Severe Thunderstorm Warning 63, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
435 AM CDT SAT APR 13 2002

MAIN FOCUS THIS MORNING IS ON SEVERE POTENTIAL. SURFACE ANALYSES
ACKNOWLEDGE A N-S DEWPOINT GRADIENT INDICATING A SURFACE FRONT
VICINITY CENTRAL OK...BUT ANOTHER BOUNDARY LIES ACROSS N TX FROM
BETWEEN LBB-ABI E-WARD TO DFW AREA...THEN NE INTO AR. THIS BOUNDARY
SEPARATES MID-UPPER 60 TEMPS AND S-SE WINDS TO S FROM UPPER
50S-LOWER 60S AND E WINDS TO N. EXPECT MCS OVER PANHANDLES WILL ROLL
ESE ALONG THETA-E GRADIENT AND SET UP THE N TX BOUNDARY AS THE
PRIMARY SURFACE FRONT LATER TODAY. THIS COUPLED WITH ADDITIONAL
DEVELOPMENT FARTHER N...PER CURRENT TRENDS AND MODEL QPFS...SUGGEST
FAIRLY WIDESPREAD PRECIP TODAY THAT WOULD CLOBBER AT LEAST THE N
PARTS OF THE MODERATE RISK AREA WITH EITHER PRECIP/CONVECTION OR
RESIDUAL CLOUD COVER THEREFROM. 00Z AVN WANTS TO LIFT THE EFFECTIVE
BOUNDARY N INTO CENTRAL OK BY 18Z...BUT WE DO NOT SEE THIS
HAPPENING. LOW LEVEL WINDS CURRENTLY ARE WEAK ACROSS MOST OF TX AND
OK...AND WHILE THE SOUTHERLY FLOW SHOULD INCREASE TODAY IN RESPONSE
TO THE APPROACHING UPPER TROF...IT IS NOT LIKELY TO BE ENOUGH TO
DISPLACE THE GUNGE ACROSS MUCH OF THE CWA. MID-UPPER 60S SURFACE
DEWPOINTS PROGGED BY AVN ARE LIKELY TOO HIGH...WITH LOWER 60S
EXPECTED AT BEST ACROSS AREA BASED ON CURRENT SURFACE DEWPOINTS TO
S. BOTTOM LINE IS THAT WE THINK THE MAX SEVERE RISK WILL BE A BIT
FARTHER S...ACROSS S OK AND N TX...ALTHO THERE WILL BE SOME RISK OF
SEVERE AREAWIDE WITH MAIN THREAT ACROSS N BEING HAIL. HEAVY RAIN
ALSO POSSIBLE...WILL INSERT WORDING ACCORDINGLY.

POPS AT 100PCT TODAY ACROSS MOST OF NW OK WITH ONGOING ACTIVITY...
AND WILL PUSH MOST OF THE REST OF THE AREA TO AT OR NEAR CATEGORICAL
LEVELS. RATHER STEEP POP GRADIENT ACROSS SW ZONES AS S EDGE OF MCS
ACTIVITY MAY SWEEP THRU THE TX ZONES. POP GRADIENT TONIGHT WILL BE W
TO E AS UPPER TROF TRAVERSES AREA. WILL HANG ON TO SOME LOW POPS
EARLY SUN IN SOME OF THE E ZONES...OTHERWISE MOST AREAS SHOULD CLEAR
OUT BEHIND TROF AND END UP WITH A WARM AND PLEASANT DAY AS PATTERN
BEGINS TRANSITION TO A WESTERN-US LONGWAVE TROF. TEMPS WILL BE
MODELED AFTER THE MESOETA GRIDS EXCEPT FOR LOWERING THE DAYTIME
TEMPS TODAY TO ACCOUNT FOR CLOUDS/PRECIP.

NO CHANGES MADE BEYOND MON.

COORD W/ICT...TUL...FTW...THANKS.

FCSTID = 24
OKC   70  59  78  60 /  80  60  10   0
HBR   73  57  81  60 /  90  40  10   0
SPS   75  57  82  62 /  70  40  10   0
GAG   68  53  82  58 / 100  20  10   0
PNC   68  55  78  58 /  90  40  10   0
DUA   75  62  78  60 /  70  70  20   0

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

OKZ004>048-050>052-TXZ083>090-141200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
710 AM CDT SAT APR 13 2002

THUNDERSTORM OUTLOOK...
THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THROUGH THIS
EVENING ACROSS WESTERN NORTH TEXAS AND PARTS OF SOUTHERN OKLAHOMA.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH THIS EVENING
ACROSS NORTHERN OKLAHOMA.

LOCATION...
THE MODERATE RISK AREA IS SOUTH OF A LINE FROM ERICK TO CHICKASHA TO
HOLDENVILLE. THE SLIGHT RISK AREA INCLUDES THE REST OF CENTRAL AND
NORTHERN OKLAHOMA NORTH OF THIS LINE.

TIMING...
SEVERE THUNDERSTORMS ARE IN PROGRESS AS OF 7 AM ACROSS PARTS OF
SOUTHWEST OKLAHOMA. THE MOST LIKELY TIME FOR SEVERE THUNDERSTORMS
WILL BE THROUGH MIDDAY...AND AGAIN FROM MID AFTERNOON THROUGH LATE
EVENING.

IMPACTS...
DAMAGING HAIL UP TO 2.50 INCHES.
DAMAGING WIND GUSTS TO 65 MPH.
WEAK TORNADOES WILL BE POSSIBLE...MAINLY IN THE MODERATE RISK AREA.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL SHOULD
ALREADY BE ACTIVATED ACROSS WESTERN NORTH TEXAS AND PARTS OF WESTERN
OKLAHOMA. SPOTTER GROUPS IN CENTRAL OKLAHOMA WILL LIKELY REQUIRE
ACTIVATION LATER THIS MORNING. GROUPS IN ALL PARTS OF OKLAHOMA AND
NORTH TEXAS SHOULD CONTINUE TO MONITOR CONDITIONS FOR POSSIBLE
REACTIVATION LATER THIS AFTERNOON OR EVENING.

DISCUSSION...
A STRONG UPPER LEVEL DISTURBANCE WILL MOVE SOUTHEAST ACROSS OKLAHOMA
LATE TODAY AND TONIGHT. AHEAD OF THIS SYSTEM...A COMPLEX OF STRONG
THUNDERSTORMS WILL MOVE ACROSS THE AREA THIS MORNING RESULTING IN A
RISK OF SEVERE THUNDERSTORMS. LARGE HAIL WILL BE THE MAIN THREAT. IF
THE CURRENT COMPLEX MOVES EAST OF THE AREA THIS AFTERNOON...AND
SKIES CLEAR TO ALLOW AFTERNOON HEATING...ANOTHER ROUND OF SEVERE
THUNDERSTORMS MAY DEVELOP OVER PARTS OF WESTERN OKLAHOMA AND NORTH
TEXAS BY AROUND MID AFTERNOON...MOVING EAST INTO CENTRAL OKLAHOMA
THIS EVENING.

THREAT TABLE...
VALID THROUGH 700 AM CDT SUNDAY APR 14.
PROBABILITY OF THUNDERSTORMS...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...100 PERCENT.

OTHER HAZARDOUS WEATHER...
NONE IS EXPECTED THROUGH TONIGHT.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT NOON
TODAY.

A GRAPHICAL OUTLOOK CAN BE FOUND ON THE WEB AT WWW.SRH.NOAA.GOV/OUN.