SPC AC 311930

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0230 PM CDT SAT OCT 31 2015

   VALID 312000Z - 011200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON ACROSS
   PARTS OF SOUTHEAST LOUISIANA INTO SOUTHERN MISSISSIPPI...

   ...THERE IS A MRGL RISK OF SVR TSTMS INTO THIS EVENING ACROSS
   SURROUNDING CENTRAL GULF COASTAL AREAS...

   ...SUMMARY...
   THUNDERSTORM ACTIVITY ACCOMPANIED BY A RISK FOR LOCALLY DAMAGING
   WIND GUSTS AND ISOLATED TORNADOES WILL CONTINUE ACROSS THE CENTRAL
   GULF COAST REGION INTO THE EVENING HOURS.

   ...20Z OUTLOOK UPDATE...
   SEVERE PROBABILITIES HAVE BEEN ADJUSTED ACROSS THE CENTRAL GULF
   COAST REGION TO ACCOUNT FOR THE EASTWARD PROGRESSION OF THE
   CONGLOMERATE CONVECTIVE OUTFLOW BOUNDARY ACROSS MISSISSIPPI AND
   LOUISIANA.  LOW-LEVEL HODOGRAPHS REMAIN LARGE AND CLOCKWISE CURVED
   AHEAD OF ONGOING CONVECTION ACROSS SOUTHEAST LOUISIANA INTO SOUTHERN
   MISSISSIPPI AND ADJACENT ALABAMA...IN THE PRESENCE OF A SEASONABLY
   MOIST AND WEAKLY UNSTABLE BOUNDARY LAYER AIR MASS.  THIS IS ALIGNED
   ROUGHLY ALONG A STRONG SOUTHERLY 850 MB JET STREAK.  WITH
   TIME...MODELS CONTINUE TO INDICATE THAT THE STRONGER SOUTHERLY 850
   MB FLOW WILL TEND TO SHIFT NORTH NORTHEASTWARD ACROSS THE TENNESSEE
   VALLEY INTO THE APPALACHIANS...WITH LITTLE IF ANY NORTHWARD
   PROGRESSION OF THE UNSTABLE BOUNDARY LAYER.  AS THIS OCCURS...AND
   LOW-LEVEL WIND FIELDS WEAKEN/VEER ACROSS THE CENTRAL GULF COAST
   REGION...DAMAGING WIND/ISOLATED TORNADO POTENTIAL IS EXPECTED TO
   GRADUALLY WEAKEN LATE THIS AFTERNOON AND EVENING.

   AS THE MAIN IMPULSE WITHIN LINGERING UPSTREAM UPPER TROUGHING
   ACCELERATES NORTHEAST OF THE LOWER RIO GRANDE VALLEY LATER
   TONIGHT...THERE STILL APPEARS POTENTIAL FOR RENEWED THUNDERSTORM
   DEVELOPMENT NEAR OR WEST THROUGH SOUTH OF THE ARKLATEX REGION.  IF
   THIS OCCURS...IT IS EXPECTED TO BE GENERALLY ROOTED ABOVE A STABLE
   BOUNDARY LAYER WITH LITTLE APPRECIABLE SEVERE WEATHER RISK.

   ..KERR.. 10/31/2015

   .PREV DISCUSSION... /ISSUED 1108 AM CDT SAT OCT 31 2015/

   ...SYNOPTIC SETUP...
   W TX UPR TROUGH EXPECTED TO BECOME FURTHER REMOVED FROM THE MAIN
   BELT OF THE WLYS THIS PERIOD AS LAST ASSOCIATED JET STREAK...NOW
   ENTERING CHIHUAHUA...CONTINUES E ACROSS NRN MEXICO LATER TODAY/TNGT
   AND APPROACHES THE BRO AREA EARLY SUN. AS A RESULT...THE TROUGH WILL
   ASSUME A MORE NEUTRAL TILT OVER TIME THAT SHOULD MAINTAIN OR
   SLIGHTLY BACK DEEP SWLY FLOW ACROSS THE CNTRL GULF CST.

   AT LWR LVLS...SFC RIDGE WILL CONTINUE TO EDGE E ACROSS THE WRN
   ATLANTIC. THIS WILL ALLOW INCREASINGLY MOISTURE-RICH SSELY FLOW TO
   OVERSPREAD THE CNTRL GULF CST REGION/LWR MS VLY AHEAD OF STALLING F
   OUTFLOW BOUNDARY NOW OVER WRN LA AND ENTERING THE NWRN GULF.

   ...WRN/CNTRL GULF CST AND LWR MS VLY THROUGH EARLY SUN...
   LEWPY SQLN EXPECTED TO CONTINUE MOVING E ACROSS CNTRL/SRN LA
   TODAY...WELL AHEAD OF SLOWLY PROGRESSIVE SSW-NNE COLD FRONT OVER E
   TX. AREA VWP DATA ATTM SHOW ASSOCIATED 40-50 KT SLY LLJ BEGINNING TO
   SLIGHTLY VEER AS SUPPORTING UPR IMPULSE CONTINUES NNE TOWARD THE
   OZARKS. IN ADDITION...MID-LVL LAPSE RATES ACROSS REGION WILL REMAIN
   WEAK...WITH 500 MB TEMPS AROUND MINUS 6 OR 7 C.

   NEVERTHELESS...GIVEN EXISTING WELL-ORGANIZED NATURE OF SQLN WITH
   EMBEDDED SUPERCELLS...STRENGTH OF FLOW /50-60 KTS IN THE 2-5 KM
   LAYER/...AND QUALITY OF MOISTURE RETURN /PW AOA 2 INCHES/...SETUP
   LIKELY WILL CONTINUE TO FOSTER OCCASIONAL LEWPS/BOWS ACROSS
   SRN/CNTRL LA AND SRN MS...WITH AN ATTENDANT THREAT FOR ISOLD
   TORNADOES AND LOCALLY DMGG WIND THROUGH THE DAY. ALTHOUGH THE SVR
   THREAT MAY SOMEWHAT DIMINISH TNGT AS LOW-LVL JET STREAM WEAKENS AND
   FURTHER VEERS...LINGERING STORMS COULD REJUVENATE AND/OR BE
   ACCOMPANIED BY NEW DEVELOPMENT OVER SRN LA AND SRN MS AS LARGE-SCALE
   TROUGH ASSUMES A MORE NEUTRAL TILT AND ADVANCES CLOSER TO REGION.

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z