Severe Thunderstorm Warning 591, NWS Tulsa, OK

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
345 AM CST SAT DEC 4 1999

CURRENT MESONET DATA SHOWS A COLD FRONT LOCATED ALONG I-44 WITH A 20
DEGF TEMP DIFF ON EITHER SIDE OF FRONT.  ISENTROPIC LIFT ALONG THE
FRONT IS THE PRIMARY FORCING MECHANISM FOR SHRA ACTIVITY ALONG AND
NORTH OF I-44.  WITH TEMPS ALREADY IN THE MID TO UPPER 60S IN THE
WARM SECTOR BEFORE SUNRISE...SHOULD BE A WARM MORNING IN SE OK/NW AR.
THE SURFACE LOW CURRENLY ANALYZED NEAR KSPS SHOULD MOVE NORTHEAST
LATE IN THE MORNING...FINALLY DRAGGING THE FRONT THROUGH SEOK/NWAR
WITH A NEAR-CERTAIN CHANCE OF SHRA/TSRA ALONG THE ADVANCING FRONT.  A
MID-LEVEL DRY SLOT SHOULD WORK IN BEHIND THE FRONT AND QUICKLY LOWER
THE RAIN CHANCES IN SEOK/WRN AR FOLLOWING THE FROPA.  IN NE
OK...ISENTROPIC LIFT SHOULD KEEP RAIN CHANCES GOING MOST OF THE DAY
WITH LITTLE TEMP RISE NOTED TODAY.

ONCE THE SURFACE LOW PASSES...THE STRONGER SYNOPTIC LIFT EXITS THE
AREA...LEAVING MAINLY WRAP-AROUND MOISTURE TO DEAL WITH AND LIMITED
MID-LEVEL FORCING ASSOCIATED WITH THE UPPER LOW MOVING ACROSS SRN KS.
WILL TAPER POPS FROM NORTH TO SOUTH ON SAT NGT AND SUNDAY MORNING
WITH ALL PRECIP CHANCES ENDING BY SUN AFTN.  SHOULD BE ENOUGH COLD
AIR ASSOCIATED WITH THE UPPER LOW ALONG AND NW OF I-44 FOR SOME
SNOWFLAKES TO MIX IN WITH ANY LIGHT PRECIP THAT FALLS ON SUN MRNG.
THE ETA FCST SOUNDING FOR PNC AT 12Z SUNDAY SHOWS A FREEZING LEVEL
LESS THAN 1000 FT AGL.

IN THE EXTENDED...STRONG SUBSIDENCE ON SUN NGT BEHIND THE UPPER LOW
WILL KEEP SKIES CLEAR AND ALLOW FOR THE COLDEST NIGHT YET THIS
SEASON.  AS THE SURFACE RIDGE MOVES EAST ON MON AND TUE...SRLY FLOW
AND A WARMUP BEGIN WITH RIDGING ALONG THE GULF COAST KEEPING MOISTURE
RETURN NON-EXISTENT.  DEVELOPING LOW PRESSURE OVER THE SRN HIGH
PLAINS ON WED SHOULD FINALLY DRAW MOISTURE NORTHWARD FROM THE
GULF...KEEPING LOW TEMPS WARMER AND LEADING ME TO INTRODUCE SMALL
POPS ON WED DUE TO MOISTURE AVAILABILITY AND ISENTROPIC LIFT.  LOOKS
LIKE MAIN PRECIP EVENT WILL HOLD OFF UNTIL THU WITH THE APPROACH OF
THE NEXT FRONT TO ACT AS A FOCUS.

FCSTID = 22
TUL   56  39  45  25 / 100  30  20   0
FSM   69  43  48  26 / 100  20  10   0
MLC   72  38  46  25 / 100  20  10   0
BVO   49  34  44  22 / 100  40  30   0
FYV   66  40  44  22 / 100  30  20   0
BYV   66  40  44  22 / 100  30  20   0
MIO   56  39  45  25 / 100  30  20   0
MKO   72  38  46  25 / 100  20  10   0
F10   72  38  46  25 / 100  20  10   0
HHW   75  43  50  28 /  80  10  10   0

.TUL...
AR...NONE.
OK...NONE.

ARZ001-002-010-011-019-020-029-OKZ049-053>076-051200-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
605 AM CST SAT DEC 4 1999

...A FEW SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS PARTS OF EASTERN AND
NORTHWEST ARKANSAS THIS MORNING AND AFTERNOON...

.SYNOPSIS...
A STRONG UPPER LEVEL STORM SYSTEM OVER THE TEXAS PANHANDLE EARLY THIS
MORNING WILL MOVE INTO NORTHEAST OKLAHOMA BY SUNDAY MORNING.
MEANWHILE...A SURFACE LOW ACROSS NORTHWEST TEXAS WILL LIFT NORTHEAST
TODAY...AND MOVE INTO NORTHERN ARKANSAS OVERNIGHT.  AS THE SURFACE LOW
MOVES NORTHEAST...THE COLD FRONT OVER NORTHEAST OKLAHOMA WILL PUSH
THROUGH THE REMAINDER OF EASTERN OKLAHOMA THIS AFTERNOON AND NORTHWEST
ARKANSAS TONIGHT.

.PRIMARY HAZARD...
SCATTERED SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE ACROSS
EAST CENTRAL AND SOUTHEAST OKLAHOMA EARLY THIS MORNING...AND THEN MOVE
INTO NORTHWEST ARKANSAS BY LATE MORNING.  A FEW OF THESE STORMS MAY
BECOME SEVERE...WITH WINDS GUSTS TO 60 MPH AND LARGE HAIL UP TO 1 INCH
IN DIAMETER POSSIBLE.  THE MOST FAVORABLE TIME FRAME FOR SEVERE
THUNDERSTORMS WILL BE BETWEEN 6 AM AND NOON FOR EASTERN OKLAHOMA...AND
BETWEEN 10 AM AND 4 PM FOR NORTHWEST ARKANSAS.

.DISCUSSION...
THE ATMOSPHERE OVER SOUTHEAST OKLAHOMA AND NORTHWEST ARKANSAS REMAINS
VERY MOIST AND UNSTABLE THIS MORNING...WITH SURFACE DEWPOINTS GENERALLY
IN THE LOWER 60S.  THIS MOISTURE...COMBINED WITH INCREASING LIFT AHEAD
OF THE UPPER SYSTEM...WILL ALLOW THUNDERSTORMS TO INCREASE OVER MUCH OF
SOUTHEAST OKLAHOMA THIS MORNING.  STRONG BUT UNIDIRECTIONAL WIND
PROFILES SUGGEST THAT THUNDERSTORMS MAY FORM INTO SHORT LINES AND BOW
SEGMENTS...WITH DAMAGING STRAIGHT-LINE WINDS BEING THE PRIMARY SEVERE
WEATHER THREAT.

.SPOTTER ACTIVATION...
SPOTTER ACTIVATION MAY BE REQUIRED THIS MORNING AND AFTERNOON OVER
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS.

THE NWS IN TULSA IS ALSO CREATING A GRAPHICAL VERSION OF THE
HAZARDOUS WEATHER OUTLOOK WITH SOME ENHANCED TECHNICAL INFORMATION.  YOU
MAY ACCESS THIS GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT
HTTP://WWW.NWSTULSA.NOAA.GOV/HWO.HTML.



ARZ001-002-010-011-019-020-029-OKZ049-053>076-051200-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
610 AM CST SAT DEC 4 1999

...A FEW SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS PARTS OF EASTERN
OKLAHOMA AND NORTHWEST ARKANSAS THIS MORNING AND AFTERNOON...

.SYNOPSIS...
A STRONG UPPER LEVEL STORM SYSTEM OVER THE TEXAS PANHANDLE EARLY THIS
MORNING WILL MOVE INTO NORTHEAST OKLAHOMA BY SUNDAY MORNING.
MEANWHILE...A SURFACE LOW ACROSS NORTHWEST TEXAS WILL LIFT NORTHEAST
TODAY...AND MOVE INTO NORTHERN ARKANSAS OVERNIGHT.  AS THE SURFACE LOW
MOVES NORTHEAST...THE COLD FRONT OVER NORTHEAST OKLAHOMA WILL PUSH
THROUGH THE REMAINDER OF EASTERN OKLAHOMA THIS AFTERNOON AND NORTHWEST
ARKANSAS TONIGHT.

.PRIMARY HAZARD...
SCATTERED SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE ACROSS
EAST CENTRAL AND SOUTHEAST OKLAHOMA EARLY THIS MORNING...AND THEN MOVE
INTO NORTHWEST ARKANSAS BY LATE MORNING.  A FEW OF THESE STORMS MAY
BECOME SEVERE...WITH WINDS GUSTS TO 60 MPH AND LARGE HAIL UP TO 1 INCH
IN DIAMETER POSSIBLE.  THE MOST FAVORABLE TIME FRAME FOR SEVERE
THUNDERSTORMS WILL BE BETWEEN 6 AM AND NOON FOR EASTERN OKLAHOMA...AND
BETWEEN 10 AM AND 4 PM FOR NORTHWEST ARKANSAS.

.DISCUSSION...
THE ATMOSPHERE OVER SOUTHEAST OKLAHOMA AND NORTHWEST ARKANSAS REMAINS
VERY MOIST AND UNSTABLE THIS MORNING...WITH SURFACE DEWPOINTS GENERALLY
IN THE LOWER 60S.  THIS MOISTURE...COMBINED WITH INCREASING LIFT AHEAD
OF THE UPPER SYSTEM...WILL ALLOW THUNDERSTORMS TO INCREASE OVER MUCH OF
SOUTHEAST OKLAHOMA THIS MORNING.  STRONG BUT UNIDIRECTIONAL WIND
PROFILES SUGGEST THAT THUNDERSTORMS MAY FORM INTO SHORT LINES AND BOW
SEGMENTS...WITH DAMAGING STRAIGHT-LINE WINDS BEING THE PRIMARY SEVERE
WEATHER THREAT.

.SPOTTER ACTIVATION...
SPOTTER ACTIVATION MAY BE REQUIRED THIS MORNING AND AFTERNOON OVER
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS.

THE NWS IN TULSA IS ALSO CREATING A GRAPHICAL VERSION OF THE
HAZARDOUS WEATHER OUTLOOK WITH SOME ENHANCED TECHNICAL INFORMATION.  YOU
MAY ACCESS THIS GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT
HTTP://WWW.NWSTULSA.NOAA.GOV/HWO.HTML.