Severe Thunderstorm Warning 53, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
240 PM CST FRI APR 2 1999

FRONT HAS FINALLY STOPPED MOVING AND THE NW 1/4 OF THE FA IS IN THE
COOL AIR.  SHOWERS HAVE BEGUN TO DEVELOP ALONG THE FRONT AND AN
APPARENT SWEET SPOT NEAR THE OKLAHOMA-LOGAN COUNTY LINE.  THE CAP
SEEMS BREAKABLE ESPECIALLY WITH CONVERGENCE ALONG THE DRYLINE AND/OR
FRONT SO EXPECT CONVECTION TO INCREASE OVER THE NEXT COUPLE OF
HOURS.  ALL OF THE MODELS... ESPECIALLY THE ETA DEVELOP A GOOD
AMOUNT OF LIFT ALONG THE DRYLINE BY MIDNIGHT AND MOVES IT EAST
ACROSS THE AREA THROUGH 12Z WHICH SUGGESTS THE POTENTIAL OF A SQUALL
LINE.  FOR THIS AFTERNOON AND EVENING... ALTHOUGH NOT STRONG SHEAR
THERE IS ENOUGH FOR ISOLATED SUPERCELLS THROUGH EARLY EVENING.
AFTER THAT THE PRIMARY CONCERN WILL BE SQUALL LINE ACTIVITY AND
WINDS/HAIL. AM SOMEWHAT ON THE FENCE ABOUT POPS DUE TO UNCERTAINTY
ABOUT AREAL COVERAGE.  THIS ROUND OF FORCING MOVES TO THE EAST WHILE
THE UPPER STORM REDEVELOPS IN THE SOUTHWEST UNITED STATES.  MOISTURE
PROGS SUGGEST THAT AREA WILL BE DRY SLOTTED TOMORROW ALTHOUGH AM NOT
SURE THE SURFACE MOISTURE WILL GET COMPLETELY PUSHED AWAY.  SO WILL
LEAVE POPS IN FOR MAINLY MORNING ACTIVITY.

AFTER A BREAK SATURDAY NIGHT AND SUNDAY... THE CHANCE OF RAIN
INCREASES AGAIN SUNDAY NIGHT AND MONDAY AS THE NEXT SYSTEM HEADS OUR
WAY.  ANOTHER BREAK TUESDAY THEN ANOTHER POTENTIAL ROUND OF STORMS
WEDNESDAY ACCORDING TO THE MRF.

...SPEG.
FIRST ITERATION.  FIRST PERIOD POPS SUBJECT TO CHANGE WITH LITTLE OR
NO ADVANCE WARNING.
OKC   60  73  51  73 /  40  30   0   0
HBR   55  70  47  74 /  20  10   0   0
SPS   60  76  51  76 /  30  20   0   0
GAG   41  65  42  70 /  20  10  10   0
PNC   59  71  50  72 /  40  30  10   0
DUA   65  72  49  74 /  40  30   0  10

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

OKZ004>048-050>052-TXZ083>090-022100-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1230 PM CST FRI APR 2 1999

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT ACROSS A LARGE PART OF OKLAHOMA AND WESTERN NORTH TEXAS. THE
SLIGHT RISK AREA IS SOUTHEAST OF A LINE FROM REYDON TO ALVA. ..

DISCUSSION...A COLD FRONT FROM WEST CENTRAL TO NORTH CENTRAL
OKLAHOMA AT MIDDAY IS EXPECTED TO STALL BY THIS EVENING FROM NEAR
CLINTON TO NEAR ENID AND PONCA CITY. MEANWHILE... A DRY LINE FROM
THE EXTREME SOUTHEAST TEXAS PANHANDLE... AND EXTENDING SOUTH... WILL
MOVE SLOWLY EAST INTO SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS.
ABUNDANT LOW LEVEL MOISTURE IS IN PLACE TO THE SOUTH AND EAST OF
BOTH THE FRONT AND THE DRY LINE... WITH DEW POINT TEMPERATURES IN
THE 60S. AFTERNOON HEATING WILL RESULT IN DESTABILIZATION OF THE AIR
NEAR BOTH BOUNDARIES... AND WILL HELP TO WEAKEN A CAPPING LAYER OF
VERY WARM AIR LYING JUST ABOVE THE LOW LEVEL MOIST LAYER.

THUNDERSTORMS ARE EXPECTED TO DEVELOP AS EARLY AS 2 OR 3 PM ALONG
THE FRONT IN NORTH CENTRAL OKLAHOMA... AND MAY DEVELOP SOUTHWESTWARD
ALONG THE FRONT INTO PARTS OF WEST CENTRAL OKLAHOMA BY LATE
AFTERNOON. OTHER THUNDERSTORMS MAY DEVELOP LATE THIS AFTERNOON ALONG
THE DRYLINE AS IT MOVES INTO SOUTHWEST OKLAHOMA AND WESTERN NORTH
TEXAS. THE AREA WHERE THE TWO BOUNDARIES INTERSECT... KNOWN AS THE
TRIPLE POINT... WILL BE A FAVORED AREA FOR SEVERE THUNDERSTORM
DEVELOPMENT LATE THIS AFTERNOON OR EARLY THIS EVENING. THAT AREA IS
EXPECTED TO BE IN SOUTHWEST OKLAHOMA.

THUNDERSTORMS MAY ORGANIZE INTO A LINE THIS EVENING AND MOVE EAST
INTO CENTRAL... SOUTH CENTRAL... AND SOUTHEAST OKLAHOMA OVERNIGHT.
THE MAIN SEVERE THREAT WILL BE AFTER DARK OVER THESE AREAS.

LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY SEVERE THREAT.
HOWEVER... VERTICAL WIND PROFILES AND THE EXPECTED LEVELS OF
INSTABILITY SUGGEST THAT SUPERCELLS WILL BE POSSIBLE THIS AFTERNOON
AND EVENING... MAINLY FROM WEST CENTRAL OKLAHOMA SOUTH AND
SOUTHWESTWARD INTO WESTERN NORTH TEXAS. ISOLATED TORNADOES WILL BE
POSSIBLE IN THESE AREAS THIS AFTERNOON AND EVENING.

SPOTTER GROUPS AND EMERGENCY MANAGERS ACROSS NORTH CENTRAL OKLAHOMA
SHOULD BE READY FOR POSSIBLE ACTIVATION AS EARLY AS MID AFTERNOON.
THOSE FROM WEST CENTRAL OKLAHOMA SOUTH INTO WESTERN NORTH TEXAS MAY
REQUIRE ACTIVATION LATER THIS AFTERNOON... WHILE THOSE FROM CENTRAL
OKLAHOMA INTO SOUTHEAST OKLAHOMA WILL MOST LIKELY SEE ACTION AFTER
SUNSET.

24

OKZ004>048-050>052-TXZ083>090-022100-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1230 PM CST FRI APR 2 1999

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT ACROSS A LARGE PART OF OKLAHOMA AND WESTERN NORTH TEXAS. THE
SLIGHT RISK AREA IS SOUTHEAST OF A LINE FROM REYDON TO ALVA. ..

DISCUSSION...A COLD FRONT FROM WEST CENTRAL TO NORTH CENTRAL
OKLAHOMA AT MIDDAY IS EXPECTED TO STALL BY THIS EVENING FROM NEAR
CLINTON TO NEAR ENID AND PONCA CITY. MEANWHILE... A DRY LINE FROM
THE EXTREME SOUTHEAST TEXAS PANHANDLE... AND EXTENDING SOUTH... WILL
MOVE SLOWLY EAST INTO SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS.
ABUNDANT LOW LEVEL MOISTURE IS IN PLACE TO THE SOUTH AND EAST OF
BOTH THE FRONT AND THE DRY LINE... WITH DEW POINT TEMPERATURES IN
THE 60S. AFTERNOON HEATING WILL RESULT IN DESTABILIZATION OF THE AIR
NEAR BOTH BOUNDARIES... AND WILL HELP TO WEAKEN A CAPPING LAYER OF
VERY WARM AIR LYING JUST ABOVE THE LOW LEVEL MOIST LAYER.

THUNDERSTORMS ARE EXPECTED TO DEVELOP AS EARLY AS 2 OR 3 PM ALONG
THE FRONT IN NORTH CENTRAL OKLAHOMA... AND MAY DEVELOP SOUTHWESTWARD
ALONG THE FRONT INTO PARTS OF WEST CENTRAL OKLAHOMA BY LATE
AFTERNOON. OTHER THUNDERSTORMS MAY DEVELOP LATE THIS AFTERNOON ALONG
THE DRYLINE AS IT MOVES INTO SOUTHWEST OKLAHOMA AND WESTERN NORTH
TEXAS. THE AREA WHERE THE TWO BOUNDARIES INTERSECT... KNOWN AS THE
TRIPLE POINT... WILL BE A FAVORED AREA FOR SEVERE THUNDERSTORM
DEVELOPMENT LATE THIS AFTERNOON OR EARLY THIS EVENING. THAT AREA IS
EXPECTED TO BE IN SOUTHWEST OKLAHOMA.

THUNDERSTORMS MAY ORGANIZE INTO A LINE THIS EVENING AND MOVE EAST
INTO CENTRAL... SOUTH CENTRAL... AND SOUTHEAST OKLAHOMA OVERNIGHT.
THE MAIN SEVERE THREAT WILL BE AFTER DARK OVER THESE AREAS.

LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY SEVERE THREAT.
HOWEVER... VERTICAL WIND PROFILES AND THE EXPECTED LEVELS OF
INSTABILITY SUGGEST THAT SUPERCELLS WILL BE POSSIBLE THIS AFTERNOON
AND EVENING... MAINLY FROM WEST CENTRAL OKLAHOMA SOUTH AND
SOUTHWESTWARD INTO WESTERN NORTH TEXAS. ISOLATED TORNADOES WILL BE
POSSIBLE IN THESE AREAS THIS AFTERNOON AND EVENING.

SPOTTER GROUPS AND EMERGENCY MANAGERS ACROSS NORTH CENTRAL OKLAHOMA
SHOULD BE READY FOR POSSIBLE ACTIVATION AS EARLY AS MID AFTERNOON.
THOSE FROM WEST CENTRAL OKLAHOMA SOUTH INTO WESTERN NORTH TEXAS MAY
REQUIRE ACTIVATION LATER THIS AFTERNOON... WHILE THOSE FROM CENTRAL
OKLAHOMA INTO SOUTHEAST OKLAHOMA WILL MOST LIKELY SEE ACTION AFTER
SUNSET.

24

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
349 PM CST FRI APR  2 1999

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

0250 PM    10 SSW PERRY              OK   1.00 INCH HAIL
04/02/99   LOGAN

0307 PM    PERRY                     OK   .75 INCH HAIL
04/02/99   NOBLE

DC