Severe Thunderstorm Warning 237, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
1110 AM CDT SUN MAY 20 2001

THUNDERSTORM COMPLEX THAT MOVED ACROSS THE AREA OVERNIGHT HAS FOR THE
MOST PART CLEARED THE STATE.  CLOUDS LATE THIS MORNING ARE FAIRLY
EXTENSIVE ACROSS MOST OF THE AREA WITH THE EXCEPTION OF SOUTHWEST
COUNTIES.  12Z ETA HUMIDITY FIELDS SUGGEST THAT CLOUDS WILL LINGER
MOST OF THE AFTERNOON ACROSS NORTH CENTRAL AND CENTRAL GROUPS...WHILE
CLOUDS ERODE ACROSS SOUTHWEST AND SOUTH CENTRAL ZONES.

15Z SURFACE ANALYSIS HAS STRONG COLD FRONT ENTERING FAR NORTHWEST KANSAS
WITH LOW 70 DEWPOINTS ADVECTING BACK NORTH INTO SOUTH CENTRAL AND SOUTHEAST
OKLAHOMA.  COMBINATION OF TROUGH AXIS TO OUR WEST...100KT JET PUSHING
INTO WESTERN NORTH TEXAS...AND SURFACE CONVERGENCE WILL LIKELY
RESULT IN CONVECTION FORMING ACROSS EASTERN PARTS OF SOUTHWEST OKLAHOMA
INTO SOUTH CENTRAL AND SOUTHEAST ZONES.  OTHER CONVECTION WILL LIKELY
FORM ALONG COLD FRONT EARLY IN THE EVENING ACROSS NORTHERN SECTIONS
OF FA.  WILL UPDATED ZONES SHORTLY.

.OUN...
OK...NONE.
TX...NONE.

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LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1028 AM CDT SUN MAY 20 2001

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

0223 PM    4 W ALTUS                 OK   TORNADO
05/19/01   JACKSON                        LASTED APPROXIMATELY
                                          TWO MINUTES...REPORTED
                                          BY METEOROLOGIST
 
KT

OKZ004>048-050>052-TXZ083>090-202030-

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE NORMAN OK
100 PM CDT SUN MAY 20 2001

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING OVER PARTS OF CENTRAL OKLAHOMA.  THE MODERATE RISK AREA IS
ALONG AND EAST OF INTERSTATE 35...AND SOUTHEAST OF A OKLAHOMA CITY
TO TULSA LINE.  TO THE WEST OF THE MODERATE RISK AREA... THERE IS A
SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE REMAINDER OF CENTRAL
AND PORTIONS OF WESTERN OKLAHOMA AND WESTERN NORTH TEXAS.  THE
SLIGHT RISK AREA IS GENERALLY EAST OF A WICHITA FALLS TO THOMAS
LINE...AND NORTH OF A GAGE TO CEILING LINE.  LARGE HAIL... DAMAGING
WIND AND TORNADOES WILL BE POSSIBLE.

CLOUDS WILL CONTINUE TO THIN ACROSS MOST OF CENTRAL OKLAHOMA
THIS AFTERNOON WHICH WILL ALLOW FOR STRONG HEATING AND
DESTABILIZATION.  THE COMBINATION OF A STRONG SUBTROPICAL JET MOVING
ACROSS NORTH TEXAS...A MID LEVEL TROUGH OVER WESTERN OKLAHOMA AND
SURFACE CONVERGENCE WILL LIKELY RESULT IN THUNDERSTORMS DEVELOPMENT
BY EARLY TO MID AFTERNOON.   THE BEST CHANCE FOR INITIAL DEVELOPMENT
APPEARS TO BE JUST WEST OF THE MODERATE RISK AREA.  SOME OF THESE
STORMS ARE LIKELY TO BECOME SUPERCELLS WITH THE POTENTIAL TO PRODUCE
VERY LARGE HAIL AND DAMAGING WIND GUSTS. LOW LEVEL WIND SHEAR MAY
ALSO BE ENHANCED ALONG AND NORTH OF THE RESIDUAL OUTFLOW BOUNDARY
FROM MORNING CONVECTION... AND ANY SUPERCELLS THAT ARE ABLE TO
INTERACT WITH AREAS OF ENHANCED LOW LEVEL SHEAR WILL BE CAPABLE OF
PRODUCING TORNADOES.

A STRONG COLD FRONT WILL ALSO APPROACH OKLAHOMA FROM THE NORTH THIS
EVENING.  OTHER STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO
DEVELOP OVER KANSAS ALONG THE FRONT LATE THIS AFTERNOON AND ORGANIZE
INTO A SQUALL LINE.  THIS SQUALL LINE WILL SWEEP SOUTHEASTWARD
ACROSS MUCH OF OKLAHOMA AND WESTERN NORTH TEXAS WITH THE COLD FRONT
OVERNIGHT WITH THE POTENTIAL FOR DAMAGING WINDS AND LARGE HAIL.

PERSONS ACROSS THE AREA TODAY SHOULD PAY ATTENTION TO THE LATEST
WEATHER INFORMATION AND BE ALERT FOR FURTHER UPDATES ON THE SEVERE
WEATHER SITUATION. EMERGENCY MANAGERS AND STORM SPOTTER GROUPS
SHOULD BE PREPARED FOR SEVERE WEATHER OPERATIONS THIS AFTERNOON AND
TONIGHT.

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