May 15, 2014 0600 UTC Day 1 Convective Outlook

DAY 1 CONVECTIVE OUTLOOK  

   NWS STORM PREDICTION CENTER NORMAN OK
   1241 AM CDT THU MAY 15 2014

   VALID 151200Z - 161200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF VA AND THE
   CAROLINAS...

   ...SUMMARY...
   SEVERE THUNDERSTORMS CAPABLE OF DAMAGING WINDS AND A FEW TORNADOES
   WILL BE POSSIBLE TODAY OVER PARTS OF VIRGINIA AND THE CAROLINAS.

   ...SUMMARY...
   A DEEP UPPER TROUGH IS PRESENT OVER THE CENTRAL UNITED STATES...WITH
   A SERIES OF SHORTWAVE TROUGHS ROTATING ACROSS THE SOUTHERN PLAINS
   INTO THE EASTERN STATES.  DEEP SOUTHERLY WINDS EAST OF THE UPPER
   TROUGH HAVE RESULTED IN A PLUME OF MOIST/UNSTABLE AIR FROM FL TO
   NY...WHERE SCATTERED THUNDERSTORMS ARE EXPECTED TODAY.  DESPITE
   SUFFICIENT LOW LEVEL AND DEEP LAYER SHEAR FOR ORGANIZED/SEVERE
   STORMS...WIDESPREAD CLOUDINESS AND PRECIPITATION WILL LIKELY HINDER
   THE DEVELOPMENT OF INTENSE THUNDERSTORMS OVER MOST AREAS.  THEREFORE
   HAVE MAINTAINED A LARGE AREA OF ONLY MARGINAL SEVERE WEATHER
   PROBABILITIES.

   ...VA/CAROLINAS...
   ONE AREA THAT APPEARS TO HAVE A MORE FOCUSED RISK OF SEVERE STORMS
   IS OVER VA AND THE CAROLINAS THIS AFTERNOON AND EVENING.  LOW LEVEL
   CYCLOGENESIS IS FORECAST TO BEGIN LATER THIS MORNING OVER PARTS OF
   GA AND THE WESTERN CAROLINAS.  AS THIS OCCURS...STRENGTHENING
   SOUTHERLY LOW LEVEL WINDS WILL ENLARGE THE HODOGRAPHS AND ENHANCE
   WARM ADVECTION/LIFT.  INSTABILITY WILL BE A LIMITING FACTOR DUE TO
   EXTENSIVE CLOUDS/PRECIPITATION.  HOWEVER...WITH DEWPOINTS IN THE
   MID/UPPER 60S...EVEN MODEST HEATING COULD BE SUFFICIENT FOR A FEW
   STRONG TO SEVERE STORMS.  EMBEDDED SUPERCELL STRUCTURES CAPABLE OF
   DAMAGING WINDS AND/OR ISOLATED TORNADOES APPEAR TO BE THE MAIN RISK.

   DURING THE EVENING...IT APPEARS POSSIBLE THAT CONVECTION WILL
   ORGANIZE UPSCALE WITH A QLCS TRACKING EASTWARD ACROSS PARTS OF
   VA/NC.  AGAIN...INSTABILITY AND UNCERTAINTY REGARDING BOUNDARY LAYER
   LAPSE RATES WILL BE THE LIMITING FACTOR FOR SEVERE STORMS...AND IS
   THE REASON FOR NOT EXTENDING THE SLIGHT RISK FARTHER EAST. THIS AREA
   WILL NEED FURTHER EVALUATION IN LATER UPDATES.

   ...ARKLATEX...
   A POCKET OF COLD MID LEVEL TEMPERATURES WILL RESIDE OVER MUCH OF THE
   CENTRAL UNITED STATES TODAY...WITH 500MB TEMPERATURES AOB -20C
   ACROSS MUCH OF OK/AR AND NORTHEAST TX.  MEANWHILE...A SECONDARY
   SHORTWAVE TROUGH AND ASSOCIATED MID LEVEL JET MAX WILL BEGIN TO
   AFFECT THE ARKLATEX REGION DURING THE AFTERNOON.  STEEP LOW/MID
   LEVEL LAPSE RATES WILL COMPENSATE FOR MEAGER LOW LEVEL MOISTURE
   /SURFACE DEWPOINTS IN THE 40S/...YIELDING MLCAPE VALUES OF 400-800
   J/KG.  SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP
   IN EASTERN OK AND NORTHEAST TX...TRACKING INTO PARTS OF AR/LA DURING
   THE EVENING BEFORE WEAKENING.  THE STRONGER CELLS WILL BE CAPABLE OF
   HAIL.