Severe Thunderstorm Warning 54, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
1025 AM CDT FRI APR 12 2002

STRONG TO SEVERE STORMS ONGOING FROM CENTRAL TO SOUTHWEST OK THIS
MORNING.  STORMS EARLY THIS MORNING WERE LOCATED ALONG 9-8H FRONT
WHICH IS FORECAST BY 12Z ETA TO LOCATED FROM NORTH OF FTW TO ABI
BY EARLY THIS AFTERNOON.  SURFACE BOUNDARY IS LOCATED FROM
ROUGHLY HOLDENVILLE TO SPS.  EXPECT AS STORMS NEAR THIS BOUNDARY
THAT WIND THREAT WILL INCREASE ALONG WITH THE LARGE HAIL.  EXPECT
AS UPPER WAVE...CENTERED OVER CENTRAL KS...MOVES EAST THIS
MORNING AND AFTERNOON THAT WILL HAVE SOME RECOVERY FROM WEST TO
EAST.  AFTERNOON HIGHS WILL BE TRICKY WITH CLOUD COVER BUT WILL
NOT MAKE SIGNIFICANT CHANGES AND SHOULD SEE MORE SUN FROM ACROSS
WEST AND CENTRAL SECTIONS BY MID TO LATE AFTERNOON.  WILL INCREASE
CHANCES ACROSS SOUTH CENTRAL AND SOUTHEAST SECTIONS FOR LATE THIS
MORNING AND EARLY THIS AFTERNOON.

SIX

NATIONAL WEATHER SERVICE NORMAN OK
843 AM CDT FRI APR 12 2002

DID A QUICK UPDATE TO ZONES TO INCREASE POPS ROUGHLY 50 MILES NORTH
AND SOUTH OF I-40 CORRIDOR FOR THIS MORNING.  LOOKS LIKE WEAK WAVE
MOVING ACROSS WESTERN KANSAS THIS MORNING SHOULD KEEP ELEVATED
STORMS GOING THROUGH THE MORNING HOURS.

SIX

AREA FORECAST DISCUSSION
432 AM CDT FRI APR 12 2002

WEAK LARGE-SCALE FEATURES SURFACE AND ALOFT ARE MORE REMINISCENT OF
JUNE THAN EARLY APRIL. AS SUCH...WHAT HAPPENS NEXT 2-3 DAYS IS MOST
LIKELY TO BE DRIVEN BY MESOSCALE FEATURES. THERE WILL BE ENOUGH
FORCING ALOFT FROM SHORTWAVE IMPULSES ON S EDGE OF WESTERLIES... AND
FORCING AT LOW LEVELS MAINLY FROM UPSLOPE AND RESIDUAL FRONTAL
CONVERGENCE...TO CREATE A RISK OF MCS DEVELOPMENT TONIGHT OVER
HIGHER TERRAIN OF S HIGH PLAINS. LL MOISTURE IS MORE TYPICAL OF
APRIL BUT IS ADEQUATE...EVEN THO LL RETURN FLOW/INFLOW INTO ANY
CONVERGENCE ZONES WILL BE DEPLORABLY WEAK. ON THIS BASIS...WE THINK
THE ETA QPF MAY BE MORE ACCURATE IN TAKING MORE ORGANIZED PRECIP
TONIGHT SE-WARD FROM PANHANDLE MORE TOWARD NW TX AND PERHAPS S
OK...WHILE LL RIDGING SHIELDS THE NE ZONES. THIS IS IN KEEPING WITH
THE JUNE-LIKE NW FLOW PATTERN. THUS WILL LEAN AWAY FROM THE MORE
NORTHERN SOLUTION OF THE AVN AND ASSOCIATED COLD/WET GUIDANCE ACROSS
N...WITH THE THINKING BEING THAT CLOUDS/PRECIP WILL MORE LIKELY
AFFECT THE SW ZONES LATE TONIGHT INTO SAT. THIS RESULTS IN NUMBERS
CLOSER TO NGM/FWC N AND AVN/MAV S. ACTIVITY TONIGHT SHOULD REINFORCE
SURFACE BOUNDARY ACROSS N TX PER SWODY2...FURTHER SHIFTING EMPHASIS
TO S ZONES SAT.

PATTERN CHANGE BY EARLY NEXT WEEK YIELDS SOMETHING MEATIER FOR
EARLY-MID SPRING AS LONGWAVE TROF DEVELOPS IN W. TRANSITION EXPECTED
TO BE MOSTLY DRY AS CAP BECOMES A FACTOR WHILE THE W TROF SETS UP.
WILL KEEP LOW POPS IN FOR SUN BUT REMOVE THEM MON. TUE ALSO MAY END
UP CAPPED AS FIRST CHUNK OF ENERGY EJECTS TO OUR N...BUT WILL NEED
TO HOLD ON TO SOME LOW POPS. POPS THEN INCREASE WED-THU AS LONGWAVE
TROF PROGRESSES INTO CENTRAL STATES. TEMPS WILL BE TRENDED TOWARD
LATEST MRF MOS...COOLER N WED-THU.

ALL PRODUCTS LIKELY DELAYED BY UP TO 1/2 HR THIS MORNING DUE TO IFPS
PROBLEMS.

FCSTID = 24
OKC   75  54  75  56 /  20  30  30  20
HBR   77  57  74  56 /  20  40  50  30
SPS   78  58  73  57 /  20  40  50  30
GAG   75  55  75  53 /  20  30  30  20
PNC   73  51  78  53 /  20  20  30  20
DUA   78  57  75  63 /  20  30  40  40

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

OKZ004>048-050>052-TXZ083>090-131200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
710 AM CDT FRI APR 12 2002

THUNDERSTORM OUTLOOK...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
ACROSS PORTIONS OF OKLAHOMA AND WESTERN NORTH TEXAS.

LOCATION...
THE SLIGHT RISK AREA INCLUDES MOST OF WESTERN AND SOUTHWEST
OKLAHOMA...AND WESTERN NORTH TEXAS. THE RISK AREA IS WEST OF A LINE
EXTENDING FROM GAGE TO WAURIKA.

TIMING...
THUNDERSTORM ACTIVITY ONGOING EARLY THIS MORNING WILL MOVE SOUTHEAST
ACROSS WESTERN...AND INTO PORTIONS OF CENTRAL OKLAHOMA DURING THE
MORNING HOURS. ANOTHER COMPLEX OF STORMS IS EXPECTED TO AFFECT
SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS TONIGHT.

IMPACTS...
HAIL UP TO 1.75 INCHES IN DIAMETER AND WIND GUSTS TO 60 MPH ARE
POSSIBLE.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS. PERSONNEL
ACROSS WESTERN AND CENTRAL OKLAHOMA WILL BE AFFECTED MAINLY THIS
MORNING...WITH SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS HAVING THE
MAIN THREAT TONIGHT.

DISCUSSION...
ELEVATED STRONG TO SEVERE THUNDERSTORMS WILL CONTINUE THIS MORNING
ACROSS WESTERN INTO PORTIONS OF CENTRAL OKLAHOMA...AIDED BY A WEAK
MID LEVEL DISTURBANCE MOVING ACROSS KANSAS. THIS ACTIVITY IS
EXPECTED TO WEAKEN BY MID-DAY. ADDITIONAL ACTIVITY IS EXPECTED TO
DEVELOP OVER THE HIGH PLAINS OF COLORADO AND NEW MEXICO THIS
AFTERNOON...AND MOVE SOUTHEAST TOWARD SOUTHWEST OKLAHOMA AND WESTERN
NORTH TEXAS THIS EVENING AND TONIGHT. LARGE HAIL WILL BE THE PRIMARY
SEVERE WEATHER THREAT.

THREAT TABLE...
VALID THROUGH 700 AM CDT SAT APR 13.
PROBABILITY OF THUNDERSTORMS...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...60 PERCENT.

OTHER HAZARDOUS WEATHER...
NO HAZARDOUS WEATHER 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.

11

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1035 AM CDT FRI APR 12 2002

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

0600 AM    5 W ARNETT                OK   1.75 INCH HAIL
04/12/02   ELLIS

0625 AM    3 W CARTER                OK   .75 INCH HAIL
04/12/02   BECKHAM

0930 AM    ROOSEVELT                 OK   .88 INCH HAIL
04/12/02   KIOWA                          REPORTED BY ROOSEVELT FIRE
                                          DEPT.

1026 AM    4 W LAWTON                OK   .88 INCH HAIL
04/12/02   COMANCHE                       HAM SPOTTER

1028 AM    3 W LAWTON                OK   1.00 INCH HAIL
04/12/02   COMANCHE                       HAM SPOTTER

SPEG

OKZ004>048-050>052-TXZ083>090-131200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1205 PM CDT FRI APR 12 2002

THUNDERSTORM OUTLOOK...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
ACROSS PORTIONS OF OKLAHOMA AND WESTERN NORTH TEXAS.

LOCATION...
THE SLIGHT RISK AREA INCLUDES MOST OF SOUTHWEST AND SOUTH CENTRAL
OKLAHOMA AND ALL OF WESTERN NORTH TEXAS.  THE SLIGHT RISK AREA IS
GENERALLY SOUTHEAST OF A LINE FROM CLINTON TO BINGER TO NORMAN AND
ATOKA.

TIMING...
THUNDERSTORMS ONGOING ACROSS PARTS OF CENTRAL AND SOUTH CENTRAL
OKLAHOMA...WILL CONTINUE TO PUSH INTO SOUTHEAST OKLAHOMA
DURING THE EARLY AFTERNOON.  ADDITIONAL THUNDERSTORMS ARE EXPECTED
TO DEVELOP ACROSS THE HIGH PLAINS OF COLORADO AND NEW MEXICO AND
THEN MOVE SOUTHEAST INTO WESTERN OKLAHOMA AND WESTERN NORTH TEXAS
OVERNIGHT.

IMPACTS...
HAIL UP TO 1.75 INCHES.
DAMAGING WIND GUSTS TO 65 MPH.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS THROUGH MID
AFTERNOON TODAY AND AGAIN EARLY SATURDAY MORNING.

DISCUSSION...
A LINE OF STRONG TO SEVERE THUNDERSTORMS...AHEAD OF A WEAK UPPER AIR
DISTURBANCE...WILL PUSH INTO SOUTHEAST OKLAHOMA DURING THE EARLY TO
MID AFTERNOON.  THUNDERSTORMS CLOSE TO THE RED RIVER WILL BE MORE
SURFACE BASED WHICH WILL INCREASE THE RISK OF DAMAGING WIND GUSTS.
OTHERWISE THE MAIN THREAT WILL BE LARGE HAIL.  THIS ACTIVITY SHOULD
MOVE SOUTH OR EAST OF THE AREA BY 3 TO 4 PM.  ADDITIONAL ACTIVITY IS
EXPECTED TO DEVELOP OVER THE HIGH PLAINS OF COLORADO AND NEW MEXICO
THIS EVENING...AND MOVE SOUTHEAST TOWARD SOUTHWEST OKLAHOMA AND
WESTERN NORTH TEXAS TONIGHT. LARGE HAIL WILL BE THE PRIMARY SEVERE
WEATHER THREAT.

THREAT TABLE...
VALID THROUGH 700 AM CDT SAT APR 13.
PROBABILITY OF THUNDERSTORMS...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...90 PERCENT.

OTHER HAZARDOUS WEATHER...
NO HAZARDOUS WEATHER IS EXPECTED THROUGH TONIGHT.

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