Severe Thunderstorm Warning 44, NWS Tulsa, OK

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
1014 AM CDT TUE APR 10 2001

WEAK HIGH-BASED CONVECTION CONTINUES TO DEVELOP ACROSS WESTERN AND
CENTRAL OKLAHOMA...WEAKENING AS IT MOVES NORTHEAST INTO NORTH
CENTRAL OKLAHOMA. THE BEST CHANCE FOR RAIN THIS AFTERNOON WILL BE
ACROSS NORTHEAST OKLAHOMA WHERE DEEPEST MOISTURE AND BEST WARM
ADVECTION NOTED ON MORNING ANALYSES.

CLOUD COVER REMAINED THICK ACROSS THE ENTIERE FORECAST AREA THIS
MORNING...AND TEMPERATURES MAY NOT QUITE REACH CURRENT FORECAST
VALUES WITHOUT A LITTLE SUN. WILL UPDATE ZONES AND LOWER
TEMPERATURES SLIGHTLY THIS AFTERNOON...WITH THE EXPECTATION OF
MOSTLY CLOUDY SKIES WITH PERHAPS A FEW BREAKS OR THIN SPOTS AIDING A
LATE AFTERNOON RISE IN TEMPERATURES.

NEW MODEL DATA STILL SUPPORTS A LIKELIHOOD OF CONVECTION TONIGHT AS
THE UPPER LOW OVER WESTERN ARIZONA THIS MORNING MOVES QUICKLY
EASTWARD. NO CHANGES NEEDED TO LATER PERIODS OF FORECAST.

UPDATED ZONES WILL BE ISSUED BY 1030 AM.

FCSTID = 9

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

ARZ001-002-010-011-019-020-029-OKZ049-053>076-111100-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
100 PM CDT TUE APR 10 2001

...ISOLATED THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING...
...A FEW SEVERE THUNDERSTORMS POSSIBLE EARLY WEDNESDAY MORNING...

A WARM FRONTAL BOUNDARY EXTENDED ACROSS SOUTHERN KANSAS INTO CENTRAL
MISSOURI EARLY THIS AFTERNOON...WHILE A SURFACE DRYLINE STRETCHED
FROM SOUTHWESTERN KANSAS TO THE OKLAHOMA PANHANDLE AND INTO WEST
TEXAS. THE WARM FRONT WILL CONTINUE LIFTING NORTH THROUGH
TONIGHT AS AN UPPER LEVEL STORM SYSTEM APPROACHES FROM THE
SOUTHWEST. ISOLATED THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON
AND EVENING ACROSS PARTS OF EASTERN OKLAHOMA...MAINLY NORTHWEST OF
INTERSTATE 44.  THUNDERSTORMS THAT FORM THIS AFTERNOON OR EVENING
ARE EXPECTED TO REMAIN BELOW SEVERE LIMITS.

AS THE STRONG UPPER LEVEL STORM SYSTEM APPROACHES TONIGHT AND THE
DRYLINE ADVANCES EAST...THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
WESTERN OKLAHOMA AND ORGANIZE INTO A SQUALL LINE. UPPER LEVEL WIND
PROFILES SUGGEST THAT DAMAGING WINDS WILL BE POSSIBLE AS THE SQUALL
LINE APPROACHES EASTERN OKLAHOMA AFTER MIDNIGHT.

.SPOTTER ACTIVATION...
SPOTTER GROUPS...EMERGENCY MANAGERS AND OTHER INTERESTED PARTIES
SHOULD MONITOR THE LATEST FORECASTS AND UPDATED HAZARDOUS WEATHER
OUTLOOKS ISSUED BY THE TULSA NATIONAL WEATHER SERVICE. SPOTTER
ACTIVATION MAY BE REQUIRED ACROSS EASTERN OKLAHOMA AND NORTHWEST
ARKANSAS AFTER MIDNIGHT.

.DISCUSSION...
AN UPPER LEVEL DISTURBANCE WAS LIFTING ACROSS CENTRAL OKLAHOMA AND
SOUTHEAST KANSAS THIS AFTERNOON. A BROAD UPPER DIFLUENCE ZONE WAS
SET UP ACROSS WESTERN AND CENTRAL OKLAHOMA. THESE FACTORS MAY
GENERATE ENOUGH LIFT FOR ISOLATED THUNDERSTORMS ACROSS PARTS OF
NORTHEAST OKLAHOMA THIS AFTERNOON AND EVENING ...MAINLY AREAS
NORTHWEST OF
INTERSTATE 44. SEVERE STORMS ARE NOT EXPECTED THIS AFTERNOON AND
EVENING AS NO SIGNIFICANT FOCUSING MECHANISM WILL BE IN PLACE.

A POWERFUL UPPER LEVEL STORM SYSTEM WILL APPROACH THE AREA TONIGHT.
AS IT DOES...A SURFACE LOW PRESSURE WILL DEVELOP ACROSS EASTERN
COLORADO...AND SOUTHERLY WINDS WILL INCREASE ACROSS THE AREA. MID
LEVEL COOLING ASSOCIATED WITH THE UPPER SYSTEM WILL AID IN FURTHER
DESTABILIZATION OF THE ATMOSPHERE TONIGHT. STRONG UPPER DIVERGENCE
ASSOCIATED WITH THE LEFT EXIT REGION OF A 120 KNOT JET WILL DEVELOP
BY TONIGHT ACROSS EASTERN OKLAHOMA...AND A 70 KNOT JET WILL DEVELOP
AT 850MB. STORMS WILL LIKELY INITIATE ALONG THE DRYLINE LATE THIS
AFTERNOON OR EARLY EVENING....AND RACE TOWARD EASTERN OKLAHOMA.
UPPER LEVEL WIND PROFILES INDICATE THAT STORMS WILL EVOLVE INTO A
SQUALL LINE AS THEY RACE TOWARD EASTERN OKLAHOMA...WITH DAMAGING
WINDS POSING THE MAIN THREAT.

IF THE SYSTEM TAKES A MORE NORTHERLY TRACK...UPPER LEVEL DYNAMICS
WOULD NOT BE AS FAVORABLE FOR A SEVERE SQUALL LINE REACHING EASTERN
OKLAHOMA. IT DOES APPEAR LIKELY THAT SHOWERS AND THUNDERSTORMS WILL
AFFECT MUCH OF EASTERN OKLAHOMA BY EARLY WEDNESDAY MORNING...AND
NORTHWEST ARKANSAS AFTER 5 AM.

THREAT TABLE
VALID THROUGH 1200 UTC WEDNESDAY
AREA 1...WEST OF A BARTLESVILLE TO TULSA TO MCALESTER LINE
THUNDERSTORM PROBABILITY...70
SEVERE PROBABILITY IF STORMS OCCUR...40
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...10

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...
A VERY HIGH FIRE DANGER WILL CONTINUE TODAY ACROSS EASTERN OKLAHOMA
AND NORTHWEST ARKAONSAS.  SEE THE LATEST FIRE DANGER STATEMENT
/OKCFWMTUL/ FOR FURTHER DETAILS.

ADDITIONAL WEATHER INFORMATION...INCLUDING RELATED GRAPHICS CAN BE
FOUND AT: WWW.SRH.NOAA.GOV/TULSA.