Severe Thunderstorm Warning 440, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
325 PM CDT SUN OCT 22 2000

AFTERNOON HEATING OVER WESTERN PORTIONS OF THE FORECAST AREA HAS
INCREASED THE INSTABILITY ACROSS THE REGION...RESULTING IN THE
DEVELOPMENT OF SHWRS/TSTMS. STLT ALSO SUGGESTING A WEAK WAVE MOVING
THROUGH WESTERN TEXAS. THE SHWRS/TSTMS ARE EXPECTED TO CONTINUE
MOVING NORTH NORTHEAST THROUGH THE EVENING HOURS AFFECTING MAINLY
WEST CENTRAL AND CENTRAL SECTIONS OF THE FORECAST AREA. COVERAGE
SHOULD DECREASE LATER THIS EVENING... BUT WILL STILL NEED TO MAINTAIN A
CHANCE OF SHWRS/TSTMS OVERNIGHT AS WEAK MID LEVEL WARM ADVECTION AND
WEAK UPPER LEVEL DIFLUENCE PERSIST. UPPER SYSTEM OVER NORTHERN
BAJA/SOUTHWEST US WILL CONTINUE TO PROVIDE A CHANCE OF SHWRS/TSTMS
THROUGH MID WEEK AS IT SLOWLY LIFTS OUT INTO THE PLAINS. LOWEST POPS
ON MON WILL BE IN FAR SOUTHEAST ZONES WHERE TEMPORARY RETROGRADING
OF THE EASTERN US UPPER RIDGE IS EXPECTED TO PROVIDE SOME
SUBSIDENCE. LITTLE CHANGE IN THE AIRMASS IS LIKELY TO OCCUR THROUGH
MID WEEK... THUS MOST OF THE DAY TO DAY TEMP CHANGES WILL BE DRIVEN
BY THE DISTRIBUTION OF CLOUD COVER.

LOOKING FARTHER OUT... ANOTHER UPPER TROUGH IS EXPECTED TO DROP INTO
THE WESTERN US BY THURSDAY. HOWEVER...MODELS OFFERING VARIOUS
SOLUTIONS IN THE HANDLING OF THIS SYSTEM. MRF TRIES TO MAINTAIN AN
OPEN TROUGH WHILE THE CANADIAN SOLUTION IS TO CLOSE OFF THE LOW OVER
EASTERN NEVADA AND DIG IT SOUTH INTO ARIZONA BY FRIDAY. WHILE THE
OFFICIAL MRF SOLUTION DOESN'T AGREE... IT DOES HAVE A FEW ENSEMBLE
SOLUTIONS THAT ARE SIMILAR. MRF ALSO BRINGING A COLD FRONT INTO THE
AREA ON THURSDAY... WITH COOLER AIR SETTLING IN ON FRIDAY. WILL
TREND TEMPS DOWN A LITTLE LATE IN THE WEEK... BUT WON'T GO WHOLE HOG
DUE TO LOWER CONFIDENCE IN THE MODEL SOLUTIONS LATE IN THE FORECAST
PERIOD.

FCSTID = 32
OKC   63  72  64  72 /  50  40  50  60
HBR   63  72  63  72 /  50  50  |60  60
SPS   66  78  66  76 /  50  50  60  60
GAG   60  71  61  72 /  30  40  50  60
PNC   63  72  63  72 /  60  40  50  60
DUA   66  77  66  75 /  50  30  40  50

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

OKZ004>048-050>052-TXZ083>090-221830-

THUNDERSTORM OUTLOOK...CORRECTED...
NATIONAL WEATHER SERVICE NORMAN OK
1235 PM CDT SUN OCT 22 2000

A FEW THUNDERSTORMS ARE EXPECTED TO CONTINUE ACROSS MOST OF CENTRAL
AND WESTERN OKLAHOMA AND WESTERN NORTH TEXAS INTO TONIGHT.  A STORM
OR TWO MAY BRIEFLY REACH SEVERE LEVELS... BUT FOR THE MOST PART ANY
STORMS ARE EXPECTED TO BE NON-SEVERE. HOWEVER...WITH ANY STRONGER
STORMS...THERE WILL BE A VERY SMALL PROBABILITY OF A DAMAGING WIND
GUST OR A BRIEF WEAK TORNADO.

DISCUSSION...PARTIAL CLEARING HAS DEVELOPED FROM PARTS OF WESTERN
OKLAHOMA SOUTHWARD INTO CENTRAL TEXAS EARLY THIS AFTERNOON.  AS A
RESULT... SLIGHTLY STRONGER INSTABILITY THAN PREVIOUSLY EXPECTED
EXISTS ACROSS THE AREA. WIND SHEAR PROFILES ARE RELATIVELY WEAK
ACROSS THE AREA.  HOWEVER... A SUFFICIENT AMOUNT OF INSTABILITY AND
WIND SHEAR WILL REMAIN IN PLACE OVER THE AREA THROUGH THIS EVENING
TO SUPPORT ADDITONAL SHOWERS AND A FEW THRUNDERSTORMS.

IN THIS TYPE OF NEARLY TROPICAL ENVIRONMENT... IT IS NOT OUT OF THE
QUESTION THAT A FEW SMALL QUASI-SUPERCELL THUNDERSTORMS MAY
DEVELOP... SIMILAR TO WHAT HAPPENED SATURDAY EVENING AND EARLY THIS
MORNING IN SOUTHWEST OKLAHOMA.  IF ANY OF THESE TYPES OF STORMS ARE
ABLE TO FORM... THERE WILL BE A SMALL AND GENERALLY SHORT-LIVED
THREAT OF A DAMAGING WIND GUST OR TWO AND POSSIBLY A WEAK
SHORT-LIVED TORNADO.  IT SHOULD BE EMPHASIZED THAT ALTHOUGH THERE IS
A SMALL THREAT... IT IS VERY MINIMAL.  THESE TYPES OF STORMS ARE
EXTREMELY DIFFICULT TO FORECAST... AND TEND TO DEVELOP AND DECAY
VERY RAPIDLY.

SPOTTER GROUPS MAINLY IN WESTERN NORTH TEXAS AND THE SOUTHWEST THIRD
OF OKLAHOMA SHOULD REMAIN ALERT FOR ADDITIONAL WEATHER INFORMATION
THIS AFTERNOON AND THIS EVENING...AND BE PREPARED FOR POSSIBLE
ACTIVATION.

 MILLER

OKZ004>048-050>052-TXZ083>090-221830-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1235 PM CDT SUN OCT 22 2000

A FEW THUNDERSTORMS ARE EXPECTED TO CONTINUE ACROSS MOST OF CENTRAL
AND WESTERN OKLAHOMA AND WESTERN NORTH TEXAS INTO TONIGHT.  A STORM
OR TWO MAY BRIEFLY REACH SEVERE LEVELS... BUT FOR THE MOST PART ANY
STORMS ARE EXPECTED TO BE NON-SEVERE. HOWEVER...WITH ANY STRONGER
STORMS...THERE WILL BE A VERY SMALL PROBABILITY OF A DAMAGING WIND
GUST OR A BRIEF WEAK TORNADO.

DISCUSSION...PARTIAL CLEARING HAS DEVELOPED FROM PARTS OF WESTERN
OKLAHOMA SOUTHWARD INTO CENTRAL TEXAS EARLY THIS AFTERNOON.  AS A
RESULT... SLIGHTLY STRONGER INSTABILITY THAN PREVIOUSLY EXPECTED
EXISTS ACROSS THE AREA. WIND SHEAR PROFILES ARE RELATIVELY WEAK
ACROSS THE AREA.  HOWEVER... A SUFFICIENT AMOUNT OF INSTABILITY AND
WIND SHEAR WILL REMAIN IN PLACE OVER THE AREA THROUGH THIS EVENING
TO SUPPORT ADDITONAL SHOWERS AND A FEW THRUNDERSTORMS.

IN THIS TYPE OF NEARLY TROPICAL ENVIRONMENT... IT IS NOT OUT OF THE
QUESTION THAT A FEW SMALL QUASI-SUPERCELL THUNDERSTORMS MAY
DEVELOP... SIMILAR TO WHAT HAPPENED SATURDAY EVENING AND EARLY THIS
MORNING IN SOUTHWEST OKLAHOMA.  IF ANY OF THESE TYPES OF STORMS ARE
ABLE TO FORM... THERE WILL BE A SMALL AND GENERALLY SHORT-LIVED
THREAT OF A DAMAGING WIND GUST OR TWO AND POSSIBLY A WEAK
SHORT-LIVED TORNADO.  IT SHOULD BE EMPHASIZED THAT ALTHOUGH THERE IS
A SMALL THREAT... IT IS VERY MINIMAL.  THESE TYPES OF STORMS ARE
EXTREMELY DIFFICULT TO FORECAST... AND TEND TO DEVELOP AND DECAY
VERY RAPIDLY.

SPOTTER GROUPS MAINLY IN WESTERN NORTH TEXAS AND THE SOUTHWEST THIRD
OF OKLAHOMA SHOULD REMAIN ALERT FOR ADDITIONAL WEATHER INFORMATION
THIS AFTERNOON AND THIS EVENING...AND BE PREPARED FOR POSSIBLE
ACTIVATION.

11