Flood and Hail in Oklahoma, May 11, 2001

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

UPDATING THE FORECAST TO UP POPS TO LIKELY OR BETTER IN THE
NORTHWEST PART OF THE FORECAST AREA AND TO LOWER TEMPERATURES IN
ARKANSAS FOR THE REST OF THE AFTERNOON.

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

PLATE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
1206 PM CDT FRI MAY 11 2001

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

1120 AM    CENTERTON                 AR    .75 INCH HAIL
05/11/01   BENTON                          REPORTED BY SHERIFFS
                                           DEPT.

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

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

...ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE OVER PORTIONS OF
EASTERN OKLAHOMA AND WEST CENTRAL ARKANSAS THIS AFTERNOON...

EARLY THIS AFTERNOON...ONE AREA OF THUNDERSTORMS WAS PUSHING SLOWLY
SOUTHWARD ACROSS NORTHWEST ARKANSAS AND EAST CENTRAL OKLAHOMA...
WHILE A SECOND AREA OF THUNDERSTORMS WAS MOVING SOUTHWARD INTO NORTH
CENTRAL OKLAHOMA.  AT THE SURFACE...A COLD FRONT EXTENDED FROM
NORTHWEST OKLAHOMA INTO WESTERN MISSOURI...WHILE AN OUTFLOW BOUNDARY
EXTENDED EASTWARD ACROSS NORTH CENTRAL AND NORTHEAST OKLAHOMA AND
THEN SOUTHEAST AHEAD OF THE STORMS IN NORTHWEST ARKANSAS.

BOTH AREAS OF THUNDERSTORMS ARE EXPECTED TO CONTINUE MOVING SOUTH
ACROSS EASTERN OKLAHOMA AND WEST CENTRAL ARKANSAS THROUGH THE
AFTERNOON.  WITH SOME AFTERNOON HEATING...THE ATMOSPHERE AHEAD OF
THE STORMS WILL BECOME MORE UNSTABLE AND A FEW OF THE STORMS MAY
BRIEFLY INTENSIFY TO SEVERE LEVELS.  THE STRONGEST STORMS WILL
PRODUCE HAIL UP TO ONE INCH IN DIAMETER AND VERY ISOLATED OUTFLOW
WINDS UP TO 60 MPH.  A POTENTIALLY MORE SIGNIFICANT THREAT COULD BE
LOCALLY HEAVY RAINFALL...AS BETWEEN 1 AND 2 INCHES OF RAIN COULD
FALL THIS AFTERNOON IN A FEW ISOLATED AREAS.

THE SEVERE WEATHER THREAT WILL COME TO AN END FROM NORTH TO SOUTH
ACROSS THE AREA AND SHOULD BE ENTIRELY OUT OF THE AREA THIS EVENING.

.SPOTTER ACTIVATION...
STORM SPOTTER GROUPS AND EMERGENCY MANAGERS SHOULD MONITOR THE
LATEST FORECASTS AND UPDATES...AND BE PREPARED FOR POSSIBLE
ACTIVATION THIS AFTERNOON.

.DISCUSSION...
THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP IN THE VICINITY OF
THE OUTFLOW BOUNDARY...LIKELY FORMING A LARGE BAND OF SHOWERS AND
THUNDERSTORMS ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS BY 3 PM.
DESPITE CAPE VALUES OVER 2000 J/KG IN THE AREA AHEAD OF THE
BOUNDARY...A VERY WEAK WIND FIELD ALOFT AND THE LARGE NUMBER OF
STORMS EXPECTED WILL LIKELY PREVENT THE DEVELOPMENT OF ANY ORGANIZED
SEVERE STORMS THIS AFTERNOON.  HOWEVER...A FEW EMBEDDED
THUNDERSTORMS MAY BRIEFLY PULSE UP TO SEVERE LEVELS...BUT ANY SEVERE
WEATHER EVENT WILL BE VERY SHORT-LIVED AND ISOLATED.

GIVEN THE RELATIVELY SLOW MOTION OF THE AREA OF STORMS...SOME AREAS
MAY RECEIVE UP TO 2 INCHES OF RAINFALL.  ISOLATED RUNOFF PROBLEMS
COULD RESULT.

THREAT TABLE
VALID THROUGH 1200 UTC SATURDAY

THREAT AREA 1...SOUTHWEST OF A PONCA CITY TO TULSA TO FORT SMITH
LINE.
THUNDERSTORM PROBABILITY...90
SEVERE PROBABILITY IF STORMS OCCUR...20
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...2

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

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

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

...ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE OVER PORTIONS OF
EASTERN OKLAHOMA AND WEST CENTRAL ARKANSAS THIS AFTERNOON...

EARLY THIS AFTERNOON...ONE AREA OF THUNDERSTORMS WAS PUSHING SLOWLY
SOUTHWARD ACROSS NORTHWEST ARKANSAS AND EAST CENTRAL OKLAHOMA...
WHILE A SECOND AREA OF THUNDERSTORMS WAS MOVING SOUTHWARD INTO NORTH
CENTRAL OKLAHOMA.  AT THE SURFACE...A COLD FRONT EXTENDED FROM
NORTHWEST OKLAHOMA INTO WESTERN MISSOURI...WHILE AN OUTFLOW BOUNDARY
EXTENDED EASTWARD ACROSS NORTH CENTRAL AND NORTHEAST OKLAHOMA AND
THEN SOUTHEAST AHEAD OF THE STORMS IN NORTHWEST ARKANSAS.

BOTH AREAS OF THUNDERSTORMS ARE EXPECTED TO CONTINUE MOVING SOUTH
ACROSS EASTERN OKLAHOMA AND WEST CENTRAL ARKANSAS THROUGH THE
AFTERNOON.  WITH SOME AFTERNOON HEATING...THE ATMOSPHERE AHEAD OF
THE STORMS WILL BECOME MORE UNSTABLE AND A FEW OF THE STORMS MAY
BRIEFLY INTENSIFY TO SEVERE LEVELS.  THE STRONGEST STORMS WILL
PRODUCE HAIL UP TO ONE INCH IN DIAMETER AND VERY ISOLATED OUTFLOW
WINDS UP TO 60 MPH.  A POTENTIALLY MORE SIGNIFICANT THREAT COULD BE
LOCALLY HEAVY RAINFALL...AS BETWEEN 1 AND 2 INCHES OF RAIN COULD
FALL THIS AFTERNOON IN A FEW ISOLATED AREAS.

THE SEVERE WEATHER THREAT WILL COME TO AN END FROM NORTH TO SOUTH
ACROSS THE AREA AND SHOULD BE ENTIRELY OUT OF THE AREA THIS EVENING.

.SPOTTER ACTIVATION...
STORM SPOTTER GROUPS AND EMERGENCY MANAGERS SHOULD MONITOR THE
LATEST FORECASTS AND UPDATES...AND BE PREPARED FOR POSSIBLE
ACTIVATION THIS AFTERNOON.

.DISCUSSION...
THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP IN THE VICINITY OF
THE OUTFLOW BOUNDARY...LIKELY FORMING A LARGE BAND OF SHOWERS AND
THUNDERSTORMS ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS BY 3 PM.
DESPITE CAPE VALUES OVER 2000 J/KG IN THE AREA AHEAD OF THE
BOUNDARY...A VERY WEAK WIND FIELD ALOFT AND THE LARGE NUMBER OF
STORMS EXPECTED WILL LIKELY PREVENT THE DEVELOPMENT OF ANY ORGANIZED
SEVERE STORMS THIS AFTERNOON.  HOWEVER...A FEW EMBEDDED
THUNDERSTORMS MAY BRIEFLY PULSE UP TO SEVERE LEVELS...BUT ANY SEVERE
WEATHER EVENT WILL BE VERY SHORT-LIVED AND ISOLATED.

GIVEN THE RELATIVELY SLOW MOTION OF THE AREA OF STORMS...SOME AREAS
MAY RECEIVE UP TO 2 INCHES OF RAINFALL.  ISOLATED RUNOFF PROBLEMS
COULD RESULT.

THREAT TABLE
VALID THROUGH 1200 UTC SATURDAY

THREAT AREA 1...SOUTHWEST OF A PONCA CITY TO TULSA TO FORT SMITH
LINE.
THUNDERSTORM PROBABILITY...90
SEVERE PROBABILITY IF STORMS OCCUR...20
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...2

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