May 17, 2016 0600 UTC Day 1 Convective Outlook
Updated: Tue May 17 05:56:52 UTC 2016 (20160517 1200Z Day 1 shapefile | 20160517 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20160517 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 29,947 2,291,244 Austin, TX...Killeen, TX...Round Rock, TX...San Angelo, TX...Cedar Park, TX...
SLIGHT 110,565 13,876,715 Houston, TX...San Antonio, TX...Fort Worth, TX...Corpus Christi, TX...Laredo, TX...
MARGINAL 106,232 9,457,380 Dallas, TX...Arlington, TX...Plano, TX...Garland, TX...Shreveport, LA...
Probabilistic Tornado Graphic
20160517 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
5 % 30,055 2,266,076 Austin, TX...Killeen, TX...Round Rock, TX...San Angelo, TX...Cedar Park, TX...
2 % 40,865 3,102,024 San Antonio, TX...Laredo, TX...Temple, TX...San Marcos, TX...New Braunfels, TX...
Probabilistic Damaging Wind Graphic
20160517 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 % 140,307 16,109,359 Houston, TX...San Antonio, TX...Austin, TX...Fort Worth, TX...Corpus Christi, TX...
5 % 106,470 9,526,928 Dallas, TX...Arlington, TX...Plano, TX...Garland, TX...Shreveport, LA...
Probabilistic Large Hail Graphic
20160517 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
SIG SEVERE 29,809 2,260,844 Austin, TX...Killeen, TX...Round Rock, TX...San Angelo, TX...Cedar Park, TX...
30 % 30,163 2,270,470 Austin, TX...Killeen, TX...Round Rock, TX...San Angelo, TX...Cedar Park, TX...
15 % 92,476 10,777,487 Houston, TX...San Antonio, TX...Corpus Christi, TX...Laredo, TX...Pasadena, TX...
5 % 73,849 10,508,723 Dallas, TX...Fort Worth, TX...Arlington, TX...Plano, TX...Garland, TX...
   SPC AC 170556

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1256 AM CDT TUE MAY 17 2016

   VALID 171200Z - 181200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PARTS OF THE TX HILL
   COUNTRY...

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN PLAINS
   OUTSIDE OF THE ENHANCED RISK AREA...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE SRN PLAINS
   AND ARKLATEX OUTSIDE OF THE SLIGHT RISK AREA...

   ...SUMMARY...
   SEVERE THUNDERSTORMS WITH LARGE HAIL AND ISOLATED WIND DAMAGE ARE
   EXPECTED TODAY INTO TONIGHT ACROSS PARTS OF CENTRAL TEXAS.  STRONG
   TO SEVERE STORMS WITH ISOLATED LARGE HAIL AND WIND DAMAGE ARE ALSO
   POSSIBLE ACROSS SURROUNDING PORTIONS OF THE SOUTHERN PLAINS...THE
   LOWER RIO GRANDE VALLEY AND ACROSS THE TEXAS COASTAL PLAINS.

   ...SRN PLAINS...
   AN UPPER-LEVEL LOW OVER THE INTERMOUNTAIN WEST WILL MOVE SWD INTO
   THE DESERT SOUTHWEST TODAY AS WEST TO NORTHWEST FLOW REMAINS IN
   PLACE ACROSS THE SRN PLAINS. AT THE SFC...A COLD FRONT WILL ADVANCE
   SWD ACROSS NRN AND CNTRL TX INTO A MOIST AIRMASS. SFC DEWPOINTS IN
   THE UPPER 60S TO LOWER 70S F SHOULD BE IN PLACE ACROSS THE TX HILL
   COUNTRY EXTENDING SEWD TO THE TX GULF COAST. THIS SHOULD RESULT IN A
   MODERATELY UNSTABLE WARM SECTOR BY AFTERNOON. AS LOW-LEVEL
   CONVERGENCE INCREASES ALONG THE FRONT...THUNDERSTORM INITIATION IS
   EXPECTED TO OCCUR DURING THE MID AFTERNOON WITH AN EAST TO WEST LINE
   OF STORMS ORGANIZING AND MOVING SWD ACROSS WRN PARTS OF THE TX HILL
   COUNTRY. THIS LINE MAY AFFECT PARTS OF SCNTRL TX DURING THE EVENING.
   OTHER STORMS MAY DEVELOP FURTHER TO THE EAST ACROSS THE TX COASTAL
   PLAINS ALONG CORRIDORS OF ENHANCED LOW-LEVEL CONVERGENCE. 

   THE NAM AND GFS ARE IN GENERAL AGREEMENT CONCERNING THE POSITION OF
   THE INSTABILITY AXIS THIS AFTERNOON. BOTH MODELS GENERATE 2000 TO
   3000 J/KG OF MLCAPE ACROSS MUCH OF THE TX HILL COUNTRY WITH THE
   HIGHEST VALUES IN THE RIO GRAND VALLEY. IN SPITE OF A POCKET OF
   STRONG INSTABILITY...LARGE-SCALE ASCENT IS FORECAST TO REMAIN WEAK
   ACROSS MUCH OF THE SRN PLAINS TODAY. DUE TO THIS...MESOSCALE
   PROCESSES WILL BE IMPORTANT FOR HOW THE SCENARIO PLAYS OUT. THE
   CURRENT THINKING IS THAT CONVECTION WILL FIRST INITIATE IN THE SAN
   ANGELO AREA IN THE 19Z TO 21Z TIMEFRAME NEAR THE NRN EDGE OF
   STRONGEST INSTABILITY. FORECAST SOUNDINGS NEAR AND TO THE SOUTH OF
   SAN ANGELO AT 21Z/TUE SHOW SUBSTANTIAL DIRECTIONAL SHEAR IN THE
   LOW-LEVELS WITH WIND SPEEDS INCREASING TO AROUND 40 KT AT 500 MB.
   THIS SHOULD PRODUCE 0-6KM SHEAR IN THE 50 TO 60 KT RANGE WHICH WILL
   BE FAVORABLE FOR SUPERCELLS INITIALLY. DUE TO STRONG INSTABILITY AND
   STEEP LAPSE RATES...LARGE HAIL WILL BE LIKELY WITH SUPERCELLS.
   HAILSTONES GREATER THAN 2 INCHES IN DIAMETER WILL BE POSSIBLE WITH
   THE MORE DOMINANT SUPERCELLS. A TORNADO OR TWO MAY ALSO OCCUR. AS
   LOW-LEVEL CONVERGENCE INCREASES ALONG THE BOUNDARY...CELLS SHOULD
   GRADUALLY CONGEAL INTO A LINE BY EARLY EVENING. THIS MAY RESULT IN
   AN INCREASED POTENTIAL FOR WIND DAMAGE AS THE LINE MOVES SWD ACROSS
   WRN AND SRN PARTS OF THE TX HILL COUNTRY. 

   ...EAST TX/LA/ARKLATEX...
   WEST TO NORTHWEST MID-LEVEL FLOW WILL BE IN PLACE IN THE SRN PLAINS
   TODAY AS A COLD FRONT ADVANCES SWD ACROSS NORTH TX AND SRN AR. AHEAD
   OF THIS BOUNDARY...SFC DEWPOINTS SHOULD BE IN THE MID TO UPPER 60S F
   WITH THE WARM SECTOR EXTENDING SWD TO THE UPPER TX AND LA GULF
   COASTS. LOW-LEVEL CONVERGENCE ALONG THE FRONT AND SWD ACROSS THE
   WARM SECTOR MAY BE ENOUGH FOR CONVECTIVE INITIATION THIS AFTERNOON.
   FORECAST SOUNDINGS IN EAST TX AT 21Z SHOW MODERATE DEEP-LAYER SHEAR
   IN PLACE WITH STEEP LOW-LEVEL LAPSE RATES SUGGESTING THAT A MARGINAL
   THREAT FOR DAMAGING WIND GUSTS MAY DEVELOP. ANY MARGINAL SEVERE
   THREAT IS EXPECTED TO BE STRONGLY DIURNAL AND CONCENTRATED NEAR PEAK
   HEATING.

   ..BROYLES/PICCA.. 05/17/2016

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