Tornado Warning 17, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
330 PM CDT SUN MAY 25 1997

SCT STG TSTMS ARE NOW BGNG TO DVLP IN WRN OK.  XPCT THE STMS TO INCR
SIGLY IN CVRG OVR THE NEXT CPL HOURS.  AS A RSLT...HAVE GONE WITH HI
POPS XCPT IN FAR NW OK WHERE DRIER AIR HAS ARRIVED.  WL MNTN CHC SVR
OVR MOST OF THE FA DUE TO HIGHLY FVRBL CONDS FOR SVR WX.

ONCE THE STMS EXIT THE FA...PROB LATE THIS EVE...THE NEXT BIG
QUESTION IS WHETHER THERE WL BE ENUF MSTR ARND TMRW TO SUPPORT
CNVCTN.  INSTAB AND PROXIMITY OF SFC BNDRYS AND UPR LOW ALL SEEM TO
SUGGEST THE PSBLTY OF SCT TSTMS AGN TMRW...BUT THE AMT OF MSTR FCST
APPEARS TOO LOW FOR MUCH TO DVLP.  SO HAVE OPTED FOR LOW POPS...MNLY
CLOSE TO THE FOCUSING MECHANISMS.

ETA BRNGS A SIG COOL DOWN INTO THE NWRN ZNS ON TUE.  SITN APPEARS TO
BE THE TYPE WHERE COOL TEMPS WOULD BE ACCOMPANIED BY LOW CLDS AND
GUSTY N WNDS.  IF THAT IS IN FACT WHAT HAPPENS...THE MAX TEMPS IN
THAT AREA COULD EASILY BE BLO 60 DEG.  AM NOT YET THAT CONFIDENT OF
SUCH A SIG DEPARTURE FM NRML...BUT WL STILL GO BLO FWC BY ABT 5 DEG.

AGN ELECTED TO GENERALLY FOLLOW NCEP GDNC RATHER THAN MRF FOR EXTDD.

FCSTID = 23 = CMS

OKC   63  87  60  84 /  60  20  10  20
HBR   60  88  58  79 /  40  20  10  10
SPS   67  90  60  82 /  40   0   0  10
GAG   55  84  55  70 /  10  20  20  20
PNC   65  86  58  78 /  50  30  30  30
DUA   68  92  67  86 /  50  20   0  10

.OKC...
OK...NONE.
TX...NONE.

OKZ004>053-TXZ083>090-261130-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1230 PM CDT SUN MAY 25 1997

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
OKLAHOMA AND PORTIONS OF WESTERN NORTH TEXAS THIS AFTERNOON AND TONIGHT.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER WESTERN OKLAHOMA AND
PORTIONS OF WESTERN NORTH TEXAS THIS AFTERNOON...

THE MODERATE RISK AREA IS EAST OF A LINE FROM ALVA TO WEATHERFORD TO
FREDERICK TO ARCHER CITY TEXAS. SURROUNDING THE MODERATE RISK AREA...THE
SLIGHT RISK AREA IS EAST OF A LINE FROM BUFFALO TO ALTUS TO SEYMOUR
TEXAS. LARGE HAIL...DAMAGING STRAIGHT-LINE WIND...AND TORNADOES WILL BE
POSSIBLE...ESPECIALLY IN THE MODERATE RISK AREA.

A POTENTIALLY DANGEROUS WEATHER SITUATION IS SETTING UP FOR THIS
AFTERNOON AND TONIGHT AS AN AREA OF LOW PRESSURE OVER SOUTHWEST KANSAS
MOVES INTO NORTHERN OKLAHOMA. A DRY LINE WILL EXTEND SOUTHWARD FROM THE
LOW PRESSURE SYSTEM INTO WESTERN OKLAHOMA AND WESTERN NORTH TEXAS
BY MID AFTERNOON...AND WILL ACT AS A FOCUSING MECHANISM FOR THUNDERSTORM
DEVELOPMENT AS IT MOVES TO THE EAST THROUGH THE EVENING.

AFTERNOON HEATING OF THE WARM AND MOIST AIRMASS OVER THE AREA EAST OF
THE DRYLINE WILL RESULT IN VERY UNSTABLE CONDITIONS. IN ADDITION...
INCREASING VERTICAL WIND SHEAR WILL RESULT IN FAVORABLE CONDITIONS FOR
SUPERCELL THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THE DRY LINE
DURING THE AFTERNOON. STORMS THAT DEVELOP WILL BE CAPABLE OF PRODUCING
TORNADOES...VERY LARGE HAIL...AND DAMAGING STRAIGHT-LINE WIND.

THE NATIONAL WEATHER SERVICE ENCOURAGES PERSONS ACROSS OKLAHOMA AND
WESTERN NORTH TEXAS TO REVIEW SEVERE WEATHER SAFETY RULES AND STAY
INFORMED ON THE LATEST WEATHER FORECASTS...AND POSSIBLE WATCHES AND
WARNINGS. THOSE PARTICIPATING IN OUTDOOR ACTIVITIES TODAY AND
TONIGHT SHOULD REMAIN ESPECIALLY ALERT FOR THREATENING WEATHER.
EMERGENCY MANAGERS AND STORM SPOTTER GROUPS SHOULD BE PREPARED FOR
POSSIBLE ACTIVATION THROUGH TONIGHT.

11

OKZ004>053-TXZ083>090-261130-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1230 PM CDT SUN MAY 25 1997

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
OKLAHOMA AND PORTIONS OF WESTERN NORTH TEXAS THIS AFTERNOON AND TONIGHT.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER WESTERN OKLAHOMA AND
PORTIONS OF WESTERN NORTH TEXAS THIS AFTERNOON...

THE MODERATE RISK AREA IS EAST OF A LINE FROM ALVA TO WEATHERFORD TO
FREDERICK TO ARCHER CITY TEXAS. SURROUNDING THE MODERATE RISK AREA...THE
SLIGHT RISK AREA IS EAST OF A LINE FROM BUFFALO TO ALTUS TO SEYMOUR
TEXAS. LARGE HAIL...DAMAGING STRAIGHT-LINE WIND...AND TORNADOES WILL BE
POSSIBLE...ESPECIALLY IN THE MODERATE RISK AREA.

A POTENTIALLY DANGEROUS WEATHER SITUATION IS SETTING UP FOR THIS
AFTERNOON AND TONIGHT AS AN AREA OF LOW PRESSURE OVER SOUTHWEST KANSAS
MOVES INTO NORTHERN OKLAHOMA. A DRY LINE WILL EXTEND SOUTHWARD FROM THE
LOW PRESSURE SYSTEM INTO WESTERN OKLAHOMA AND WESTERN NORTH TEXAS
BY MID AFTERNOON...AND WILL ACT AS A FOCUSING MECHANISM FOR THUNDERSTORM
DEVELOPMENT AS IT MOVES TO THE EAST THROUGH THE EVENING.

AFTERNOON HEATING OF THE WARM AND MOIST AIRMASS OVER THE AREA EAST OF
THE DRYLINE WILL RESULT IN VERY UNSTABLE CONDITIONS. IN ADDITION...
INCREASING VERTICAL WIND SHEAR WILL RESULT IN FAVORABLE CONDITIONS FOR
SUPERCELL THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THE DRY LINE
DURING THE AFTERNOON. STORMS THAT DEVELOP WILL BE CAPABLE OF PRODUCING
TORNADOES...VERY LARGE HAIL...AND DAMAGING STRAIGHT-LINE WIND.

THE NATIONAL WEATHER SERVICE ENCOURAGES PERSONS ACROSS OKLAHOMA AND
WESTERN NORTH TEXAS TO REVIEW SEVERE WEATHER SAFETY RULES AND STAY
INFORMED ON THE LATEST WEATHER FORECASTS...AND POSSIBLE WATCHES AND
WARNINGS. THOSE PARTICIPATING IN OUTDOOR ACTIVITIES TODAY AND
TONIGHT SHOULD REMAIN ESPECIALLY ALERT FOR THREATENING WEATHER.
EMERGENCY MANAGERS AND STORM SPOTTER GROUPS SHOULD BE PREPARED FOR
POSSIBLE ACTIVATION THROUGH TONIGHT.

11

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OKLAHOMA
0415 PM CDT SUN MAY 25 1997

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

0352 PM    1 W AMBER                 OK   1.00 INCH HAIL
05/25/97   GRADY

0412 PM    2.5 E MIDDLEBURG          OK   1.00 INCH HAIL
05/25/97   GRADY

0414 PM    MIDDLEBURG                OK   TORNADO
05/25/97   GRADY

J

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OKLAHOMA
0440 PM CDT SUN MAY 25 1997

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

415 PM     2.5 E MIDDLEBURG          OK   2.50 INCH HAIL
05/25/97   GRADY

0417 PM    2.5 N TABLER              OK   WIND DAMAGE
05/25/97   GRADY                          ROOF OFF MOBILE HOME

0425 PM    1 N BLANCHARD             OK   1.00 HAIL
05/25/97   MCCLAIN

J