Severe Thunderstorm Warning 313, NWS Tulsa, OK

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
1045 AM CDT WED AUG 20 1997

MORN UA AND SATELLITE IMAGERY INDICATE AN UPR LVL SPEED MAX
MOVG SEWD THRU WRN/CNTRL KS THIS MORN. THE SPEED MAX SHOWS
UP BEST AT 200 MB ON PROFILER WINDS AND WAS ALSO ASSD WITH
SLIGHTLY COOLER AIR AT H5. ALREADY SOME STG/SVR CONVECTION
OCCURRING ACRS WRN KS. AS THIS POCKET OF INSTBY MOVES SE...
SO WILL THE THREAT OF TSRA. WL PUT IN LO POPS THIS AFTN FOR
WRN PARTS OF FA AS THE KS ACTIVITY SPREADS SE. WL ALSO
THROW IN A 20 POP OVR SE OKLA WHERE TERRAIN INFLUENCES
AND LEFTOVER SFC BNDRIES MAY AID DVLPMENT IN WEAKLY CAPPED
AIRMASS.

NO CHGS TO LATER PDS ATTM...BUT MAY NEED TO ADD SOME LO
POPS INTO THIS EVE OR OVERNITE PD DEPENDING ON PERSISTENCE
OF KS CONVECTION.

FCSTID = 9

.TUL...
OK...NONE.
AR...NONE.

ARZ001-002-010-011-019-029-OKZ054>076-211200-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
100 PM CDT WED AUG 20 1997

ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS PORTIONS OF
NORTHEAST OKLAHOMA THIS AFTERNOON AND EARLY EVENING.

THE MORNING WEATHER BALLOON AND SATELLITE DATA INDICATED THAT THERE
MAY BE A SLIGHTLY INCREASED THREAT OF THUNDERSTORMS ACROSS PORTIONS
OF EASTERN OKLAHOMA AND NORTHWEST ARKANSAS.

ACROSS NORTHEAST OKLAHOMA...STRONGER WINDS IN THE UPPER LEVELS OF
THE ATMOSPHERE ARE EXPECTED TO WORK THEIR WAY DOWN INTO THE REGION
LATER TODAY...IN ADDITION TO COOLING OF MID AND UPPER LEVEL
TEMPERATURES.  THE SLIGHTLY COOLER MID LEVEL TEMPERATURES WILL HELP
MAKE THE ATMOSPHERE MODERATELY UNSTABLE BY LATE AFTERNOON.  IN
ADDITION...A WEAK LOW LEVEL BOUNDARY WILL SET UP ACROSS THE REGION
BY LATE AFTERNOON AND MAY PROVIDE JUST ENOUGH LOW LEVEL CONVERGENCE
TO FOCUS SCATTERED STRONGER STORMS...MAINLY WEST OF U.S. HIGHWAY
75.

SOME OF THE THUNDERSTORMS ACROSS NORTHEAST OKLAHOMA MAY BRIEFLY
BECOME SEVERE IN THE LATE AFTERNOON HOURS.  LIMITED SHEAR IN THE
LOWEST LAYERS OF THE ATMOSPHERE SUGGEST THAT THE MAIN THREAT WITH
ANY POTENTIALLY SEVERE STORMS WILL BE IN THE FORM OF DAMAGING
DOWNBURST WINDS...LARGE HAIL...AND BRIEF BUT VERY HEAVY RAINS.

FARTHER SOUTHEAST...RESIDUAL MOISTURE IN THE LOWEST 5 THOUSAND FEET
OF THE ATMOSPHERE MAY BECOME FOCUSED NEAR HIGHER TERRAIN DURING
LATE AFTERNOON HEATING ACROSS SOUTHEAST OKLAHOMA AND THE FORT SMITH
AREA OF ARKANSAS.  WITH THE LACK OF UPPER LEVEL SUPPORT...THESE
STORMS SHOULD NOT BECOME SEVERE.

EMERGENCY MANAGEMENT AGENCIES AND STORM SPOTTER GROUPS SHOULD
MONIT>OR LATER STATEMENTS AND UPDATED FORECASTS REGARDING POTENTIAL
THUNDERSTORMS LATER THIS AFTERNOON AND EARLY EVENING.