Dec 20, 2014 0830 UTC Day 3 Severe Thunderstorm Outlook
Updated: Sat Dec 20 08:28:16 UTC 2014 (20141220 0830Z Day 3 shapefile | 20141220 0830Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
0830 UTC Day 3 Outlook Graphic
Day 3 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Graphic
20141220 0830 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 3 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 200828

   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0228 AM CST SAT DEC 20 2014

   VALID 221200Z - 231200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   SHOWERS AND A FEW THUNDERSTORMS WILL BE POSSIBLE FROM THE LOWER
   MISSISSIPPI VALLEY INTO THE GULF COAST STATES AND NORTHERN FLORIDA
   MONDAY AND MONDAY NIGHT.

   ...SYNOPSIS...

   MODEL CONSENSUS IS THAT SYNOPTIC UPPER TROUGH WILL UNDERGO FURTHER
   AMPLIFICATION OVER THE CNTRL U.S. EARLY MONDAY AS A STRONG UPPER JET
   DROPS SWWD THROUGH THE CNTRL AND SRN ROCKIES. THE UPPER TROUGH WILL
   BE ACCOMPANIED BY A COLD FRONT THAT WILL EXTEND FROM THE UPPER MS
   VALLEY SWWD THROUGH CNTRL TX BY THE END OF THE PERIOD. FARTHER
   DOWNSTREAM...A WARM FRONT WILL LIFT NWD INTO TO THE GULF COAST
   REGION MONDAY NIGHT. 

   ...LOWER MS VALLEY REGION...

   THE BOUNDARY LAYER OVER THE GULF WILL CONTINUE TO MODIFY WITH A
   BROAD FETCH OF SLY NEAR-SFC WINDS SUPPORTING DEWPOINTS IN THE UPPER
   60S TO NEAR 70 OFFSHORE AND LOW-MID 60S ADVECTING INLAND MONDAY
   NIGHT AS WARM FRONT LIFTS NWD. STEEPER MID-LEVEL LAPSE RATES WILL
   SPREAD EWD AND EVENTUALLY INTERCEPT WRN FRINGE OF RICHER LOW-LEVEL
   MOISTURE FROM SERN TX INTO THE LOWER MS VALLEY WHERE MUCAPE COULD
   APPROACH 1500 J/KG MONDAY NIGHT. CAPE WILL REMAIN MARGINAL FARTHER
   EAST INTO THE GULF COAST STATES. SLY LLJ WILL STRENGTHEN OVERNIGHT
   AS THE UPPER TROUGH AMPLIFIES...RESULTING IN AN INCREASE IN FORCING
   FOR ASCENT. SHOWERS AND A FEW THUNDERSTORMS SHOULD DEVELOP LATER
   MONDAY NIGHT...MOST LIKELY ON THE ERN FRINGE OF THE EML WHERE THE
   CAP WILL BE WEAKER FROM A PORTION OF THE LOWER MS VALLEY INTO THE
   GULF COAST STATES. STRONG EFFECTIVE BULK SHEAR IN PRESENCE OF AT
   LEAST MODEST CAPE RAISES CONCERN FOR AT LEAST A MARGINAL SEVERE
   RISK. HOWEVER...TIME OF DAY AND LIKELIHOOD THAT RICHER MOISTURE WILL
   REMAIN OFFSHORE SUGGEST CONVECTION WILL PROBABLY BE ELEVATED ABOVE A
   STABLE SFC LAYER. NEVERTHELESS...A FEW STORMS COULD POSE A THREAT
   FOR MARGINALLY SEVERE HAIL.

   ..DIAL.. 12/20/2014

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0830Z