Reed Stough Posted January 29, 2011 Share Posted January 29, 2011 Ok I started the post. Things look interesting from the 12Z GFS run, it looks like LA/MS could start the show, and then move to AL/GA/FL following on FEB 2nd. CAPE looks low, but LI's look sufficient. What are your thoughts? Link to comment Share on other sites More sharing options...
janetjanet998 Posted January 30, 2011 Share Posted January 30, 2011 jan 30th slight risk DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1150 PM CST SAT JAN 29 2011 VALID 301200Z - 311200Z ..THERE IS A SLGT RISK OF SVR TSTMS OVER ERN TX AND ERN LA ..SYNOPSIS SHORTWAVE TROUGH OVER NRN MEXICO AND TX WILL DEAMPLIFY AND SHEAR EWD THROUGH THE REMAINDER OF TX AND THE LOWER MS VALLEY IN RESPONSE TO STRONGER UPSTREAM VORT MAX NOW DROPPING SEWD INTO NRN CA. WEAK SFC LOW AND DRYLINE FEATURE WILL ACCOMPANY THE PRIMARY SHORTWAVE TROUGH THROUGH CNTRL AND ERN TX THIS AFTERNOON...WHILE A POLAR FRONT ADVANCES SWD THROUGH NRN TX AND THE LOWER MS VALLEY. ..ERN TX THROUGH LA PARTIALLY MODIFIED GULF AIR WITH LOW 60S DEWPOINTS IS ADVECTING NWD THROUGH SRN AND ERN TX BENEATH PLUME OF STEEP LAPSE RATES. THE EML THAT HAS CONTRIBUTED TO THE STEEP LAPSE RATES HAS ALSO RESULTED IN A CAP. HIGH BASED THUNDERSTORMS PERSIST OVER N-CNTRL TX EARLY THIS MORNING IN ASSOCIATION WITH PROGRESSIVE LEAD IMPULSE...BUT THIS ACTIVITY REMAINS ELEVATED ABOVE CAP. FURTHER MOISTENING OF THE BOUNDARY LAYER AND POTENTIAL FOR DEEPER VERTICAL MOTION ATTENDING PRIMARY SHORTWAVE TROUGH MAY EVENTUALLY WEAKEN THE CAP SUFFICIENTLY FOR MORE ROBUST CONVECTION TO DEVELOP EARLY SUNDAY. THIS APPEARS MOST LIKELY OVER ERN TX ALONG ERN PERIPHERY OF EML WHERE CAP SHOULD BE WEAKER. MUCAPE FROM 500-800 J/KG...STEEP LAPSE RATES AND SUFFICIENT VERTICAL SHEAR FOR UPDRAFT ROTATION...ESPECIALLY NEAR THE COAST...WILL SUPPORT A THREAT FOR MAINLY ISOLATED LARGE HAIL. CONVECTION WILL CONTINUE THROUGH LOWER MS VALLEY AREA DURING THE DAY...BUT SEVERE THREAT WILL DECREASE WITH EWD EXTENT DUE TO WEAKER INSTABILITY. SOME POTENTIAL WILL EXIST FOR REDEVELOPMENT OVER ERN TX AHEAD OF VORT MAX AND IN WAKE OF ONGOING STORMS DURING THE AFTERNOON. IF THIS OCCURS A SOMEWHAT MORE ROBUST SEVERE THREAT COULD MATERIALIZE. ISOLATED LARGE HAIL AND STRONG WIND GUSTS WILL BE THE MAIN THREATS. Link to comment Share on other sites More sharing options...
janetjanet998 Posted January 30, 2011 Share Posted January 30, 2011 day 3 DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0130 AM CST SUN JAN 30 2011 VALID 011200Z - 021200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS VALLEY... ..EAST TX/LA/MS/AL A VIGOROUS UPPER-LEVEL TROUGH IS FORECAST TO MOVE QUICKLY EWD ACROSS THE SRN PLAINS TUESDAY AS AN IMPRESSIVE LOW-LEVEL JET STRENGTHENS ACROSS THE LOWER MS VALLEY. THUNDERSTORMS SHOULD BE ONGOING EARLY TUESDAY MORNING IN THE ARKLATEX WITH CONVECTION MOVING EWD ACROSS THE LOWER MS VALLEY TUESDAY AFTERNOON. FORECAST SOUNDINGS AT THAT TIME SHOW MUCAPE VALUES AROUND 500 J/KG...SFC DEWPOINTS IN THE LOWER 60S F AND STRONG DEEP LAYER SHEAR. THIS COMBINATION OF FACTORS COULD BE STRONG ENOUGH FOR A SEVERE THREAT. FOR THIS REASON...A SLIGHT RISK AREA IS INTRODUCED FROM SE TX EWD TO THE FL PANHANDLE. ATTM...THE GREATEST POTENTIAL FOR SEVERE STORMS WOULD BE IN LA AND WRN MS DURING THE EARLY AFTERNOON WHEN SFC TEMPS WOULD HAVE A CHANCE TO BE WARMER. SOME QUESTIONS STILL REMAIN ON THE TIMING OF THE SYSTEM COMING OUT INTO THE LOWER MS VALLEY. HOWEVER...THE GFS AND NAM ARE PRETTY CLOSE SUGGESTING ENOUGH CONFIDENCE EXISTS TO GO WITH A SLIGHT RISK AREA. THE MAGNITUDE OF THE SEVERE THREAT SHOULD DEPEND ON THE QUALITY OF THE WARM SECTOR. Link to comment Share on other sites More sharing options...
janetjanet998 Posted January 30, 2011 Share Posted January 30, 2011 DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0130 AM CST SUN JAN 30 2011 VALID 011200Z - 021200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS VALLEY... ..EAST TX/LA/MS/AL A VIGOROUS UPPER-LEVEL TROUGH IS FORECAST TO MOVE QUICKLY EWD ACROSS THE SRN PLAINS TUESDAY AS AN IMPRESSIVE LOW-LEVEL JET STRENGTHENS ACROSS THE LOWER MS VALLEY. THUNDERSTORMS SHOULD BE ONGOING EARLY TUESDAY MORNING IN THE ARKLATEX WITH CONVECTION MOVING EWD ACROSS THE LOWER MS VALLEY TUESDAY AFTERNOON. FORECAST SOUNDINGS AT THAT TIME SHOW MUCAPE VALUES AROUND 500 J/KG...SFC DEWPOINTS IN THE LOWER 60S F AND STRONG DEEP LAYER SHEAR. THIS COMBINATION OF FACTORS COULD BE STRONG ENOUGH FOR A SEVERE THREAT. FOR THIS REASON...A SLIGHT RISK AREA IS INTRODUCED FROM SE TX EWD TO THE FL PANHANDLE. ATTM...THE GREATEST POTENTIAL FOR SEVERE STORMS WOULD BE IN LA AND WRN MS DURING THE EARLY AFTERNOON WHEN SFC TEMPS WOULD HAVE A CHANCE TO BE WARMER. SOME QUESTIONS STILL REMAIN ON THE TIMING OF THE SYSTEM COMING OUT INTO THE LOWER MS VALLEY. HOWEVER...THE GFS AND NAM ARE PRETTY CLOSE SUGGESTING ENOUGH CONFIDENCE EXISTS TO GO WITH A SLIGHT RISK AREA. THE MAGNITUDE OF THE SEVERE THREAT SHOULD DEPEND ON THE QUALITY OF THE WARM SECTOR. Link to comment Share on other sites More sharing options...
blackjack123 Posted January 31, 2011 Share Posted January 31, 2011 Could this be similar to 11-29-10? Link to comment Share on other sites More sharing options...
Reed Stough Posted January 31, 2011 Author Share Posted January 31, 2011 Was just looking at the GFS for 2/2 and the low and mid level shear over MS/AL looks incredible. But what is odd is that the LI's are barely below 0. Which I can't believe for this kind of system. I think we will see at least a moderate risk go there soon. The winds/shear/ negative tilt trough are all there. Even dewpoints will be in the low to mid 60's. I think anyone from Jackson MS to Hattisburg Ms, to Mobile AL, to Dothan AL to Birmingham AL should be ready for some nasty severe weather. If not tornadoes - some very serious damaging wind events. Link to comment Share on other sites More sharing options...
janetjanet998 Posted January 31, 2011 Share Posted January 31, 2011 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1103 AM CST MON JAN 31 2011 VALID 011200Z - 021200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM EAST TX TO THE FL PANHANDLE... ..CENTRAL GULF STATES LATEST NAM AND GFS ARE IN REASONABLE AGREEMENT REGARDING THE LARGE SCALE EVOLUTION OF SWRN U.S. UPPER TROUGH AS IT PROGRESSES INTO THE SRN PLAINS LATE DAY1 INTO THE EARLY DAY2 PERIOD. SHORT RANGE GUIDANCE SUGGEST A STRONG H5 SPEED MAX...ON THE ORDER OF 90KT...WILL EJECT NEWD ACROSS SERN TX BEFORE INTENSIFYING IN EXCESS OF 100-110KT OVER THE TN VALLEY BY 02/12Z. THIS FEATURE WILL UNDOUBTEDLY AID IN SIGNIFICANT DEEPENING OF SFC LOW AS IT LIFTS NEWD ACROSS SERN TX TO A POSITION OVER WRN TN BY LATE AFTERNOON. WARM SECTOR RECOVERY WILL BE MODIFIED IN NATURE WITH BOUNDARY LAYER DESTABILIZATION SOMEWHAT LIMITED AND CHARACTERIZED BY SFC DEW POINTS RISING TO NEAR 60F AS FAR NORTH AS I-20 OVER LA...AND PERHAPS INTO NERN MS IMMEDIATELY AHEAD OF SFC FRONT AT 00Z. AS A RESULT...FORECAST SOUNDINGS IMPLY MUCH OF THE PRE-FRONTAL CONVECTION WILL BE SLIGHTLY ELEVATED IN NATURE WITH THE GREATEST POTENTIAL FOR NEAR-SFC DEVELOPMENT EXPECTED WITHIN THE FRONTAL ZONE WHERE STRONG LOW LEVEL CONVERGENCE IS EXPECTED. GIVEN THE LIMITED BUOYANCY...AOB 500 J/KG...IT/S NOT ENTIRELY CLEAR HOW MUCH PRE-FRONTAL SEVERE THREAT WILL TRANSPIRE. AT THIS TIME IT APPEARS A NARROW BAND OF FORCED CONVECTION WILL DEVELOP ALONG THE WIND SHIFT NEAR THE I-35 CORRIDOR OVER TX EARLY IN THE PERIOD. THIS FRONTAL CONVECTION WILL EVOLVE WITHIN A STRONGLY SHEARED ENVIRONMENT FAVORABLE FOR AT LEAST A DAMAGING WIND THREAT AS A PROGRESSIVE NARROW SQUALL LINE ADVANCES FROM WEST-EAST ACROSS THE SLIGHT RISK AREA. THE GREATEST THREAT FOR TORNADIC SUPERCELLS MAY BE LIMITED TO THAT ZONE NEAR THE IMMEDIATE GULF COAST FROM LA INTO THE WRN FL PANHANDLE AS SOMEWHAT HIGHER SFC DEW POINTS MAY SUPPORT MORE ROBUST PRE-FRONTAL CONVECTION ACROSS THIS ZONE. Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 1, 2011 Share Posted February 1, 2011 URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 9 NWS STORM PREDICTION CENTER NORMAN OK 840 AM CST TUE FEB 1 2011 THE NWS STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF MUCH OF LOUISIANA WEST CENTRAL AND SOUTHWEST MISSISSIPPI COASTAL WATERS EFFECTIVE THIS TUESDAY MORNING AND AFTERNOON FROM 840 AM UNTIL 300 PM CST. TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 100 STATUTE MILES EAST AND WEST OF A LINE FROM 60 MILES NORTH OF NATCHEZ MISSISSIPPI TO 45 MILES SOUTH OF INTRACOASTAL CITY LOUISIANA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9). REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. DISCUSSION...A STRONGLY FORCED SQUALL LINE MOVE QUICKLY EWD IN CONJUNCTION WITH A SURFACE COLD FRONT PROGRESSING EWD FROM TX INTO LA...AND STRONG MIDLEVEL TROUGH EJECTING ENEWD OVER TX/OK. GRADUAL SURFACE MOISTENING/DESTABILIZATION WILL SUPPORT CONVECTION BASED NEAR THE SURFACE AS DEWPOINTS INCREASE INTO THE 60S...WHILE VERTICAL SHEAR WILL BE VERY STRONG AND SUPPORTIVE OF EMBEDDED BOW/SUPERCELL STRUCTURES IN THE LINE. A FEW TORNADOES AND DAMAGING WINDS WILL BE THE MAIN THREATS INTO THE AFTERNOON. Link to comment Share on other sites More sharing options...
Ellinwood Posted February 1, 2011 Share Posted February 1, 2011 Two tornado warnings already today, with the latest just N of Lake Charles, LA. Looks like we'll see a good deal of embedded rotation within the main line of storms. Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 1, 2011 Share Posted February 1, 2011 This thread is getting no love is there somehting else going on that has the attention of the normal severe weather posters or something? Link to comment Share on other sites More sharing options...
blackjack123 Posted February 1, 2011 Share Posted February 1, 2011 This thread is getting no love is there somehting else going on that has the attention of the normal severe weather posters or something? Probably this historic snowstorm. There might be some tornadoes today but I doubt many. If temperatures were about 5-10 degrees warmer, instability a little bit stronger, and lapse rates just a tad bit steeper this probably would be not only a historic snowstorm for the plains/northeastern states but possibly a historic tornado outbreak for parts of dixie alley. It may be possible that a cell could get out ahead of the line and spawn a strong/violent tornado but I am not going to bank on that. Link to comment Share on other sites More sharing options...
Reed Stough Posted February 1, 2011 Author Share Posted February 1, 2011 Looks like all the decent CAPE stayed offshore. No instability. I have to hand it to the Models - they did a good job of forecasting the lack of severe weather. Link to comment Share on other sites More sharing options...
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