May 19, 2011 1630 UTC Day 1 Convective Outlook
Updated: Thu May 19 16:26:09 UTC 2011
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20110519 1630 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20110519 1630 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
20110519 1630 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
20110519 1630 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.
   SPC AC 191622
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1122 AM CDT THU MAY 19 2011
   
   VALID 191630Z - 201200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE SOUTHERN
   AND CENTRAL PLAINS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM DELMARVA NWD INTO NY...
   
   ...CENTRAL/SOUTHERN PLAINS...
   SATELLITE IMAGERY THE PAST 6 HOURS SHOWS THE UPPER WINDS HAVE
   STARTED TO BACK ACROSS THE SRN/CENTRAL HIGH PLAINS...IN RESPONSE TO
   ONE SHORTWAVE TROUGH LIFTING NWWD FROM THE CENTRAL PLAINS TOWARD THE
   NRN ROCKIES...AND AN IMPRESSIVE SHORTWAVE TROUGH MOVING ESEWD
   THROUGH SRN CA TOWARD AZ. THIS SHOULD RESULT IN THE DRYLINE TO NOT
   MIXING AS FAR EAST AS WED...PERHAPS ONLY TO NEAR A DDC-GAG-ABI LINE
   BY LATE AFTERNOON. WV IMAGERY SUGGESTS A WEAK WAVE IS MOVING INTO
   WRN NM AND PRIMARY LIFT WILL SPREAD TOWARD ERN CO/WRN KS LATE IN THE
   DAY...BUT THE DYNAMICAL FORCING SHOULD  BE WEAK OVER MOST OF THE
   WARM SECTOR. MOST MODELS...INCLUDING THE HIGH RESOLUTION
   VERSIONS...ARE CONSISTENT IN STORMS DEVELOPING 21-00Z IN AREA OF
   STRONGER LOW LEVEL CONVERGENCE NEAR INTERSECTION OF DRYLINE AND WARM
   FRONT IN CENTRAL KS. THE APPROACHING WAVE MAY ALSO AID STORM
   DEVELOPMENT SWD ALONG DRYLINE INTO NWRN OK. MODERATE INSTABILITY AND
   DEEP LAYER SHEAR AT 50-60 KT WILL FAVOR SUPERCELLS. THIS COMBINATION
   OF SHEAR AND INSTABILITY SHOULD SUPPORT HAIL IN EXCESS OF 2
   INCHES...WIND DAMAGE AND TORNADOES...ESPECIALLY CLOSER TO THE WARM
   FRONT IN KS.
   
   ...SWRN OK SWWD INTO SWRN TX...
   DRYLINE WILL RETREAT WWD DURING THE NIGHT AND MAY PROVIDE FOCUS FOR
   THUNDERSTORMS TO DEVELOP...AFTER 06Z...AS LARGE SCALE FORCING
   INCREASES FROM THE WEST. THE COMBINATION OF DEWPOINTS CLIMBING BACK
   INTO THE MID 60S...STEEP MID LEVEL LAPSE RATES AND MID LEVEL SPEED
   MAX AT 50 KT WILL PROVIDE SUFFICIENT SHEAR AND INSTABILITY FOR
   SUPERCELLS. GIVEN THE TIME OF NIGHT AND SLIGHTLY STABLE BOUNDARY
   LAYER...EXPECT SEVERE HAIL TO BE THE MAIN THREAT... THOUGH STRONG
   DOWNDRAFTS MAY ALSO RESULT IN WIND DAMAGE.
   
   ...MID ATLANTIC STATES INTO SOUTHERN NEW ENGLAND...
   THE UPPER LOW IS CURRENTLY LOCATED OVER FAR NRN WV AND IS FORECAST
   TO SHIFT EWD ACROSS NRN MD THROUGH THE DAY. AT MID MORNING...WV
   IMAGERY SHOWS AN IMPRESSIVE SHORTWAVE MOVING NEWD AROUND UPPER LOW
   FROM NRN VA TOWARD ERN PA/NJ. CONVECTION HAS RECENTLY DEVELOPED
   AHEAD OF THIS FEATURE IN ERN PA AND SHOULD MOVE/SPREAD NWD THROUGH
   THE DAY ACROSS ERN PA/NJ AND NY. ALTHOUGH INSTABILITY IS NOT
   PARTICULARLY STRONG...SOME WARMING HAS RESULTED IN MLCAPES TO AROUND
   500 J/KG. THIS INSTABILITY COMBINED WITH DEEP LAYER SHEAR AROUND 30
   KT AND MID LEVEL LAPSE RATES BETWEEN 6.5-7.0 C/KM FAVOR MULTICELL
   STORMS WITH HAIL AND STRONG GUSTY WINDS. 
   
   ANOTHER IMPULSE WAS LOCATED NEAR THE KY/WV BORDER AND ALL MODELS ARE
   SUGGESTIVE OF CONVECTION DEVELOPING LATER THIS AFTERNOON IN THE
   DELMARVA AREA WITH THIS SYSTEM. STORMS THAT DEVELOP WILL BE
   WITHIN A SLOWLY DRYING BOUNDARY LAYER AND WHEN COMBINED WITH WLY
   WINDS ALOFT AND STEEPENING LOW LEVEL LAPSE RATES...STRONG AND
   POSSIBLY SEVERE WIND GUSTS ARE POSSIBLE.
   
   ..IMY.. 05/19/2011
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z