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DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1050 AM CST MON DEC 19 2011 VALID 201200Z - 211200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF MS/AL/TN... A LEAD SHORTWAVE TROUGH CURRENTLY OVER WEST TX WILL TRACK EASTWARD AND ACROSS THE LOWER MS VALLEY TUESDAY MORNING. THIS SYSTEM WILL BRING WIDESPREAD CLOUDS AND PRECIPITATION TO PORTIONS OF AR/MS/TN. STRONG SOUTHERLY LOW LEVEL WINDS THROUGH THE DAY WILL ALSO HELP TO BEGIN TRANSPORTING GULF MOISTURE NORTHWARD INTO THE REGION. BRIEF SHORTWAVE RIDGING IS LIKELY THROUGH THE EARLY AFTERNOON...BEFORE THE NEXT AND STRONGER UPPER IMPULSE APPROACHES AFTER DARK. COOLING MID LEVEL TEMPERATURES AND DEWPOINTS IN THE UPPER 50S/LOWER 60S WILL RESULT IN AT LEAST MARGINAL CAPE VALUES OVER PORTIONS OF MS/AL/TN WHERE FAVORABLE LOW LEVEL AND DEEP LAYER VERTICAL SHEAR WILL CO-EXIST. ISOLATED STRONG OR EVEN SUPERCELL STORMS WILL BE POSSIBLE TUESDAY EVENING-NIGHT OVER THIS AREA WITH A RISK OF HAIL...GUSTY WINDS...OR A BRIEF TORNADO. THE LACK OF A MORE ROBUST RETURN OF RICH GULF MOISTURE IS THE MAIN LIMITING FACTOR FOR THIS SEVERE WEATHER THREAT. ..HART.. 12/19/2011
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1022 AM CST TUE DEC 20 2011 VALID 201630Z - 211200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... MIDLEVEL LOW OVER NWRN OK WILL GRADUALLY WEAKEN THROUGH THE D1 PERIOD WHILE TRANSLATING NEWD INTO AN INCREASINGLY CONFLUENT FLOW REGIME IN PLACE OVER THE MIDWEST. THIS SYSTEM WILL BE ACCOMPANIED BY A 70-80 KT MIDLEVEL JET STREAK AND A CORRIDOR OF 12-HR HEIGHT FALLS /AT 500 MB/ OF 50-100 M SHIFTING FROM THE OZARK PLATEAU INTO MID MS AND LOWER OH VALLEYS. IN THE LOW LEVELS...OCCLUDED SURFACE LOW OVER CNTRL OK WILL DEVELOP NEWD IN TANDEM WITH THE UPPER SYSTEM...REACHING IL/IND LATE TONIGHT INTO WED MORNING. MEANWHILE...A TRAILING COLD FRONT WILL ADVANCE EWD THROUGH THE MIDDLE AND LOWER MS VALLEY. ...LOWER MS/TN/SRN OH VALLEYS EWD ALONG THE GULF COAST... A PRE-FRONTAL BAND OF TSTMS IS PRESENT THIS MORNING FROM CNTRL LA SWWD INTO THE SHELF WATERS OFF THE MIDDLE TX COAST. THIS ACTIVITY IS LIKELY BEING FORCED BY LOW-LEVEL CONFLUENT FLOW AND GLANCING INFLUENCE OF MIDLEVEL SYSTEM PASSING TO THE NW OF THE REGION. 12Z OBSERVED SOUNDINGS INDICATE THAT AMBIENT ENVIRONMENT IS CHARACTERIZED BY WEAK LAPSE RATES AND BOUNDARY LAYER DEWPOINTS IN THE LOW/MID 60S WITH MLCAPE VALUES OF 500-1000 J/KG. THE NEWD PROGRESSION OF MIDLEVEL SYSTEM AND ASSOCIATED SURFACE LOW WILL RESULT IN THE STRONGER FORCING FOR ASCENT GRADUALLY BECOMING DISPLACED FROM THE MORE MOIST/UNSTABLE BOUNDARY LAYER IN PLACE ACROSS THE LOWER MS VALLEY. AND WHILE MOISTURE WILL INCREASE NWD INTO THE MID SOUTH AND SRN OH VALLEY...WIDESPREAD CLOUDS WILL TEMPER HEATING AND RESULTANT DESTABILIZATION WITH MLCAPE VALUES REMAINING AOB 500 J/KG. CURRENTLY...IT APPEARS THE MARGINAL INSTABILITY WILL BE THE LIMITING INGREDIENT FOR A MORE ROBUST SEVERE WEATHER THREAT LATER TODAY AND TONIGHT E/SE OF SURFACE LOW TRACK FROM NRN MS INTO SRN OH VALLEY. A LOW PROBABILITY RISK FOR DAMAGING WINDS AND TORNADOES REMAINS WARRANTED GIVEN THE RELATIVELY STRONG LOW- AND DEEP-LAYER SHEAR IN PLACE. ELSEWHERE...A SEPARATE BAND OF TSTMS MAY EVOLVE IN CONFLUENT LOW-LEVEL FLOW REGIME OVER THE NERN GULF OF MEXICO BEFORE MOVING INLAND ACROSS THE FL PNHDL INTO SRN AL LATER TODAY INTO TONIGHT. BASED ON CURRENT SATELLITE-DERIVED PW IMAGERY...IT APPEARS THAT THIS ACTIVITY MAY BE ASSOCIATED WITH A PLUME OF HIGHER THETA-E AIR ORIGINATING FROM THE NRN CARIBBEAN. HERE TOO...A LOW PROBABILITY RISK FOR A BRIEF TORNADO AND/OR LOCALLY DAMAGING WIND GUST WILL EXIST DUE TO THE CO-LOCATION OF A MOIST/WEAKLY BUOYANT BOUNDARY LAYER AND VERTICALLY VEERING WIND PROFILE. ..MEAD/SMITH.. 12/20/2011
Middle TN is still in the 2% chance of tornadoes for this evening according to the update at 1:30 PM. Does anybody think we will actually have any severe weather? Do you think they'll drop that 2% zone when they update the Day 1 at about 6:00 PM?Thanks!
SPC AC 211644 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1044 AM CST WED DEC 21 2011 VALID 221200Z - 231200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF LA/MS/AL... CURRENT WATER VAPOR IMAGERY SHOWS A WELL-DEFINED SHORTWAVE TROUGH OVER NORTHWEST MEXICO. THIS FEATURE WILL TRACK EAST-NORTHEASTWARD ACROSS SOUTH TX TONIGHT AND INTO THE LOWER MS VALLEY ON THURSDAY. A SURFACE BOUNDARY IS CURRENTLY STALLED JUST OFF THE LA/MS COAST...AND SHOULD RAPIDLY RETURN NORTHWARD TONIGHT AS SOUTHERLY LOW LEVEL WINDS STRENGTHEN AHEAD OF THE APPROACHING THROUGH. BY 22/12Z...THE BOUNDARY IS EXPECTED TO EXTEND FROM SOUTHERN LA INTO CENTRAL MS AND NORTHERN AL. SURFACE DEWPOINTS IN THE MID 60S WILL ALSO RETURN NORTHWARD INTO LA/MS/AL LEADING TO THE DEVELOPMENT OF AT LEAST MARGINAL SURFACE-BASED INSTABILITY ALONG AND SOUTH OF THE FRONT. MODEL SOLUTIONS ARE IN GENERAL AGREEMENT THAT SURFACE CYCLOGENESIS WILL BE OCCURRING AT THE BEGINNING OF THE FORECAST PERIOD OVER LA/MS. THE DEEPENING LOW WILL TRACK INTO NORTHERN AL BY AFTERNOON. DESPITE ONLY MARGINAL CAPE...BACKING AND STRENGTHENING LOW LEVEL WIND FIELDS COUPLED WITH STRONG LARGE SCALE FORCING FOR ASCENT...WILL PROMOTE A RISK OF STRONG TO LOCALLY SEVERE STORMS. SUPERCELLS APPEAR TO BE THE MOST LIKELY STORM-MODE WITH DAMAGING WINDS AND ISOLATED TORNADOES POSSIBLE. LOW LEVEL MOISTURE AND INSTABILITY WILL WEAKEN WITH NORTHEASTWARD EXTENT INTO TN/GA WITH DIMINISHING SEVERE WEATHER THREATS. ..HART.. 12/21/2011
Couple of TORs down in AL this morning but the signatures are quite marginal....James Spann sounds like he's about to go Dave Brown on BMX...
I kinda agree with him... It looks like they're TOR warning everything that moves.
Damage reported in the town of Marbury, AL...report came in around 2:20.
BMX: 3 Sse Marbury [Autauga Co, AL] trained spotter reports TSTM WND DMG at 02:16 PM CST -- large tree down near rollins.
Only official report for Marbury right now is a tree down.
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Topic: 12/20 & 12/22 Slight Risk from the SPC (Read 1236 times)
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