Apr 26, 2015 0600 UTC Day 1 Convective Outlook
Updated: Sun Apr 26 06:00:13 UTC 2015 (20150426 1200Z Day 1 shapefile | 20150426 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150426 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 195,700 18,789,337 San Antonio, TX...Dallas, TX...Austin, TX...Fort Worth, TX...Oklahoma City, OK...
MARGINAL 220,078 22,318,804 Houston, TX...Jacksonville, FL...Orlando, FL...Little Rock, AR...Amarillo, TX...
Probabilistic Tornado Graphic
20150426 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 % 66,227 8,277,591 Dallas, TX...Fort Worth, TX...Arlington, TX...Plano, TX...Garland, TX...
2 % 120,374 9,234,025 San Antonio, TX...Austin, TX...Oklahoma City, OK...Shreveport, LA...Amarillo, TX...
Probabilistic Damaging Wind Graphic
20150426 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 % 195,359 18,789,794 San Antonio, TX...Dallas, TX...Austin, TX...Fort Worth, TX...Oklahoma City, OK...
5 % 218,542 22,248,669 Houston, TX...Jacksonville, FL...Orlando, FL...Little Rock, AR...Amarillo, TX...
Probabilistic Large Hail Graphic
20150426 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 66,023 6,827,599 Dallas, TX...Fort Worth, TX...Arlington, TX...Irving, TX...Grand Prairie, TX...
15 % 194,820 18,754,132 San Antonio, TX...Dallas, TX...Austin, TX...Fort Worth, TX...Oklahoma City, OK...
5 % 219,865 22,051,578 Houston, TX...Jacksonville, FL...Orlando, FL...Little Rock, AR...Amarillo, TX...
   SPC AC 260600

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT SUN APR 26 2015

   VALID 261200Z - 271200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SOUTHERN PLAINS TO
   PARTS OF WESTERN/SOUTHERN AR AND NORTHERN LA...

   ...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLIGHT RISK
   AREA FROM THE SOUTHERN PLAINS TO THE LOWER MS VALLEY...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE SOUTHEAST
   STATES...

   ...SUMMARY...
   SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP
   ACROSS THE SOUTHERN PLAINS THIS AFTERNOON AND CONTINUE INTO THE
   OVERNIGHT HOURS.  ISOLATED STRONG TO POTENTIALLY SEVERE STORMS MAY
   ALSO DEVELOP ACROSS THE SOUTHEAST STATES.

   ...SYNOPSIS...
   A MID- TO UPPER-LEVEL TROUGH...CURRENTLY LOCATED ACROSS THE LOWER CO
   RIVER VALLEY PER WATER VAPOR IMAGERY...WILL MIGRATE EWD THIS
   FORECAST PERIOD ACROSS AZ/NM...LIKELY EVOLVING INTO A CLOSED LOW
   OVER THE SRN HIGH PLAINS BY 12Z MONDAY.  MEANWHILE...A STATIC
   PATTERN FEATURING A MID-LEVEL ANTICYCLONE OVER THE MID MO VALLEY
   WILL BE LOCATED TO THE W OF A SERIES OF DISTURBANCES MAINTAINING A
   LARGE-SCALE WSW-ENE ORIENTED TROUGH OVER THE ERN STATES.  A COLD
   FRONT WILL ADVANCE SWD ACROSS THE SOUTHEAST STATES AND CENTRAL GULF
   COAST STATES.  THE WRN PORTION OF THIS BOUNDARY IS EXPECTED TO
   REMAIN QUASI-STATIONARY FROM NRN LA TO THE RED RIVER TO NORTHWEST
   TX/NERN NM WHERE A SURFACE LOW WILL BE DEVELOPING.  A NORTH-SOUTH
   DRYLINE WILL LIKELY SHARPEN ACROSS PORTIONS OF W-CNTRL AND NW TX
   DURING THE DAY.

   ...SRN PLAINS...
   SURFACE MOISTURE...WITH DEW POINTS IN THE UPPER 60S TO LOWER
   70S...CURRENTLY RESIDES ACROSS THE TX COASTAL PLAINS INTO
   SOUTH-CENTRAL TX.  POLEWARD MOISTENING IS EXPECTED ACROSS THE WARM
   SECTOR TODAY AS SLY LOW-LEVEL WINDS INCREASE IN RESPONSE TO HEIGHT
   FALLS AHEAD OF THE APPROACHING SWRN STATES TROUGH.  SURFACE DEW
   POINTS INTO THE LOWER 60S SHOULD REACH THE RED RIVER VALLEY REGION
   BY AFTERNOON...WHILE UPPER 60S REACH THE VICINITY OF WACO TX BY LATE
   AFTERNOON.  

   STRONG HEATING IS FORECAST OVER SWRN TX AND MIDLEVEL LAPSE RATES OF
   AT LEAST 8 C/KM WILL LIKELY OVERSPREAD THE WEST EDGE OF THE MOISTURE
   RETURN/DRY LINE ACROSS CNTRL TX DURING THE DAY LEADING TO THE
   DEVELOPMENT OF A MODERATE TO VERY STRONG INSTABILITY /MLCAPE OF
   1500-3000 J PER KG/ ACROSS THE WARM SECTOR.  HEIGHT FALLS WILL
   OVERSPREAD W-CNTRL INTO CENTRAL TX AS THE NOSE OF A 70-80-KT H5
   SPEED MAX OVER NRN CHIHUAHUA MOVES INTO SW TX BY LATE AFTERNOON. 
   ISOLD TO WIDELY SCATTERED STORMS SHOULD DEVELOP NEAR THE DRYLINE
   THIS AFTERNOON...WITH THE POTENTIAL EXISTING FOR STORMS TO DEVELOP
   AS EARLY AS 18-20Z IN CENTRAL TO NORTHERN TX AS SUGGESTED BY THE 00Z
   NAM4/NSSL4/NMM4.  VEERING AND STRENGTHENING WINDS WITH HEIGHT WILL
   FAVOR SUPERCELLS CAPABLE PRIMARILY OF ISOLATED LARGE TO VERY LARGE
   HAIL AND STRONG WINDS.  HOWEVER...AN ISOLATED TORNADO RISK WILL BE
   POSSIBLE AS STORMS MOVE E/NEWD INTO RICHER MOISTURE TO THE E OF THE
   DRYLINE.  THE POTENTIAL ALSO EXISTS FOR A SECOND ROUND OF STORMS TO
   DEVELOP AND MOVE E/NEWD ACROSS PORTIONS OF CENTRAL AND NRN TX WITH
   SIMILAR SEVERE WEATHER THREATS.  EACH ROUND OF STORMS SHOULD MOVE
   INTO OK WITH HAIL AND DAMAGING WINS BEING THE PRIMARY THREATS AS
   ACTIVITY DEVELOPS WITHIN A INCREASING DEEP-LAYER ASCENT PER LOW- TO
   MID-LEVEL WAA AND ASCENT WITHIN THE EXIT REGION OF THE SWLY JET
   STREAK SPREADING ACROSS THE SRN PLAINS TO THE ARKLATEX.

   FARTHER NW...MODELS SHOW AN ELY-COMPONENT AND UPSLOPE FLOW INVOF THE
   SWD SAGGING FRONTAL ZONE OVER OK INTO THE TX PANHANDLE.  INCREASING
   UPPER-LEVEL FORCING FOR ASCENT COUPLED WITH STRONG HEATING AND
   CONVERGENCE ALONG THE ARCING DRYLINE INTO FAR SWRN OK AND THE TX
   PANHANDLE WILL PROBABLY ERODE THE CAP BY MID-LATE AFTERNOON. 
   FORECAST SOUNDINGS SHOW MODERATE BUOYANCY DEVELOPING WITHIN AN AXIS
   OF 50S SURFACE DEWPOINTS.  STRONG VEERING WINDS WITH HEIGHT WILL
   FAVOR THE DEVELOPMENT OF SUPERCELLS WITH THE MORE ROBUST UPDRAFTS. 
   COOL MID-LEVEL TEMPS /-16 TO -18 DEG C AT H5/ COULD SUPPORT LARGE TO
   VERY LARGE HAIL GROWTH DURING THE MATURE PHASE OF THE STORM LIFE
   CYCLE.  

   ...SOUTHEAST STATES...
   ASIDE FROM FL...INSTABILITY IS EXPECTED TO BE RATHER WEAK ACROSS
   THIS REGION TODAY.  HOWEVER...EFFECTIVE BULK SHEAR WILL BE MORE THAN
   SUFFICIENT FOR ORGANIZED STORMS...WITH THE POTENTIAL FOR SUSTAINED
   UPDRAFTS DEVELOPING NEAR THE SWD MOVING COLD FRONT.

   ..PETERS/ROGERS.. 04/26/2015

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z