Sep 18, 2014 0600 UTC Day 1 Convective Outlook
Updated: Thu Sep 18 05:25:46 UTC 2014 (20140918 1200Z Day 1 shapefile | 20140918 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140918 1200 UTC Day 1 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Tornado Graphic
20140918 1200 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20140918 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 187,830 9,395,128 Tulsa, OK...Wichita, KS...Little Rock, AR...Salt Lake City, UT...Savannah, GA...
Probabilistic Large Hail Graphic
20140918 1200 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 186,052 9,304,412 Tulsa, OK...Wichita, KS...Little Rock, AR...Salt Lake City, UT...Savannah, GA...
   SPC AC 180525

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1225 AM CDT THU SEP 18 2014

   VALID 181200Z - 191200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   ISOLATED STRONG STORMS...POSSIBLY SEVERE...WILL DEVELOP ACROSS
   COASTAL SOUTH CAROLINA AND COASTAL GEORGIA.  A FEW SEVERE STORMS MAY
   ALSO DEVELOP FROM THE ARKLATEX REGION INTO SOUTH CENTRAL KANSAS AND
   FROM SOUTHERN MONTANA INTO NORTHERN UTAH.  GUSTY WINDS AND HAIL ARE
   THE PRIMARY THREATS.

   ...COASTAL SC/GA...

   MEAN LONG-WAVE TROUGH IS EXPECTED TO HOLD ACROSS THE ERN U.S.
   THROUGH THE UPCOMING DAY1 PERIOD WITH MODEST NWLY FLOW ON THE ORDER
   OF 15-20KT AT 500MB FORECAST ACROSS GA/SC DURING THE DAY.  LOW LEVEL
   CONVERGENCE SHOULD FOCUS NEAR THE COAST WITH INTERIOR BOUNDARY LAYER
   HEATING EXPECTED TO AID CONVECTIVE DEVELOPMENT BY MID-DAY.  LATEST
   NAM FORECAST SOUNDINGS SUGGEST 2000 J/KG SBCAPE SHOULD BE UNCAPPED
   BY 18Z AND ANY STORMS THAT FORM ALONG THIS DIURNALLY ENHANCED SEA
   BREEZE SHOULD DRIFT SOUTH TOWARD THE COAST.


   ...KS TO THE ARKLATEX...

   SEVERAL BOUTS OF WARM-ADVECTION CONVECTION ACROSS ERN KS/SRN MO
   SHOULD FORCE EFFECTIVE SFC BOUNDARY SWWD TO A POSITION FROM SCNTRL
   KS...SEWD INTO THE ARKLATEX.  WITH SFC PRESSURES EXPECTED TO RISE
   ACROSS THE MID-MS VALLEY THIS FRONT SHOULD BE DISPLACED A BIT
   FARTHER SW ON THURSDAY WHERE A CONCENTRATION OF CONVECTION IS
   EXPECTED.  FORECAST SOUNDINGS SUGGEST A NARROW CORRIDOR OF STRONG
   HEATING SHOULD CONTRIBUTE TO 2500-3000 J/KG SBCAPE WITHIN MODEST
   WARM ADVECTION REGIME.  GUSTY WINDS AND SOME HAIL MAY ACCOMPANY THE
   STRONGEST CONVECTION...SIMILAR TO WEDNESDAY AFTERNOON WHEN A FEW
   TSTM CLUSTERS DEVELOPED OVER SRN MO AND PROPAGATED SSWWD. 


   ...SRN MT TO NRN UT...

   SIGNIFICANT BAROCLINIC ZONE WILL ADVANCE ACROSS THE INTER-MOUNTAIN
   REGION TO A POSITION FROM WRN MT...ERN ID INTO NV BY PEAK HEATING. 
   STRONG HEATING IS EXPECTED ALONG THIS CORRIDOR AND HIGH-BASED
   CONVECTION SHOULD DEVELOP BY 22-23Z WITHIN DEEP SWLY FLOW REGIME
   CHARACTERIZED BY MODEST BULK SHEAR IN THE LOWEST 6KM...ROUGHLY
   30-35KT.  GUSTY WINDS AND MARGINALLY SEVERE HAIL COULD BE NOTED WITH
   THIS PRE-FRONTAL CONVECTION.

   ..DARROW/COHEN.. 09/18/2014

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z