SPC AC 071251

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0751 AM CDT THU AUG 07 2014

   VALID 071300Z - 081200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   STRONG THUNDERSTORMS ARE EXPECTED DURING DAYLIGHT HOURS OVER AREAS
   FROM SOUTHERN ILLINOIS INTO ARKANSAS.  ISOLATED DAMAGING GUSTS
   CANNOT BE RULED OUT.  OTHER STRONG TO ISOLATED SEVERE THUNDERSTORMS
   MAY PRODUCE HAIL AND POTENTIALLY DAMAGING GUSTS OVER THE CENTRAL
   HIGH PLAINS REGION.

   ...SYNOPSIS...
   PROGRESSIVE UPPER-AIR PATTERN IS FCST THROUGH PERIOD...AS STG
   SHORTWAVE TROUGH ACCOMPANYING QUE CYCLONE MOVES THROUGH MOST OF NEW
   ENGLAND.  ANOTHER SUBSTANTIAL TROUGH -- EVIDENT IN MOISTURE-CHANNEL
   IMAGERY FROM NRN UT TO SERN NV -- SHOULD SHIFT EWD TO SRN WY AND ERN
   UT THROUGH 12Z...WHILE GRADUALLY LOSING AMPLITUDE.  ON SMALLER
   SCALES...SHORTWAVE TROUGH OVER MO IS ASSOCIATED WITH ONE BINARY MCV
   FEATURE OVER CENTRAL/NWRN MO AND SMALLER MCV BETWEEN TUL-BVO
   ATTM...ALL EVIDENT IN RADAR REFLECTIVITY ANIMATIONS.

   MORE PROMINENT/BINARY CIRCULATION OVER MO AND ACCOMPANYING TROUGH
   ARE FCST TO MOVE SLOWLY EWD TO WRN IL AND SERN MO THROUGH
   PERIOD...PRECEDED BY RELATED SFC/CONVECTIVE BOUNDARY.  THAT BOUNDARY
   WAS ANALYZED AT 12Z ARCHING NEAR STL...UNO...FSM...OUN...JWG...TO
   HARPER COUNTY OK.  THERE...IT INTERSECTED ANOTHER OUTFLOW BOUNDARY
   EMANATING FROM CONVECTION THAT MOVED OVER SWRN NEB OVERNIGHT AND NOW
   IS WEAKENING OVER CENTRAL KS.  THAT BOUNDARY WAS EVIDENT FROM EWK
   THROUGH HARPER COUNTY THEN WNWWD INTO SERN CO...STILL MOVING SWD BUT
   DECELERATING IN CENTRAL/WRN PORTIONS.  AGGREGATE OF THESE OUTFLOW
   BOUNDARIES SHOULD SETTLE ACROSS SERN CO AND WRN/NERN OK THROUGH
   EARLY AFTN...WHILE CONTINUING EWD/SEWD OVER SERN MO AND AR.

   ...CENTRAL HIGH PLAINS...
   ALTHOUGH SHORTWAVE RIDGING PREVAILS OVER MUCH OF THIS REGION
   ATTM...SOME LOSS OF AMPLITUDE AND EWD SHIFT IS EXPECTED THROUGH
   TODAY...WHILE BOUNDARY LAYER DESTABILIZES AFTER DISSIPATION OF
   ONGOING CLOUD COVER.  BY MID-LATE AFTN...WIDELY SCATTERED TSTMS ARE
   EXPECTED TO FORM IN AREAS OF WEAK UPSLOPE FLOW BEHIND THOSE OUTFLOWS
   AND MOVE EWD TO SEWD ACROSS SOME OF ERN CO...WRN KS...SERN WY AND
   WRN NEB.  SFC DEW POINTS MAINLY IN 50S F AND DIABATIC HEATING WILL
   OFFSET MODEST MIDLEVEL LAPSE RATES ENOUGH TO BUILD MLCAPES INTO
   800-1200 J/KG RANGE IN MUCH OF THIS CORRIDOR...WHILE SUBSTANTIALLY
   WEAKENING MLCINH.  VENTING ALOFT WILL BE AIDED BY 60-70-KT SWLY
   250-MB SPEED MAX...WITH DIFLUENCE TO ITS SE.  WITH TSTMS OCCURRING
   OVER WELL-MIXED SUBCLOUD LAYERS...SOME HAIL/GUSTS NEAR SVR LIMITS
   MAY REACH SFC.  ONE OR TWO CLUSTERS OF CONVECTION ALSO MAY COALESCE
   FROM EARLY ACTIVITY AND PERSIST INTO THIS EVENING...ESPECIALLY
   WITHIN AROUND 150 NM N OF AGGREGATE OUTFLOW BOUNDARY.  CONDITIONAL
   POTENTIAL FOR DAMAGING GUSTS EXISTS IN THAT EVENT.

   ...S-CENTRAL PLAINS TO OZARKS...
   CONSIDERABLE ADJUSTMENTS ARE MADE TO MRGL SVR PROBABILITIES IN
   DEFERENCE TO STABILIZING EFFECTS OF EXTENSIVE OVERNIGHT MCS THAT HAS
   MOVED THROUGH MAJORITY OF ORIGINAL AREAS AND IS CONTINUING TO SHIFT
   EWD TO SEWD ATTM...SW-SE-E OF BINARY MCV FEATURE.  AS ASSOCIATED
   MID-UPPER TROUGH PROCEEDS EWD AND OUTFLOW CONTINUES TO SHIFT SEWD
   OVER OZARKS REGION...EXISTING CONVECTION AND/OR RELATED BOUNDARY
   WILL IMPINGE UPON INCREASINGLY WELL-HEATED SFC AIR MASS CONTAINING
   DEW POINTS GENERALLY RANGING FROM UPPER 60S TO LOW 70S F. 
   QUASI-LINEAR ARRANGEMENT OF CONVECTION SHOULD CONTINUE WITH LIFT
   ALONG CURRENTLY PROGRESSIVE PORTION OF OUTFLOW
   BOUNDARY...ENCOUNTERING MLCAPE RANGING FROM 2000-2500 J/KG OVER AR
   TO 1000-1500 J/KG IN EXTREME SRN IL. WEAKNESS OF LOW-MIDDLE-LEVEL
   WINDS AND OF VERTICAL SHEAR SUGGESTS MULTICELLS WITH MOISTURE-LOADED
   DOWNDRAFTS ARE POSSIBLE...SOME POTENTIALLY REACHING DAMAGING
   INTENSITIES.

   ..EDWARDS/SMITH.. 08/07/2014

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