May 21, 2014 2000 UTC Day 1 Convective Outlook
Updated: Wed May 21 19:59:39 UTC 2014 (20140521 2000Z Day 1 shapefile | 20140521 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140521 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20140521 2000 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.
Probabilistic Damaging Wind Graphic
20140521 2000 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.
Probabilistic Large Hail Graphic
20140521 2000 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.
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 380,062 43,009,047 Indianapolis, IN...Columbus, OH...Denver, CO...Washington, DC...Louisville, KY...
   SPC AC 211956

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0256 PM CDT WED MAY 21 2014

   VALID 212000Z - 221200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL/SRN HIGH PLAINS
   TO THE MID-ATLANTIC COAST...

   ...SUMMARY...
   ISOLATED TO SCATTERED SEVERE STORMS WITH PRIMARY RISKS OF LARGE HAIL
   AND DAMAGING WINDS WILL PERSIST INTO TONIGHT FROM THE LOWER MISSOURI
   VALLEY TO THE MID-ATLANTIC STATES. THE GREATEST CONCENTRATION OF
   SEVERE STORMS IS EXPECTED OVER THE OHIO VALLEY. 

   ISOLATED TO SCATTERED SEVERE STORMS WITH LARGE HAIL...DAMAGING
   WINDS...AND A FEW TORNADOES WILL CONTINUE ACROSS PORTIONS OF THE
   CENTRAL AND SOUTHERN HIGH PLAINS THROUGH THE EVENING.

   ...OH VALLEY...
   SCATTERED STRONG TO SEVERE STORMS ARE UNDERWAY ALONG THE FRONT
   ACROSS CNTRL IL/IND/OH...WITH ADDITIONAL STORMS LIKELY TO DEVELOP
   THROUGH THE AFTERNOON. LARGE HAIL /SOME SIGNIFICANT/ WILL BE THE
   PRIMARY INITIAL THREAT. CONSOLIDATION OF UPDRAFTS INTO A
   S/SEWD-MOVING MCS IS ANTICIPATED WITH AN INCREASED RISK FOR DAMAGING
   WINDS NEAR THE OH RIVER INTO NRN KY AND WRN WV. 

   ...MID-ATLANTIC STATES...
   WEAK INSTABILITY AS SAMPLED BY AN 18Z IAD RAOB AND RELATIVELY
   ABUNDANT CLOUDINESS APPEARS TO HAVE LESSENED/DELAYED THE OVERALL
   SEVERE RISK. STILL...A FEW STRONGER STORMS SHOULD DEVELOP WHERE
   STRONGER HEATING HAS OCCURRED ACROSS VA BY EARLY EVENING WITH
   ISOLATED DAMAGING WINDS AND SEVERE HAIL POSSIBLE.

   ...CNTRL/SRN PLAINS...
   OVERALL METEOROLOGICAL SCENARIOS REMAIN GENERALLY ON-TRACK WITH
   MINOR REFINEMENTS TO SEVERE PROBABILITIES. GREATEST POTENTIAL FOR A
   COUPLE OF SUSTAINED SUPERCELLS IS STILL EXPECTED OVER N-CNTRL/NERN
   CO WITH A SWATH OF VERY LARGE HAIL AND OCCASIONAL TORNADOES
   PROBABLE.

   ..GRAMS.. 05/21/2014

   .PREV DISCUSSION... /ISSUED 1130 AM CDT WED MAY 21 2014/

   ...MID ATLANTIC STATES...
   VISIBLE SATELLITE IMAGERY SHOWS RELATIVELY CLEAR SKIES ACROSS MUCH
   OF VA...WHERE DEWPOINTS ARE IN THE UPPER 50S TO LOWER 60S.  A WEAK
   SHORTWAVE TROUGH OVER OH WILL TRACK SOUTHEASTWARD AND APPROACH THE
   REGION LATER THIS AFTERNOON.  12Z MODEL SOLUTIONS ARE SLIGHTLY LESS
   CONSISTENT IN EXTENT OF THUNDERSTORM COVERAGE AND INTENSITY OVER THE
   MID ATLANTIC STATES THAN PRIOR RUNS.  HOWEVER...THE POTENTIAL EXISTS
   FOR MULTIPLE CLUSTERS OF THUNDERSTORMS TO FORM OVER SOUTHERN PA AND
   MD...SPREADING SOUTHEASTWARD ALONG AN EXISTING SURFACE BOUNDARY
   ACROSS THE CHESAPEAKE BAY AREA THIS EVENING.  LOCALLY DAMAGING WINDS
   APPEAR TO BE THE MAIN THREAT...ALTHOUGH HAIL OR EVEN A BRIEF TORNADO
   IS POSSIBLE.

   ...OH VALLEY...
   A RESERVOIR OF MODERATE TO STRONG INSTABILITY WILL DEVELOP THIS
   AFTERNOON OVER PARTS OF IND/KY/OH INTO WESTERN WV.  STRONG DAYTIME
   HEATING AND SHOULD HELP TO INITIATE SCATTERED THUNDERSTORMS AHEAD OF
   A WEAK SURFACE BOUNDARY SAGGING SOUTHWARD ACROSS IND/OH.  FORECAST
   SOUNDINGS SHOW STEEP MID LEVEL LAPSE RATES AND STRONG NORTHWEST FLOW
   ALOFT.  THIS WILL PROMOTE A RISK OF RATHER WIDESPREAD STRONG-SEVERE
   THUNDERSTORMS CAPABLE OF DAMAGING WINDS AND LARGE HAIL.

   ...CO/WY...
   TODAY WILL SEE ANOTHER ROUND OF ISOLATED SUPERCELL THUNDERSTORMS
   OVER NORTHEAST CO AND SOUTHEAST WY.  SOUTHEASTERLY LOW LEVEL WIND
   FIELDS APPEAR MORE FAVORABLE THAN YESTERDAY FOR MORE SUSTAINED
   ROTATING UPDRAFTS.  ALSO...EASTERLY/SOUTHEASTERLY LOW LEVEL WINDS
   OVER EASTERN CO WILL HELP TO STRENGTHEN THE DCVZ WHERE A LOCALLY
   ENHANCED RISK OF TORNADOES IS EXPECTED TODAY.  VERY LARGE HAIL AND
   DAMAGING WINDS WILL ALSO BE POSSIBLE.  STORMS MAY PERSIST INTO THE
   EVENING AND SPREAD INTO WESTERN NEB AND FAR WESTERN KS BEFORE
   WEAKENING.

   ...W TX/ERN NM...
   THE SURFACE DRYLINE IS EXPECTED TO BECOME ESTABLISHED LATER THIS
   AFTERNOON FROM SOUTHEAST NM INTO THE TX PANHANDLE.  STRONG HEATING
   ALONG THIS CORRIDOR WILL YIELD A DEEP MIXED BOUNDARY LAYER AND WEAK
   CAP BY LATE AFTERNOON. THUNDERSTORM DEVELOPMENT APPEARS PROBABLE IN
   THIS ZONE...WITH SUFFICIENT MID LEVEL FLOW AND STEEP LOW/MID LEVEL
   LAPSE RATES TO PROMOTE A RISK OF LOCALLY DAMAGING WIND GUSTS.  THIS
   RISK SHOULD DIMINISH A FEW HOURS AFTER SUNSET.

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