Apr 20, 2014 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Sun Apr 20 06:55:49 UTC 2014 (20140420 0730Z Day 3 shapefile | 20140420 0730Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
0730 UTC Day 3 Outlook Graphic
Probabilistic Graphic
20140420 0730 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.
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 200653

   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0153 AM CDT SUN APR 20 2014

   VALID 221200Z - 231200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   A FEW STRONG STORMS MAY FORM ACROSS THE HIGH PLAINS FROM NORTHWEST
   KANSAS INTO SOUTHEAST MONTANA DURING THE AFTERNOON AND EARLY EVENING
   HOURS.

   ...NRN/CNTRL HIGH PLAINS...

   A NOTABLE CHANGE WITHIN THE LARGE-SCALE PATTERN SHOULD LEAD TO
   STRENGTHENING LEE TROUGH ACROSS THE NRN AND CNTRL HIGH PLAINS
   TUESDAY.  LATEST SHORT-RANGE MODEL GUIDANCE IS IN FAIRLY GOOD
   AGREEMENT REGARDING THE EVOLUTION OF UPPER TROUGH AS IT MOVES INLAND
   ACROSS THE INTERIOR NWRN U.S.  BY THE END OF THE PERIOD A
   SUBSTANTIAL SPEED MAX WILL ROUND THE BASE OF THE PROGRESSIVE TROUGH
   AND BEGIN TO EJECT NEWD ACROSS CO/WY.  WHILE THIS FEATURE WILL NOT
   TIME PARTICULARLY WELL FOR HIGH PLAINS CONVECTION DURING THE
   AFTERNOON HOURS...IT APPEARS SUFFICIENT LOW-LEVEL CONVERGENCE WILL
   DEVELOP ALONG THE LEE TROUGH FOR AT LEAST ISOLATED TSTMS DURING PEAK
   HEATING ON DAY3.

   MOISTURE WILL INITIALLY BE SOMEWHAT MARGINAL ACROSS THE HIGH PLAINS
   BUT STRENGTHENING LLJ SHOULD AID MODIFIED BOUNDARY LAYER MOISTURE TO
   ADVECT NNWWD ACROSS WRN KS INTO SERN MT WHERE SFC DEW POINTS ARE
   EXPECTED TO RISE INTO THE 40S.  STRONG HEATING ALONG THIS CORRIDOR
   SHOULD PROVE INSTRUMENTAL IN CONVECTIVE INITIATION WHERE SFC
   TEMPERATURES RISE INTO THE 70S...YIELDING SBCAPE VALUES OF 500-1000
   J/KG.  WHILE ABSOLUTE MOISTURE CONTENT IS EXPECTED TO REMAIN
   MARGINAL...STRENGTHENING WIND FIELDS WILL BECOME INCREASINGLY
   FAVORABLE FOR SUSTAINED ROTATING UPDRAFTS.  FOR THIS REASON...ALONG
   WITH STEEP LAPSE RATES...HAVE OPTED TO INTRODUCE 5 PERCENT SEVERE
   PROBS TO ACCOUNT FOR HAIL/GUSTY WINDS WITH HIGH-BASED CONVECTION.

   ...ERN U.S...

   WEAK POSITIVE-TILT LONG-WAVE TROUGH SHOULD MIGRATE ACROSS THE ERN
   U.S. DURING THE DAY3 PERIOD.  MODEST MOISTURE AND SUFFICIENT
   INSTABILITY SHOULD EXIST AHEAD OF WEAK SFC FRONT FOR ISOLATED-SCT
   TSTMS WITHIN A BROAD CORRIDOR FROM THE LOWER SABINE RIVER VALLEY OF
   THE UPPER TX COAST...NEWD INTO THE NRN MIDDLE ATLANTIC. 
   ENVIRONMENTAL SHEAR/INSTABILITY APPEAR INADEQUATE FOR ORGANIZED
   SEVERE THUNDERSTORMS.

   ..DARROW.. 04/20/2014

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z