Severe Thunderstorm Warning 274, NWS Tulsa, OK

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
1025 AM CDT THU JUN 28 2001

NORTH/SOUTH CONVECTIVE BAND HAS SET UP ACROSS THE AREA THIS
MORNING...AND WILL CONTINUE MOVING TO THE SOUTH THROUGH THE DAY.
SOULD SEE ACTIVITY WEAKEN SOME WITH TIME...BUT ISOALTED
STRONG/SEVERE STORMS WILL REMAIN POSSIBLE WITH ADDITIONAL THREAT OF
LOCALIZED HEAVY RAIN.  ALONG THE NORTHERN FRINGES OF THE AREA A
LITTLE SUN HELPING THINGS WARM UP...AND ADDITIONAL ACTIVITY EXPECTED
THERE BY THIS AFTERNOON.  WILL ALSO HAVE TO CONTEND WITH ANY
RESIDUAL BOUNDRIES LEFT BY THIS MORNINGS ACTIVITY...SO SCATTERED
SHOWERS AND THUNDERSTORMS WILL BE THE RULE ACROSS THE ENTIRE AREA.
WILL UPDATE ZONES BY AROUND 16Z TO ADJUST FOR CURRENT TRENDS INTO
THE AFTERNOON HOURS.  REMAINDER OF THE FORECAST LOOKS FINE FOR NOW.

.TSA...
AR...NONE.
OK...NONE.

ARZ001-002-010-011-019-020-029-OKZ049-053>076-291100-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
100 PM CDT THU JUN 28 2001

...ISOLATED SEVERE THUNDERSTORMS EXPECTED ACROSS EASTERN OKLAHOMA
   AND NORTHWEST ARKANSAS THIS AFTERNOON AND TONIGHT...

AN UPPER LEVEL LOW PRESSURE SYSTEM OVER SOUTHERN MISSOURI WILL MOVE
LITTLE THROUGH TONIGHT. CLUSTERS OF THUNDERSTORMS ARE EXPECTED TO
CONTINUE ACROSS PARTS OF OKLAHOMA AND ARKANSAS AS COLD AIR ALOFT
NEAR THE UPPER LOW HELPS KEEP THE ATMOSPHERE UNSTABLE.

THE BEST CHANCE FOR STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON
WILL BE ACROSS THE NORTHWEST CORNER OF ARKANSAS AND THE NORTHEAST
CORNER OF OKLAHOMA. SUNSHINE IN THESE AREAS WILL ALLOW TEMPERATURES
TO RISE INTO THE 80S THIS AFTERNOON...WHICH WILL RESULT IN SCATTERED
TO NUMEROUS THUNDERSTORMS NEAR THE UPPER LOW CENTER. THUNDERSTORMS
IN THESE AREAS THIS AFTERNOON WILL BE CAPABLE OF PRODUCING HAIL TO
THE SIZE OF QUARTERS BEFORE WEAKENING THIS EVENING.

THUNDERSTORMS ARE EXPECTED TO DEVELOP IN A NORTH-SOUTH BAND AGAIN
TONIGHT ACROSS EASTERN OKLAHOMA. A FEW OF THESE STORMS COULD BECOME
SEVERE AND PRODUCE DIME SIZE HAIL AND WIND GUSTS TO 50 MPH AS THEY
MOVE SOUTH.

.DAY TWO...ISOLATED SEVERE THUNDERSTORMS ARE AGAIN EXPECTED ON
FRIDAY OVER EASTERN OKLAHOMA AND NORTHWEST ARKANSAS AS THE UPPER
LEVEL LOW PRESSURE SYSTEM REMAINS IN THE VICINITY.

.SPOTTER ACTIVATION...
ACTIVATION OF STORM SPOTTERS MAY BE NECESSARY ACROSS PARTS OF
EXTREME NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON.
SPOTTERS WILL NEED TO MONITOR THE LATEST FORECASTS AND BE PREPARED
FOR ACTIVATION ACROSS EASTERN OKLAHOMA LATE TONIGHT.

.DISCUSSION...
LIFTED INDEX VALUES AROUND -8 WILL DEVELOP ACROSS AREAS NORTH OF A
PRYOR OKLAHOMA TO OZARK ARKANSAS LINE THIS AFTERNOON. SCATTERED
THUNDERSTORMS WILL CONTINUE TO DEVELOP AND INCREASE IN INTENSITY
THROUGH THE AFTERNOON HOURS...AND A FEW OF THE STORMS ARE LIKELY TO
BE SEVERE AND PRODUCE HAIL UP TO ONE INCH IN DIAMETER.

THUNDERSTORMS ARE EXPECTED TO CONTINUE ACROSS THE REST OF EASTERN
OKLAHOMA THROUGH AT LEAST MID AFTERNOON. A FEW OF THESE STORMS COULD
BRIEFLY INTENSIFY AND PRODUCE DIME SIZE HAIL...BUT LIMITED
INSTABILITY IN THIS AREA IS EXPECTED TO LIMIT THE SEVERE POTENTIAL
THIS AFTERNOON.

THUNDERSTORMS ACROSS EXTREME NORTHWEST ARKANSAS AND THE NORTHEAST
CORNER OF OKLAHOMA WILL WEAKEN RAPIDLY AFTER SUNSET. LATER
TONIGHT...CONVECTION IS FORECAST TO REDEVELOP ALONG AN ELEVATED
BAROCLINIC ZONE LOCATED ROUGHLY FROM TULSA TO MCALESTER. IMPROVING
WIND SHEAR LATE TONIGHT IS EXPECTED TO COMPENSATE FOR THE MARGINAL
INSTABILITY...AND A FEW SEVERE STORMS WILL BE POSSIBLE AFTER
MIDNIGHT IN A BROAD ZONE BETWEEN TULSA AND MCALESTER. MARGINALLY
SEVERE HAIL WILL BE THE THREAT FROM ANY STRONG THUNDERSTORMS
OVERNIGHT.

THREAT TABLE
VALID THROUGH 1100 UTC FRIDAY

AREA 1...NORTH OF A PRYOR TO OZARK LINE THIS AFTERNOON/EARLY EVENING
THUNDERSTORM PROBABILITY...100
SEVERE PROBABILITY IF STORMS OCCUR...90
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...10

AREA 2...REST OF EASTERN OKLAHOMA AND NORTHWEST ARKANSAS
THUNDERSTORM PROBABILITY...100
SEVERE PROBABILITY IF STORMS OCCUR...50
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...05

THREAT AREAS DEFINE THE GREATEST RISK. PROBABILITIES ARE IN PERCENT.
SIGNIFICANT SEVERE IS DEFINED AS F1 OR GREATER WIND/TORNADO DAMAGE
AND/OR GOLF BALL SIZE HAIL OR LARGER.

.OTHER HAZARDS...
LOCALLY HEAVY RAIN WILL BE POSSIBLE...MAINLY ACROSS EASTERN OKLAHOMA
TONIGHT...WHERE THUNDERS?TORMS MAY REPEATEDLY DEVELOP AND MOVE OVER
THE SAME AREAS.

RELATED GRAPHICAL INFORMATION CAN BE FOUND AT:WWW.SRH.NOAA.GOV/TULSA