SPC Day 1 Convective Outlook Valid 20Z 14 October 2014

   SPC AC 141937

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0237 PM CDT TUE OCT 14 2014

   VALID 142000Z - 151200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON INTO
   TONIGHT ACROSS PARTS OF THE SOUTHEAST AND SOUTHERN/CENTRAL
   APPALACHIANS...

   ...SUMMARY...
   THUNDERSTORMS WITH LOCALLY DAMAGING WIND AND ISOLATED TORNADOES MAY
   OCCUR THROUGH THIS EVENING OVER PARTS OF THE CENTRAL AND SOUTHERN
   APPALACHIANS...THE CAROLINAS...GEORGIA...AND NORTHERN FLORIDA.
   AFTERNOON STORMS WITH MARGINALLY SEVERE HAIL AND STRONG GUSTS ALSO
   MAY OCCUR FROM PARTS OF THE MIDWEST SOUTHEAST INTO THE MID-OHIO
   VALLEY.

   ...20Z OUTLOOK UPDATE...
   CATEGORICAL AND PROBABILISTIC LINES HAVE BEEN ADJUSTED TO ACCOUNT
   FOR THE SLOW EASTWARD PROGRESSION OF THE ELONGATED CLOSED LOW/UPPER
   TROUGH...AND THE LEADING EDGE OF ASSOCIATED LOW-LEVEL COOLING/DRYING
   EAST OF THE MISSISSIPPI VALLEY.  OTHERWISE...THERE ARE GENERALLY NO
   CHANGES TO EITHER THE PRIOR OUTLOOK AREA OR REASONING APPENDED
   BELOW.

   ..KERR.. 10/14/2014

   .PREV DISCUSSION... /ISSUED 1125 AM CDT TUE OCT 14 2014/

   ...SYNOPTIC SETUP...
   ELONGATED MO-IL TROUGH SHOULD CONTINUE SLOWLY E THROUGH EARLY WED AS
   UPSTREAM TROUGH REACHES THE PACIFIC NW. LEAD SHORTWAVE IMPULSE
   WITHIN THE MO-IL SYSTEM...NOW OVER CNTRL IL...SHOULD MOVE NNE INTO
   LWR MI BY THIS EVE...WHILE ARKLATEX SHORTWAVE IMPULSE CONTINUES E
   INTO AL/E TN. TO THE EAST...RIDGE WILL FURTHER AMPLIFY OVER THE WRN
   ATLANTIC.

   AT LWR LVLS...SFC LOW NOW N OF ST LOUIS SHOULD DRIFT NE TO NEAR
   GRAND RAPIDS THIS EVE AND BECOME STNRY AS TRAILING OCCLUDED/COLD
   FRONT ADVANCES NE/E ACROSS THE OH AND TN VLYS. FARTHER E...EXPECT
   WEAK FRONT NOW EXTENDING FROM WRN VA SSE TO OFF THE SC CST TO EDGE
   ONLY SLOWLY E THROUGH THE PERIOD.

   ...NRN FL/SRN GA THIS TODAY...
   BROKEN SQLN NOW EXTENDING FROM SW GA SSW INTO THE ERN GULF OF MEXICO
   IS LOCATED RELATIVELY CLOSE TO ASSOCIATED COLD FRONT. LARGE-SCALE
   ASCENT WILL BE NEUTRAL-TO-WEAK AS ARKLATEX SHORTWAVE IMPULSE REMAINS
   WELL TO THE WEST OF THE REGION UNTIL LATE IN THE DAY.
   NEVERTHELESS...SFC HEATING WILL SUPPORT AT LEAST MODEST DIURNAL
   DESTABILIZATION OF VERY MOIST /2-INCH PW/ LOW-LVL ENVIRONMENT AMIDST
   35-40 SSWLY DEEP SHEAR. THIS SETUP MAY SUPPORT SOME INTENSIFICATION
   AND OR RE-DEVELOPMENT OF THE STORMS DURING THE AFTN...WITH AN
   ASSOCIATED RISK FOR LOCALLY DMGG WIND AND POSSIBLY A TORNADO OR TWO
   EWD TOWARD THE FL-GA ATLANTIC CST /REF WW 547/.

   ...NRN GA/UPSTATE CAROLINAS NWD INTO CNTRL APPALACHIANS
   TODAY/TNGT...
   NRN PART OF SAME SQLN AFFECTING S GA AND THE FL PANHANDLE HAS
   PROGRESSED COMPARATIVELY FARTHER E OF ASSOCIATED COLD FRONT AND
   UPR-LVL SUPPORT. SQLN CLOUD DEBRIS WILL LIMIT SFC HEATING...AND
   MORNING UPR AIR DATA SUGGEST THAT WEAK WARMING WILL OCCUR OVER THE
   REGION AT MID-LVLS. BUT GIVEN VERY STRONG /50-60 KTS AT 700
   MB/...DEEP UNIDIRECTIONAL SLY FLOW ON ERN SIDE OF SLOWLY-PROGRESSIVE
   LARGE-SCALE TROUGH...EVEN SFC MODEST HEATING COULD PROMOTE
   SUFFICIENT UPDRAFT STRENGTHENING TO YIELD A RISK FOR LOCALLY DMGG
   WIND AND POSSIBLY A COUPLE TORNADOES. THIS RISK COULD REACH NWD FROM
   NE GA/UPSTATE SC INTO PARTS OF TN...ERN KY...VA...AND WV THROUGH
   TNGT.

   ...FAR ERN SC NWD INTO CNTRL VA TODAY/TNGT...
   WEAK...PREVIOUSLY MENTIONED N-S FRONT WILL SERVE AS A FOCUS FOR
   LOW-LVL CONFLUENCE/POTENTIAL STORM DEVELOPMENT TODAY FROM FAR ERN SC
   THROUGH CNTRL NC INTO CNTRL VA. WHILE WEAK WARM ADVECTION IS
   EXPECTED OVER THE REGION AT MID-LVLS...AND FORCING FOR ASCENT WILL
   BE MINIMAL...SSWLY DEEP SHEAR WILL STRENGTHEN WITH THE CONTINUED EWD
   MOTION OF MO-IL UPR TROUGH. GIVEN 40-45 KT SLY LOW-LVL FLOW ALREADY
   PRESENT OVER THE REGION...AND SLIGHTLY-BACKED NEAR-SFC WINDS NEAR
   FRONT...ANY INTENSIFYING STORMS ALONG THE BOUNDARY COULD POSE A
   CONDITIONAL RISK FOR LOCALLY DMGG WIND AND PERHAPS A
   TORNADO...ESPECIALLY LATER THIS AFTN/EARLY TNGT.

   ...NRN IL-IND-SW MI SSE INTO MID-OH VLY THIS AFTN/EVE...
   SATELLITE SUGGESTS THAT AT LEAST POCKETS OF ENHANCED SFC HEATING
   WILL OCCUR ALONG/AHEAD OF OCCLUDED/COLD FRONT OVER PARTS OF THE
   MIDWEST/OH VLY TODAY AND NEAR ASSOCIATED SFC LOW. RELATIVE TO
   YESTERDAY...SOMEWHAT COLDER AIR ALOFT WILL OVERLIE NRN PARTS OF THE
   PRE-FRONTAL WARM SECTOR. THIS SETUP COULD SUPPORT A CONDITIONAL RISK
   FOR DIURNALLY-DRIVEN STORMS CAPABLE OF MARGINALLY SVR HAIL/LOCALLY
   DMGG WIND AND PERHAPS A BRIEF TORNADO INTO EARLY TNGT.

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