Jun 20, 2013 0600 UTC Day 1 Convective Outlook

DAY 1 CONVECTIVE OUTLOOK  

   NWS STORM PREDICTION CENTER NORMAN OK
   1248 AM CDT THU JUN 20 2013

   VALID 201200Z - 211200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS FOR THE NRN/CNTRL PLAINS AND
   UPPER MS VALLEY...

   ...SYNOPSIS...
   A LARGE UPPER TROUGH WILL RESIDE ACROSS THE WRN CONUS DURING THE D1
   FORECAST PERIOD...WHILE DOWNSTREAM...AN UPPER RIDGE WILL BE PRESENT
   FROM THE MO VALLEY INTO THE UPPER MS VALLEY. A SHORTWAVE TROUGH
   LOCATED OVER THE NRN ROCKIES EARLY THIS MORNING WILL LIFT NWD AROUND
   THE ERN EDGE OF THE LARGER-SCALE WAVE INTO CANADA BY LATE MORNING.
   AS THIS OCCURS...A SURFACE LOW PRESSURE SYSTEM WILL OCCLUDE...WITH A
   COLD FRONT/OCCLUDED FRONT ARCING NWWD FROM THE DAKOTAS INTO SRN
   ALBERTA...AND A WARM FRONT EXTENDING SEWD FROM CNTRL ND INTO E-CNTRL
   MN. THE SRN PORTION OF THE COLD FRONT WILL THEN TRAIL SWWD INTO THE
   CNTRL HIGH PLAINS...WHERE A SECOND AREA OF LOW PRESSURE IS FORECAST
   TO RESIDE LATER IN THE AFTERNOON.

   ...NRN/CNTRL PLAINS AND UPPER MS VALLEY...
   A BROAD AREA OF SLY LOW-LEVEL FLOW WILL AID IN TRANSPORTING MID 60S
   DEWPOINTS INTO THE NRN PLAINS AND UPPER MS VALLEY AHEAD OF THE
   SURFACE OCCLUDED/COLD FRONT...WITH UPPER 60S DEWPOINTS POSSIBLE OVER
   ERN NEB AND WRN IA. BY MIDDAY...AN EML IS FORECAST TO SPREAD ACROSS
   THE AREA...WITH STEEP MIDLEVEL LAPSE RATES COMBINED WITH SURFACE
   TEMPERATURES IN THE 80S AND A MOIST BOUNDARY LAYER AIDING IN MLCAPE
   VALUES AOA 2000 J/KG. 

   LATEST MODEL GUIDANCE INDICATES UPPER FORCING FOR ASCENT WILL BE
   NEBULOUS THROUGH LATE AFTERNOON...WITH WEAK/SUBTLE MIDLEVEL
   VORTICITY MAXIMA EJECTING NEWD FROM THE WRN TROUGH.
   HOWEVER...CURRENT THINKING IS AN MCV EMANATING FROM AN MCS OVER ERN
   MT EARLY THIS MORNING WILL ROUND THE UPPER RIDGE AND AID IN RENEWED
   THUNDERSTORM DEVELOPMENT BY AFTERNOON ALONG AND N OF THE WARM FRONT
   OVER ERN ND AND NRN/CNTRL MN. THIS ACTIVITY MAY QUICKLY GROW UPSCALE
   INTO ANOTHER MCS AND MOVE SEWD ALONG THE WARM FRONT. DAMAGING WINDS
   AND LARGE HAIL WILL BE THE PRIMARY THREATS...BUT A COUPLE OF
   TORNADOES WILL ALSO BE POSSIBLE. MCS MAINTENANCE WILL CONTINUE TO BE
   SUPPORTED INTO THE NIGHT AS A SWLY LOW-LEVEL JET STRENGTHENS AND
   EXPANDS NWD INTO THE UPPER MS VALLEY.