Tornado Warning 57, NWS Little Rock, AR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
200 PM CST FRI DEC 7 2001

.SHORT TERM...MODELS IN VERY GOOD AGREEMENT THIS AFTERNOON WITH ONLY
MINOR DIFFERENCES NOTED THOUGH 60 HOURS. MODELS ARE ALSO CONSISTENT
WITH SLOWING DOWN THE LARGE SCALE FEATURES EVEN MORE SO RUN TO RUN
CONSISTENCY REMAINS GOOD. WITH NO GLARING DIFFERENCES TO DISTINGUISH
BETWEEN THE MODELS...A BLEND OF THEM SEEMS REASONABLE.

WATER VAPOR IMAGERY CONTINUES TO SHOW PLUME OF MOISTURE STRETCHING
FROM THE EASTERN PACIFIC OVER THE MID SOUTH TO THE EAST COAST.
SURFACE BOUNDARY REMAINS STALLED OUT ACROSS THE CENTRAL PART OF THE
STATE AS WIND FLOW ALOFT REMAINS PARALLEL TO IT. FRONT IS ILL
DEFINED WITH A DROP IN DEW POINTS REALLY THE ONLY WAY TO IDENTIFY
IT. FRONT SEEMS TO BE LOCATED FROM NORTH OF RUSSELLVILLE TO NORTH OF
JONESBORO. WEAK IMPULSE RIDING ALONG THIS FRONT CONTINUES TO
GENERATE SHOWERS AND STORMS...MAINLY OVER EASTERN PARTS OF THE
STATE. MUCH COOLER AIR OFF TO THE NORTH WILL BRING MUCH COOLER AND
DRIER AIR TO THE AREA ON SATURDAY.

BEFORE THAT TRANSITION...SURFACE LOW PRESSURE CONTINUES TO GET ITS
ACT TOGETHER OVER SOUTHERN OKLAHOMA. THIS LOW WILL TRACK ALONG THE
FRONT AND INTO WESTERN ARKANSAS BY LATE AFTERNOON. THE LOW WILL MOVE
NORTHEAST OVERNIGHT AND INTO NORTHERN TENN BY MORNING. CROSS
SECTIONS SHOW GOOD LOW LEVEL MOISTURE AND IMPRESSIVE LIFT ALONG WITH
HIGH PRECIPITABLE WATER IN PLACE OVERNIGHT. PREVIOUS RUNS WERE
CONFINING THE PRECIP TO MAINLY SOUTHERN ARKANSAS BUT BELIEVE IT WILL
BE A STATEWIDE EVENT WITH HIGHER AMOUNTS TO THE SOUTH INSTEAD. BEST
DYNAMICS OCCUR OVERNIGHT SO LIKELY POPS WILL BE INTRODUCED WITH
CLEARING MOVING FROM NORTHWEST TO SOUTHEAST SATURDAY. WILL HOLD ONTO
MINIMAL POPS EARLY ON SATURDAY OVER THE SOUTH UNTIL FRONT CLEARS THE
AREA. THE MUCH COOLER AIR WILL THEN BEGIN TO SPILL OVER THE AREA AS
NORTHWEST FLOW GETS ESTABLISHED. PRESSURE GRADIENT TIGHTENS SO WILL
CONTINUE TO MENTION BREEZY IN THE FORECAST. HIGH PRESSURE WILL THEN
BUILD OVER THE AREA SATURDAY AND INTO SUNDAY. THICKNESS VALUES DROP
SIGNIFICANTLY OVER THE WEEKEND AS STRONG H5 TROF SWINGS THROUGH. AVN
TEMPS SEEM MORE REASONABLE AND WILL GENERALLY BE FOLLOWED.

.EXTENDED...MODELS IN FAIRLY GOOD AGREEMENT WITH HIGH PRESSURE
CONTINUING INTO TUESDAY BEFORE THE NEXT SYSTEM BEARS DOWN FOR
WEDNESDAY AND THURSDAY. MODELS SWING A TROF AND ASSOCIATED SURFACE
FRONT THROUGH THE AREA LATE WEDNESDAY WITH STRENGTH AND TIMING
DIFFERENCES GREAT ENOUGH TO CAUSE LOW CONFIDENCE. WILL SIMPLY
BROADBRUSH RAIN AND THUNDERSTORMS FOR BOTH DAYS 6 AND 7 AND HOPE THE
MODELS COME INTO BETTER AGREEMENT. FRM NUMBERS SEEM REASONABLE.

56

.LZK...NONE