2012

Mesoscale Discussion #0048


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 5 CONTINUES.

   

SEVERE POTENTIAL CONTINUES TO INCREASE ACROSS CNTRL AR AND INCIPIENT REGIONAL TORNADO OUTBREAK APPEARS TO BE UNFOLDING...WITH PROBABLE SIGNIFICANT TORNADOES DEVELOPING ACROSS S-CNTRL INTO NERN AR.

   

AS OF 0045Z...LEAD BROKEN BAND OF TSTMS EXTENDED IN A NNE-SSW ORIENTATION FROM RANDOLPH TO COLUMBIA COUNTIES. SEVERAL EMBEDDED MESOCYCLONES CONTINUE TO INTENSIFY WITH INITIAL TORNADO WARNINGS HAVING BEEN RECENTLY ISSUED ACROSS S-CNTRL AR. MODIFIED 00Z LZK/SHV/JAN RAOBS SUGGEST MLCAPE OF 750-1250 J/KG IS PREVALENT AHEAD OF THIS BAND FROM S-CNTRL TO E-CNTRL AR. WITH EFFECTIVE SRH NOW IN EXCESS OF 500-600 M2/S2...EXTREME LOW-LEVEL SHEAR/VERY LARGE HODOGRAPHS BREEDS HIGH CONFIDENCE IN SUSTAINED/LONG-TRACKED SUPERCELLS CAPABLE OF PRODUCING SIGNIFICANT TORNADOES.

Mesoscale Discussion #0205


CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 

   

VALID 021522Z - 021715Z

   

A RAPID INCREASE IN THE SEVERE STORM POTENTIAL APPEARS POSSIBLE BY MIDDAY...INCLUDING THE RISK FOR STRONG TORNADOES AND VERY LARGE HAIL.

   

MODELS INDICATE THAT THE CYCLONIC 500 MB JET CORE IS IN THE PROCESS OF INTENSIFYING IN EXCESS OF 100 KT...AS ITS EXIT REGION NOSES ACROSS THE MISSOURI OZARKS TOWARD CENTRAL ILLINOIS THROUGH EARLY AFTERNOON.  STRONGEST MID-LEVEL HEIGHT FALLS WILL BE FOCUSED JUST TO THE NORTHWEST OF THIS FEATURE...BUT THE SOUTHERN FRINGE OF STRONGER FORCING FOR UPWARD VERTICAL MOTION APPEARS LIKELY TO WEAKEN INHIBITION IN THE WARM SECTOR AN ASSOCIATED DEEPENING SURFACE CYCLONE.  AS THE CENTER OF THE LOW TRACKS EAST OF THE MISSISSIPPI RIVER...AND NORTHEASTWARD THROUGH SOUTHERN ILLINOIS... MODELS SUGGEST THE DEVELOPMENT AND SHARPENING OF A PRE-COLD FRONTAL DRY LINE BY THE 17-19Z TIME FRAME...SOUTH OF THE LOW ACROSS SOUTHERN ILLINOIS INTO THE VICINITY OF THE MISSISSIPPI RIVER.  STRENGTHENING LOW-LEVEL WARM ADVECTION ALONG AND EAST OF THIS FEATURE...COUPLED WITH WEAK TO MODERATE BOUNDARY LAYER DESTABILIZATION BENEATH THE MID-LEVEL DRY SLOT...MAY SERVE TO FOCUS THE INITIATION OF DISCRETE STORMS.  IN THE PRESENCE OF VERY STRONG SHEAR...AND LARGE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS BENEATH A 50+ KT SOUTHWESTERLY 850 MB JET...THE ENVIRONMENT WILL BE CONDUCIVE TO LONG-LIVED SUPERCELLS.

   

VERY LARGE HAIL IS POSSIBLE FROM THE OUTSET...AND TORNADIC POTENTIAL MAY ALSO INCREASE QUICKLY...WITH POTENTIAL FOR PARTICULARLY STRONG AND DAMAGING TORNADOES INCREASING THROUGH THE AFTERNOON.  GIVEN THE STRENGTH OF THE DEEP LAYER WESTERLY MEAN FLOW /50-60+ KT/...CELLS WILL BE FAST MOVING...BUT ADDITIONAL STRONG/SEVERE STORMS COULD DEVELOP IN ITS WAKE...AS THE COLD FRONT OVERTAKES THE DRY LINE EAST OF THE MISSISSIPPI VALLEY LATER THIS AFTERNOON.

Mesoscale Discussion #0206


THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 55 CONTINUES.

   

PORTIONS OF WW HAVE ALREADY BEEN UPGRADED TO A TORNADO WATCH.  AREAS FARTHER TO THE NORTH AND EAST OF THE SEVERE THUNDERSTORM WATCH WILL NEED TO BE MONITORED FOR ADDITIONAL WWS LATER THIS AFTERNOON.

   

AS THE DEEPENING SURFACE CYCLONE LIFTS NORTHEAST OF THE ST. LOUIS MO AREA INTO NORTHEAST INDIANA BETWEEN NOW AND 19-21Z...AN AREA OF ENHANCED WARM ADVECTION ALONG A NORTHEASTWARD ADVANCING WARM FRONT TO ITS EAST MAY BECOME OF FOCUS FOR INCREASING SEVERE POTENTIAL DURING THE NEXT FEW HOURS.  THIS MAY IMPACT THE MATTOON/CHARLESTON AND TERRE HAUTE AREAS AS EARLY AS 18Z-19Z...BEFORE DEVELOPING NORTHEASTWARD INTO CENTRAL INDIANA.  RAPID BOUNDARY LAYER DESTABILIZATION IN THE PRESENCE OF STRONG SHEAR...INCLUDING LARGE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS... WILL SUPPORT INCREASING POTENTIAL FOR TORNADIC DEVELOPMENT...INCLUDING THE RISK FOR PARTICULARLY STRONG AND DAMAGING TORNADOES...IN ADDITION TO A CONTINUING RISK FOR LARGE HAIL.

Mesoscale Discussion #0211


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 57 CONTINUES.

   

LONG LIVED SUPERCELLS WILL BEGIN OVERSPREADING A LARGE PORTION OF THE LOWER OHIO VALLEY BETWEEN NOW AND 20-21Z...ACCOMPANIED BY THE POTENTIAL FOR STRONG/DESTRUCTIVE TORNADOES AND VERY LARGE HAIL.  ADDITIONAL WWS ARE IN THE PROCESS OF BEING ISSUED AND WILL LIKELY BE NEEDED WITHIN THE NEXT HOUR OR TWO.

   

DISCRETE SUPERCELLS HAVE FORMED ACROSS SOUTHERN ILLINOIS INTO SOUTHEAST MISSOURI...GENERALLY NEAR A DEVELOPING DRY LINE AND JUST AHEAD OF THE SURFACE COLD FRONT...WHICH WILL CONTINUE OVERTAKING THE DRY LINE ACROSS THE LOWER OHIO VALLEY DURING THE NEXT FEW HOURS. ADDITIONAL CELLS STILL APPEAR LIKELY TO FORM AHEAD OF THE EASTWARD ADVANCING FRONT...INITIATING ALONG THE PRE-FRONTAL DRY LINE STRUCTURE ACROSS PARTS OF WESTERN AND CENTRAL KENTUCKY INTO WESTERN AND MIDDLE TENNESSEE THROUGH 20-21Z.  IN THE PRESENCE OF STRONG SHEAR...WITH LARGE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS...AND MODERATELY LARGE CAPE...CONDITIONS APPEAR VERY FAVORABLE FOR SUPERCELLS CAPABLE OF PRODUCING TORNADOES...SOME PARTICULARLY STRONG AND POTENTIALLY VERY DESTRUCTIVE.  GIVEN THE STRENGTH OF THE WESTERLY DEEP LAYER MEAN FLOW /50-60+ KT/...AND THE CONTINUING EASTWARD ADVECTION OF THE UNSTABLE  WARM SECTOR THROUGH THE LOWER OHIO VALLEY...STORMS WILL BE FAST MOVING AND LONG-LIVED.

Mesoscale Discussion #0215


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 57...58...CONTINUES.

   

AN ADDITIONAL TORNADO WATCH WILL BE NEEDED EAST OF WW 58... PROBABLY BEFORE 22Z...ACROSS THE REMAINDER OF EASTERN KENTUCKY AND SOUTHEAST OHIO INTO WEST VIRGINIA.

   

PRE-FRONTAL STORM DEVELOPMENT TO THE SOUTH OF THE OHIO RIVER...WHERE SURFACE WINDS HAVE ALREADY BEGUN TO VEER WITH SOME LOWERING OF DEW POINTS...HAS BEEN A BIT SLOWER TO OCCUR THAN PREVIOUSLY THOUGHT. HOWEVER...STORMS ARE IN THE PROCESS OF INCREASING IN CLOSER PROXIMITY TO THE COLD FRONT...APPROACHING THE MISSISSIPPI RIVER...AND WILL STILL POSE A SEVERE THREAT...WHILE POSSIBLY ORGANIZING INTO A MORE CONSOLIDATED LINE AS THE FRONT SURGES EAST OF THE RIVER THROUGH WESTERN AND CENTRAL KENTUCKY LATE THIS AFTERNOON AND EVENING.

   

MEANWHILE...TORNADIC POTENTIAL IS EXPECTED TO REMAIN HIGH WITH DISCRETE SUPERCELLS AS THEY MIGRATE ACROSS THE MORE SLOWLY NORTHEASTWARD ADVANCING WARM FRONT ACROSS NORTH CENTRAL KENTUCKY INTO SOUTHERN OHIO BETWEEN NOW AND 22-23Z.  AS ADDITIONAL PRE-FRONTAL DISCRETE STORMS GRADUALLY FORM AND RAPIDLY MOVE EAST NORTHEASTWARD ACROSS CENTRAL INTO EASTERN KENTUCKY...THEY WILL PROGRESS INTO A LESS STRONGLY HEATED...BUT MOISTENING...BOUNDARY LAYER.  AND HIGHER HUMIDITIES MAY ACTUALLY ENHANCE THE TORNADIC POTENTIAL...CONTRIBUTING TO THE RISK FOR STRONG/DESTRUCTIVE TORNADOES.

Mesoscale Discussion #0217


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 59 CONTINUES.

   

RADAR TRENDS INDICATE AN INCREASE IN COVERAGE OF DISCRETE SUPERCELLS ACROSS PORTIONS OF WRN/MIDDLE TN AND NRN AL/MS OVER THE PAST 1-2 HRS. THIS IS OCCURRING AS STRONGER LARGE-SCALE FORCING /ASSOCIATED WITH MIDLEVEL HEIGHT FALLS...INCREASING LOW-LEVEL WAA...AND GLANCING INFLUENCE OF A MID-MS RIVER VALLEY UPPER IMPULSE/ IS NOW ENTERING WRN PORTIONS OF THE WW AREA. 21Z SFC ANALYSIS SHOWS A DRYLINE/WIND SHIFT NOW ENTERING WRN TN. ONE SUCH SUPERCELL FORMING IMMEDIATELY AHEAD OF THIS BOUNDARY COULD POTENTIALLY AFFECT THE NASHVILLE METRO AREA NEAR/AFTER 22Z /PER CURRENT MOTION EXTRAPOLATION VIA OHX RADAR LOOP/. VWP DATA FROM HTX/OHX INDICATES LOW-LEVEL WIND FIELDS /0-1 KM BULK SHEAR RANGING FROM 25-40 KTS/ REMAIN FAVORABLE FOR THE DEVELOPMENT OF TORNADOES /POTENTIALLY STRONG/ ACROSS THE WW AREA...IN ADDITION TO LARGE HAIL AND DMGG WINDS. 

   

THE THREAT IS EXPECTED TO DECREASE IN THE WAKE OF THE EWD MOVING DRYLINE...AS VEERING WINDS AND A DRIER BOUNDARY LAYER SHOULD LEAD TO A REDUCTION IN TSTM/SVR POTENTIAL. LOCAL OFFICES MAY CONSIDER CLEARING THE WW FROM W-E AS THE DRYLINE SHIFTS E.

Mesoscale Discussion #0220


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 58...62...CONTINUES.

   

DAMAGING TORNADO OUTBREAK UNDERWAY ACROSS ERN KY WITH SEVERAL SUPERCELLS LIKELY CONTAINING STRONG TO VIOLENT TORNADOES. SUPERCELL OVER MORGAN COUNTY KY IS MOVING INTO LAWRENCE COUNTY AND LIKELY CONTAINS A VERY DAMAGING TORNADO. THIS STORM SHOULD EVENTUALLY CONTINUE EWD INTO WAYNE COUNTY WV.

   

SUPERCELLS MOVING THROUGH ERN KY WILL CONTINUE THROUGH AN ENVIRONMENT VERY FAVORABLE FOR STRONG TO VIOLENT TORNADOES AS THE LLJ STRENGTHENS TO IN EXCESS OF 60 KT. LAST VWP DATA FROM JACKSON KY INDICATE VERY LARGE 0-1 KM HODOGRAPHS WITH STORM RELATIVE HELICITY ON THE ORDER OF 800 M2/S2 AND 500 J/KG MLCAPE. THESE PARAMETERS ALONG WITH THE DISCRETE NATURE OF THE CONVECTION WILL CONTINUE TO PROMOTE A THREAT OF TORNADOES...VERY LARGE HAIL AND DAMAGING WIND NEXT FEW HOURS.

Mesoscale Discussion #0221


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 59...61...63...CONTINUES.

   

TORNADIC SUPERCELL POTENTIAL WILL CONTINUE TO INCREASE THIS EVENING AND INTO THE EARLY OVERNIGHT HOURS ACROSS A LARGE PORTION OF AL AND WRN-NWRN GA.  ASIDE FROM THE THREAT OF TORNADOES /POTENTIALLY SIGNIFICANT/...SUPERCELLS WILL ALSO POSE AN ACCOMPANYING DMGG STRAIGHT-LINE WINDS RISK.

   

23Z SURFACE ANALYSIS SHOWS A LARGE UNIMPEDED WARM/MOIST SECTOR ACROSS AL AND MOVING INTO WRN PARTS OF GA --AHEAD OF A DRYLINE OVER NWRN MS.  3 HR CHANGE IN SURFACE TEMP/DEWPOINT SHOW A DECREASE OF 2-7 DEG F AND A 2 DEG F INCREASE...RESPECTIVELY.  THE FORECAST CONTINUED TREND IN LOWERING SURFACE SPREADS AND LESS SUBSTANTIAL BOUNDARY LAYER MIXING WILL SEEMINGLY PROVE MORE FAVORABLE FOR LOW LEVEL MESOCYCLONES.  SLIGHT IMPROVEMENTS IN THE LOW LEVEL THERMODYNAMIC PROFILE WILL ACCOMPANY A STRENGTHENING IN THE LLJ/40-55 KTS/ FROM SWRN AND W-CNTRL AL NEWD INTO NRN GA IN THE NEXT FEW HOURS.  THIS WILL SET THE STAGE FOR A POSSIBLE NOCTURNAL TORNADO EPISODE FROM CNTRL AND E-CNTRL AL NEWD INTO N-CNTRL GA.  THIS SCENARIO IS AT LEAST SUPPORTED TO A CERTAIN EXTENT BY THE LATEST STORM-SCALE MODEL ENSEMBLE /SSEO/.  AS SUCH...SCATTERED DISCRETE SUPERCELLS WILL POSE AN ATTENDANT ISOLD TORNADO THREAT --WITH PERHAPS A FEW STRONG TORNADOES WITH THE MORE INTENSE SUPERCELLS.

Mesoscale Discussion #0222


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 58...62...CONTINUES.

   

THREAT FOR STRONG TORNADOES...DAMAGING WIND AND VERY LARGE HAIL WILL CONTINUE THROUGH MID EVENING THROUGH THE REMAINDER OF ERN KY...THE WRN HALF OF WV INTO SWRN VA.

   

SEVERAL TORNADIC SUPERCELLS CONTINUE THROUGH ERN KY...WRN WV AND SWRN VA WITHIN AN ENVIRONMENT CHARACTERIZED BY VERY LARGE 0-1 KM HODOGRAPHS...60-70 KT EFFECTIVE BULK SHEAR AND 500 J/KG MLCAPE. TENDENCY HAS BEEN FOR SOME STORMS TO EVOLVE INTO LINES...BUT A FEW DISCRETE SUPERCELLS REMAIN AHEAD OF THE LINE. THE UPSCALE GROWTH WILL INCREASE THE POTENTIAL FOR DAMAGING WIND...BUT THREAT FOR TORNADOES WILL PERSIST WITH ANY SUPERCELLS EMBEDDED WITHIN OR AHEAD OF THE LINE.

   

LATEST SURFACE ANALYSIS INDICATES A WEDGE FRONT PERSISTING FROM WRN NC INTO ERN WV. THE SURFACE LAYER EAST OF THIS BOUNDARY IS STABLE WITH TEMPERATURES IN THE 40S TO AROUND 50F...SUGGESTING THE STORMS SHOULD BEGIN TO WEAKEN LATER THIS EVENING AS THEY CROSS INTO THE COOLER AIR OVER ERN WV AND FARTHER EAST INTO VA.

Mesoscale Discussion #0223


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 61 CONTINUES.

   

THREAT FOR TORNADOES...A FEW OF WHICH COULD BE STRONG...DAMAGING WIND AND VERY LARGE HAIL WILL CONTINUE THE REMAINDER OF THIS EVENING ACROSS ERN TN...NRN GA INTO A PORTION OF THE WRN CAROLINAS.

   

A SSWLY LLJ HAS BEEN STRENGTHENING THE LAST COUPLE OF HOURS OVER CNTRL AL...NRN/CNTRL GA...ERN TN AND WRN CAROLINAS IN ASSOCIATION WITH AGEOSTROPHIC FORCING ATTENDING A PROGRESSIVE UPPER JET SHIFTING NEWD THROUGH THE TN AND OH VALLEYS. THIS HAS RESULTED IN AN INCREASE IN HODOGRAPH SIZE WITH EFFECTIVE STORM RELATIVE HELICITIES EXCEEDING 400 M2/S2. BOUNDARY LAYER COOLING WILL BE SLOWED SOMEWHAT BY WARM ADVECTION ATTENDING THE SWLY LLJ...AND BASE OF THE EFFECTIVE INFLOW LAYER IS EXPECTED TO REMAIN AT OR NEAR THE SURFACE THIS EVENING. THIS ENVIRONMENT WILL CONTINUE TO SUPPORT SUPERCELLS AND LINES WITH BOWING STRUCTURES AND A THREAT FOR TORNADOES...DAMAGING WIND AND LARGE HAIL. 

   

ERN EXTENT OF SEVERE THREAT IS LIMITED BY A WEDGE FRONT EXTENDING ACROSS WRN NC INTO WRN VA. THERE IS SOME EVIDENCE THAT THIS BOUNDARY IS BEGINNING TO LIFT SLOWLY NWD ACROSS SCNTRL NC WHERE THE SEVERE THREAT MIGHT INCREASE LATER THIS EVENING.

Mesoscale Discussion #0430


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 133 CONTINUES.

   

ISOLATED TORNADO THREAT ONGOING -- PARTICULARLY INVOF THE DFW METROPLEX.

   

LATEST SURFACE ANALYSIS INDICATES THE WRN EXTENSION OF A W-E OUTFLOW BOUNDARY IS CURRENTLY LYING OVER THE SRN THIRD OF TARRANT AND DALLAS COUNTIES -- CONFIRMED BY RECENT VISIBLE SATELLITE IMAGERY.  WHILE A LARGER CLUSTER OF STORMS CONTINUES ACROSS N TX...SMALL SUPERCELL STORMS MOVING TOWARD -- AND DEVELOPING NEAR -- THE METROPLEX HAVE PRODUCED A FEW TORNADOES IN THE PAST HALF HOUR TO HOUR -- LIKELY AS THEY CROSS/INTERACT WITH THE MORE FAVORABLE VORTICITY/LOW-LEVEL SHEAR ASSOCIATED WITH THE BOUNDARY.  THOUGH IN GENERAL EXPECT ANY SINGLE TORNADO TO BE RELATIVELY BRIEF AS STORMS MOVE QUICKLY NEWD ACROSS THE BOUNDARY...THE ENHANCED POTENTIAL ACROSS THE METROPLEX AREA ITSELF SUGGESTS CONTINUED/HEIGHTENED RISK FOR A DAMAGING EVENT.


**This MCD preceded the localized, multi-SigTor event in the DFW metroplex

Mesoscale Discussion #0510


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 160 CONTINUES.

   

SCATTERED SUPERCELLS OVER SWRN/CNTRL OK AND PARTS OF WRN NORTH TX WILL CONTINUE TO TRACK ENEWD/EWD AND APPROACH THE I-35 CORRIDOR DURING THE NEXT COUPLE OF HOURS. THESE STORMS WILL PERSIST IN AN ENVIRONMENT CHARACTERIZED BY SBCAPE VALUES OF 2500-3500 J/KG AND EFFECTIVE BULK SHEAR MAGNITUDES OF 35-50 KT...WITH SUSTAINED MID-LEVEL MESOCYCLONES NOTED ON AREA RADAR IMAGERY. VERY LARGE HAIL WILL BE A CONCERN WITH ANY PERSISTENT SUPERCELL STRUCTURES THROUGH LATE AFTERNOON. ONE SUPERCELL EXHIBITING NOTABLE EWD DEVIANT MOTION FROM THE MEAN FLOW IS APPROACHING PARTS OF THE OKC/NORMAN AREAS...WHICH WILL LIKELY BE IMPACTED BETWEEN 2050 AND 2130Z. A LOCAL EWD EXTENSION OF THE TORNADO WATCH HAS BEEN COORDINATED WITH THE NORMAN WFO TO ADDRESS A SHORT-TERM THREAT OUTSIDE OF WW160 IN CNTRL OK...AND AN ADDITIONAL WW TO THE EAST MAY EVENTUALLY BE REQUIRED.

   

DESPITE LOW-LEVEL SHEAR CURRENTLY BEING SOMEWHAT MARGINAL FOR TORNADOES -- 0-1 KM SRH OF 135 M2/S2 PER TWIN LAKES VWP DATA -- LOW-LEVEL SHEAR WILL LIKELY INCREASE LATER THIS AFTERNOON INTO THIS EVENING COMMENSURATE WITH THE STRENGTHENING NOCTURNAL BOUNDARY-LAYER WIND MAXIMUM. AS SUCH...THE THREAT FOR TORNADOES WILL INCREASE. ALSO...ADDITIONAL STORMS...INCLUDING SUPERCELLS...WILL LIKELY DEVELOP W/NW OF THE ONGOING SUPERCELLS DURING THE NEXT FEW HOURS. THIS WILL OCCUR AS THE FRINGES OF THE RICHER LOW-LEVEL MOISTURE EXPAND WWD/NWWD OWING TO THE ISALLOBARIC FLOW ASSOCIATED WITH SFC PRESSURE FALLS OVER NM/SRN CO. AS SUCH...A CORRESPONDING INCREASE IN THE THREAT FOR SVR STORMS INCLUDING TORNADOES WILL BUILD INTO PARTS OF W-CNTRL...NWRN...AND N-CNTRL OK AFTER 2230Z.

Mesoscale Discussion #0512


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 160 CONTINUES.

   

TORNADO WATCH 160 CONTINUES UNTIL 02Z. LARGE HAIL ASIDE...TORNADO POTENTIAL MAY FURTHER INCREASE THROUGH SUNSET...ESPECIALLY ACROSS SOUTHWEST/WEST-CENTRAL OK. WW 160 ADJACENT PORTIONS OF NORTHWEST TX/EASTERN TX PANHANDLE ARE BEING MONITORED FOR AN ADDITIONAL WATCH THIS EVENING.

   

SUPERCELLS CONTINUE TO DEVELOP/SPLIT OVER THE PAST FEW HOURS ACROSS SOUTHWEST OK INTO MUCH OF CENTRAL OK...WITH LONGER-LIVED/SEVERE PRODUCING EAST-NORTHEASTWARD MOVING RIGHT-MOVING SUPERCELLS. WITHIN A CORRIDOR OF MODERATE INSTABILITY /1500-2500 J PER KG MLCAPE/...VERY FAVORABLE WIND PROFILES WILL CONTINUE TO SUPPORT LONG-LIVED SUPERCELLS CAPABLE OF LARGE HAIL/TORNADOES WITHIN THIS SAME CORRIDOR...WITH A NORTHWARD EXPANSION INTO ADDITIONAL PORTIONS OF WESTERN/NORTHERN OK AND PERHAPS ADJACENT NORTHWEST TX AS A LOW LEVEL JET INCREASES AND FRONTAL BOUNDARY/DRYLINE AND ASSOCIATED MOIST SECTOR RETREATS. REGARDING THE TORNADO THREAT...THE AFOREMENTIONED SOUTHERLY LOW LEVEL JET IS EXPECTED TO STRENGTHEN ESPECIALLY TOWARD/AFTER SUNSET. THIS LLJ INCREASE...COUPLED WITH A MORE DISCRETE INITIATION/LONG-LIVED SUPERCELLULAR MODE AND MODIFYING OUTFLOW-AIDED TRIPLE POINT...MAY LEAD TO A HEIGHTENED TORNADO THREAT ESPECIALLY ACROSS SOUTHWEST/WEST-CENTRAL OK. THIS INCLUDES THE POTENTIAL FOR A STRONG TORNADO.

Mesoscale Discussion #0523


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 165 CONTINUES.

   

SEVERE WEATHER THREAT ACROSS PARTICULARLY DANGEROUS SITUATION TORNADO WATCH 165 WILL BE EVOLVING WITHIN TWO SPATIAL REGIMES THROUGH 1730Z:

   

1. ONGOING ELEVATED THUNDERSTORMS...INCLUDING SUPERCELLS...NORTH A OF A DODGE CITY TO GARDEN CITY KANSAS LINE...WILL SHIFT NEWD. WITH THE DOWNSTREAM AIR MASS REMAINING RELATIVELY COOL OWING TO THE STRATUS DECK...MODIFIED 12Z DDC RAOB SUGGESTS THAT THESE STORMS WILL REMAIN SOMEWHAT ELEVATED DURING THE NEXT HOUR OR SO AND POSE MAINLY A THREAT FOR SEVERAL HAIL...SOME POSSIBLY VERY LARGE. HOWEVER...STRONG LOW-LEVEL SHEAR MAY SUPPORT THE THREAT FOR ONE OR TWO TORNADOES WITH THIS INITIAL ROUND OF STORMS AS THE INHIBITION ERODES WITH AT LEAST SOME DIURNAL HEATING.

   

2. INCREASING CONVECTION DEVELOPING IN SWRN KS SWD INTO THE ERN TX PANHANDLE WILL MOVE NEWD BEHIND THE INITIAL ROUND OF STORMS. VERY LITTLE CINH FOR A SFC-BASED PARCEL INTO THE TX/OK PANHANDLES PER 12Z AMA RAOB SUGGESTS THAT SURFACE-BASED SUPERCELLS MAY QUICKLY EVOLVE FROM THIS ACTIVITY DURING THE NEXT HOUR OR TWO...WITH THE THREAT FOR TORNADOES INCREASING INTO THE AFTERNOON.

Mesoscale Discussion #0524


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 165 CONTINUES.

   

WICHITA WSR-88D RADAR DATA INDICATE CONVECTION DEVELOPING OVER ERN KINGMAN COUNTY AND SURROUNDING AREAS IN ASSOCIATION WITH A LOBE OF ASCENT TRANSLATING NEWD FROM NRN OK PER WATER VAPOR IMAGERY. WITH DEEPENING BOUNDARY-LAYER CIRCULATIONS AMIDST STRENGTHENING INSTABILITY AND WEAKENING CINH /SBCINH ALREADY LESS NEGATIVE THAN -10 J PER KG ACCORDING TO MODIFIED RUC SOUNDINGS/...CONVECTION MAY RAPIDLY DEEPEN AND BECOME TORNADIC GIVEN THE STRONG LOW-LEVEL AND DEEP-LAYER SHEAR. AS SUCH...THE PARTICULARLY DANGEROUS SITUATION TORNADO WATCH 165 MAY NEED TO BE EXPANDED EWD INTO MORE OF SERN KS AND POSSIBLY NERN OK IF THIS THREAT CONTINUES TO INCREASE.

Mesoscale Discussion #0525


THE THREAT FOR SEVERE THUNDERSTORMS INCLUDING TORNADOES MAY INCREASE THIS AFTERNOON...AND THE ISSUANCE OF A TORNADO WATCH IS POSSIBLE.

   

CONVECTIVE INITIATION MAY BECOME OF INCREASING CONCERN INTO MID-AFTERNOON OWING TO A FEW APPARENT MESOSCALE PROCESSES:

1. LOW-LEVEL ASCENT ALONG A N-S-ORIENTED DRYLINE FROM THE ERN TX/OK PANHANDLES ACROSS W TX THAT WILL SLOWLY MIX EWD DURING THE NEXT COUPLE OF HOURS...AND MAY AID IN STORM INITIATION. SFC WINDS HAVE SLIGHTLY VEERED WEST OF THE DRYLINE DURING THE LAST HOUR...SUGGESTING THAT THE DRYLINE MAY BE MODESTLY SHARPENING WITH AN ATTENDANT INCREASE IN LOW-LEVEL ASCENT. THE CUMULUS FIELD JUST EAST OF THE DRYLINE APPEARS TO HAVE BECOME INCREASINGLY AGITATED PER RECENT VIS SATELLITE IMAGES...WHICH COULD EVOLVE INTO DEEPENING CONVECTION. STRONG HEATING AND DEEP BOUNDARY-LAYER CIRCULATIONS JUST WEST OF THE DRYLINE WILL ALSO AID IN INITIATION.

2. A SECONDARY MOISTURE GRADIENT IS NOTED 30-50 MILES WEST OF THE DRYLINE...WITH ATTENDANT ASCENT AUGMENTED BY AN EWD-MIGRATING...SUBTLE MID-LEVEL SHORTWAVE TROUGH CROSSING THE AREA PER WATER VAPOR IMAGERY. HIGH-BASED CUMULUS IS DEVELOPING OVER THE CNTRL TX PANHANDLE WHERE THE MID-LEVEL ASCENT OVERLAYS THE SECONDARY MOISTURE GRADIENT...AND THESE FEATURES MAY FOCUS INITIATION IN THE ERN TX PANHANDLE DURING THE NEXT FEW HOURS.

3. A DIFFERENTIAL HEATING ZONE IS NOTED OVER WRN OK FROM ROGER MILLS COUNTY SWD TOWARD WILBARGER COUNTY TX. THE VERTICAL CIRCULATION WITHIN THIS ZONE OWING TO DIFFERENTIAL DIABATIC HEATING AND DIFFERENTIAL VERTICAL MIXING RATES COULD ALSO FOCUS CONVECTIVE INITIATION THIS AFTERNOON.

   

THUNDERSTORMS MAY ERUPT ALONG THE AFOREMENTIONED FEATURES BETWEEN 1930 AND 2100Z. IF CONVECTIVE INITIATION OCCURS...STORMS WOULD RAPIDLY BECOME SEVERE. EFFECTIVE BULK SHEAR MAGNITUDES OF 45-55 KT WILL FAVOR RAPID EVOLUTION TO FAST MOVING SUPERCELL STRUCTURES. WITH 531 M2/S2 OF EFFECTIVE SRH ACCORDING TO THE 17Z NORMAN RAOB...AND A LARGE DEGREE OF STREAMWISE VORTICITY IN THE LOWEST 0.5 KM...TORNADOES...SOME STRONG...WILL BE OF CONCERN...CONTINGENT ON THE INITIATION OF STORMS. THE MORE SUBSTANTIAL THREAT FOR STRONGER TORNADOES WILL BE NORTH OF THE RED RIVER...WHERE THE ISSUANCE OF A PARTICULARLY DANGEROUS SITUATION TORNADO WATCH WILL BE POSSIBLE. THE THREAT COULD BE SOMEWHAT LOWER SOUTH OF THE RED RIVER...WHERE LOW-LEVEL SHEAR MAY NOT BE AS STRONG AND CONVECTIVE COVERAGE NOT AS GREAT.

   

ULTIMATELY...THE ISSUANCE OF A TORNADO WATCH WILL BE CONTINGENT ON AN INCREASINGLY APPARENT UPTICK IN CONVECTION...FOR WHICH SOME UNCERTAINTY REMAINS. SATELLITE AND OBSERVATIONAL TRENDS WILL CONTINUE TO BE MONITORED...WITH A WW...OR PERHAPS MULTIPLE WATCHES...POSSIBLY BEING ISSUED BY MID-AFTERNOON.

Mesoscale Discussion #0527


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 165 CONTINUES.

   

THE THREAT FOR SIGNIFICANTLY TORNADIC SUPERCELLS IS INCREASING OVER PARTS OF SWRN KS INCLUDING THE DODGE CITY AREA. INFLOW INTO DISCRETE SUPERCELLS EVOLVING OVER MEADE AND GRAY/FORD COUNTIES IS LIKELY BECOMING SURFACE BASED PER MODIFIED RUC/OBSERVED SOUNDINGS. SBCAPE VALUES OF 2000-3000 J/KG AMIDST STRONG DEEP-LAYER SHEAR WILL SUPPORT RAPID INTENSIFICATION WITH THESE STORMS. STRONG LOW-LEVEL SHEAR -- 0-1 KM SRH OF 297 M2/S2 PER HAVILAND KS PROFILER THAT ALSO INDICATES A LARGE AMOUNT OF STREAMWISE VORTICITY CONCENTRATED IN THE LOWEST 0.5 KM AGL -- COULD SUPPORT SIGNIFICANT TORNADOES. ADDITIONAL CLUSTERS OF STORMS INCLUDING SUPERCELLS FARTHER NORTH ACROSS THE WW AREA WILL POSE MAINLY A LARGE/VERY LARGE HAIL THREAT AND PERHAPS A COUPLE OF TORNADOES BEFORE A MORE FAVORABLE THERMODYNAMIC ENVIRONMENT FOR SFC-BASED SUPERCELLS ARRIVES WITHIN A FEW HOURS.

Mesoscale Discussion #0529


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 165 CONTINUES.

   

A LARGE...AND POTENTIALLY TORNADIC SUPERCELL IN MITCHELL COUNTY KANSAS IS INTERACTING WITH A NWD-MOVING SFC WARM FRONT. THE BAROCLINIC CIRCULATION ALONG THE WARM FRONT...ALONG WITH STRONGLY UNSTABLE...BACKGROUND SSELY INFLOW OF 20-25 KT PER SFC OBS...WILL SUPPORT A SUSTAINED SUPERCELL/TORNADO THREAT DURING THE NEXT HALF HOUR TO HOUR...POSSIBLY LONGER. THE SUPERCELL MAY REORGANIZE AS A LARGER MASS OF CONVECTION MOVES NEWD FROM LINCOLN COUNTY...WITH ADDITIONAL MESOCYCLONES POTENTIALLY DEVELOPING OVER THE SRN FLANKS OF MERGING CONVECTION THAT MAY APPROACH CLOUD AND OTTAWA COUNTIES...POSSIBLY EVEN FARTHER EAST/NORTHEAST.

Mesoscale Discussion #0530


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 165 CONTINUES.

   

DRYLINE CIRCULATIONS ADJACENT TO A N-S-ORIENTED ZONE OF SFC CONFLUENCE CONTINUE TO FOSTER THE DEVELOPMENT OF DISCRETE SUPERCELLS FROM CNTRL/SWRN KS INTO WRN OK. DURING THE NEXT HALF HOUR TO HOUR...THE HIGHEST THREAT FOR TORNADOES ALONG WITH VERY LARGE HAIL WILL EXTEND FROM CNTRL/SWRN KS INTO NWRN OK WITH NEWD/ENEWD-TRACKING SUPERCELLS CURRENTLY IN HODGEMAN/PAWNEE COUNTIES KS...KIOWA COUNTY KS...HARPER COUNTY OK...AND AN INCIPIENT CONVECTIVE PLUME IN ELLIS COUNTY. VISIBLE SATELLITE IMAGERY SUGGESTS ADDITIONAL CUMULUS DEVELOPING NEAR THE DRYLINE TOWARD THE RED RIVER...AND THE PARTICULARLY DANGEROUS SITUATION TORNADO WATCH 165 HAD EARLIER BEEN EXTENDED SWD TO THE TX/OK BORDER. WITH DEEP-LAYER SHEAR VECTORS EXHIBITING A SUBSTANTIAL DRYLINE-ORTHOGONAL COMPONENT AND EFFECTIVE SRH VALUES OF AROUND 300-500 M2/S2...DISCRETE SUPERCELLS CAPABLE OF PRODUCING TORNADOES...SOME POSSIBLY STRONG TO VIOLENT...ALONG WITH VERY LARGE HAIL AND DMGG STRAIGHT-LINE WINDS WILL BE OF CONCERN.

Mesoscale Discussion #0531


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 165 CONTINUES.

   

THE SVR THREAT WITHIN THE NEXT HOUR OR TWO WILL BE DISTRIBUTED WITHIN 3 SPATIAL REGIMES:

   

1. DISCRETE/POTENTIALLY TORNADIC SUPERCELLS FROM EDWARDS COUNTY KS SWD TO WOODWARD COUNTY OK WILL POSE THE GREATEST THREAT FOR STRONG TO VIOLENT...LONG-TRACK TORNADOES AS THEY TRACK NEWD/ENEWD AMIDST STRONG INSTABILITY. HILLSBORO/HAVILAND PROFILER DATA SUGGEST 0-1-KM SRH AROUND 350 M2/S2 WITH A LARGE AMOUNT OF STREAMWISE VORTICITY WITHIN THE LOWEST 0.5 KM AGL...WHICH WILL ENHANCE THE THREAT FOR SIGNIFICANT TORNADOES.

   

2. FARTHER SOUTH INTO SWRN OK AND FAR ERN PARTS OF THE TX PANHANDLE...THE DRYLINE HAS BECOME JUXTAPOSED WITH A NARROW...NNE-SSW-ORIENTED RIBBON OF MID-LEVEL ASCENT PER WATER VAPOR IMAGERY...SUPPORTING ISOLATED CONVECTIVE INITIATION. CONVECTIVE PLUMES MAY EVOLVE INTO DISCRETE AND POTENTIALLY TORNADIC SUPERCELLS DURING THE NEXT HOUR OR TWO AS THEY ENTER OK WHERE DEEPER MOISTURE AND STRONGER LOW-LEVEL SHEAR ARE PRESENT.

   

3. FARTHER NORTH INTO N-CNTRL KS...A QLCS SEGMENT AND EMBEDDED LEWP STRUCTURE WILL POSE A THREAT FOR DMGG WINDS AND PERHAPS A TORNADO OR TWO WHILE TRACKING ACROSS PARTS OF WASHINGTON COUNTY. THE GREATEST THREAT FOR TORNADOES WITH THIS SYSTEM WILL BE FOUND AT ITS INTERSECTION WITH A W-E-ORIENTED WARM FRONT.

Mesoscale Discussion #0533


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 165 CONTINUES.

   

A NEW WW WILL BE NEEDED PRIOR TO SCHEDULED 23Z EXPIRATION.

   

THE DRY LINE REMAINS ROUGHLY ALONG A LINE FROM GAGE...DODGE CITY INTO THE MCCOOK AREA...AND LATEST RUC GUIDANCE SUGGESTS LITTLE EASTWARD ACCELERATION PRIOR TO THE 00-02Z TIME FRAME...WHEN THE EXIT REGION OF THE MAIN UPPER JET STREAK /AROUND 100 KT AT 500 MB/FINALLY BEGINS TO NOSE NORTHEASTWARD INTO SOUTHWEST KANSAS.  THIS WILL CONTINUE TO PROVIDE A FOCUS FOR INTENSE NEW DISCRETE STORM DEVELOPMENT IN THE PRESENCE OF STEEP LAPSE RATES...MODERATELY LARGE CAPE AND STRONG SHEAR.  50+ KT SOUTHWESTERLY DEEP LAYER MEAN FLOW WILL CONTINUE TO AIDE THE PROPAGATION OF SUPERCELLS AWAY FROM THE INITIATING ZONE...ACROSS CENTRAL...AND PERHAPS PARTS OF EASTERN...KANSAS...AS WELL AS NORTHWEST OKLAHOMA...WHERE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS WILL CONTINUE TO ENLARGE AND BECOME INCREASINGLY SUPPORTIVE OF POTENTIAL FOR STRONG TORNADOES.

Mesoscale Discussion #0534


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 167...169...171...CONTINUES.

   

A NEW WW HAS BEEN ISSUED FOR PORTIONS OF SERN NEB FOR POTENTIAL NEW DEVELOPMENT AND ONGOING CONVECTION TO THE WEST OF AN EXITING MCS. INTENSIFICATION OF STORMS REMAINS POSSIBLE ACROSS SRN IA...AND NRN MO...ESPECIALLY IN ADVANCE OF A BOWING SEGMENT OVER SWRN IA.

   

23Z SURFACE ANALYSIS REFLECTS A DEEPENING SURFACE LOW OVER NWRN KS/SWRN NEB...WITH SURFACE PRESSURE FALLS NOTED OVER NERN NEB/NWRN IA IN RESPONSE TO HEIGHT FALLS ALOFT / A VORT MAX NOTED ON WV IMAGERY OVER SERN WY/NERN CO. WITH A SURFACE LOW DEVELOPING INTO NERN NEB...NOTABLE BACKING IS PROJECTED ACROSS FAR ERN NEB AND IA. AREA VAD WIND PROFILE DATA IS ALREADY SHOWING SIGNIFICANT STRENGTHENING OF LOW LEVEL WINDS.../50 KT AT 1000 FT ACROSS NERN KS/NWRN MO...WITH HODOGRAPHS LARGELY BECOMING FAVORABLE FOR SUPERCELLS CAPABLE OF DMGG WINDS...LARGE HAIL...AND POTENTIALLY SIGNIFICANT TORNADOES. WARM ADVECTION REGIME WILL CONTINUE TO SUPPORT A DESTABILIZING/RECOVERING AIR MASS...WITH NEW DEVELOPMENT OF STORMS POSSIBLE.

Mesoscale Discussion #0535


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 170 CONTINUES.

   

LONG-LIVED...MODESTLY FAST MOVING SUPERCELLS WITH THE POTENTIAL FOR ISOLATED STRONG TORNADOES WILL PERSIST THIS EVENING.

   

SEVERAL DISCRETE SUPERCELLS CONTINUE MOVE NORTHEASTWARD AROUND 30 KT...THROUGH THE OPEN WARM SECTOR OF THE DEEPENING CYCLONE CENTERED OVER THE HIGH PLAINS.  MID-LEVEL FORCING FOR UPWARD VERTICAL MOTION REMAINS WEAK/UNCERTAIN ACROSS NORTH CENTRAL OKLAHOMA AND CENTRAL/EASTERN KANSAS...AND INHIBITION FOR BOUNDARY LAYER PARCELS MAY BEGIN TO INCREASE SOME WITH SURFACE COOLING.  HOWEVER...BENEATH DIFLUENT AND AT LEAST WEAKLY DIVERGENT HIGH LEVEL FLOW...STORM-SCALE DYNAMICS MAY BE STRONG ENOUGH TO MAINTAIN ACTIVITY INTO AT LEAST THE 02-04Z TIME FRAME.  CELLS APPEAR GENERALLY FOCUSED ALONG THE INTENSIFYING LOW-LEVEL JET AXIS /50-70 KT AT 850 MB/...WHERE ENLARGING CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS WILL STILL SUPPORT THE RISK FOR STRONG TORNADOES.

   

THE HIGHEST TORNADIC POTENTIAL MAY BE WITH CELLS DEVELOPING NORTHEASTWARD FROM NORTH CENTRAL OKLAHOMA INTO SOUTH CENTRAL KANSAS...NEAR/SOUTH OF WICHITA...ASSOCIATED WITH INFLOW OF AT LEAST A BIT MORE MOIST AND UNSTABLE AIR THAN CELLS FARTHER NORTH.

   

OTHERWISE...NW STORM DEVELOPMENT WILL CONTINUE BACK TO THE WEST ALONG THE DRY LINE ACROSS THE HIGHER PLAINS...WHICH HAS ACTUALLY RETREATED WESTWARD SOME THE PAST HOUR OR TWO.

Mesoscale Discussion #0540


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 170 CONTINUES.

   

GIVEN INCREASING INHIBITION FOR WARM SECTOR BOUNDARY LAYER PARCELS...THE PERSISTENCE OF THE PAIR OF LONG-LIVED TORNADO PRODUCING SUPERCELLS BEYOND ANOTHER HOUR OR TWO IS SOMEWHAT UNCERTAIN. HOWEVER...THE CELL NOW APPROACHING AREAS SOUTH OF SALINA APPEARS TO BE AIDED BY AN AREA OF STRONGER MID-LEVEL FORCING FOR UPWARD VERTICAL MOTION...DOWNSTREAM OF THE UPPER TROUGH NOW BEGINNING TO LIFT ACROSS THE ROCKIES.  THIS IS EXPECTED TO SHIFT NORTHEASTWARD ACROSS THE I-70 CORRIDOR AREA JUST EAST OF MANHATTAN THROUGH 05-06Z. LATEST RUC GUIDANCE SUGGESTS THAT THIS WILL COINCIDE WITH A 70 KT SOUTHERLY 850 MB JET CORE...WHICH PROBABLY WILL MAINTAIN A HIGH TORNADO RISK.  OTHERWISE...AS LONG AS THE SUPERCELL NOW NEAR WICHITA MAINTAINS STRENGTH AS IT TRACKS NORTHEASTWARD NEAR THE I-35 CORRIDOR...TOWARD THE EMPORIA AREA...THE TORNADO THREAT SHOULD REMAIN HIGH.

Mesoscale Discussion #0542


CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   

VALID 150448Z - 150615Z

   

GIVEN CONTINUED GRADUAL BOUNDARY LAYER COOLING...THERE STILL APPEARS TO BE A GOOD CHANCE THAT THE LONG-LIVED SUPERCELL MIGRATING NORTHEASTWARD ALONG THE I-35 CORRIDOR WILL WEAKEN OR DISSIPATE PRIOR TO PROJECTED PROGRESSION THROUGH THE WESTERN AND NORTHERN KANSAS CITY METROPOLITAN AREA BY 07-08Z.  HOWEVER...IF THIS CELL DOES NOT SHOW SUBSTANTIVE FURTHER WEAKENING TRENDS DURING THE NEXT HOUR...A NEW TORNADO WATCH PROBABLY WILL HAVE TO BE ISSUED.

Mesoscale Discussion #


THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 281...282...CONTINUES.

   

SUMMARY...TORNADO THREAT WILL LIKELY WANE IN THE NEXT HOUR WITH TSTMS DEVELOPING SWWD ALONG THE COLD FRONT ALONG THE KS/OK BORDER.

   

DISCUSSION...NUMEROUS TORNADO REPORTS HAVE OCCURRED IN THE PAST HOUR WITH A TSTM CLUSTER JUST AHEAD OF AND ALONG A COLD FRONT ANALYZED FROM AROUND 20 W CNK TO 20 SE P28. THIS THREAT HAS BEEN MAXIMIZED ALONG THE N/S TO NE/SW INFLECTION POINT OF THE FRONT WITH THE ORIENTATION OF THE CLUSTER...INTERCEPTING THE LOW-LEVEL MOIST AXIS CHARACTERIZED BY LOWER 60S SURFACE DEW POINTS. THIS THREAT WILL WANE AS LOW-LEVEL FLOW HAS COMMENCED WEAKENING PER TIME-SERIES OF ICT VWP DATA. THIS WEAKENING SHOULD PERSIST WITH FLOW BECOMING INCREASINGLY DIVERGENT AS WELL WITH NEB SHORT WAVE IMPULSE PROGRESSING AWAY FROM THE REGION.


**This MCD covered the mesoscale accident event near Harper, KS

Mesoscale Discussion #0900


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 298 CONTINUES.

   

SUMMARY...THREAT FOR LARGE HAIL AND LOCALLY DAMAGING WINDS ALONG WITH ISOLATED TORNADOES CONTINUES ACROSS W CENTRAL KS -- IN AND NEAR TORNADO WATCH 298.

   

DISCUSSION...LATEST RADAR IMAGERY SHOWS A PERSISTENT CLUSTER OF SUPERCELL STORMS ACROSS NESS/RUSH/ELLIS/RUSSELL COUNTIES IN W CENTRAL KS...ALONG A SLOWLY NWD-MOVING WARM FRONT AND JUST EAST OF THE RETREATING DRYLINE.  

   

WHILE THE EVENING DDC RAOB SHOWED A DEEP/WELL-MIXED BOUNDARY LAYER...OBSERVED SURFACE TEMPERATURES ARE ROUGHLY 10 DEGREES F COOLER AND DEWPOINTS ROUGHLY 10 DEGREES F HIGHER NEAR THIS CLUSTER OF STORMS.  THIS COMBINED WITH FAVORABLY VEERING LOW-LEVEL FLOW WITH HEIGHT SUGGESTS THAT ISOLATED TORNADO POTENTIAL WILL CONTINUE FOR AT LEAST ANOTHER HOUR OR TWO BEFORE DIURNAL EFFECTS LIKELY BEGIN TO RESULT IN A SLOW DECREASE IN STORM INTENSITY/SEVERE WEATHER POTENTIAL.


**This MCD preceded the La Crosse, Kansas photogenic EF2 & satellites

Mesoscale Discussion #0954


CONCERNING...OUTLOOK UPGRADE 

   

VALID 291543Z - 291645Z

   

SUMMARY...AN UPGRADE TO MDT RISK APPEARS TO BE WARRANTED ACROSS PORTIONS OF THE NORTHEAST WITH THE 1630Z OUTLOOK. A PRIMARY THREAT OF DMGG WIND IS EXPECTED...THOUGH LARGE HAIL IS ALSO POSSIBLE. AN ENHANCED TORNADO THREAT MAY EXIST ALONG THE HUDSON VALLEY AND PORTIONS OF WRN NEW ENGLAND LATER TODAY.

   

DISCUSSION...NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON WITH THE APPROACH OF A STRONG UPPER TROUGH. WITH VARIOUS AREAS OF INITIATION POSSIBLE AND STORMS APPROACHING FROM THE W...SEVERAL ROUNDS OF THUNDERSTORMS MAY BE POSSIBLE ACROSS THE REGION. GIVEN STRONGER LOW LEVEL WINDS ACROSS CNTRL NY INTO WRN NEW ENGLAND AND THE SEASONABLY MOIST/UNSTABLE AIR MASS...AN UPGRADE TO MDT FOR DMGG WINDS APPEARS WARRANTED. PLEASE SEE THE UPCOMING 1630Z OUTLOOK FOR ADDITIONAL INFORMATION.

Mesoscale Discussion #0958


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 313 CONTINUES.

   

SUMMARY...SEVERE THUNDERSTORMS CAPABLE OF DMGG WINDS AND HAIL/POSSIBLY SIGNIFICANT/ WILL CONTINUE FOR THE WW AREA...GRADUALLY PROGRESSING EWD WITH TIME. TORNADOES REMAIN POSSIBLE...ESPECIALLY INVOF THE HUDSON VALLEY AND A WARM FRONT ACROSS WRN NEW ENGLAND.

   

DISCUSSION...DISCRETE STORMS HAVE DEVELOPED ALONG SEVERAL FEATURES...INCLUDING THE ADIRONDACKS...AND A REMNANT W-E ORIENTED OUTFLOW BOUNDARY ORIENTED ALONG THE MOHAWK VALLEY. AMPLE SURFACE-BASED DESTABILIZATION HAS OCCURRED AMIDST TEMPERATURES IN THE MID TO UPPER 80S AND DEW POINTS IN THE UPPER 60S TO NEAR 70 F. 17Z ALBANY SOUNDING REFLECTS A MODIFIED EML...WITH THE STEEPER MID-LEVEL LAPSE RATES CONTRIBUTING TO SUBSTANTIAL VERTICAL DEVELOPMENT OF THE ONGOING STORMS. WITH STRONGER DEEP-LAYER SHEAR AROUND THE PERIPHERY OF THE RIDGE AND APPROACHING TROUGH...LOCALIZED TERRAIN ENHANCEMENTS TO THE LOW-LEVEL WIND PROFILES AND THE PRESENCE OF A N-S ORIENTED WARM FRONT MAY SUPPORT A THREAT OF TORNADOES WITH THE SUPERCELLS NOW APPROACHING THE HUDSON VALLEY.

Mesoscale Discussion #1258


PROBABILITY OF WATCH ISSUANCE...60 PERCENT

   

SUMMARY...TORNADO THREAT FROM EXPANSIVE OUTER CIRCULATION TS DEBBY CIRCULATION IS INCREASING ESPECIALLY OVER PORTIONS WRN FL...WHERE WW MAY BE REQUIRED.  AT LEAST MRGL TORNADO THREAT ALSO STILL IS APPARENT SEWD ACROSS PORTIONS S FL...AND IN COASTAL SLIVER AS FAR NW AS AAF AREA.

   

DISCUSSION...DESPITE BEING CENTERED WELL W OF PENINSULA OVER GULF...PER NHC ADVISORIES...LARGE LOW-LEVEL WIND ENVELOPE OF TS DEBBY RESULTS IN FAVORABLE LOW-LEVEL SHEAR ACROSS MAJORITY OF FL GULF COAST FROM AAF AREA AROUND W COAST TO EVERGLADES CITY.  TBW VWP HODOGRAPHS HAVE BEEN MOST FAVORABLE WITH 0-1 KM AGL SRH 250-300 J/KG...USING OBSERVED NWD CELL MOTIONS.  WITH SLOW MOVEMENT OF PARENT CYCLONE...AND EXPANSION OF TS WINDS PER NHC SPECIAL ADVISORY...ANY WWD TRANSLATION OF WIND FIELDS SHOULD BE OFFSET BY THAT EXPANDED LOW-LEVEL WIND FIELD...NET EFFECT BEING TO MAINTAIN FAVORABLE SHEAR OVER EXISTING AREAS IN NEAR TERM.

   

ALTHOUGH HODOGRAPHS DECREASE IN SIZE SEWD TOWARD MIA AREA...WITH 0-1 KM SRH LESS THAN 50 J/KG...CIRCULATIONS HAVE BEEN EVIDENT OFFSHORE WHERE LOW-LEVEL VORTICITY MAY BE ENHANCED ALONG WEAK BOUNDARY OVER GULF STREAM.  STRONGEST LOW-LEVEL DESTABILIZATION AND BUOYANCY WILL REMAIN OVER SERN FL WHERE GREATEST DIABATIC SFC HEATING AND LACK OF RAIN-COOLED AIR WILL PERSIST...WHILE LARGEST LOW-LEVEL SHEAR WILL REMAIN OVER W COAST.  LACK OF MLCINH IN VERY MOIST ENVIRONMENT...COMBINED WITH ADVECTION OF HIGHER THETAE AIR NWWD FROM S FL...SHOULD RESULT IN MOST FAVORABLE JUXTAPOSITION OF LOW-LEVEL SHEAR AND MRGL-MDT INSTABILITY OVER W-CENTRAL/SW FL...EVENTUALLY EXTENDING INTO TBW AREA.  MODIFIED RAOBS AND FCST SOUNDINGS SUGGEST MLCAPE NEAR 2000 J/KG OVER EVERGLADES...DECREASING TO 500 J/KG OR LESS BETWEEN PIE-AAF.

Mesoscale Discussion #1261


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 422 CONTINUES.

   

SUMMARY...CONTINUE WW.  TORNADO THREAT REMAINS RELATIVELY MAXIMIZED IN CORRIDOR FROM TBW REGION SEWD ACROSS INTERIOR SWRN FL NEAR BOUNDARY DESCRIBED BELOW.

   

OVERALL THREAT SHOULD SHIFT SLOWLY NWD WITH TIME IN STEP WITH POLEWARD COMPONENT OF CYCLONE TRACK...PER NHC PATH FCST.  AS SUCH...MORE OF NWRN AND PERHAPS CENTRAL FL MAY REQUIRE WW COVERAGE LATER THIS EVENING.

   

DISCUSSION...SFC MESOANALYSIS SHOWS MESOSCALE BAROCLINIC ZONE FROM NEAR FLL-FMY-SRQ...DRIFTING NWD.  N OF THIS BOUNDARY...SFC WINDS ARE SLIGHTLY MORE BACKED...WHILE BUOYANCY DECREASES AND MLCINH INCREASES. MLCAPE TO ITS S AVERAGES AROUND 1500 J/KG...BASED ON MODIFIED RAOBS AND FCST SOUNDINGS...WITH SLGT DECREASE LIKELY AFTER SUNSET DUE TO DIABATIC SFC COOLING.  THAT DECREASE...HOWEVER...WILL BE VERY GRADUAL GIVEN VERY RICH BOUNDARY-LAYER MOISTURE AND SUSTAINED MOISTURE TRANSPORT FROM SERN GULF/STRAITS AIR MASS.  ALONG AND WITHIN ABOUT 60 NM N OF BOUNDARY...AT LEAST MRGL BUOYANCY JUXTAPOSED WITH ENHANCED LOW-LEVEL SHEAR/SRH WILL YIELD RELATIVELY MAXIMIZED CORRIDOR OF TORNADO POTENTIAL FOR ANY RELATIVELY DISCRETE/ROTATING CELLS INTERACTING WITH BAROCLINIC ZONE.  FAVORABLE LOW-LEVEL SHEAR IS EVIDENT FARTHER NE ACROSS E-CENTRAL FL...PER MLB VWP...BUT BOTH REFLECTIVITIES AND CELL-SCALE ROTATION HAVE BEEN WEAKENING AS ACTIVITY MOVES INTO PROGRESSIVELY MORE STABLE AIR MASS WITH NWD EXTENT AWAY FROM FRONT.  TBW VWP REMAINS FAVORABLE WITH 0-1 KM AGL SRH 250-300 J/KG FOR CELL MOTION BEARING SLIGHTLY E OF DUE N...REPRESENTING MOST DEVIANT ROTATION TRACK VECTORS OBSERVED SO FAR IN WDSS DATA.

   

REF NHC ADVISORIES FOR LATEST PATH/INTENSITY/WATCH/WARNING GUIDANCE ON TS DEBBY.

Mesoscale Discussion #1305


PROBABILITY OF WATCH ISSUANCE...80 PERCENT

   

SUMMARY...CLUSTER OF ELEVATED TSTMS CROSSING THE MS VALLEY IN IA/IL SHOULD GROW UPSCALE AND BECOME SURFACE-BASED AS DOWNSTREAM HEATING INTENSIFIES. PRIMARY SEVERE THREATS WILL BE DAMAGING WINDS AND LARGE HAIL...WHICH SHOULD BECOME SCATTERED IN COVERAGE THIS AFTERNOON.

   

DISCUSSION...DOWNSTREAM OF AN MCV OVER ERN NEB...CLUSTER OF ELEVATED TSTMS HAS ERUPTED IN ERN IA INTO NWRN IL. THIS ACTIVITY IS N OF THE QUASI-STATIONARY FRONT EXTENDING FROM NEAR BRL TO IND. WITH EXTREMELY BUOYANT MU PARCELS NOTED IN THE 12Z DVN/ILX RAOBS...MUCAPE AOA 6000 J/KG...CONVECTION-ALLOWING MODELS ARE FAIRLY CONSISTENT THAT AN MCS SHOULD EVOLVE E/SEWD FROM THE MS VALLEY ACTIVITY...ESPECIALLY RECENT HRRR RUNS. WITH INTENSE SURFACE HEATING EXPECTED DOWNSTREAM...THIS SCENARIO APPEARS PROBABLE WITHIN A MODERATE NEARLY UNIDIRECTIONAL WLY FLOW REGIME. GIVEN THE DEGREE OF INSTABILITY...THREATS FOR LARGE HAIL AND DAMAGING WINDS SHOULD INCREASE THROUGH THE AFTERNOON ESPECIALLY WITHIN BOWING LINEAR SEGMENTS.

Mesoscale Discussion #1308


CONCERNING...OUTLOOK UPGRADE 

   

VALID 291907Z - 292000Z

   

SUMMARY...A WIND-DRIVEN MODERATE RISK WILL BE ISSUED AT THE 20Z FOR BOWING MCS CURRENTLY IN IND.

   

DISCUSSION...PLEASE SEE FORTHCOMING 20Z SWODY1 FOR FURTHER INFORMATION.

Mesoscale Discussion #1310


THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 435...436...CONTINUES.

   

SUMMARY...THREAT FOR SCATTERED TO WIDESPREAD DAMAGING WINDS WITH EMBEDDED SIGNIFICANT SEVERE WIND GUSTS WILL PERSIST WITH FAST-MOVING BOWING MCS FROM NWRN OH TO CNTRL IND. AREAS IN THE WAKE OF THE MCS HAVE BEEN SUFFICIENTLY OVERTURNED TO ALLOW FOR CLEARING BEFORE SCHEDULED WW EXPIRATION.

   

DISCUSSION...APEX OF BOWING LINE IS MOVING SEWD AOA 50 KT. THIS LINE HAS HAD A HISTORY OF SIGNIFICANT SEVERE WITH MEASURED WIND GUSTS OF 65-80 KT AND REPORTS OF STRUCTURAL AND SUBSTANTIAL TREE DAMAGE. THIS BOW WILL PROPAGATE ACROSS THE AXIS OF EXTREME INSTABILITY CENTERED ALONG THE OH RIVER TO CNTRL OH...WITH COLD POOL/WARM SECTOR TEMPERATURE DIFFERENTIAL AROUND 30-35 DEG F. AS SUCH...EXPECT THE THRUST OF THE SEVERE WIND THREAT TO EVOLVE ACROSS OH THE NEXT COUPLE OF HOURS /ACROSS THE COLUMBUS OH METRO AREA/ AND EVENTUALLY TOWARDS WV AND FAR NRN KY.

Mesoscale Discussion #1311


THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 436 CONTINUES.

   

SUMMARY...WIDESPREAD/LOCALLY SIGNIFICANT WIND DAMAGE WILL CONTINUE WITH THE ONGOING DERECHO.

   

DISCUSSION...LATEST RADAR LOOP SHOWS A WELL-ORGANIZED/INTENSE BOWING ARC OF STORMS MOVING ESEWD AT 50 KT ACROSS CENTRAL AND SRN OH ATTM. NUMEROUS REPORTS OF WIND DAMAGE AS WELL AS OBSERVED GUSTS IN EXCESS OF 80 MPH HAVE BEEN RECEIVED.  WITH AN EXTREMELY UNSTABLE DOWNSTREAM AIRMASS WHERE SURFACE TEMPERATURES HAVE HEATED INTO THE LOW 100S IN MANY LOCATIONS...EXPECT THE DERECHO TO CONTINUE -- CROSSING THE OH VALLEY AND MOVING INTO THE APPALACHIANS OVER THE NEXT 1-2 HOURS.  EXPECT THAT WIND DAMAGE POTENTIAL WILL CONTINUE INTO VA/MD THIS EVENING...GIVEN THE ORGANIZATION OF THE SYSTEM AND THE FAVORABLE THERMODYNAMIC ENVIRONMENT.  THUS...NEW WW DOWNSTREAM OF WATCH 436 WILL BE ISSUED WHICH WILL EXTEND EWD TO THE CHESAPEAKE BAY.

Mesoscale Discussion #1312


THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 437 CONTINUES.

   

SUMMARY...A CONVECTIVE MASS ACROSS POWESHIEK/IOWA COUNTIES IN IA WILL POSE A HIGH-END SVR THREAT AS IT TRACKS EWD ACROSS IOWA AND JOHNSON COUNTIES...AS WELL AS PARTS OF BENTON AND LINN COUNTIES. THIS MAY IMPACT THE CEDAR RAPIDS AREA AND POINTS SOUTH.

   

DISCUSSION...MID-ALTITUDE RADIAL CONVERGENCE SIGNATURES OF OVER 90 KT IN ASSOCIATION WITH A CONVECTIVE MASS ACROSS POWESHIEK/IOWA COUNTIES IN IA ARE AN INDICATION OF THE POTENTIAL FOR LOCALLY SIGNIFICANTLY SVR SFC WINDS. SVR HAIL IS ALSO EXPECTED. IMPACTS DOWNSTREAM ARE ANTICIPATED...WITH STORMS REACHING THE ERN EXTENT OF LINN/JOHNSON COUNTIES BY AROUND 2300 UTC. SUBTLY BACKED SFC WINDS INVOF LEADING CONVECTIVELY AUGMENTED BOUNDARY ARE SUPPORTING 90 M2/S2 OF 0-1 KM SRH PER DAVENPORT VWP DATA...AND A WEAK/BRIEF TORNADO MAY ALSO OCCUR WITH THE STORM OWING TO EXTREME INSTABILITY/STRONG VERTICAL STRETCHING. STORMS MAY HAVE A PROPENSITY TO EXHIBIT SOME NWD PROPAGATIONAL COMPONENT GIVEN INTERACTION OF DEVELOPING MESOCYCLONE AND AFOREMENTIONED BOUNDARY.

Mesoscale Discussion #2068


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 667 CONTINUES.

   

SUMMARY...TORNADO THREAT CONTINUES ACROSS PARTS OF WW 667.

   

DISCUSSION...LATEST RADAR LOOP REVEALS SEVERAL ROTATING STORMS NOW MOVING ENEWD ACROSS ERN AND SRN AR...WITHIN FAVORABLY MOIST/UNSTABLE/SHEARED ENVIRONMENT.  THE EVENING SHV /SHREVEPORT LA/ RAOB REVEALS A DEEP/MOIST BOUNDARY LAYER AND OVER 2000 J/KG MIXED-LAYER CAPE...ALONG WITH 0-1 KM SHEAR OF 28 KT.  GIVEN THIS...POTENTIAL FOR A STRONG/LONGER-LIVED TORNADO REMAINS EVIDENT WITHIN THIS REGION.

Mesoscale Discussion #2210


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 692...694...CONTINUES.

   

SUMMARY...TORNADO THREAT WILL CONTINUE TO INCREASE ACROSS SE TX INTO SWRN AND CENTRAL LA ACROSS WW 694...WITH A TORNADO POTENTIAL ALSO INTO THE FAR SRN EXTENT OF SVR WW 693.

   

A NEW TORNADO WATCH WILL BE NEEDED TO REPLACE CURRENT WW 692 PRIOR TO 19Z...WITH THE POTENTIAL FOR THIS NEW WW TO BE A PDS GIVEN A SIGNIFICANT INCREASE IN EFFECTIVE SRH THIS AFTERNOON AS THE LLJ STRENGTHENS ACROSS THE LOWER MS VALLEY.

   

DISCUSSION...LATE THIS MORNING...THERE HAS BEEN AN INCREASE IN C LIGHTNING STRIKES ACROSS SE THROUGH EAST CENTRAL TX TO NWRN LA INVOF A SURFACE LOW NOW LOCATED IN FAR EAST CENTRAL TX /NEAR JASPER TX/. THIS LIGHTNING AND SIMILAR INCREASE IN REFLECTIVITIES EXTENDED SSWWD ALONG A DRY LINE/PACIFIC FRONT THROUGH SE TX/UPPER TX COAST /TO THE N-SW OF THE HOUSTON METRO AREA/. TSTMS /MAINLY ELEVATED/ ALSO EXTENDED NEWD OF THE SURFACE LOW INTO NWRN LA. THIS INCREASE IN TSTM DEVELOPMENT IS LIKELY INDICATIVE OF THE ARRIVAL OF STRONG FORCING FOR ASCENT WITHIN THE EXIT REGION OF A 90-100 KT MIDLEVEL JET ACCOMPANYING THE POWERFUL SRN PLAINS SHORTWAVE TROUGH.  SUBSEQUENT AND EXPECTED STRENGTHENING OF A SSWLY LLJ WAS EVIDENT OVER SWRN-CENTRAL LA PER 17Z LCH WSR-88D VAD SHOWING 60 KT AT 1 KM AGL.  THE STRONG VERTICALLY VEERING WINDS HAVE GREATLY ENHANCED THE EFFECTIVE SRH VALUES UP TO 400-600 M2/S2 TO SUPPORT AN INCREASED TORNADO THREAT...EXPECTED TO SPREAD EWD THIS AFTERNOON INTO THE SRN PART OF THE LOWER MS VALLEY...WITHIN THE WARM SECTOR. 

   

LATE MORNING SURFACE ANALYSES SHOWED THE LOW HAS CONTINUED TO DEEPEN AND AT 17Z WAS LOCATED INVOF JASPER TX. A WARM FRONT HAS MOVED STEADILY NWD AND EXTENDED EWD THROUGH CENTRAL LA...SRN MS /N OF KMCB/...TO THE N OF KMOB AND INTO THE WRN FL PANHANDLE.  GIVEN THE LOCATION OF THE WARM FRONT...THE SRN EXTENT OF SVR WATCH 693 WILL ALSO HAVE A TORNADO POTENTIAL AS STORMS WILL BE SFC-BASED OR NEAR SFC-BASED.

   

MEANWHILE...THE WARM FRONT HAS MOVED N OF WW 692...THOUGH THE WARM SECTOR ACROSS THIS WW HAS ONLY SLOWLY DESTABILIZED THUS FAR DUE TO THE MIXING RELATED DECREASE IN THE DEWPOINTS. 18Z SLIDELL SPECIAL SOUNDING INDICATED AN INVERSION LOCATED BETWEEN 700-800 MB AND THIS SHOULD CONTINUE TO INHIBIT DEEPER CU DEVELOPMENT UNTIL THE ARRIVAL OF GREATER ASCENT WITH THE EXIT REGION OF THE IMMEDIATELY UPSTREAM MIDLEVEL JET.  SOME VEERING OF LOW LEVEL WINDS ACROSS SWRN LA SHOULD ADVECT RICHER MOISTURE INTO SERN LA/SRN MS SUPPORTING STRONGER DESTABILIZATION TO SUPPORT AN ENVIRONMENT FAVORABLE FOR SUSTAINED...DEEP UPDRAFTS.

Mesoscale Discussion #2218


THE SEVERE WEATHER THREAT FOR TORNADO WATCH 694...695...CONTINUES.

   

SUMMARY...TORNADO THREAT CONTINUES ACROSS WW 695...WITH LOCAL WFO AREAL EXTENSION ACROSS SOUTH CENTRAL AL. LOCAL WFO TEMPORAL EXTENSION EXPECTED FOR ERN PARTS OF WW 694 UNTIL 23Z FOR A CONTINUED TORNADO THREAT.  THE GREATEST POTENTIAL FOR LONG-LIVED...STRONG TORNADOES EXISTS ACROSS SERN LA /INCLUDING THE NEW ORLEANS METRO AREA/INTO SERN MS.

   

DISCUSSION...MID AFTERNOON SURFACE ANALYSIS SHOWED AN AREA OF LOW PRESSURE OVER WEST CENTRAL MS /W OF JAN/...WITH A WARM FRONT EXTENDING EWD THROUGH ERN MS /15 S MEI/ AND THEN INTO SERN AL AND FAR SRN GA. A MODERATELY UNSTABLE AIR MASS EXISTS IN THE WARM SECTOR WITH EFFECTIVE BULK SHEAR OF 60-70 KT CONTINUING TO SUPPORT ROTATING UPDRAFTS LATE THIS AFTERNOON INTO THE EVENING.  SURFACE OBSERVATIONS AND AREA WSR-88D WIND PROFILES INDICATED A LOW LEVEL CONVERGENCE ZONE EXTENDING FROM THE NWRN GULF /70 SSW HUM/...NNEWD THROUGH SERN LA /INCLUDING THE NEW ORLEANS METRO AREA TO SERN MS /NEAR PIB/...AND THEN INTERSECTING THE WARM FRONT /20 WSW MEI/.  STORMS DEVELOPING WITHIN THIS CORRIDOR HAVE THE GREATEST POTENTIAL TO BE OF DISCRETE MODE AND LONGER-LIVED...GIVEN STRONG EFFECTIVE SRH OF 400-600 M2/S2.

   

MEANWHILE...FARTHER W FROM CENTRAL MS /INVOF JAN/ SWWD INTO SOUTH CENTRAL LA...A QLCS WILL CONTINUE TO REDEVELOP EWD WITH THE THREAT FOR BOTH DAMAGING WINDS AND TORNADOES.  THE LATTER THREAT WILL BE ATTENDANT TO EMBEDDED SUPERCELLS AND/OR MESOVORTICES. HERE TOO...THE EFFECTIVE SRH /300-500 M2 PER S2/ PER OBJECTIVE ANALYSES IS SUPPORTIVE FOR A TORNADO THREAT WITHIN THE QLCS.