Severe Thunderstorm Warning 260, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
1014 AM CDT SAT JUN 8 2002

PROPER ADJUSTMENTS TO THIS MORNINGS FORECAST WERE MADE AROUND 7 AM
TO ADDRESS MORE RAPID SHRA DEVELOPMENT NEAR THE RED RIVER THAN
EXPECTED OVERNIGHT. AS THE DAY PROGRESSES BELIEVE SUBSTANTIAL
MID/UPPER LEVEL CLOUDS WILL CONTINUE TO DEVELOP NEAR THE RED RIVER
IN REGION OF 700 MB WARM ADVECTION WITH SOME UPPER LEVEL SUPPORT
POSSIBLY PROVIDED BY ANTICYCLONIC CURVED UPPER JET OVER NORTH TEXAS.
12Z OUN SOUNDING SHOWS CONDITIONALLY UNSTABLE AIRMASS IN THE LOWEST
LEVELS TOPPED BY AN ABSOLUTELY STABLE LAYER BETWEEN 700-525MB.
CONTINUED SENSIBLE HEATING SHOULD ALLOW CAP TO BE OVERCOME BY
AFTERNOON WITH AN INCREASING TREND IN BOTH TS PROBABILITY AND AREAL
COVERAGE EXPECTED. DIFFICULT TO DETERMINE EXACTLY WHERE BUT BELIEVE
DIFFERENTIAL HEATING WILL FOCUS ADEQUATE CONVERGENCE ON A LOCAL
SCALE. LOW POPS WILL BE CONTINUED FOR NOW WHERE POPS EXIST CURRENTLY
BUT WOULD NOT BE SURPRISED TO SEE MORE COVERAGE WARRANTING HIGHER
POPS NEAR THE RED RIVER LATER ON. UPDATED HWO WILL CONTINUE TO
EMPHASIZE LOCALLY HEAVY RAIN AND NO SEVERE TS.

JAMES

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725 AM CDT SAT JUN 8 2002

WILL UPDATE FORECAST TO REMOVE AFTERNOON WORDING ASSOCIATED WITH
POPS AND TO RAISE POPS A BIT ACROSS SOUTHERN AND SOUTHEASTERN ZONES.
BASED ON NEW OUN SOUNDING...MID LEVEL TEMPS SOME 2 TO 3 DEGREES
CELSIUS COOLER THAN PROGD BY MODELS.

FCSTID = 11

--------------------------

WILL MAKE A FEW CHANGES TO GOING FORECAST...MAINLY TO HANDLING OF
POPS TODAY/TONIGHT...AND THE FIRST PORTION OF NEXT WEEK AHEAD OF
MAIN FRONTAL BOUNDARY. OUTFLOW BOUNDARY EVIDENT ON AREA RADARS AND
SATELLITE LATE YESTERDAY AFTERNOON AND EVENING ENTERED SOUTHWEST
INTO CENTRAL PORTIONS OF THE FORECAST AREA. THIS COULD BE A FOCUS
FOR AN ISOLATED THUNDERSTORM LATE THIS AFTERNOON AND EARLY
EVENING...AS FORCING ASSOCIATED WITH WEAKENING UPPER SYSTEM MOVES
CLOSER FROM SOUTHWEST TEXAS. MORE SCATTERED ACTIVITY STILL POSSIBLE
CLOSER TO THE RED RIVER VALLEY AND SOUTHEAST OKLAHOMA...IN VICINITY
OF DEEPER MOISTURE AND MORE FAVORABLE MID LEVEL TEMPERATURES.
HAZARDOUS WEATHER OUTLOOK WILL CONTINUE WITH NON-SEVERE WORDING.

IT APPEARS THAT CAP WILL BE SUFFICIENT TO PRECLUDE ANY CONVECTIVE
DEVELOPMENT AHEAD OF NEXT MAIN FRONTAL BOUNDARY...WHICH NOW IS PROGD
TO NOT AFFECT FORECAST AREA UNTIL SOMETIME WEDNESDAY. AVN HAS NOW
TRENDED TO A SLOWER FRONTAL ARRIVAL THAN THE ECMWF...WHICH IS QUITE
DIFFERENT FROM 2 OR 3 RUNS AGO. WITH NORTHWARD TRACK OF UPPER
LOW...AND TIME OF YEAR...THIS MAKES SENSE. DRYLINE COULD LIGHT UP
ACROSS PANHANDLES MONDAY AND TUESDAY...BUT ACTIVITY WILL BE ISOLATED
AND HARD PRESSED TO REACH OUR AREA. THUS...POPS WILL BE LOWERED TO
10 PERCENT ON TUESDAY...WHICH WILL TAKE THEM OUT OF ZONE FORECASTS.
WITH LATEST DATA...APPEARS BEST CHANCES FOR WIDESPREAD/HEAVY
RAINFALL WOULD BE WEDNESDAY THROUGH THURSDAY...ALTHOUGH THREAT OF
HIGH PLAINS DRIFTERS WILL CONTINUE THROUGH FRIDAY ACROSS WESTERN AND
SOUTHERN SECTIONS OF CWA.

FCSTID = 11

PRELIMINARY CCF NUMBERS...
OKC   86  70  87  70 /  30  20  10  10
HBR   90  70  93  70 /  20  20   0  10
SPS   90  72  92  72 /  40  30  10  10
GAG   92  70  93  70 /   0  10   0  10
PNC   88  70  89  70 /  20  10  10  10
DUA   86  70  87  70 /  40  30  20  10

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

OKZ004>048-050>052-TXZ083>090-081900-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1200 PM CDT SAT JUN 8 2002

THUNDERSTORM OUTLOOK...
NO SEVERE THUNDERSTORMS ARE EXPECTED THROUGH TONIGHT.

DISCUSSION...
A WEAK UPPER LEVEL DISTURBANCE COMBINED WITH AFTERNOON HEATING WILL
ALLOW SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS PORTIONS
OF CENTRAL AND SOUTHERN OKLAHOMA THIS AFTERNOON. WEAK MID AND UPPER
LEVEL WINDS SHOULD PREVENT THESE THUNDERSTORMS FROM BECOMING SEVERE.
HOWEVER THESE WEAK WINDS WILL SUPPORT LOCALLY HEAVY RAIN WITH
STRONGER THUNDERSTORMS. SCATTERED THUNDERSTORM DEVELOPMENT IS
EXPECTED TO CONTINUE THROUGH SUNDAY.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT SUN JUN 9.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...10 PERCENT.

OTHER HAZARDOUS WEATHER...
NO OTHER HAZARDOUS WEATHER IS EXPECTED THROUGH TONIGHT.

JAMES