Apr 19, 2015 0600 UTC Day 1 Convective Outlook

DAY 1 CONVECTIVE OUTLOOK  

   NWS STORM PREDICTION CENTER NORMAN OK
   0103 AM CDT SUN APR 19 2015

   VALID 191200Z - 201200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS OVER PARTS OF THE S-CNTRL
   STATES...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN GREAT PLAINS TO
   THE SOUTHEAST...

   ...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLGT RISK AND
   INCLUDING THE LOWER OH VALLEY...

   ...SUMMARY...
   SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED OVER PARTS OF THE
   SOUTH-CENTRAL STATES MAINLY THIS AFTERNOON AND EVENING...WITH VERY
   LARGE HAIL...DAMAGING WINDS...AND A FEW TORNADOES. ISOLATED SEVERE
   STORMS MAY ALSO OCCUR OVER PARTS OF THE SOUTHEAST STATES THROUGH THE
   PERIOD.

   ...SYNOPSIS...
   A BROAD UPPER TROUGH WILL GRADUALLY SHIFT E AND AMPLIFY OVER THE
   CNTRL CONUS WITH A FEW EMBEDDED SHORTWAVE IMPULSES. OF PARTICULAR
   CONVECTIVE INTEREST IS AN IMPULSE CURRENTLY OVER THE CNTRL HIGH
   PLAINS THAT SHOULD REACH THE CONFLUENCE OF THE MS/OH RIVERS EARLY
   MON. CONVECTIVELY INDUCED IMPULSES FROM E TX TO THE NRN GULF MAY
   EVOLVE NE WITHIN THE BROADER CYCLONIC FLOW REGIME. MEANWHILE...AN
   INTENSE UPPER-LEVEL JET WILL BECOME CENTERED FROM NW MEXICO
   BISECTING TX AND INTO LA. A COMPLEX SURFACE EVOLUTION IS EXPECTED
   GIVEN THE MULTITUDE OF MID-LEVEL IMPULSES. A WEAK SURFACE CYCLONE
   SHOULD TRACK ALONG THE RED RIVER TODAY WHILE LARGE-SCALE
   CYCLOGENESIS SHOULD OCCUR PRIMARILY LATE IN THE PERIOD OVER PARTS OF
   THE MIDWEST. A DRYLINE WILL LIKELY MIX E INTO E TX AND BE OVERTAKEN
   BY A COLD FRONT THAT SHOULD REACH THE LOWER MS VALLEY TO TX GULF
   COAST BY 12Z/MON.

   ...S-CNTRL STATES...
   IN THE WAKE OF DECAYING EARLY MORNING CONVECTION AND AHEAD OF THE
   CNTRL HIGH PLAINS SHORTWAVE IMPULSE...DIABATIC HEATING SHOULD BE
   PRONOUNCED. WITH A GRADUALLY EWD-EXPANDING EML PLUME ATOP RESIDUAL
   60S SURFACE DEW POINTS EMANATING FROM S TX/LA...A MODERATELY TO
   STRONGLY UNSTABLE AIR MASS SHOULD DEVELOP BY LATE DAY IN THE
   ARKLATEX AREA. INITIAL DIURNALLY DRIVEN TSTM DEVELOPMENT WILL
   PROBABLY OCCUR IMMEDIATELY AHEAD OF THE SHORTWAVE IMPULSE OVER PARTS
   OF CNTRL OK WITH THE MAIN HAZARD BEING SEVERE HAIL. ADDITIONAL
   STORMS SHOULD DEVELOP ALONG THE DRYLINE NEAR THE WEAK SURFACE
   CYCLONE BY LATE AFTERNOON AS MLCIN WEAKENS. SETUP SHOULD YIELD
   INITIALLY DISCRETE SUPERCELLS WITH PRIMARY HAZARDS OF VERY LARGE
   HAIL AND A COUPLE TORNADOES. STRENGTHENING 700-500 MB W/SWLYS DURING
   THE EVENING AND PREDOMINANT VEERED LOW-LEVEL WINDS SHOULD TEND TO
   FAVOR UPSCALE GROWTH AND BOWING STRUCTURES WITH A CORRESPONDINGLY
   INCREASE IN THE DAMAGING WIND RISK TOWARDS THE LOWER MS VALLEY.

   ...SOUTHEAST STATES...
   WIDESPREAD CLOUDINESS AND ABUNDANT SHOWERS WITH EMBEDDED TSTM
   ACTIVITY ARE EXPECTED TO BE ONGOING AT 19/12Z...AIDED BY LARGE-SCALE
   HEIGHT FALLS AND A FEW MID-LEVEL VORTICITY MAXIMA. THIS ALONG WITH
   POOR MID-LEVEL LAPSE RATES SAMPLED BY 19/00Z RAOBS ACROSS THE REGION
   WILL HAMPER DIURNAL DESTABILIZATION. NEVERTHELESS...A BELT OF
   STRENGTHENING LOW-LEVEL SLYS FROM THE FL PANHANDLE TOWARDS THE CNTRL
   APPALACHIANS SHOULD YIELD ENLARGED LOW-LEVEL HODOGRAPHS AND
   POTENTIAL FOR A COUPLE TORNADOES AND ISOLATED DAMAGING WINDS.
   GREATER DIABATIC HEATING IS ANTICIPATED FARTHER W OVER PARTS OF
   MS/AL WHERE A REMNANT MCV FROM A DECAYING MCS OVER E TX MAY FOCUS
   AFTERNOON/EVENING TSTM DEVELOPMENT AND PROVIDE SUFFICIENT DEEP SHEAR
   FOR ORGANIZED UPDRAFTS.