Tornado and Flash Flood in Oklahoma, May 19, 2001

AREA FORECAST DISCUSSION...UPDATED...
NATIONAL WEATHER SERVICE NORMAN OK
1040 AM CDT SAT MAY 19 2001

UPDATED ZONE PACKAGE ALREADY SENT. SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED OVER WESTERN OKLAHOMA... AND ACTIVITY CONTINUES OVER
EASTERN TEXAS PANHANDLE.  THIS APPEARS RELATED TO AN UPPER SPEED MAX
AS SEEN ON PROFILERS AND NEW MESO-ETA... WHICH IS LIFTING NORTHEAST
OVER THE TX PANHANDLE AND PEELING OFF OF STRONGER UPPER JET STILL TO
THE SOUTHWEST. MESOETA BRINGS A ROUND OF PRECIP INTO WESTERN
OKLAHOMA INTO EARLY THIS AFTERNOON WHICH TRENDS WELL WITH OBSERVED
RADAR.  MODEL THEN TENDS TO REDEVELOP CONVECTION BACK TO THE WEST
WHICH IS FORECAST TO MOVE OUT ACROSS THE CWA THIS EVENING AND
OVERNIGHT WHEN MAIN SYSTEM EJECTS.

MAIN CHANGE TO FORECAST WAS TO BRING POPS UP TO THE LIKELY CATEGORY
ACROSS WESTERN OKLAHOMA FOR THIS AFTERNOON... AND TO SHAVE WIND
SPEEDS OFF A TAD IN THE WEST THIS AFTERNOON WHERE A WEAKER GRADIENT
IS FORECAST AND CLOUDS WILL LIMIT MIXING.

FCSTID = 33/DLF

.OUN...
OK...FLASH FLOOD WATCH TONIGHT ZONES 04>21.
TX...NONE.

OKZ004>048-050>052-TXZ083>090-191430-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
700 AM CDT SAT MAY 19 2001

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT OVER ALL OF CENTRAL AND WESTERN OKLAHOMA AND WESTERN NORTH
TEXAS.  THROUGH EARLY EVENING... THE THREAT OF SEVERE WEATHER IS
EXPECTED TO BE PRIMARILY OVER WESTERN SECTIONS OF THE AREA... WITH
THE SEVERE WEATHER THREAT SHIFTING EASTWARD OVERNIGHT. LARGE HAIL
AND DAMAGING WIND WILL BE THE PRIMARY THREATS THROUGH THE EVENING...
WITH AN INCREASING THREAT FOR HEAVY RAINFALL OVERNIGHT.

TWO WEATHER DISTURBANCES... ONE OVER THE CENTRAL ROCKY MOUNTAIN
REGION... AND ANOTHER OVER NORTHWEST MEXICO EARLY THIS MORNING...
WILL BOTH MOVE TOWARD OKLAHOMA AND WESTERN NORTH TEXAS TODAY.  A
SURFACE WARM FRONT OVER NORTHERN TEXAS IS FORECAST TO MOVE SLOWLY
NORTHWARD TODAY... WHICH WILL ALLOW LOW LEVEL MOISTURE TO INCREASE
AS THE DAY PROGRESSES.

THUNDERSTORMS ONGOING THIS MORNING OVER PORTIONS OF SOUTHEAST
COLORADO... SOUTHWEST KANSAS... AND THE TEXAS AND OKLAHOMA
PANHANDLES MAY AFFECT PARTS OF THE NORTHWEST THIRD OF OKLAHOMA THIS
MORNING INTO EARLY AFTERNOON.  ADDITIONAL THUNDERSTORMS ARE FORECAST
TO DEVELOP THIS AFTERNOON AND EVENING FROM SOUTHWEST KANSAS...
SOUTHWARD INTO NORTHWEST TEXAS.  THE COMBINATION OF MODERATE TO HIGH
INSTABILITY AND SUFFICIENT VERTICAL WIND SHEAR IS EXPECTED TO
SUPPORT SEVERE THUNDERSTORMS.  WEAK LOW LEVEL STORM RELATIVE WIND
FIELDS SHOULD RESULT IN A VERY LOW RISK OF TORNADOES.  HOWEVER...
THE STRONGEST STORMS WILL BE CAPABLE OF PRODUCING LARGE HAIL AND
DAMAGING WIND GUSTS.

THUNDERSTORMS ARE EXPECTED TO EVOLVE INTO A LARGE COMPLEX DURING THE
LATE EVENING THAT WILL MOVE EASTWARD ACROSS MUCH OF OKLAHOMA
OVERNIGHT. SUSTAINED INFLOW OF MOIST AND UNSTABLE AIR INTO THE
COMPLEX OF STORMS SHOULD INCREASE THE THREAT FOR HEAVY RAINFALL.
ANY FURTHER RAINFALL OVER PARTS OF CENTRAL AND NORTH CENTRAL
OKLAHOMA THAT HAVE ALREADY RECEIVED HEAVY RAIN DURING THE PAST TWO
DAYS MAY RESULT IN FLASH FLOODING DURING THE OVERNIGHT HOURS.

EMERGENCY MANAGERS AND STORM SPOTTER GROUPS SHOULD BE PREPARED FOR
POSSIBLE ACTIVATION THIS AFTERNOON AND OVERNIGHT TONIGHT.

 MILLER