Severe Thunderstorm Warning 277, NWS Tulsa, OK

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
410 AM CDT THU JUL 20 2000

COLD POOL HAS FORMED WITH THE CONVECTIVE COMPLEX IN KANSAS AND
STORMS ARE NOW MAKING A BEELINE RIGHT DOWN THE INSTABILITY AXIS
TOWARDS OUR FORECAST AREA. AS HAS BEEN THE CASE LATELY...MODELS ARE
LAGGING BEHIND OBSERVED RADAR DATA BY SEVERAL HOURS SO HAVE
BASICALLY FOLLOWED THE 06Z ETA MODEL AS THE BASIS FOR THIS FORECAST
BUT SPED IT UP A FEW HOURS.

WITH UPPER RIDGE RETROGRADING TODAY AND NORTHWEST FLOW INCREASING
ACROSS THE AREA...EXPECT THE COMPLEX TO MAKE ITS WAY ACROSS MUCH OF
THE FORECAST AREA TODAY SO WILL GO LIKELY POPS IN MOST AREAS EXCEPT
FOR CHANCE POPS DOWN NEAR THE RED RIVER. IT WILL BE ANOTHER HOT DAY
IN SOUTHEAST OKLAHOMA AND WEST CENTRAL ARKANSAS AS THEY WILL HAVE
PLENTY OF TIME TO HEAT UP BEFORE THE STORMS ARRIVE BUT MUCH COOLER
WEATHER IS ON TAP FURTHER NORTH. TEMPERATURE RECOVERY THIS
AFTERNOON WILL BE HAMPERED BY DEBRIS CLOUDINESS AND ALSO COOL NORTH
TO NORTHEAST LOW LEVEL FLOW BEHIND THE COLD FRONT WHICH WILL GET A
GOOD KICK SOUTH TODAY FROM THE STORMS.

FORECAST TRICKIER BEYOND TODAY AS TIMING AND LOCATION OF ADDITIONAL
CONVECTIVE COMPLEXES WILL BE TOUGH TO PIN DOWN. WITH THE AIRMASS
STABILIZED BY TODAYS CONVECTION...MAIN SHOW TONIGHT MAY BE TO OUR
WEST BUT CONFIDENCE ON THIS IS NOT HIGH. WILL BROADBRUSH 50% POPS
ACROSS MOST OF THE AREA TONIGHT THROUGH FRIDAY NIGHT AS MOIST
AIRMASS WILL REMAIN IN PLACE AND BE CONDUCIVE TO SEVERAL ROUNDS OF
CONVECTION WITH TIMING AND LOCATION THE BIG UNKNOWNS AT THIS POINT.

PATTERN CHANGES LITTLE THROUGH THE WEEKEND SO WILL KEEP POPS GOING
THROUGH THE EXTENDED BUT LOWER THEM TO SLIGHT CHANCE MONDAY. WILL
SEE A WELCOME BREAK FROM THE HEAT FOR SEVERAL DAYS BUT THINGS START
WARMING BACK UP DURING THE FIRST PART OF NEXT WEEK.

GENERALLY UNDERCUT GUIDANCE MAXIMUM TEMPERATURES DUE TO CLOUDS AND
CONVECTION THE NEXT COUPLE DAYS BUT STAYED CLOSER TO GUIDANCE ON
MINIMUMS. WENT WAY ABOVE GUIDANCE POPS TODAY BASED ON CURRENT RADAR
AND MAY MAKE FURTHER ADJUSTMENTS TO POPS TODAY AT THE LAST MINUTE.

FCSTID = 5
TUL   87  70  85  68 /  70  50  50  50
FSM   98  71  89  70 /  60  30  50  40
MLC   98  72  87  70 /  50  30  50  40
BVO   84  68  83  66 /  70  50  50  50
FYV   90  69  84  66 /  70  50  50  50
BYV   90  69  84  66 /  70  50  50  50
MIO   86  68  83  66 o/  70  50  50  50
MKO   92  70  86  69 /  60  40  50  50
F10   92  70  86  69 /  60  40  50  50
HHW  100  73  90  71 /  30  30  40  30

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

PLATE

ARZ001-002-010-011-019-020-029-OKZ049-053>076-211100-

EASTERN OKLAHOMA AND NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
600 AM CDT THU JUL 20 2000

...A FEW SEVERE THUNDERSTORMS POSSIBLE TODAY MAINLY NORTH OF A
MCALESTER TO POTEAU LINE...

.SYNOPSIS...
A CLUSTER OF STRONG TO SEVERE THUNDERSTORMS OVER SOUTH CENTRAL KANSAS
WILL MOVE INTO NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS THIS
MORNING...AND INTO SOUTHEAST OKLAHOMA BY THIS AFTERNOON. NORTHWEST FLOW
ALOFT WILL STEER THIS COMPLEX ACROSS MUCH OF EASTERN OKLAHOMA AND
NORTHWEST ARKASAS TODAY. A SURFACE COLD FRONT ALSO EXTENDS ACROSS FAR
NORTHEAST OKLAHOMA.

.PRIMARY HAZARD...
A FEW SEVERE THUNDERSTORMS ARE POSSIBLE TODAY MAINLY NORTH OF A
MCALESTER TO POTEAU OKLAHOMA LINE. THE MAIN THREAT FROM ANY SEVERE
THUNDERSTORMS WILL BE DAMAGING WIND GUSTS IN EXCESS OF 60 MILES AN
HOUR.

.DISCUSSION...
A COLD POOL HAS FORMED WITH THE ONGOING CONVECTION ACROSS KANSAS THIS
MORNING...AND NORTHWEST FLOW ALOFT WILL DRIVE THIS COMPLEX SOUTHEAST
ACROSS MUCH OF NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS THIS MORNING.
A COLD FRONT/OUTFLOW BOUNDARY CURRENTLY ACROSS FAR NORTHEAST OKLAHOMA
WILL ALSO MOVE SOUTH THROUGH THE MORNING WITH THE THUNDERSTORMS.

THE GREATEST SURFACE BASED INSTABILITY THIS MORNING WAS LOCATED FROM
AROUND ENID TO TULSA TO FORT SMITH...WHERE CAPES WERE IN EXCESS OF 2000
J/KG. DAMAGING WIND GUSTS WILL BE THE MAIN THREAT FROM STORMS THIS
MORNING. LARGE HAIL MAY BECOME MORE OF A THREAT THIS AFTERNOON...AS THE
OUTFLOW BOUNDARY MOVES INTO MORE UNSTABLE AIR ACROSS SOUTHEAST
OKLAHOMA.

.SPOTTER ACTIVATION...
SPOTTER ACTIVATION MAY BE REQUIRED THIS MORNING ACROSS NORTHEAST
OKLAHOMA.

AN UPDATED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AROUND 1 PM.

SJT