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
5 %
103,945
3,087,440
San Antonio, TX...Lubbock, TX...Laredo, TX...Amarillo, TX...Garden City, KS...
Probabilistic Large Hail 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.
San Antonio, TX...Lubbock, TX...Laredo, TX...Garden City, KS...Dodge City, KS...
SPC AC 111241
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0741 AM CDT SAT APR 11 2015
VALID 111300Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER A SMALL PART OF THE CNTRL
AND SRN HIGH PLAINS...
...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLIGHT RISK
AREA OVER PORTIONS OF THE CNTRL AND SRN HIGH PLAINS...
...THERE IS A MRGL RISK OF SVR TSTMS OVER PORTIONS OF S-CNTRL TX...
...SUMMARY...
ISOLATED SEVERE STORMS ARE POSSIBLE OVER THE CENTRAL AND SOUTHERN
HIGH PLAINS THIS AFTERNOON INTO EVENING. ELSEWHERE...A FEW STRONG
TO SEVERE STORMS MAY OCCUR ACROSS PORTIONS OF SOUTH-CENTRAL TEXAS
THIS AFTERNOON AND EVENING. LARGE HAIL WILL BE THE PRIMARY SEVERE
WEATHER HAZARD IN BOTH OF THESE AREAS.
...SYNOPSIS...
IN THE WAKE OF A SHORT-WAVE TROUGH MOVING THROUGH THE NERN U.S...A
COUPLE OF UPSTREAM SHORT-WAVE TROUGHS WILL ADVANCE FROM THE ERN
PACIFIC INTO THE WRN U.S. AND NWRN MEXICO AMIDST AN EVOLVING
SPLIT-FLOW REGIME. THE POLAR-BRANCH TROUGH /CURRENTLY MOVING ONTO
THE PACIFIC NW COAST/ WILL CONTINUE EWD...REACHING THE NRN HIGH
PLAINS BY 12Z/SUNDAY. MEANWHILE...THE SUBTROPICAL-BRANCH WAVE WILL
FORM A CLOSED MID-LEVEL CIRCULATION AS IT MOVES GENERALLY EWD TO
OVER NRN PARTS OF BAJA AND THE GULF OF CA BY TONIGHT.
AT THE SURFACE...THE EWD PROGRESSION OF THE POLAR-BRANCH TROUGH
MENTIONED ABOVE WILL PROMOTE THE DEVELOPMENT AND SUBSEQUENT
INTENSIFICATION OF A LEE TROUGH OVER THE HIGH PLAINS. THIS
UPPER-AIR SYSTEM WILL ALSO BE ATTENDED BY A PACIFIC FRONT WHICH WILL
ADVANCE THROUGH THE NRN INTER-MOUNTAIN REGION TODAY BEFORE
OVERTAKING THE LEE TROUGH OVER THE NRN PLAINS TONIGHT.
ELSEWHERE....A COLD FRONT STRETCHING FROM OFF THE NC COAST SWWD INTO
THE NWRN GULF OF MEXICO WILL WEAKEN WHILE DRIFTING SLOWLY SWD.
...CNTRL/SRN PLAINS THIS AFTERNOON AND EVENING...
THE COMBINATION OF WAA ATOP A SHALLOW NEAR-SURFACE STABLE LAYER AND
FORCING FOR ASCENT ATTENDANT TO AN UPPER-LEVEL JET STREAK MOVING
THROUGH THE REGION HAS FOSTERED WIDELY SCATTERED TSTMS EARLY THIS
MORNING FROM THE TX PNHDL AND LOW ROLLING PLAINS INTO OK. LATEST
MODEL GUIDANCE SUGGESTS THAT THIS CONVECTION MAY PERSIST THROUGH THE
MORNING WITH A RISK FOR SMALL HAIL...BEFORE GRADUALLY WEAKENING OVER
OK THIS AFTERNOON. THEREAFTER...NUMERICAL SOLUTIONS BECOME RATHER
DISPERSIVE WITH RESPECT TO AFTERNOON STORM DEVELOPMENT ALONG THE
DRYLINE...LIKELY DUE TO VARYING IMPACTS OF THE EARLY-DAY TSTMS ON
AIR MASS DESTABILIZATION.
CURRENT THINKING IS THAT DECREASING CLOUDS COUPLED WITH STEEPENING
LAPSE RATES AND INCREASING BOUNDARY-LAYER MOISTURE WILL CONTRIBUTE
TO A NARROW AXIS OF MODEST INSTABILITY /I.E. MLCAPE AROUND 1000 J
PER KG/ AHEAD OF THE DRYLINE/LEE TROUGH FROM PORTIONS OF THE TX
SOUTH PLAINS NWD INTO SERN CO/SWRN KS. AND WHILE LARGE-SCALE
FORCING FOR ASCENT MAY TEND TO WEAKEN LATER TODAY...STRONG HEATING
WEST OF THE DRYLINE MAY BE SUFFICIENT TO INITIATE ISOLATED TO WIDELY
SCATTERED TSTMS BY LATE AFTERNOON OR EARLY EVENING.
VERTICALLY VEERING WIND PROFILES WITH 35-45 KT OF DEEP-LAYER SHEAR
WILL BE SUPPORTIVE OF ORGANIZED STORM MODES...INCLUDING SUPERCELLS
WITH THE PRIMARY HAZARD BEING LARGE HAIL. EXPECT STORMS TO
GRADUALLY WEAKEN BY MID TO LATE EVENING WITH THE COOLING AND
STABILIZATION OF THE BOUNDARY LAYER.
...S-CNTRL TX THIS AFTERNOON AND EVENING...
MOIST...LOW-LEVEL UPSLOPE FLOW INTO THE HIGH TERRAIN W OF THE RIO
GRANDE COUPLED WITH THE POSSIBLE INFLUENCE OF WEAK MID-LEVEL
PERTURBATIONS EMBEDDED WITH THE SUBTROPICAL AIR STREAM WILL PROMOTE
AN INCREASE IN TSTMS OVER NRN MEXICO THIS AFTERNOON. WSWLY MEAN
FLOW WILL ALLOW SOME OF THIS ACTIVITY TO SPREAD EWD ACROSS THE
REGION LATER TODAY INTO TONIGHT. THE COMBINATION OF MODEST AMOUNTS
OF INSTABILITY AND VERTICAL SHEAR MAY GIVE RISE TO SOME STORM
ORGANIZATION AND A RISK FOR HAIL AND LOCALLY STRONG WIND GUSTS.
..MEAD/GLEASON.. 04/11/2015
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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