Severe Thunderstorm Warning 189, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
930 PM CDT SAT APR 29 2000

CONVECTION OVER NW TX ORGANIZING INTO AN MCS AND IS EXPECTED TO ROLL
E ALONG QUASI-STATIONARY FRONT/OUTFLOW BOUNDARY ACROSS N TX
OVERNIGHT. INCREASING LOW LEVEL JET AND DIVERGANCE ALOFT EXPECTED TO
ENHANCE CONVECTIVE DEVELOPMENT, WHILE RELATIVELY WEAK MID-UPPER
TROPOSPHERIC FLOW WILL RESULT IN RELATIVELY SLOW MOVEMENT OF SYSTEM.
SLOW MOVEMENT OF INDIVIDUAL CORES, DUE IN LARGE PART TO
BACKBUILDING, ALREADY HAS RESULTED IN LOCAL HOURLY RADAR RAINFALL
ESTIMATES IN EXCESS OF 2-3 INCHES LOCALLY. SCENARIO LOOKING MORE
LIKE A POTENTIAL MADDOX FRONTAL AND/OR MESOHIGH TYPE FLASH FLOOD
SITUATION. FLASH FLOOD WATCH THUS WILL BE ISSUED FOR TX ZONES,
EFFECTIVE OVERNIGHT.

MCS MAY INTERCEPT BEST INFLUX OF MOISTURE, AND THUS MAY ROB AREAS
FARTHER N OVER W CENTRAL, NORTHERN AND CENTRAL OKLAHOMA. THIS AND
PERIPHERAL MESOSCALE SUBSIDENCE AROUND MCS LEAVE US WITH DOUBTS AS
TO WHETHER MUCH NEW CONVECTION WILL BE ABLE TO GET GOING IN THESE
AREAS OVERNIGHT. BUT DUE TO STRENGTH OF APPROACHING UPPER SYSTEM,
AND A GOOD CHANCE THAT THE MCS WILL MOVE E AND WILL CLEAR THE WAY
FOR MOISTURE TO RETURN N INTO NW ZONES LATE TONIGHT, WILL KEEP POPS
AS IS FOR MOST PART.

ANY OTHER CHANGES THIS EVENING LIKELY TO BE MINOR, BASED ON CURRENT
CONDITIONS.

FFA OUT BY 945 PM, UPDATED ZFP BY 10PM.

24

.OUN...
OK...NONE.
TX...FLASH FLOOD WATCH TONIGHT TXZ083>090.

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
854 PM CDT SAT APR 29 2000

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

0727 PM    RHINELAND                 TX   .75 INCH HAIL
04/29/00   KNOX                           COUNTY SHERIFF REPORT

0800 PM    12 SW CROWELL             TX   .75 INCH HAIL
04/29/00   FOARD                          PUBLIC REPORT

0840 PM    12 SW CROWELL             TX   1.75 INCH HAIL
04/29/00   FOARD                          PUBLIC REPORT

FM