Severe Thunderstorm Warning 263, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
355 PM CDT SUN MAY 27 2001

WILL NOT GET TOO INVOLVED IN DETAILS - MAINLY BECAUSE ITS HARD TO
KNOW WHAT THE DETAILS ARE GOING TO BE. STRONGER CAP IN SW PARTS OF
AREA LEADS TO LESS CERTAINTY THAT STORMS WILL GO IN THAT AREA, SO
POPS WILL INCREASE TONIGHT FROM SW TO NE ACROSS AREA. SHEAR AND
INSTABILITY MORE THAN ADEQUATE FOR SEVERE, WITH SUPERCELL/TORNADO
POTENTIAL THIS EVENING GRADUALLY EVOLVING MORE INTO A HIGH WIND/
HEAVY RAIN THREAT LATER TONIGHT AS STORMS ORGANIZE INTO 1 OR MORE
MCSS. BOUNDARIES WILL PLAY A KEY ROLE IN DETERMINING WHEN/WHERE THE
MAXIMUM RISKS WILL BE. SURFACE PATTERN HAS BEEN A MESS TODAY, BUT
SHOULD TAKE SHAPE AS SURFACE LOW DEVELOPS OVER SE CO AND DROPS INTO
NW TX. CURRENT ANALYSES AND ALL MODEL PROGS INDICATE 2 E-W TROFS/
BOUNDARIES, ONE ACROSS KS AND ONE ACROSS N TX. CONVECTION/OUTFLOW
SHOULD NUDGE THE KS BOUNDARY S THIS EVENING, WITH THE TWO FEATURES
EVENTUALLY CONSOLIDATING SOMEWHERE NEAR THE RED RIVER TONIGHT.
WIDESPREAD CONVECTION EXPECTED N OF WHERE THE BOUNDARY/IES END UP,
ESPECIALLY THIS EVENING AS LLJ INCREASES CONVERGENCE/LIFT.

EVOLVING SCENARIO BEARS STRONG RESEMBLANCE TO MADDOX FRONTAL-TYPE
FLASH FLOOD PATTERN. HOWEVER, MID/UPPER FLOW WILL REMAIN STRONG,
WHICH SHOULD KEEP ANY DEVELOPING COMPLEXES MOVING FAST. LLJ ALSO IS
PROGGED TO VEER TO MORE WESTERLY LATE TONIGHT ACROSS TX AND SE OK,
AT LEAST BY NGM/AVN, WHICH WOULD REDUCE LOW-LEVEL CONVERGENCE AND
WARM ADVECTION N OF THE FRONTAL ZONE. DUE TO THESE FACTORS, AND
CONTINUED UNCERTAINTY REGARDING THE FRONTAL POSITION/S, WE WILL NOT
ISSUE A FLASH FLOOD WATCH AT THIS TIME. WE WILL INCLUDE MENTION OF
HEAVY RAIN POTENTIAL, THO, AND IF MESOSCALE FEATURES BECOME BETTER
DEFINED THIS EVENING, A WATCH MAY BE NEEDED FOR PARTS OF THE CWA IF
THE RISK OF TRAINING MATERIALIZES.

CONVECTION EXPECTED TO ROLL SE OF THE AREA EARLY MON, ALLOWING
AIRMASS TO RECOVER SO WE CAN DO THE WHOLE THING AGAIN LATE MON AND
MON NIGHT. THUS LOWER POPS MON, THEN HIGH POPS AGAIN MOST AREAS MON
NIGHT. MAIN BOUNDARY EXPECTED TO LIE ACROSS N TX BY THEN, BUT WITH
UPPER RIDGE OVERHEAD, PRECIP MAY NOT BE AS WIDESPREAD.

TUE INTO WED LOOKING MORE TROUBLESOME AS WELL, WITH SW US TROF
APPROACHING AND SURFACE BOUNDARY STILL IN THE AREA. GOOD CHANCE TO
LIKELY POPS IN THESE PERIODS. COLD FRONT WED AND WED NIGHT LEADS TO
CONTINUED CHANCE INTO EARLY THU PER LATEST MRF MOS POPS. THEN DRY
AND SEASONABLY COOL FRI/SAT AS ANOTHER TROF DEVELOPS IN THE E AND
COOLER AIRMASS DROPS INTO AREA. DRY/WARMER SUN WITH INCREASING S
WINDS AS WESTERN RIDGE PROGRESSES INTO CENTRAL US.

FCSTID = 24
OKC   64  80  65  80 /  70  20  40  60
HBR   64  82  65  83 /  60  20  50  60
SPS   65  84  66  85 /  40  20  40  50
GAG   59  78  60  80 /  70  20  40  60
PNC   63  80  63  78 /  80  20  30  60
DUA   65  84  67  84 /  60  40  50  60

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

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
651 PM CDT SUN MAY 27 2001

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

0615 PM    WOODS                     OK   1.00 INCH HAIL
05/27/01   WOODS                          CAPRON FD

0644 PM    BURLINGTON                OK   .75 =INCH HAIL
05/27/01   ALFALFA                        SPOTTER REPORT

FM