Hail in Arkansas, May 11, 2001

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
1045 AM CDT FRI MAY 11 2001

CONVECTIVE COMPLEX PUSHING INTO NORTHWEST ARKANSAS AT THIS TIME WITH
SOME DEVELOPMENT ON THE WESTERN END INTO NORTHEAST OKLAHOMA. MESONET
DATA SHOWS THAT OUTFLOW BOUNDARY HAS PUSHED DOWN INTO FAR NORTHEAST
OKLAHOMA BUT NEW 12Z ETA LOOKS TOO AGGRESSIVE IN PUSHING THIS
BOUNDARY SOUTHWEST ACROSS THE AREA TODAY. LATEST RUC AND PREVIOUS
MM5 LOOK MORE IN TOUCH WITH REALITY WITH BOUNDARY PUSHING SOUTH IN
ARKANSAS WITH THE WESTERN END HANGING UP FROM EAST CENTRAL OKLAHOMA
BACK TO NEAR TULSA. THESE MODELS THEN REFIRE CONVECTION ALONG THE
BOUNDARY LATE THIS AFTERNOON.

AIRMASS WILL BE PLENTY UNSTABLE FOR SEVERE CONVECTION LATER THIS
AFTERNOON AND EVENING BUT MID LEVEL FLOW WILL BE QUITE WEAK. GOOD
VEERING WITH HEIGHT MAY STILL RESULT IN SOME STORM ORGANIZATION WITH
LARGE HAIL AND POSSIBLY DAMAGING WINDS STILL A THREAT.

WILL UPDATE SHORTLY TO ACCOUNT FOR CURRENT AND EXPECTED TRENDS. WILL
NEED TO KEEP A MENTION OF CONVECTION INTO TONIGHT IN ALL BUT
POSSIBLY THE FAR NORTHWEST PART OF THE FORECAST AREA.

QUICK GLANCE INTO THE FUTURE SUGGESTS A VERY WARM END OF THE WEEKEND
AND BEGINNING OF NEXT WEEK WITH THE FIRST 90 DEGREE READINGS OF THE
SEASON POSSIBLE. LITTLE OR NO CLOUD COVER EXPECTED OVER THE WEEKEND
EXCEPT POSSIBLY IN FAR SOUTHEAST OKLAHOMA SATURDAY BUT WILL LET THE
CURRENT PARTLY CLOUDY RIDE FOR NOW PENDING THE EXAMINATION OF MORE
DATA.

IT IS OF INTEREST TO NOTE THAT THE LOCAL WORKSTATION ETA MODEL WE
HAVE JUST BEGUN RUNNING HERE AT THE OFFICE PRETTY MUCH NAILED THE
MAIN AREA OF CONVECTION THIS MORNING (FROM THE 18Z RUN THURSDAY).
THIS MODEL ALSO SUPPORTS REDEVELOPMENT IN NORTHEAST OKLAHOMA LATE
THIS AFTERNOON. THE OPERATIONAL ETA WAS TOO FAR SOUTH AND WEST WITH
THE CURRENT CONVECTION AND DID NOT ALLOW REDEVLOPMENT LATER DUE TO
THE OUTFLOW BEING PUSHED SOUTH OF THE AREA. 06Z RUN OF THE LOCAL
MODEL WAS NOT AVAILABLE THIS MORNING.

UPDATED ZONES WILL BE OUT SHORTLY.

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

PLATE

ARZ001-002-010-011-019-020-029-OKZ049-053>076-121100-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
600 AM CDT FRI MAY 11 2001

...ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE TODAY OVER EASTERN
OKLAHOMA AND NORTHWEST ARKANSAS...

EARLY THIS MORNING...A COLD FRONT WAS LOCATED FROM CENTRAL KANSAS
INTO THE OKLAHOMA AND TEXAS PANHANDLES.  SCATTERED THUNDERSTORMS HAD
DEVELOPED ALONG AND SOUTH OF THIS BOUNDARY...MAINLY OVER NORTHEAST
OKLAHOMA.  THIS ACTIVITY SHOULD WEAKEN DURING THE MORNING HOURS.  AS
THE COLD FRONT PUSHES INTO NORTHEAST OKLAHOMA THIS
AFTERNOON...SCATTERED THUNDERSTORMS MAY ONCE AGAIN FORM AND MOVE
SOUTH ACROSS THE REMAINDER OF EASTERN OKLAHOMA AND NORTHWEST
ARKANSAS.  WHILE WIDESPREAD SEVERE IS NOT EXPECTED...AN ISOLATED
THUNDERSTORM OR TWO MAY BRIEFLY BECOME SEVERE WITH UP TO ONE INCH
HAIL POSSIBLE...MAINLY THIS AFTERNOON.

ANY LINGERING THUNDERSTORMS WILL WEAKEN DURING THE EARLY EVENING.

.SPOTTER ACTIVATION...
DUE TO THE ISOLATED AND BRIEF NATURE OF ANY SEVERE
THUNDERSTORMS...STORM SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS
TIME.  HOWEVER...STORM SPOTTER GROUPS AND EMERGENCY MANAGERS SHOULD
MONITOR THE LATEST FORECASTS AND UPDATES.

.DISCUSSION...
SCATTERED ELEVATED THUNDERSTORMS DEVELOPED OVER NORTHEAST OKLAHOMA
OVERNIGHT IN RESPONSE TO A STRENGTHENING SOUTHWESTERLY LOW-LEVEL
JET.  THE LOW-LEVEL JET WILL WEAKEN SHORTLY AFTER SUNRISE...AND ANY
ONGOING CONVECTION IS EXPECTED TO WEAKEN OR DIMINISH AS WELL.

THE COLD FRONT OVER SOUTHEAST KANSAS THIS MORNING WILL MOVE INTO
NORTHEAST OKLAHOMA EARLY THIS AFTERNOON.  THE ATMOSPHERE AHEAD OF
THE COLD FRONT WILL BECOME UNSTABLE...WITH CAPE VALUES AROUND 1500
TO 2000 J/KG.  WHILE THE STRONGEST WIND FIELDS ALOFT WILL REMAIN
WELL NORTH OF THE AREA...THE EXPECTED INSTABILITY MAY BE SUFFICIENT
TO SUPPORT AN ISOLATED BRIEF SEVERE THUNDERSTORM OR TWO OVER THE
AREA.

THREAT TABLE
VALID THROUGH 1200 UTC SATURDAY

THREAT AREA 1...EASTERN OKLAHOMA AND NORTHWEST ARKANSAS
THUNDERSTORM PROBABILITY...80
SEVERE PROBABILITY IF STORMS OCCUR...10
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...1

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

A GRAPHICAL VERSION OF THIS OUTLOOK CAN BE FOUND AT:
WWW.SRH.NOAA.GOV/TULSA

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