SPC AC 251953

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0253 PM CDT WED MAR 25 2015

   VALID 252000Z - 261200Z

   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CNTRL AND NERN
   OK...FAR SE KS...FAR SW MO AND FAR NW AR...

   ...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PARTS OF OK...FAR SE
   KS...NRN AR AND SRN MO...

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
   PLAINS...OZARKS...MID MS VALLEY AND OH VALLEY...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
   PLAINS...CNTRL PLAINS...OZARKS...MID MS VALLEY AND OH VALLEY...

   ...SUMMARY...
   NUMEROUS SEVERE THUNDERSTORMS...CAPABLE OF VERY LARGE
   HAIL...DAMAGING WINDS AND PERHAPS A TORNADO ARE EXPECTED OVER PARTS
   OF THE SOUTHERN PLAINS AND OZARKS LATE THIS AFTERNOON AND
   EVENING...PERHAPS CONTINUING INTO PARTS OF THE LOWER OHIO VALLEY
   LATE TONIGHT.

   THE ONLY CHANGE TO THE OUTLOOK IS TO WIDEN THE SLIGHT AND MARGINAL
   RISK AREAS JUST A BIT OVER SCNTRL MO AND CNTRL AR. STRONG
   THUNDERSTORMS JUST NORTH OF SPRINGFIELD MO ARE IN THE NRN EDGE OF WW
   6. THE CHANGE MAKES SURE THAT THESE AREAS ARE NOW CONTAINED BY THE
   SLIGHT RISK AREA. CONCERNING CONVECTIVE TRENDS IN NW TX...REFERENCE
   MCD 141.

   ..BROYLES.. 03/25/2015

   .PREV DISCUSSION... /ISSUED 1130 AM CDT WED MAR 25 2015/

   ...SYNOPSIS...
   WITHIN A BROAD UPPER-LEVEL TROUGH OVER THE CENTRAL CONUS...A
   SHORTWAVE IMPULSE OVER WY/CO WILL MOVE EAST ACROSS KS/OK THIS
   AFTERNOON AND INTO THE OZARKS/MID-MS VALLEY BY 12Z THURSDAY. TWO
   WEAKER UPPER-LEVEL IMPULSES OVER WRN NM AND W TX WILL ALSO MOVE
   ACROSS THE SRN PLAINS THIS AFTN/EVENING. A SURFACE COLD FRONT NOW
   MOVING SWD THROUGH THE CENTRAL PLAINS WILL SURGE SWD ACROSS THE SRN
   PLAINS TONIGHT...WHILE A FRONTAL BOUNDARY THAT MOVED THROUGH THE SRN
   PLAINS/OZARKS TUESDAY WILL LIFT NORTH TODAY. SLY LOW-LEVEL FLOW
   ACROSS THE SRN PLAINS TODAY WILL RESULT IN UPPER 50S/NEAR 60 DEW
   POINTS AS FAR NORTH AS CENTRAL/ERN OK...AR...EWD TO WRN PORTIONS OF
   TN/KY. 

   ...SRN PLNS/OZARKS TO LWR OH VLY TODAY/TNGT...
   BROAD SURFACE LOW OVER THE TX PANHANDLE WILL BECOME BETTER FOCUSED
   BY MID/LATE AFTN ACROSS SWRN/W-CENTRAL OK...WITH A NEARLY STATIONARY
   FRONTAL BOUNDARY EXTENDING EWD FROM THE LOW ACROSS SRN PORTIONS OF
   MO/IL. A DRY LINE WILL EXTEND SWD FROM THE SURFACE LOW ACROSS WRN
   PORTIONS OF N TX. LATER THIS EVENING...THE STRONGER COLD FRONT WILL
   OVERTAKE THIS FRONTAL BOUNDARY AND BECOME THE PRIMARY SURFACE
   FEATURE.

   STG/ISOLD SVR TSTMS WITH A THREAT FOR LARGE HAIL WILL CONTINUE TO
   DEVELOP NORTH OF THE SFC BOUNDARY OVER S-CENTRAL/SERN KS AIDED BY
   LOW-LEVEL WAA. REF MCD 138 FOR THE LATEST SHORT-TERM DETAILS IN THIS
   AREA. BY MID-AFTN...STRENGTHENING LOWER-MID TROPOSPHERIC WIND
   FIELDS...STEEP MID-LEVEL LAPSE RATES AND INCREASING BOUNDARY LAYER
   MOISTURE WILL RESULT IN A VERY FAVORABLE ENVIRONMENT FOR RAPID
   SURFACE-BASED SVR TSTM DEVELOPMENT FROM SRN MO/NRN AR WWD TO
   NRN/CENTRAL OK. STRONG DIURNAL HEATING AND MODEST LARGE-SCALE
   FORCING FOR ASCENT WILL COMBINE TO REDUCE CINH ACROSS NRN OK EWD TO
   SRN MO/AR. INITIALLY DISCRETE SUPERCELL STORMS WILL POSE A LARGE
   HAIL/DAMAGING WIND RISK...WITH A TORNADO POSSIBLE. VERY LARGE
   HAIL...IN EXCESS OF TWO INCHES IN DIAMETER...IS POSSIBLE GIVEN THE
   STEEP MID-LEVEL LAPSE RATES IN PLACE. ORIENTATION OF SHEAR VECTORS
   RELATIVE TO THE FRONTAL BOUNDARY SUGGESTS EVENTUAL EVOLUTION INTO
   SHORT BOWING SEGMENTS IS LIKELY WITH DAMAGING WINDS THE DOMINANT
   RISK EWD THROUGH THE OH RIVER VALLEY TONIGHT.

   ACROSS CENTRAL/SWRN OK...LAST SEVERAL RUNS OF THE NCEP HRRR ARE
   CONSISTENT IN DEVELOPING SUPERCELLS NEAR THE SURFACE LOW AND ALONG
   THE DRYLINE BY MID TO LATE AFTN. THESE STORMS WOULD POSE A RISK FOR
   VERY LARGE HAIL AND DAMAGING GUSTS FOR A FEW HOURS BEFORE BEING
   UNDERCUT BY THE ADVANCING COLD FRONT. ALTHOUGH A TORNADO OR TWO WILL
   BE POSSIBLE...LARGE SFC TEMP-DEW POINT SPREADS AND RESULTANT HIGH
   LCL HEIGHTS WILL TEND TO MITIGATE POTENTIAL FOR PERSISTENT LOW-LEVEL
   ROTATION. WITH TIME...STORMS SHOULD DEVELOP A MORE LINEAR STRUCTURE
   ALONG THE COLD FRONT ACROSS ERN OK.

   FARTHER SOUTH...MORE ISOLD SVR TSTM DEVELOPMENT IS PSBL SWD ALONG
   THE DRYLINE INTO PORTIONS OF N TX THROUGH EARLY EVENING WHERE A
   MODERATELY UNSTABLE AIR MASS WILL EXIST IN THE PRESENCE OF 40-45 KTS
   OF DEEP-LAYER SHEAR. LARGE HAIL AND DAMAGING GUSTS WILL BE THE
   PRIMARY THREATS. LATER TONIGHT...TSTM COVERAGE SHOULD INCREASE ALONG
   THE COLD FRONT INTO N TX.  

   ...CAROLINAS...
   TSTMS WILL BE POSSIBLE ALONG A CONFLUENCE ZONE AND WITHIN A MOIST
   /PW AOA ONE INCH/ AIR MASS TONIGHT ACROSS PORTIONS OF THE CAROLINAS.
   WHILE A WEAKLY ROTATING STORM IS NOT OUT OF THE QUESTION...FORECAST
   SOUNDINGS SUGGEST THE OVERALL SVR RISK IS LOW AND WILL NOT INTRODUCE
   SVR PROBS WITH THIS OUTLOOK.

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