The SPC is forecasting ...severe thunderstorms expected over parts of the southeast us this afternoon and tonight.... Please read the latest public statement about this event.
| 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 051945 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0245 PM CDT MON SEP 05 2011 VALID 052000Z - 061200Z ...THERE IS A MDT RISK OF SVR TSTMS LATE THIS AFTN AND EVE ACROSS PARTS OF EASTERN ALABAMA THROUGH WESTERN AND NORTH CENTRAL GEORGIA... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK ACROSS A LARGE PORTION OF THE EASTERN GULF AND SOUTH ATLANTIC COAST STATES... ...20Z UPDATE... NO SUBSTANTIVE CHANGES HAVE BEEN MADE TO THE PRIOR OUTLOOK...EXCEPT TO ACCOUNT FOR THE CONTINUED PROGRESSION OF THE SURFACE LOW CENTER...WHICH HAS MIGRATED NORTH OF MOBILE BAY...AND APPEARS LIKELY TO TURN NORTH NORTHEASTWARD ACROSS EASTERN ALABAMA LATE THIS AFTERNOON AND EVENING. PRESSURE FALLS CONTINUE NEAR THE LOW CENTER...WITH AT LEAST SOME FURTHER INCREASE IN LOW-LEVEL FLOW AND SHEAR TO ITS EAST POSSIBLE. THIS PROBABLY WILL MAINTAIN THE RISK FOR TORNADOES INTO/THROUGH THE NIGHT ACROSS THE PIEDMONT OF GEORGIA...PERHAPS INTO THE CAROLINAS. WITH THE DEVELOPMENT OF A DRY SLOT...ASSOCIATED WITH MID-LEVEL SUBSIDENCE NOSING AROUND THE EASTERN PERIPHERY OF THE CYCLONIC CIRCULATION...SEVERE POTENTIAL MAY BEGIN TO DIMINISH ACROSS MUCH OF EASTERN ALABAMA AS EARLY AS 00-03Z...AND MUCH OF WESTERN GEORGIA BY 06Z. ..KERR.. 09/05/2011 .PREV DISCUSSION... /ISSUED 1129 AM CDT MON SEP 05 2011/ ...SERN STATES... VORTICITY MAXIMUM OVER SRN MS/ERN LA WILL LIFT NEWD THROUGH AL/GA TODAY IN ADVANCE OF UPSTREAM IMPULSE DIGGING SEWD INTO THE LOWER MS VALLEY. WHILE THE FORMER WILL WEAKEN/DE-AMPLIFY OVER THE CNTRL APPALACHIANS TONIGHT...DEEP ASCENT WILL BE MAINTAINED ACROSS THE REGION BY AGEOSTROPHIC CIRCULATION ATTENDANT TO ENTRANCE REGION OF UPPER-LEVEL JET LIFTING NWD FROM THE CNTRL APPALACHIANS INTO LOWER GREAT LAKES. AT THE SURFACE...MID MORNING MESOANALYSIS SHOWED LOW PRESSURE CENTERS N OF GPT AND OVER W-CNTRL AL WITH AN INTENSIFYING BAROCLINIC ZONE EXTENDING NEWD ALONG THE APPALACHIANS INTO WRN VA. THIS BOUNDARY IS EXPECTED TO REMAIN QUASI-STATIONARY THROUGH THE D1 PERIOD WITH THE SURFACE LOWS CONSOLIDATING AND DEVELOPING SLOWLY NEWD ALONG IT...REACHING NWRN GA BY 06/12Z. MEANWHILE...TRAILING COLD FRONT WILL CONTINUE SEWD THROUGH THE CNTRL GULF STATES. THE COMBINATION OF WARM-CORE...HYBRID SYSTEM AND WIDESPREAD CLOUDS WILL TEND TO LIMIT THE DEGREE OF AIR MASS DESTABILIZATION ACROSS THE WARM SECTOR TODAY WITH MLCAPE VALUES GENERALLY REMAINING AOB 1000-1500 J/KG. BUT...GIVEN THE MOIST...UNCAPPED ENVIRONMENT AND BROAD ASCENT ACROSS THE WARM SECTOR...EXPECT MULTIPLE BANDS OF TSTMS TO SPREAD NEWD THROUGH CNTRL/ERN AL AND WRN/CNTRL GA. STRENGTHENING/BROADENING 40-50+ KT SLY FLOW IN THE 850-500 MB LAYER WILL RESULT IN MORE THAN SUFFICIENT VERTICAL SHEAR FOR SUPERCELLS AND LEWP STRUCTURES CAPABLE OF TORNADOES AND DAMAGING WINDS. THOUGH INSTABILITY WILL DECREASE WITH TIME TONIGHT...MODEST LARGE-SCALE FORCING AND STRENGTHENING VERTICAL SHEAR WILL SPREAD NEWD INTO THE CAROLINA PIEDMONT...SUGGESTING A CONTINUED THREAT FOR A COUPLE TORNADOES AND DAMAGING WIND GUSTS. ...NEW ENGLAND AND MID ATLANTIC... UPLIFT ALONG COLD FRONT MAY FOSTER WIDELY SCATTERED TSTMS THIS AFTERNOON WITHIN A MODESTLY SHEARED ENVIRONMENT PRESENT IN ADVANCE OF NRN STREAM TROUGH MOVING INTO THE LOWER GREAT LAKES. THOUGH THE BOUNDARY LAYER REMAINS QUITE MOIST...WIDESPREAD CLOUDS WILL LIMIT AIR MASS DESTABILIZATION AND THE POTENTIAL FOR A MORE ROBUST SEVERE WEATHER THREAT. NONETHELESS...ISOLATED OCCURRENCES OF DAMAGING WINDS AND PERHAPS A BRIEF TORNADO WILL BE POSSIBLE WITH DIURNAL TSTM DEVELOPMENT. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z