Sep 23, 2014 1300 UTC Day 1 Convective Outlook
Updated: Tue Sep 23 12:42:14 UTC 2014 (20140923 1300Z Day 1 shapefile | 20140923 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140923 1300 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
20140923 1300 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
20140923 1300 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 % 49,156 366,248 Kearney, NE...Garden City, KS...Dodge City, KS...North Platte, NE...Hays, KS...
Probabilistic Large Hail Graphic
20140923 1300 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 % 41,725 292,010 Garden City, KS...Dodge City, KS...North Platte, NE...Hays, KS...Lexington, NE...
   SPC AC 231242

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0742 AM CDT TUE SEP 23 2014

   VALID 231300Z - 241200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   A FEW THUNDERSTORMS ACROSS THE CENTRAL PLAINS COULD BE STRONG TO
   MARGINALLY SEVERE.

   ...SYNOPSIS...
   PROGRESSIVE UPPER-AIR PATTERN OVER CONUS WILL FEATURE AMPLIFICATION
   OF RIDGING FROM GREAT BASIN ACROSS NRN ROCKIES AND NRN HIGH
   PLAINS...IN ADVANCE OF LARGE CYCLONE MOVING EWD ACROSS NERN PAC. 
   JUST E OF THAT RIDGING...SHORTWAVE TROUGH IS MOVING EWD ACROSS
   N-CENTRAL PLAINS...WITH MIDDLE-UPPER-LEVEL CIRCULATION CENTER
   EVIDENT OVER BLACK HILLS ATTM.  THIS SYSTEM WILL MOVE SLOWLY EWD
   ACROSS DAKOTAS AND NRN NEB...REACHING WRN MN AND NEB/IA BORDER BY
   12Z.  LOOSELY ATTACHED AREA OF MIDLEVEL HEIGHT WEAKNESS WILL PERSIST
   ACROSS SRN HIGH PLAINS...PARTLY RELATED TO VORTICITY RESIDUE FROM
   FORMER EAST-PAC HURRICANE ODILE.

   FARTHER E...STG SHORTWAVE TROUGH EXTENDING FROM ERN QUE SSWWD OVER
   ERN NEW ENGLAND WILL EJECT NEWD...LEAVING BEHIND SECONDARY VORTICITY
   LOBE NOW OVER GA/SC.  RESULTANT/WEAK 500-MB CYCLONE SHOULD WEAKEN
   GRADUALLY THROUGH PERIOD WHILE MEANDERING ERRATICALLY OVER SRN
   PIEDMONT REGION.

   AT SFC...11Z ANALYSIS SHOWED COLD FRONT FROM OFFSHORE GA/CAROLINAS/
   WSWWD ACROSS NRN FL AND NRN GULF TO S-CENTRAL TX...BEFORE FRONT
   LOSES IDENTITY IN HIGHER TERRAIN OF NRN MEX.  MOST OF THIS FRONT
   SHOULD BECOME QUASISTATIONARY ON SYNOPTIC SCALE THROUGH PERIOD. 
   ONLY MESOSCALE SHIFTS IN POSITION ARE LIKELY OUTSIDE POSSIBLE
   WAVE-LOW DEVELOPMENT OFFSHORE GA/CAROLINAS.  LEE-SIDE TROUGHING WITH
   WEAK ATTACHED LOWS WAS EVIDENT FROM MT/ND BORDER REGION SWD ACROSS
   ERN CO AND ERN NM.

   ...CENTRAL PLAINS...
   WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP THIS AFTN...SOME OF
   WHICH MAY PERSIST INTO EARLY-MID EVENING.  ISOLATED SVR HAIL AND
   STG-/DAMAGING GUSTS MAY OCCUR.

   GRADUAL LOW-LEVEL THETAE ADVECTION WILL CONTINUE ACROSS SRN/CENTRAL
   HIGH PLAINS E OF LEE TROUGH...WITH CONTINUING NNEWD SPREAD OF SFC
   DEW POINTS MID 50S TO LOW 60S F WITHIN NARROW CORRIDOR FROM ERN NM
   TO WRN NEB AND SRN SD.  THIS MOISTURE...COMBINED WITH POCKETS OF
   SUSTAINED INSOLATION AND WEAK LIFT INVOF TROUGH...WILL SUPPORT
   CONVECTIVE DEVELOPMENT THIS AFTN BEHIND MORNING CONVECTION NOW
   MOVING EWD ACROSS CENTRAL KS AND ERN NEB.  COLDER TEMPS ALOFT ARE
   EXPECTED WITH NWD EXTENT IN PROXIMITY TO SHORTWAVE TROUGH...WHILE PW
   GENERALLY WILL INCREASE SWD.  WITH WWD EXTENT...LAPSE RATES ALOFT
   SHOULD WEAKEN IN RELATION TO 450-500-MB STABLE LAYER EVIDENT IN
   MORNING AMA/DNR RAOBS...WHILE HEIGHTS ALOFT INCREASE WITH TIME OVER
   CENTRAL/SRN ROCKIES.  AS SUCH...MOST FAVORABLE PARAMETRIC OVERLAP
   FOR ORGANIZED TSTMS AND MRGL-SVR WIND/HAIL PROBABILITIES APPEARS TO
   BE FROM NEB SANDHILLS SWD TO W-CENTRAL/SWRN KS.  500-1500 J/KG
   MLCAPE MAY DEVELOP...WITH AROUND 30-40 KT EFFECTIVE-SHEAR MAGNITUDES
   INDICATING MULTICELLULAR AND AT LEAST TRANSIENT SUPERCELLULAR MODE.

   RELATIVE MIN OR SMALL GAP MAY DEVELOP BETWEEN COLD-CORE-INFLUENCED
   CONVECTION OVER NEB AND HIGHER-THETAE-SUPPORTED ACTIVITY IN
   KS...HOWEVER MESOSCALE UNCERTAINTIES PRECLUDE BIFURCATING AREA OF 5%
   PROBABILITY ATTM.  CONCERNS OVER COVERAGE...AS WELL AS LACK OF BOTH
   STRONGER LAPSE RATES AND GREATER VERTICAL SHEAR IN MOST BUOYANT AIR
   MASS...PRECLUDES SUFFICIENT UNCONDITIONAL PROBABILITIES FOR
   CATEGORICAL OUTLOOK ATTM.

   ..EDWARDS/MARSH.. 09/23/2014

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z