Severe Thunderstorm Warning 239, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
300 PM CDT MON MAY 8 2000

INTERESTING FORECAST COMING UP OVER THE NEXT 12 HRS ACROSS MY CWA.
SEVERAL VARIABLES FIGHTING FOR DOMINATION TO EITHER PRODUCE SEVERE
WEATHER OR NOT PRODUCE SEVERE WEATHER LATE THIS AFTERNOON AND
OVERNIGHT TONIGHT. FRONT HAS MADE MORE SOUTHEAST PROGRESS TODAY THAN
EARLIER THOUGHT BUT HAS SLOWED OVER THE PAST SEVERAL HOURS. DO NOT
THINK FRONT WILL MOVE MUCH MORE THIS AFTERNOON. FRONT WILL HOWEVER
GET ANOTHER PUSH LATER TONIGHT WITH HELP OF CONVECTION AND
PROGRESSION OF UPPER WAVE OUT OF THE SOUTHERN ROCKIES INTO SOUTHERN
PLAINS. THERE WILL ALSO BE A POTENTIAL FOR HEAVY RAINFALL ACROSS
NORTH CENTRAL OKLAHOMA AS UPPER FLOW WILL PARALLEL FRONT AND UPPER
JET DYNAMICS WILL BE MAXIMIZED ACROSS NORTH CENTRAL OK INTO SE KS.
THIS COULD LEAD TO CONVECTION CONT TO DEVELOP OVER THE SAME AREAS
AND TRAINING TOWARD THE NE. ALTHOUGH LATEST QPF FORECASTS FROM HPC
HAVE BACKED OFF ON AMOUNTS FOR THE AREA TONIGHT...WILL KEEP HEAVY
RAINFALL WORDING IN ZONES FOR TONIGHT IN NORTH CENTRAL ZONES.

SOME LINGERING TSTMS IN CENTRAL AND SOUTHEAST SECTIONS VERY EARLY ON
TUESDAY STILL POSSIBLE BEFORE WAVE MOVES INTO MID MS VALLEY AND
SURFACE COLD FRONT PUSHES EAST OF AREA. SLIGHTLY COOLER TEMPS ON TAP
FOR MUCH OF AREA ON TUESDAY EXCEPT FOR NW WHERE FRONT AND LOW CLOUDS
HAVE MADE FOR COOLER DAY TODAY. COOL DOWN WILL BE SHORT LIVED AS
WARM TEMPS RETURN ON WEDNESDAY AS SOUTHERLY FLOW RETURNS AND 850MB
TEMPS QUICKLY RECOVER. REST OF EXTENDED LOOKS VERY WARM AND DRY.

FCSTID = 30
OKC   64  77  55  89 /  60  30   0  10
HBR   58  76  52  93 /  50  10   0  10
SPS  K 66  81  56  93 /  30  10   0  10
GAG   55  73  48  91 /  50  10   0  10
PNC   62  74  51  88 /  90  30   0  10
DUA   67  80  57  90 /  30  30   0  10

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

OKZ004>048-050>052-TXZ083>090-082200-

THUNDERSTORM OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORMAN OK
343 PM CDT MON MAY 8 2000

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON
AND EARLY TONIGHT OVER PARTS OF CENTRAL AND NORTHEAST OKLAHOMA...
NORTH AND EAST OF A LINE FROM SEMINOLE TO CHICKASHA TO BINGER TO
PERRY. ALSO... THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TONIGHT
NORTH AND EAST OF A LINE FROM COALGATE TO SNYDER TO HINTON TO BRAMAN.
SEVERE WEATHER WATCHES MAY BE NEEDED IN PARTS OF THESE AREAS BEFORE
SUNSET.

DISCUSSION...THUNDERSTORM DEVELOPMENT WILL BE LIKELY BY 7 PM ALONG
AND NEAR A SLOW MOVING COLD FRONT EXTENDING FROM NEAR CUSHING TO
OKLAHOMA CITY TO SNYDER LATE THIS AFTERNOON. WHILE NORTH WINDS
CONTINUE NORTH AND WEST OF THE FRONT... SURFACE WINDS ARE EXPECTED TO
BACK FROM SOUTHWESTERLY TO MORE SOUTHERLY TO THE SOUTH AND EAST OF
THE FRONT. THESE CHANGES WILL LEAD TO INCREASING CONVERGENCE ALONG
THE FRONT... AND A MORE FAVORABLE VERTICAL WIND PROFILE FOR SEVERE
THUNDERSTORMS BY EARLY EVENING. WINDS AT MID AND UPPER LEVELS ALSO
WILL CONTINUE TO STRENGTHEN...FURTHER ENHANCING VERTICAL SHEAR.

MUCH OF WESTERN AND NORTH CENTRAL OKLAHOMA HAS COOLED AND STABILIZED
BEHIND THE COLD FRONT. BUT THE AIR REMAINS WARM...HUMID AND VERY
UNSTABLE ALONG AND SOUTHEAST OF THE SURFACE BOUNDARY. A STRONG CAP OF
WARM AIR SEVERAL THOUSAND FEET ABOVE THE GROUND IS EXPECTED TO
WEAKEN THROUGH THIS EVENING... RESULTING IN AN INCREASING CHANCE
OF THUNDERSTORM DEVELOPMENT THROUGH THE EVENING. ANY STORMS THAT
INITIATE BEFORE SUNSET ARE LIKELY TO INTENSIFY QUICKLY... AND MAY
PRODUCE VERY LARGE HAIL... DAMAGING WINDS... AND POSSIBLY
TORNADOES.

FURTHER WEAKENING OF THE CAP IS EXPECTED AFTER DARK AS AN UPPER
LEVEL STORM SYSTEM APPROACHES THE AREA FROM THE SOUTHERN ROCKIES.
AS A RESULT... MORE WIDESPREAD THUNDERSTORM DEVELOPMENT IS EXPECTED
TONIGHT ACROSS MUCH OF CENTRAL AND NORTHERN OKLAHOMA. LARGE HAIL AND
VERY HEAVY RAINFALL WILL BE THE MAIN THREATS LATER TONIGHT...
ESPECIALLY ACROSS NORTH CENTRAL OKLAHOMA.

SPOTTER GROUPS OVER CENTRAL AND SOUTHWEST OKLAHOMA... FROM AS FAR
SOUTH AND WEST AS LAWTON AND SURROUNDING AREAS... NORTHEAST ACROSS
MUCH OF CENTRAL OKLAHOMA... SHOULD BE PREPARED FOR POSSIBLE
ACTIVATION AT ANY TIME THROUGH THIS EVENING.

24

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
729 PM CDT MON MAY 8 2000

TIME (CDT) .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0710 PM    TONKAWA                   OK   1.00 INCH HAIL
05/08/00   KAY                            PUBLIC REPORT

0725 PM    4 WNW MARLAND             OK   .75 INCH HAIL
05/08/00   NOBLE                          PUBLIC REPORT

JL