Tornado Warning 48, NWS Norman, OK

TXZ020-019-041800-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WICHITA FALLS TX
1200 PM CDT SAT MAY 4 1991

...SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 300 PM CDT THIS AFTERNOON
FOR THE FOLLOWING NORTH CENTRAL TEXAS COUNTIES YOUNG AND JACK...

AT NOON RADAR SHOWED THUNDERSTORMS DEVLOPING RAPIDLY FROM NORTHEAST AND
EAST OF ABILENE EXTENDING SOUTH TO SAN ANGELO. MOVEMENT OF THUNDERSTORMS
TO THE NORTHEAST AT 35 MPH.

THUNDERSTORMS...SOME SEVERE...WILL CONTINUE TO BUILD NORTH ALONG THE DRY
LINE SHORTLY. RESIDENTS OF YOUNG COUNTY CAN EXPECT THUNDERSTORMS TO
BEGIN MOVING INTO THE AREA SHORTLY AFTER 100 PM THIS AFTERNOON.  .

RESIDENTS ACROSS THIS PORTION OF NORTH CENTRAL TEXAS...ESPECIA0LLY YOUNG
COUNTY...SHOULD KEEP ABREAST OF THE LATEST WEATHER CONDITIONS AND BE
PREPARED TO TAKE ACTION SHOULD SEVERE WEATHER BE SIGHTED OR WARNING
ISSUED.

TXZ020-019-041800-

SPECIAL WEATHER STATEMENT...CORRECTION
NATIONAL WEATHER SERVICE WICHITA FALLS TX
1210 PM CDT SAT MAY 4 1991

...SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 300 PM CDT THIS AFTERNOON
FOR THE FOLLOWING NORTH CENTRAL TEXAS COUNTIES YOUNG AND JACK...

AT NOON RADAR SHOWED THUNDERSTORMS DEVLOPING RAPIDLY FROM WEST OF YOUNG
COUNTY EXTENDING SOUTH TO EAST OF ABILENE TO SAN ANGELO. MOVEMENT OF
THUNDERSTORMS TO THE NORTHEAST 35 MPH.

THUNDERSTORMS...SOME SEVERE...WILL CONTINUE TO BUILD NORTH ALONG THE DRY
LINE SHORTLY. RESIDENTS OF YOUNG COUNTY CAN EXPECT THUNDERSTORMS TO
BEGIN MOVING INTO THE AREA IN THE NEXT 10 MINUTES.

RESIDENTS ACROSS THIS PORTION OF NORTH CENTRAL TEXAS...ESPECIALLY YOUNG
COUNTY...SHOULD KEEP ABREAST OF THE LATEST WEATHER CONDITIONS AND BE
PREPARED TO TAKE ACTION SHOULD SEVERE WEATHER BE SIGHTED OR WARNING
ISSUED.

OKZ004>021-051200-

OKLAHOMA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE OKLAHOMA CITY OK
1245 PM CDT SAT MAY 4 1991

THIS THUNDERSTORM OUTLOOK IS VALID ONLY FOR OKLAHOMA ZONES 4 THROUGH
21. A THUNDERSTORM OUTLOOK FOR THE OKLAHOMA AND TEXAS PANHANDLES IS
AVAILABLE UNDER LBBSPSAMA...AND A THUNDERSTORM OUTLOOK FOR EASTERN
OKLAHOMA IS AVAILABLE UNDER OKCSPSTUL.

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON OVER
MUCH OF NORTHERN AND WESTERN OKLAHOMA AND TONIGHT OVER THE CENTRAL AND
EASTERN SECTIONS OF THE STATE. THE MODERATE RISK AREA IS GENERALLY
EAST OF A LINE FROM ALTUS TO CORDELL TO ALVA.  THERE IS A SLIGHT RISK OF
SEVERE THUNDERSTORMS OVER THE REMAINDER OF WESTERN OKLAHOMA EAST OF THE
PANHANDLE LATE THROUGH TONIGHT.

A SURFACE LOW PRESSURE SYSTEM WAS CENTERED OVER NORTHWESTERN OKLAHOMA
LATE THIS MORNING.  A STATIONARY FRONT EXTENDED FROM CENTRAL MISSOURI
INTO EASTERN KANSAS THROUGH NORTHWESTERN OKLAHOMA TO THE LOW PRESSURE
SYSTEM... THEN NORTHWESTWARD INTO COLORADO.  A DRYLINE EXTENDS SOUTH
FROM THE LOW PRESSURE SYSTEM ALONG THE OKLAHOMA-TEXAS BORDER INTO
CENTRAL TEXAS.

A NUMBER OF FACTORS ARE COMING TOGETHER TO SUPPORT A SIGNIFICANT
SEVERE WEATHER EVENT IN OKLAHOMA TODAY. MOIST GULF AIR WITH DEWPOINTS IN
THE 60S COVERS MUCH OF THE STATE. THE ATMOSPHERE OVER OKLAHOMA WILL
CONTINUE TO DESTABILIZE AS COOL MID LEVEL AIR IS ADVECTED OVER THE LOW
LEVEL MOISTURE. THE LOW PRESSURE SYSTEM WILL MOVE EASTWARD ALONG THE
FRONTAL BOUNDARY AS A VIGOROUS UPPER LEVEL TROUGH OVER THE
SOUTHWESTERN STATES APPROACHES OKLAHOMA AND THE DRYLINE WILL
ENTER THE WESTERN PORTIONS OF THE STATE.  SURFACE HEATING WILL
FURTHER DESTABILIZE THE ATMOSPHERE.  BOTH THE DRYLINE AND FRONTAL
BOUNDARY WILL ACT AS FOCUSING MECHANISMS FOR THUNDERSTORM
DEVELOPMENT AND SOME OF THESE THUNDERSTORMS ARE LIKELY TO BECOME
SEVERE.  ADDITIONAL ISOLATED SEVERE THUNDERSTORMS COULD DEVELOP IN
ADVANCE OF THE DRYLINE LATER THIS AFTERNOON.

WINDS WILL INCREASE ALOFT WITH THE APPROACH OF THE UPPER LEVEL
TROUGH..CREATING A FAVORABLE WIND PROFILE FOR TORNADO DEVELOPMENT...
ESPECIALLY ACROSS THE NORTHWESTERN AND NORTHCENTRAL SECTIONS OF THE
STATE.

AS THE UPPER LEVEL TROUGH MOVES NORTHEASTWARD INTO THE CENTRAL US
TONIGHT A COLD FRONT WILL ADVANCE ACROSS WESTERN OKLAHOMA.  A LINE OF
INTENSE THUNDERSTORMS WILL DEVELOP ALONG THE FRONT THIS EVENING AND
PROGRESS EASTWARD ACROSS THE STATE BEFORE SUNRISE ON SUNDAY.

SPOTTER ORGqANIZATIONS ACROSS CENTRAL AND WESTERN OKLAHOMA SHOULD REMAIN
ALERT FOR POSSIBLE ACTIVATION THIS AFTERNOON.