Flash Flooding and Hail in Oklahoma, May 17 to 18, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
1105 AM CDT THU MAY 17 2001

15Z SURFACE ANALYSIS SHOWS COLD FRONT RUNNING ROUGHLY FROM NE KANSAS
SOUTHWEST INTO THE OKLAHOMA AND TEXAS PANHANDLES WITH PRE-FRONTAL/
OUTFLOW BOUNDARY EXTENDING FROM ALFALFA COUNTY SOUTHWEST INTO NORTH
TEXAS ZONES.  ELEVATED CONVECTION IN NORTHERN TEXAS PANHANDLE HAS
BEEN ON THE DECREASING THE LAST HOUR OR SO WITH DEBRIS CLOUDS MOVING
INTO NORTHWEST OK.  MORNING SUN HAS PROVIDED ENOUGH MIXING/LIFT TO
PRODUCE STRATUS AHEAD OF SURFACE BOUNDARY.

BIG QUESTION THIS AFTERNOON AND EARLY EVENING IS POTENTIAL FOR
STRONG TO SEVERE STORMS.  ALONG AND JUST AHEAD OF BOUNDARY...ETA
FORECAST SBCAPE VALUES IN THE 25-35K RANGE.  FAIRLY STRONG CAP IN
PLACE THIS MORNING PER OUN SOUNDING WITH STEEP LAPSE RATES ABOVE
INVERSION. ENOUGH CONVERGENCE ALONG BOUNDARY THIS AFTERNOON EARLY
EVENING MAY BE ENOUGH FOR ISOLATED TO MAYBE WIDELY SCATTERED
CONVECTION WHICH WILL LIKELY BECOME QUICKLY SEVERE WITH LARGE HAIL
THE MAIN THREAT.  THINK BETTER CHANCE WILL BE LATER THIS EVENING AND
OVERNIGHT WITH SHORTWAVE NEAR UTAH ALONG WITH CONTINUED COOLING IN
LOWER LAYERS.

WILL LIKELY ADJUtST TEMPS DOWN A LITTLE SOUTHWEST AND SOUTHEAST...
OTHERWISE CURRENT ZONES LOOK OK.  MAY ALSO HAVE TO ADJUST AFTERNOON
SKY CONDITION ACROSS SOUTHEAST ZONES.

.OUN...
OK...NONE.
TX...NONE.

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OKZ004>048-050>052-TXZ083>090-172030-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
100 PM CDT THU MAY 17 2001

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER ALL OF
WESTERN...CENTRAL AND SOUTHEAST OKLAHOMA...AND WESTERN NORTH TEXAS.
THE PRIMARY RISK IS LARGE HAIL AND DAMAGING WINDS.

A COLD FRONT WILL MOVE SLOWLY ACROSS NORTHWEST AND WEST
CENTRAL OKLAHOMA THIS AFTERNOON PROVIDING A FOCUS FOR STORM
DEVELOPMENT THIS AFTERNOON AND EARLY EVENING.  AHEAD OF THE COLD
FRONT...TEMPERATURES WILL WARM INTO THE 80S WITH LOW 90S ACROSS
WESTERN NORTH TEXAS.  THIS COMBINED WITH DEWPOINTS IN THE MID 60S TO
LOWER 70S WILL CREATE A MODERATELY UNSTABLE ATMOSPHERE.  A WEAK
MID-LEVEL FEATURE WILL MOVE WEST TO EAST ACROSS OKLAHOMA TONIGHT
HELPING TO DRIVE THE FRONT ACROSS CENTRAL AND SOUTHERN SECTIONS BY
FRIDAY MORNING. IN ADDITION TO THE HAIL THREAT, HEAVY RAINFALL IS
ALSO POSSIBLE.

EMERGENCY MANAGRERS SHOULD PREPARE FOR SPOTTER ACTIVATION THIS
AFTERNOON IN NORTHERN AND WESTERN OKLAHOMA AND THIS EVENING AND
OVERNIGHT IN AREAS TO THE SOUTH AND EAST...INCLUDING WESTERN NORTH
TEXAS.

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