May 21, 2016 0600 UTC Day 1 Convective Outlook
Updated: Sat May 21 06:00:20 UTC 2016 (20160521 1200Z Day 1 shapefile | 20160521 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20160521 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 123,145 1,138,860 Lubbock, TX...Amarillo, TX...Garden City, KS...Dodge City, KS...Gillette, WY...
MARGINAL 378,119 26,263,991 Jacksonville, FL...Charlotte, NC...Miami, FL...Raleigh, NC...Hialeah, FL...
Probabilistic Tornado Graphic
20160521 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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 70,994 339,279 Garden City, KS...Dodge City, KS...Liberal, KS...Pampa, TX...Dumas, TX...
Probabilistic Damaging Wind Graphic
20160521 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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 124,481 1,139,032 Lubbock, TX...Amarillo, TX...Garden City, KS...Dodge City, KS...Gillette, WY...
5 % 377,997 26,503,246 Jacksonville, FL...Charlotte, NC...Miami, FL...Raleigh, NC...Hialeah, FL...
Probabilistic Large Hail Graphic
20160521 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.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 124,563 1,149,138 Lubbock, TX...Amarillo, TX...Garden City, KS...Dodge City, KS...Gillette, WY...
5 % 274,003 2,799,391 Laredo, TX...Abilene, TX...Billings, MT...Midland, TX...Odessa, TX...
   SPC AC 210600

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT SAT MAY 21 2016

   VALID 211200Z - 221200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE NRN HIGH
   PLAINS AND NRN ROCKIES...

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE CNTRL AND
   SRN HIGH PLAINS...

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER MUCH OF THE HIGH PLAINS...

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER A PORTION OF THE SERN
   STATES...

   ...SUMMARY...
   STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE TODAY PRIMARILY ACROSS
   THE HIGH PLAINS WITH DAMAGING WIND AND LARGE HAIL THE PRIMARY
   THREATS. A MORE MARGINAL RISK FOR A FEW STRONG TO DAMAGING WIND
   GUSTS WILL ALSO EXIST OVER A PORTION OF THE SOUTHEAST UNITED STATES.

   ...SYNOPSIS...

   OMEGA BLOCKING SYNOPTIC PATTERN WILL PERSIST THROUGH TODAY. WRN U.S.
   UPPER LOW WILL DRIFT ONLY SLOWLY EWD. HOWEVER A SIGNIFICANT
   SHORTWAVE TROUGH NOW LOCATED WITHIN THE BASE OF THE UPPER LOW WILL
   EJECT NNEWD THROUGH THE NRN ROCKIES LATER TODAY.  A RIDGE WILL
   CONTINUE TO BUILD ACROSS THE PLAINS STATES. FARTHER EAST A SYNOPTIC
   UPPER TROUGH WILL CONTINUE THROUGH THE OH VALLEY...REACHING THE ERN
   STATES THIS EVENING. AT THE SFC CYCLOGENESIS IS FORECAST OFF THE NC
   COAST TODAY IN RESPONSE TO A VORTICITY MAXIMUM ROTATING THROUGH THE
   BASE OF THE UPPER LOW. TRAILING COLD FRONT WILL MOVE SEWD THROUGH
   REMAINDER OF THE CAROLINAS AND INTO NRN FL AND THE NRN GULF. FARTHER
   WEST...A LEE TROUGH/DRYLINE WILL SETUP OVER THE HIGH PLAINS WHILE A
   WARM FRONT MOVES NWD THROUGH TX.

   ...NRN HIGH PLAINS...

   MOISTURE SHOULD UNDERGO A MODEST INCREASE BUT REMAIN SOMEWHAT
   LIMITED WITH BOUNDARY-LAYER DEWPOINTS LIKELY MIXING DOWN INTO THE
   40S F THIS AFTERNOON. STEEP LOW-MIDLEVEL LAPSE RATES AND DIABATIC
   WARMING WILL BOOST MLCAPE TO 500-800 J/KG. DEEP-LAYER ASCENT WILL
   INCREASE IN ADVANCE OF THE EJECTING SHORTWAVE TROUGH AND COMBINED
   WITH OROGRAPHIC FORCING WILL PROMOTE THUNDERSTORM DEVELOPMENT OVER
   THE HIGHER TERRAIN. WINDS ALOFT WILL INCREASE AS WITH THE APPROACH
   OF A MID-LEVEL JET...AND EFFECTIVE BULK SHEAR FROM 35-45 KT WILL
   SUPPORT ORGANIZED STORMS INCLUDING A FEW SUPERCELLS. STORMS WILL BE
   HIGH BASED ABOVE INVERTED-V BOUNDARY LAYERS SUPPORTING A THREAT FOR
   DOWNBURST WINDS...BUT UPDRAFT ROTATION...STEEP MID LEVEL LAPSE RATES
   AND MLCAPE UP TO 800 J/KG WILL ALSO SUPPORT A THREAT FOR LARGE HAIL.
   ACTIVITY COULD EVOLVE INTO ONE OR MORE CLUSTERS AS THEY DEVELOP
   THROUGH THE HIGH PLAINS BEFORE WEAKENING TOWARD MID EVENING.

   ...SRN AND CNTRL HIGH PLAINS...

   RICHER LOW-LEVEL MOISTURE WITH DEWPOINTS IN THE UPPER 50S TO LOW 60S
   F WILL RETURN THROUGH THE CNTRL AND SRN HIGH PLAINS BENEATH EML
   PLUME WITH STEEP LAPSE RATES CONTRIBUTING TO AN AXIS OF MODERATE
   INSTABILITY /1500-2000 J/KG/ EAST OF DRYLINE. THE ATMOSPHERE WILL
   REMAIN CAPPED UNTIL LATE AFTERNOON WHEN DEEP MIXING IN VICINITY OF
   THE DRYLINE SHOULD CONTRIBUTE TO THUNDERSTORM INITIATION. WITH LARGE
   SCALE RIDGING ALOFT...DEEP VERTICAL SHEAR WILL INITIALLY BE
   RELATIVELY MODEST /AOB 35 KT/ SUPPORTIVE OF MAINLY MULTICELLS...BUT
   SOME SUPERCELLS ARE ALSO POSSIBLE AS THE LLJ AND VERTICAL SHEAR
   INCREASE BY EARLY EVENING. ACTIVITY WILL POSE A THREAT FOR DOWNBURST
   WINDS...LARGE HAIL AND MAYBE A BRIEF TORNADO AS IT DEVELOPS EWD INTO
   THE MOIST/INSTABILITY AXIS...POSSIBLY EVOLVING INTO ONE OR MORE
   CLUSTERS BEFORE WEAKENING AS THE LLJ STRENGTHENS.  

   ...SERN STATES...

   LOW-LEVEL WINDS WILL VEER TO WLY FROM GA INTO THE CAROLINAS IN
   RESPONSE TO OFFSHORE CYCLOGENESIS. THIS WILL KEEP RICHER LOW-LEVEL
   MOISTURE SHUNTED FARTHER EAST TOWARD THE COASTAL REGION AND FARTHER
   SOUTH ACROSS FL. AS DIABATIC WARMING COMMENCES THE ATMOSPHERE SHOULD
   BECOME MARGINALLY TO MODERATELY UNSTABLE WITH MLCAPE RANGING FROM
   NEAR 800 J/KG OVER THE CAROLINAS TO 1500+ J/KG OVER FL. OVERALL
   REGIME WILL BE DOMINATED BY MID-UPPER SUBSIDENCE WITH SIGNIFICANT
   DRYING ALOFT...BUT A WEAK CAP AND DIABATIC WARMING OF THE SFC LAYER
   SHOULD RESULT IN THUNDERSTORMS DEVELOPING OVER THE HIGHER TERRAIN OF
   THE SRN APPALACHIANS...IN PORTIONS OF WARM SECTOR...AS WELL AS ALONG
   THE EAST COAST FL SEABREEZE. ISOLATED DOWNBURST WINDS WILL BE THE
   MAIN THREAT BEFORE ACTIVITY WEAKENS DURING THE EARLY EVENING.

   ..DIAL/ROGERS.. 05/21/2016

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