MAIN THREAT. ..HART/DEAN.. 08/11/2012 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z