Severe Thunderstorm Warning 7, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
1140 AM CST TUE FEB 22 2000

ELEVATED CONVECTION STARTING TO BECOME WELL ESTABLISHED ACROSS
WESTERN ZONES...PROVIDING PRECURSOR FOR THE MAIN SHOW THIS EVENING.
WILL PULL BACK A LITTLE ON TEMPS IN NORTHWEST ZONES BASED ON TRENDS.
ALSO PLAN TO CHANGE WORDING SLIGHTLY FOR ONGOING PRECIP...ALTHOUGH
BASED ON RADAR TRENDS AND POSITION OF INSTABILITY AXIS...WE DON'T
EXPECT THIS TO GET MUCH FURTHER EAST. ALSO WILL DELAY THIS EVENING'S
PRECIP SLIGHTLY FOR EASTERN ZONES. AGREE WITH SPC'S DECISION TO
UPGRADE TO MODERATE RISK OVER WEST TEXAS ZONES...WHERE BEST COMBO OF
INSTABILITY AND DYNAMICS ARE PROGGED BY 00Z. MORE DETAILS sTO FOLLOW
IN THE THUNDERSTORM OUTLOOK. UPDATED ZONES OUT SHORTLY.

JL

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

OKZ004>048-050>052-TXZ083>090-222100-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1230 PM CST TUE FEB 22 2000

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT OVER MUCH OF WESTERN NORTH TEXAS AND A SMALL PART OF
SOUTHERN OKLAHOMA. THE MODERATE RISK AREA IS EAST AND SOUTH OF A
LINE FROM KNOX CITY... TO VERNON... TO WALTERS... TO MARIETTA. THERE
IS ALSO A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT OVER MUCH OF OKLAHOMA AND THE REMAINDER OF WESTERN NORTH
TEXAS.

.DISCUSSION...A SURFACE LOW PRESSURE CENTER LOCATED OVER SOUTHEAST
COLORADO EARLY THIS AFTERNOON IS EXPECTED TO MOVE INTO NORTHWEST
OKLAHOMA TONIGHT. MEANWHILE... A TRAILING DRYLINE BECOMING
ESTABLISHED IN WESTERN TEXAS WILL MOVE INTO WESTERN OKLAHOMA AND
WESTERN NORTH TEXAS BY LATE EVENING... AND INTO CENTRAL OKLAHOMA
LATE TONIGHT. AN UPPER AIR LOW PRESSURE SYSTEM OVER NEW MEXICO WILL
BE MOVING INTO WEST TEXAS THIS EVENING.

MEANWHILE... STRONG SOUTH WINDS ACROSS OKLAHOMA AND WESTERN NORTH
TEXAS WILL CONTINUE TO DRAW LOW LEVEL MOISTURE NORTH INTO THE AREA.

A LAYER OF WARM AIR ALOFT...OR CAPPING INVERSION... ACROSS CENTRAL
OKLAHOMA HAS BEEN SUPPRESSING ANY SIGNIFICANT SHOWER AND THUNDERSTORM
ACTIVITY THROUGH MIDDAY. HOWEVER... AS COLDER AIR ALOFT SPREADS EAST
DURING THE AFTERNOON... THE CAPPING INVERSION WILL WEAKEN. SCATTERED
THUNDERSTORMS DEVELOPING OVER WESTERN OKLAHOMA EARLY THIS AFTERNOON
WERE EVIDENCE THAT THE CAP WAS BEGINNING TO WEAKEN.

MORE ORGANIZED AND STRONGER STORMS ARE EXPECTED TO DEVELOP IN THE
VICINITY OF THE DRYLINE DURING THE AFTERNOON AND EVENING HOURS. THE
PRIMARY SEVERE WEATHER THREAT WILL BE LARGE HAIL AND STRONG WINDS.
HOWEVER... ISOLATED TORNADOES WILL ALSO BE POSSIBLE... MAINLY IN
THE MODERATE RISK AREA WHERE THE INSTABILITY IS EXPECTED TO BE THE
GREATEST.

THE STORMS ALONG THE DRYLINE ARE EXPECTED TO DEVELOP INTO AN
EXTENSIVE SQUALL LINE DURING THE EVENING HOURS AS THEY PROGRESS EAST
INTO CENTRAL OKLAHOMA.

WIDESPREAD CLOUD COVER OVER OKLAHOMA AND WESTERN NORTH TEXAS...
ALONG WITH EMBEDDED SHOWERS AND THUNDERSTORMS... HAS LIMITED THE
AMOUNT OF HEATING DURING THE DAY. THIS HAS RESULTED IN RATHER
MARGINAL INSTABILITIES THUS FAR ACROSS THE AREA. HOWEVER... THE
AIRMASS IS EXPECTED TO BECOME MORE UNSTABLE... MAINLY IN WESTERN
NORTH TEXAS... AS CLOUD COVER DECREASES AND TEMPERATURES ALOFT COOL.

EMERGENCY MANAGERS AND SPOTTER GROUPS ACROSS THE AREA SHOULD BE
ALERT TO CHANGING WEATHER CONDITIONS AND LISTEN FOR LATER UPDATES.

CJS

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
218 PM CST TUE FEB 22 2000

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

0212 PM    STRONG CITY               OK   .88 INCH HAIL
02/22/00   ROGER MILLS

CW