Damaging Winds in Arkansas, April 11, 2001

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
355 AM CDT WED APR 11 2001

RUNNING A BIT BEHIND THIS MORNING...

LARGE RAIN SHIELD WITH EMBEDDED SEVERE THUNDERSTORMS IS CURRENTLY
MOVING THROUGH ERN OK...WITH ADDITIONAL ACTIVITY FARTHER W ALONG
DRYLINE.  VAD WIND PROFILES SHOWING MARGINAL DIRECTION SHEAR...ALTHO
SPEED SHEAR IS IMPRESSIVE.  CHANCE OF SEVERE STORMS WILL CONTINUE
INTO THE MORNING...WITH ACTIVITY EXITING ERN EXTENT OF FORECAST AREA
14-16Z.  WILL USE RADAR FOR FINAL 1ST PERIOD POPS.

INTENSE 982MB SFC CYCLONE WILL LIFT INTO NE TODAY...WITH PRESSURE
GRADIENT TIGHTENING ACROSS THE AREA.  DEEP LAYERED MIXING WILL HELP
BRING DOWN GUSTY SWLY WINDS TO THE SFC...AND WILL GO WITH A WIND
ADVISORY FOR ALL ZONES TODAY.

MUCH DRIER LOW-LEVEL AIR WILL FILTER EWD LATER TODAY AND TONIGHT.
WINDS WILL SLACK OFF TONIGHT...SO THE STRING OF 5 RECORD HIGH LOWS
WILL END AT TULSA WITH MORE SEASONABLE TEMPS ON TAP.

REMAINDER OF WEEK LOOKS SEASONABLE AND DRY.

ZONAL FLOW WILL PERSIST THROUGH THE WEEKEND...WITH SEVERAL
FAST-MOVING/IMPOSSIBLE-TO-TIME WAVES PASSING ACROSS THE FORECAST
AREA.  AVN WANTS TO BRING LOW-LEVEL MOISTURE BACK ON SAT AHEAD OF
STRENGTHENING SFC LOW OVER WRN TX.  WILL KEEP LOW CHANCE POPS IN FOR
SAT AND SUN.

FCSTID = 18

PRELIM NUMBERS...
TUL   74  49  77  53 /  50   0   0  10
FSM   78  50  82  55 /  70   0   0  10
MLC   76  49  81  57 /  50   0   0  10
BVO   74  48  77  52 /  50   0   0  10
FYV   74  47  76  52 /  70   0   0  10
BYV   74  47  76  52 /  70   0   0  10
MIO   74  47  76  52 /  70   0   0  10
MKO   74  49  77  53 /  50   0   0  10
F10   74  49  77  53 /  50   0   0  10
HHW   76  51  81  58 /  60   0   0  10

.TSA...
AR...WIND ADVISORY FOR WEDNESDAY FOR ZONES ARZ001>002...ARZ010>011...
ARZ019>020...ARZ029.

OK...TORNADO WATCH UNTIL 800 AM CDT FOR ZONES
OKZ054>057...OKZ059>062...OKZ064>067...OKZ070>071...OKZ073.

WIND ADVISORY FOR WEDNESDAY FOR ZONES OKZ049...OKZ053>076.

ARZ001-002-010-011-019-020-029-OKZ049-053>076-121100-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
600 AM CDT WED APR 11 2001

...FEW SEVERE THUNDERSTORMS EXPECTED THIS MORNING...
...TORNADO WATCH FOR NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS THIS
MORNING...

EARLY THIS MORNING...A LINE OF SEVERE THUNDERSTORMS WAS MOVING
RAPIDLY ACROSS SOUTHEAST OKLAHOMA. A SECONDARY LINE OF STORMS WAS
APPROACHING NORTHEAST OKLAHOMA. THESE LINES OF THUNDERSTORMS WILL
SWEEP ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THROUGH THE
MORNING. DAMAGING WINDS WILL BE THE MAIN THREAT WITH THESE STORMS.

A SURFACE DRYLINE EXTENDED ACROSS CENTRAL OKLAHOMA...GENERALLY WEST
OF AN ENID TO OKLAHOMA CITY LINE. MEANWHILE AN INTENSE SURFACE LOW
PRESSURE WAS LOCATED IN EASTERN COLORADO WITH A FRONTAL BOUNDARY
EXTENDING THROUGH NORTHEAST KANSAS. THIS LOW PRESSURE WILL LIFT
NORTHEAST ACROSS NEBRASKA TODAY. SURFACE WINDS WILL BE VERY STRONG
TODAY OUT OF THE SOUTH...AND WILL SWITCH TO THE SOUTHWEST AS THE
DRYLINE APPROACHES LATER THIS MORNING.

.SPOTTER ACTIVATION...
SPOTTERS HAVE BEEN ACTIVATED IN EASTERN OKLAHOMA...AND MAY BE
ACTIVATED IN NORTHWEST ARKANSAS LATER THIS MORNING.

.DISCUSSION...
TWO MAIN AREAS WILL BE THE FOCUS FOR SEVERE WEATHER TODAY. THE FIRST
AREA IS GENERALLY SOUTH OF A TULSA TO JAY LINE. A SQUALL LINE WITH
EMBEDDED BOW ECHOES WILL MOVE ACROSS SOUTHEAST OKLAHOMA EARLY THIS
MORNING...WITH DAMAGING WINDS POSSIBLE. AREA PROFILERS SHOW STRONG
WINDS IN THE LOW LEVELS...RANGING FROM 40 TO 60 KNOTS. THE SHEAR IS
MAINLY UNIDIRECTIONAL WHICH WILL LIMIT THE THREAT OF TORNADOES.
HOWEVER...DOPPLER RADAR DATA HAS SHOWN ROTATION WITHIN STORMS ALONG
THE SQUALL LINE...SO TORNADOES WILL BE POSSIBLE THROUGH AT LEAST THE
MID MORNING. THE MAIN THREAT HOWEVER...WILL CONTINUE TO BE ON
DAMAGING STRAIGHT LINE WINDS. STRONG SURFACE WINDS OF 30 TO 40 MILES
AN HOUR HAVE BEEN COMMON THROUGH THE NIGHT ACROSS EASTERN OKLAHOMA...
AND WILL CONTINUE ACROSS THE ENTIRE AREA THROUGH THE DAY.

THE SECOND AREA OF CONCERN IS ACROSS NORTHEAST OKLAHOMA...AS
ANOTHER LINE OF THUNDERSTORMS CURRENTLY ACROSS CENTRAL KANSAS AND
NORTH CENTRAL OKLAHOMA APPROACHES. THE MAIN THREAT WITH THESE STORMS
WILL BE DAMAGING WINDS. THE AIRMASS ACROSS EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS REMAINS UNSTABLE...WITH LIFTED INDEX VALUES
RANGING FROM -4 TO -6 AND SURFACE BASED CAPES APPROACHING 2000 J/KG.

THREAT TABLE
VALID THROUGH 1200 UTC THURSDAY
AREA 1...SOUTH OF A TULSA TO JAY LINE
THUNDERSTORM PROBABILITY...100
SEVERE PROBABILITY IF STORMS OCCUR...70
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...30

THREAT AREAS DEFINE THE GREATEST RISK. PROBABILITIES ARE IN PERCENT.
SIGNIFICANT SEVERE IS DEFINED AS F1 OR GREATER WIND/TORNADO DAMAGE
AND/OR GOLF BALL SIZE HAIL OR LARGER.

.OTHER HAZARDS...
A WIND ADVISORY HAS BEEN ISSUED FOR THE ENTIRE AREA FOR TODAY.
PLEASE SEE THE LATEST /OKCNPWTUL/ FOR DETAILS. ALSO...THE STRONG
WINDS WILL CAUSE A VERY HIGH FIRE DANGER TODAY. PLEASE SEE
/OKCFWMTUL/ FOR THE LATEST INFORMATION ON THIS.

AN UPDATED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AROUND 1 PM.