Flash Flood Warning 4, NWS Tulsa, OK

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
500 AM CST SAT APR 3 1999

PROBLEM(S) OF THE DAY:
WILL SEVERE WEATHER RE-DEVELOP THIS AFTERNOON?
WHAT AFFECT WILL CONVECTION HAVE ON TEMPERATURES?

ZONES HAVE ALREADY BEEN SENT. SEVERE WEATHER IS ONGOING AS SQUALL
LINE PUSHES OFF TO THE EAST AND OTHER CONVECTION FIRED UP EARLIER IN
NW AR AHEAD OF THE SQUALL LINE. LOOKS LIKE THE EASTERLY VALLEY WIND
NEAR FSM INCREASED STORM RELATIVE HELICITY AND CAUSED SOME OF THESE
STORMS...PARTICULARLY AROUND CRAWFORD COUNTY TO ROTATE. SQUALL LINE
SHOULD CLEAR THE ERN EDGE OF THE FCST AREA BETWEEN 600 AND 700 AM.

SURFACE ANALYSIS SHOWS THAT DRYLINE REMAINS OVER THE TX PNHDL. NGM
AND AVN AGREE IN SURGING THE DRYLINE EAST TODAY. BY
MID-AFTERNOON...DAYTIME HEATING MAY HAVE ALLOWED THE ATMOSPHERE TO
RECOVER FROM ONGOING CONVECTION AND ALLOW TSRA RE-DEVELOPMENT ALONG
THE DRYLINE IN ERN OK. THIS NEW FCST ASSUMES THAT RE-DEVELOPMENT WILL
TAKE PLACE ALONG/EAST OF U.S. HWY 69...OR ROUGHLY FROM MIAMI TO
MCALESTER. ONGOING CONVECTION HAS PRODUCED AN OUTFLOW BOUNDARY IN ITS
WAKE ALONG I-35. BACKED SURFACE WINDS ASSOCIATED WITH THIS OUTFLOW
COULD INCREASE STORM-RELATIVE HELICITIES AND ALLOW ANY STORMS THAT
FORM TO ROTATE. DAY SHIFT WILL WANT TO KEEP TABS ON MESOSCALE
DEVELOPMENTS. MUCH OF THIS REMAINS OPEN TO DEBATE 12 HOURS OUT FROM
THE FACT.

ANY AFTN CONVECTION SHOULD MOVE EAST OF THE FCST AREA BY MID-EVNG. IT
IS UNUSUAL TO SEE A DRYLINE MOVE EAST OF THE OK/AR STATE LINE...BUT
MODELS INDICATE THIS WILL HAPPEN DURG THE EVNG. THIS WILL LEAVE A
CLEAR AND DRY ATMOS BEHIND WITH GOOD RADIATIONAL COOLING TONIGHT...SO
WENT BELOW GUIDANCE TEMPS. EASTER MRNG SUNRISE LOOKS CLEAR AND
SEASONABLY COOL...BASICALLY DELIGHTFUL. WITH SUNNY SKIES...HIGH TEMPS
ON EASTER SHOULD WARM UP NICELY. WENT A DEGREE OR TWO OVER GUIDANCE.

HOWEVER...MOISTURE WILL LURK JUST SOUTH OF THE RED RIVER AND SHOULD
MAKE A RAPID RETURN ON SUN NGT AHEAD OF NEXT POWERFUL STORM NOW
DIVING SOUTHWARD THRU NRN CA. STRONG MOISTURE ADVECTION...STRONG
ISENTROPIC LIFT...AND MODERATE ELEVATED CONVECTION SHOULD PRODUCE THE
LIKELIHOOD OF RAPID PCPN DEVELOPMENT SUN NGT. UPR SYS MOVES RAPIDLY
BY ON MON MRNG WITH ANOTHER DRYLINE SURGING ACROSS THE AREA. THIS
SHOULD CLEAR THINGS OUT AGAIN LATE MON AFTN/ERLY MON EVNG.

THE LAST IN A SERIES OF UPR SYSTEMS IS CURRENTLY OVER THE BERING
STRAITS NEAR AK AND WILL MOVE ACRS THE AREA ON WED NGT. ADDED SMALL
POPS TO FCST ON WED...BUT THINK THAT MAIN TSRA THREAT WILL BE ON WED
NGT/THU MRNG.

FCSTID = 22
TUL   74  46  73  57 /  60  10   5  70
FSM   72  47  75  55 /  90  40   0  70
MLC   76  45  74  58 /  70  20   5  70
BVO   73  45  73  55 /  60  10   5  70
FYV   69  45  74  55 /  90  40   0  60
IDB   75  48  74  62 /  80  30   5  70
BYV   68  45  75  54 /  90  40   0  60
MIO   73  44  74  54 /  80  20   0  60
MKO   75  45  74  56 /  80  20   5  70
F10   75  45  73  57 /  70  10   5  70
HHW   75  47  74  61 /  70  30   5  70

.TUL...
OK...SEVERE THUNDERSTORM WATCH UNTIL 900 AM CST FOR ZONES
OKZ056>058...OKZ061>063...OKZ067>072...OKZ074.

AR...SEVERE THUNDERSTORM WATCH UNTIL 900 AM CST FOR ZONES
ARZ001>002...ARZ010>011...ARZ019>020...ARZ029.

--------------------
EXPERIMENTAL OUTPUT:

HAZARDOUS WEATHER EXPECTED NEXT 24 HOURS: SEVERE THUNDERSTORMS
NGM CONFIDENCE:  7 ON A SCALE OF 0 TO 10
ETA CONFIDENCE:  5 ON A SCALE OF 0 TO 10
AVN CONFIDENCE:  8 ON A SCALE OF 0 TO 10
FCST CONFIDENCE: 8 ON A SCALE OF 0 TO 10

STORM REPORT CORRECTED                  ...CORRECTED FOR TIME...
NATIONAL WEATHER SERVICE TULSA, OK
352 AM CST SAT APR 03 1999

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

0344 AM    BIXBY                     OK   .75 INCH HAIL
04/03/99   TULSA

0344 AM    BIXBY                     OK   60 MPH TSTM GUST
04/03/99   TULSA

STORM REPORT CORRECTED                   ...CORRECTED FOR TIME...
NATIONAL WEATHER SERVICE TULSA, OK
402 AM CST SAT APR 03 1999

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

0359 AM    BARTLESVILLE              OK   WIND DAMAGE
04/03/99   WASHINGTON                     WINDOW BLOWN OUT OF A
                                          HOUSE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
416 AM CST SAT APR 03 1999

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

0306 AM    BRISTOW                   OK   60 MPH TSTM GUST
04/03/99   CREEK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
418 AM CST SAT APR 03 1999

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

0306 AM    MANNFORD                  OK   60 MPH TSTM GUST
04/03/99   CREEK

0306 AM    MANNFORD                  OK   .75 INCH HAIL
04/03/99   CREEK

ARZ001-002-010-011-019-020-029-OKZ049-053>076-041200-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
600 AM CST SAT APR 3 1999

...A FEW SEVERE THUNDERSTORMS ARE EXPECTED OVER SOUTHEAST OKLAHOMA AND
NORTHWEST ARKANSAS THIS MORNING...

...ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE AGAIN THIS AFTERNOON AND
INTO THE EARLY EVENING OVER FAR EASTERN OKLAHOMA AND NORTHWEST
ARKANSAS...

.SYNOPSIS...
AT 600 AM...A LINE OF STRONG TO SEVERE THUNDERSTORMS EXTENDED FROM NEAR
FAYETTEVILLE IN NORTHWEST ARKANSAS TO HUGO IN FAR SOUTHEAST OKLAHOMA.
THIS LINE OF THUNDERSTORMS EXISTED WELL AHEAD OF A COLD FRONT THAT
STRETCHED FROM SOUTHEAST KANSAS INTO SOUTHWEST OKLAHOMA.  IN
ADDITION...A DRY LINE EXTENDED FROM NEAR THE OKLAHOMA CITY AREA
SOUTHWARD INTO CENTRAL TEXAS.

.DISCUSSION...
THE LINE OF THUNDERSTORMS OVER NORTHWEST ARKANSAS AND SOUTHEAST OKLAHOMA
IS EXPECTED TO SHIFT EAST OF THE AREA BY 9 AM.  WHILE A SLOW WEAKENING
TREND IS EXPECTED...WIND GUSTS OF 60 MPH AND DIME SIZE HAIL WILL REMAIN
POSSIBLE WITH THIS LINE OF STORMS.

MEANWHILE...A STRONG UPPER LEVEL DISTURBANCE OVER NEW MEXICO EARLY THIS
MORNING WILL SWING INTO THE TEXAS PANHANDLE AND WESTERN OKLAHOMA BY LATE
MORNING OR EARLY AFTERNOON.  THIS WILL AID IN PUSHING THE COLD
FRONT/DRYLINE COMBINATION EASTWARD INTO EASTERN OKLAHOMA.  CLEARING WILL
BE SLOW BEHIND THE INITIAL LINE OF THUNDERSTORMS...BUT ENOUGH AFTERNOON
HEATING IS EXPECTED FOR THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE.
SURFACE BASED CONVERGENCE ALONG THE COLD FRONT OR DRYLINE...COMBINED
WITH INCREASING INSTABILITY MAY LEAD TO THE REDEVELOPMENT OF
THUNDERSTORMS THIS AFTERNOON ACROSS FAR EASTERN OKLAHOMA.  THIS ACTIVITY
IS EXPECTED TO DEVELOP MAINLY EAST OF HIGHWAY 69...OR EAST OF A VINITA
TO MUSKOGEE TO MCALESTER LINE.  ANY CONVECTION THAT FORMS WOULD SHIFT
EAST INTO NORTHWEST ARKANSAS BY LATE AFTERNOON OR EARLY EVENING.

WHILE SOME STORM ROTATION IS POSSIBLE...FORECAST WIND PROFILES SUGGEST
THAT STRONG WINDS WILL BE THE PRIMARY SEVERE WEATHER THREAT.

.EMERGENCY AGENCY AND SPOTTER ACTIVATION...
SPOTTERS ACTIVATION MAY BE REQUIRED AGAIN BY THIS AFTERNOON.  SPOTTER
GROUPS AND EMERGENCY MANAGEMENT AGENCIES ARE URGED TO LISTEN TO LATER
FORECASTS INCLUDING THE UPDATED HAZARDOUS WEATHER OUTLOOK TO BE ISSUED
AROUND 1 PM.

ARZ001-002-010-011-019-020-029-OKZ049-053>076-041200-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
600 AM CST SAT APR 3 1999

...A FEW SEVERE THUNDERSTORMS ARE EXPECTED OVER SOUTHEAST OKLAHOMA AND
NORTHWEST ARKANSAS THIS MORNING...

...ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE AGAIN THIS AFTERNOON AND
INTO THE EARLY EVENING OVER FAR EASTERN OKLAHOMA AND NORTHWEST
ARKANSAS...

.SYNOPSIS...
AT 600 AM...A LINE OF STRONG TO SEVERE THUNDERSTORMS EXTENDED FROM NEAR
FAYETTEVILLE IN NORTHWEST ARKANSAS TO HUGO IN FAR SOUTHEAST OKLAHOMA.
THIS LINE OF THUNDERSTORMS EXISTED WELL AHEAD OF A COLD FRONT THAT
STRETCHED FROM SOUTHEAST KANSAS INTO SOUTHWEST OKLAHOMA.  IN
ADDITION...A DRY LINE EXTENDED FROM NEAR THE OKLAHOMA CITY AREA
SOUTHWARD INTO CENTRAL TEXAS.

.DISCUSSION...
THE LINE OF THUNDERSTORMS OVER NORTHWEST ARKANSAS AND SOUTHEAST OKLAHOMA
IS EXPECTED TO SHIFT EAST OF THE AREA BY 9 AM.  WHILE A SLOW WEAKENING
TREND IS EXPECTED...WIND GUSTS OF 60 MPH AND DIME SIZE HAIL WILL REMAIN
POSSIBLE WITH THIS LINE OF STORMS.

MEANWHILE...A STRONG UPPER LEVEL DISTURBANCE OVER NEW MEXICO EARLY THIS
MORNING WILL SWING INTO THE TEXAS PANHANDLE AND WESTERN OKLAHOMA BY LATE
MORNING OR EARLY AFTERNOON.  THIS WILL AID IN PUSHING THE COLD
FRONT/DRYLINE COMBINATION EASTWARD INTO EASTERN OKLAHOMA.  CLEARING WILL
BE SLOW BEHIND THE INITIAL LINE OF THUNDERSTORMS...BUT ENOUGH AFTERNOON
HEATING IS EXPECTED FOR THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE.
SURFACE BASED CONVERGENCE ALONG THE COLD FRONT OR DRYLINE...COMBINED
WITH INCREASING INSTABILITY MAY LEAD TO THE REDEVELOPMENT OF
THUNDERSTORMS THIS AFTERNOON ACROSS FAR EASTERN OKLAHOMA.  THIS ACTIVITY
IS EXPECTED TO DEVELOP MAINLY EAST OF HIGHWAY 69...OR EAST OF A VINITA
TO MUSKOGEE TO MCALESTER LINE.  ANY CONVECTION THAT FORMS WOULD SHIFT
EAST INTO NORTHWEST ARKANSAS BY LATE AFTERNOON OR EARLY EVENING.

WHILE SOME STORM ROTATION IS POSSIBLE...FORECAST WIND PROFILES SUGGEST
THAT STRONG WINDS WILL BE THE PRIMARY SEVERE WEATHER THREAT.

.EMERGENCY AGENCY AND SPOTTER ACTIVATION...
SPOTTERS ACTIVATION MAY BE REQUIRED AGAIN BY THIS AFTERNOON.  SPOTTER
GROUPS AND EMERGENCY MANAGEMENT AGENCIES ARE URGED TO LISTEN TO LATER
FORECASTS INCLUDING THE UPDATED HAZARDOUS WEATHER OUTLOOK TO BE ISSUED
AROUND 1 PM.