Severe Thunderstorm Warning 133, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
140 PM WED MAY 8 2002

NOTE TO USERS: WE ARE STILL IN THE PROCESS OF FIXING SOME SOFTWARE
PROBLEMS. THUS..SOME PRODUCTS WILL STILL NOT BE AVAILABLE WITH THIS
PACKAGE INCLUDING THE TABULAR AFPOKC..RDFOKC AND THE TABULAR AREA
FORECAST ON THE WEB PAGE. ALL OTHER PRODUCTS..INCLUDING THE FIRE WX
FORECAST ARE SLOWLY COMING BACK TO NORMAL. ISC GRIDS MAY BE A BIT
TARDY DUE TO RECONSTRUCTION OF THE DATABASE THRU DAY 7.

EARLY AFTERNOON SFC ANAL SHOWS SFC LOW OVR WOODS COUNTY OK..WITH
DRYLINE EXTENDING SSWWD TO NEAR CHILDRESS AND COLD FRONT NOW INTO
FAR NW OK FROM MAY RANCH TO WOODWARD.  DRYLINE IS BEGINNING TO PUSH
EWD QUITE NICELY ACROSS WTEX..AND SHUD BE ABLE TO MIX A COUNTY OR
TWO INTO WRN OK BY LATE AFTERNOON.  THE ETA SO FAR THIS SPRING HAS
BEEN SYSTEMATICALLY TOO FAR EAST WITH THE DRYLINE POSITION AND TODAY
IS NO EXCEPTION.  WITH THAT IN MIND..POSSIBILITY FOR A SIGNIFICANT
SVR WX EPISODE EXISTS..ALTHOUGH CAPPING STILL REMAINS AN ISSUE WITH
AS ONE GOES FARTHER SOUTH. CURRENT TRENDS SUGGEST THAT THE MOST
RAPID SFC BASED DESTBILIZATION DUE TO MOISTURE RETURN IS CURRENTLY
UNDERWAY ACROSS SE KS..AND THIS MAY END UP BEING THE LOCATION OF
BEST FOCUS FOR TORNADIC SUPERCELLS. HOWEVER..IF LOW LEVEL WINDS CONT
TO BACK ACROSS NRN OK..AND THE CAP CAN FINALLY BE OVERCOME..A
SIGNIFICANT THREAT MAY EXIST THIS AREA AS WELL. 18Z OUN SOUNDING
INDICATES THAT THE WARM SECTOR AIRMASS REMAINS CAPPED..BUT
SIGNIFICANT DEEPENING OF THE BOUNDARY LAYER MOISTURE HAS OCCURRED
SINCE 12Z. THE WARM NOSE OF THE CAP..AND THE MEAN EML TEMP OF THE
NEARLY DRY ADIABATIC LAPSE RATE AIR ABOVE HAS COOLED AS SUGGESTED BY
HGHT FALLS AND MUCH COOLER TEMPS ALOFT ANALYZED ON THE 12Z UA ANAL.
AS NOCTURNAL LLJ ABATES AND DIURNAL PRESSURE FALLS COMMENCE..MESONET
ALREADY SHOWS SFC WINDS BACKING ACROSS THE WARM SECTOR AND THIS SHUD
CONT THRU 00Z.  ALL THIS SEEMS TO SUGGEST THAT THE CAP WILL FINALLY
BE OVERCOME IN OUR CWA TODAY.

COLD FRONT WILL THEN SURGE SWD TONITE WITH A CONTINUED THREAT OF
STORMS AHEAD OF THE FRONT AND EAST OF DRYLINE..AND WILL CONT POPS
ACCORDINGLY. FRONT WILL PROB BE A BIT SLOWER TO CLEAR THE SE ZONES
THAT THE ETA INDICATES AND WILL HANG ON TO POPS IN THE SE FOR THUR.

MOISTURE AND INSTABILITY WILL ONCE AGAIN BEGIN A TREK NWD FRI/FRI
NITE INTO A WEAKLY CAPPED ENVIRONMENT AND CHANCES FOR MORE
SHOWERS/STORMS WILL RETURN. CAP STRENGTH WILL BE ON THE INCREASE
AHEAD OF FRONT ON SUNDAY..BUT WILL STILL HANG ONTO LOW POPS UNTIL
NEXT FRONT CLEARS THE AREA MONDAY.  AS OFTEN HAPPENS IN MAY..THE
MODELS ARE SLOWING THE SWD PROGRESS OF THIS FRONT WITH EACH
SUBSEQUENT RUN..AND IT MAY TAKE ITS SWEET TIME MOVING SWD.  IF THIS
BOUNDARY MANAGES TO CLEAR THE AREA PER CURRENT ECMWF/MRF PROGS..SOME
VERY NICE MID MAY WX WILL BE IN STORE FROM MON-WED NEXT WEEK.
 MILLER

PRELIM NUMBERS..
OKC   55  70  48  73 /  40  10   0  20
HBR   51  68  49  73 /  20  10   0  20
SPS   60  72  54  76 /  20  10   0  20
GAG   45  66  42  70 /  10   0   0  10
PNC   49  67  45  70 /  40  10   0  10
DUA   66  74  52  75 /  30  30  10  20

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

OKZ004>048-050>052-TXZ083>090-082130-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1155 AM CDT WED MAY 8 2002

THUNDERSTORM OUTLOOK...
THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
THROUGH TONIGHT ACROSS PORTIONS OF NORTHERN INTO CENTRAL OKLAHOMA.
A SLIGHT RISK EXISTS ACROSS CENTRAL AND SOUTHERN OKLAHOMA...AND
PORTIONS OF WESTERN NORTH TEXAS.

LOCATION...
THE MODERATE RISK AREA INCLUDES LOCATIONS EAST AND NORTH OF A LINE
EXTENDING FROM CHEROKEE...TO WATONGA...TO EL RENO...TO CUSHING. THIS
INCLUDES THE CITIES OF ENID...STILLWATER...AND PONCA CITY. THE SLIGHT
RISK AREA SURROUNDS THE MODERATE RISK AREA...AND INCLUDES LOCATIONS
EAST OF A LINE EXTENDING FROM FREEDOM...TO WOODWARD...TO ELK CITY...
TO MANGUM...TO CROWELL AND KNOX CITY TEXAS.

TIMING...
THE MOST LIKELY TIME FOR SEVERE THUNDERSTORMS WILL BE FROM 4 PM
THROUGH 3 AM.

EXPECTED WEATHER AND IMPACTS...
THE PRIMARY THREAT WILL BE LARGE...DAMAGING HAIL...UP TO THE SIZE OF
BASEBALLS. THIS COULD RESULT IN DAMAGE TO AUTOMOBILES...HOUSE AND
BUSINESS ROOFS...AND VEGETATION. HOWEVER...THERE WILL BE AN ENHANCED
THREAT FOR TORNADOES...SOME POSSIBLY SIGNIFICANT...IN AND NEAR THE
MODERATE RISK AREA.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREAS SHOULD PLAN FOR SEVERE WEATHER OPERATIONS FROM THIS
AFTERNOON THROUGH THE OVERNIGHT HOURS.

DISCUSSION...
A DRY LINE...LOCATED ACROSS NORTHWEST OKLAHOMA...SOUTHWARD ALONG THE
OKLAHOMA TEXAS BORDER EARLY THIS AFTERNOON...WILL CONTINUE TO MOVE
EAST THIS AFTERNOON. BY MID AFTERNOON THE DRY LINE IS EXPECTED
TO BE LOCATED NEAR A FREEDOM...TO WOODWARD...TO ELK CITY...TO
MANGUM...TO CROWELL AND KNOX CITY TEXAS LINE. THIS DRY LINE WILL BE A
FOCUS FOR THUNDERSTORM DEVELOPMENT. IN ADDITION TO THE DRY LINE...A
SURFACE LOW PRESSURE SYSTEM WILL CONTINUE TO DEVELOP OVER NORTHWEST
OKLAHOMA. EAST OF THIS SURFACE LOW...AND NEAR ANY OUTFLOW BOUNDARIES
THAT EXIST BY LATE AFTERNOON...IS WHERE THE GREATEST RISK OF
SIGNIFICANT WEATHER IS EXPECTED. DUE TO HIGH AMOUNTS OF INSTABILITY
AND A STRONG WIND SHEAR ENVIRONMENT...SUPERCELLS ARE LIKELY. AGAIN...
THERE IS AN INCREASED THREAT OF TORNADOES LATE THIS AFTERNOON AND
EVENING...PRIMARILY IN AND NEAR THE MODERATE RISK AREA.

THREAT TABLE...
VALID THROUGH 700 AM CDT THU MAY 9.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...40 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...90 PERCENT.

OTHER HAZARDOUS WEATHER...
HIGH WINDS...LOW HUMIDITIES AND HOT TEMPERATURES WILL LEAD TO AN
HIGH FIRE DANGER ACROSS FAR NORTHWEST OKLAHOMA.