National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
ACUS01 KWNS 250540
SWODY1
SPC AC 250539

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1239 AM CDT SAT MAY 25 2013

VALID 251200Z - 261200Z

...THERE IS A SLGT RISK OF SVR TSTMS CNTRL THROUGH NRN HIGH
PLAINS...

...SYNOPSIS...

SYNOPTIC PATTERN WILL UNDERGO LITTLE CHANGE SATURDAY WITH AN UPPER
RIDGE OVER THE CNTRL U.S. FLANKED BY TROUGHS OVER THE WRN AND ERN
STATES. AT THE SFC A LEE TROUGH/DRYLINE WILL PERSIST OVER THE HIGH
PLAINS WHILE A WARM FRONT LIFTS SLOWLY NWD THROUGH THE CNTRL/NRN
PLAINS.

...CNTRL AND NRN PLAINS AREA...

SELY WINDS EAST OF LEE TROUGH WILL ADVECT UPPER 50S DEWPOINTS INTO
THE NRN HIGH PLAINS WITH LOW-MID 60S FARTHER SOUTH OVER THE CNTRL
PLAINS. MEANWHILE...WSWLY WINDS ALOFT WILL ADVECT STEEP MID-LEVEL
LAPSE RATES ABOVE THE MOISTENING BOUNDARY LAYER CONTRIBUTING TO AN
AXIS OF 1500-2500 J/KG MLCAPE. THE ATMOSPHERE WILL REMAIN CAPPED TO
SURFACE BASED STORMS UNTIL MID AFTERNOON WHEN DIABATIC WARMING WILL
AUGMENT OROGRAPHIC FORCING WHERE A MOIST SELY UPSLOPE REGIME WILL
EXIST FROM NERN CO...ERN WY INTO ERN MT. STORMS ARE EXPECTED TO
DEVELOP OVER THE HIGHER TERRAIN AND SUBSEQUENTLY SPREAD EWD INTO THE
AXIS OF MODERATE INSTABILITY ACROSS THE HIGH PLAINS. THIS REGION
WILL RESIDE ON SRN FRINGE OF STRONGER FLOW ALOFT WITH 35-40 KT WINDS
AT 500 MB ABOVE SELY NEAR SFC WINDS RESULTING IN FAVORABLE VERTICAL
SHEAR FOR SUPERCELLS. VERY LARGE HAIL WILL BE THE INITIAL PRIMARY
THREAT...THROUGH ISOLATED TORNADOES MAY ALSO BE POSSIBLE. A FEW
STORMS MAY EVENTUALLY CONGEAL INTO LINES/CLUSTERS WITH AN INCREASING
DAMAGING WIND THREAT DURING THE EVENING...SUSTAINED BY A
STRENGTHENING SLY LLJ. SEVERE THREAT IS EXPECTED TO GRADUALLY WANE
TOWARD LATE EVENING.

...SRN HIGH PLAINS...

ISOLATED TO WIDELY SCATTERED STORMS ARE EXPECTED TO ONCE AGAIN
DEVELOP OVER THE HIGHER TERRAIN AND SPREAD EWD INTO THE SRN HIGH
PLAINS. THESE STORMS WILL EXIST IN A WEAK SHEAR ENVIRONMENT...BUT
STEEP LAPSE RATES...MODERATE INSTABILITY AND 25+ F LOW LEVEL
TEMPERATURE-DEWPOINT SPREADS WILL SUPPORT A THREAT FOR ISOLATED
LARGE HAIL AND DOWNBURST WINDS.

..DIAL/DEAN.. 05/25/2013