FXUS64 KSHV 040442
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1042 PM CST THU DEC 3 2009
.DISCUSSION...
BUSY EVENING...AS SNOWFALL EVENT APPEARS TO BE TAKING SHAPE WITHIN
THE NEXT 16 HRS ACROSS THE REGION. REINFORCING ARCTIC HIGH
PRESSURE CONTINUES TO BUILD S ACROSS THE REGION THIS
EVENING...WITH VERY DRY AIR NOTED EARLIER THIS EVENING ON RADAR
CONTINUES TO SEEP S ACROSS THE I-20 CORRIDOR OF E TX/NW LA.
MEANWHILE...HAVE SEEN THE SUBTROPICAL JET ACCELERATE NE ACROSS THE
TX COASTAL BEND INTO CNTRL LA/MS THIS EVENING...AHEAD OF THE NEXT
LONGWAVE TROUGH THAT IS NOW ROTATING SE THROUGH THE 4 CORNERS
REGION ATTM. ALREADY SEEING EXTENSIVE AC FIELD AHEAD OF THE TROUGH
AXIS ACROSS MUCH OF NCNTRL TX/SE OK/SW AR...WITH VERY LIGHT
RETURNS NOTED ON THE MOSAIC 88-D/S. HOWEVER...GIVEN THE VERY DRY
AIR NOTED ON THE REGION 00Z RAOBS BELOW 8KFT...NONE OF THIS HAS
YET TO REACH THE GROUND...PER THE LATEST SFC OBS. GIVEN THE
REINFORCING COLDER/DRIER AIR SHIFTING SWD ACROSS THE REGION
TONIGHT...BELIEVE THIS LIGHT PRECIP. WILL REMAIN ELEVATED...AND
WILL NOT INTRODUCE POPS ATTM.
FOCUS WILL TURN TO OUR W FRIDAY MORNING...AS AREAS OF A WINTRY MIX
DEVELOP ACROSS THE TX HILL COUNTRY...AND QUICKLY SHIFT E INTO DEEP
E TX/NCNTRL LA FRIDAY AFTERNOON/EVENING. MAX TEMPS WILL STRUGGLE
TO REACH THE LOWER 40S BY MIDDAY...WITH TEMPS FALLING DURING THE
AFTERNOON DUE TO EVAPORATIVE COOLING AS THE PRECIP. COOLS THE AIR
COLUMN. FREEZING LEVELS WILL EVENTUALLY FALL AS A RESULT...WITH
THE RA/SN MIX CHANGING OVER TO ALL SNOW BY MID AFTERNOON ACROSS
DEEP E TX/TOLEDO BEND COUNTRY...AND OVER NCNTRL LA BY SUNSET. LOW
LEVEL CYCLOGENESIS WILL REMAIN A HUNDRED PLUS MILES OFFSHORE THE
SW TX/SW LA COAST FRIDAY AFTERNOON...WITH BEST FORCING EXPECTED TO
REMAIN JUST S OF THE AREA ACROSS SE TX/SW LA. HOWEVER...WILL
LIKELY SEE SOME ACCUMULATING SNOW FRIDAY AFTERNOON/EVENING...AND
HAVE ISSUED A WINTER WX ADVISORY FOR SNOW FOR AREAS S OF A
JACKSONVILLE AND CENTER TX...TO CONVERSE...DODSON...AND COLUMBIA
LA LINE. SNOWFALL ACCUMULATIONS OF A HALF INCH TO AN INCH IS
EXPECTED IN THE ADVISORY AREA...WITH ISOLATED TOTALS NEAR TWO
INCHES POSSIBLE MAINLY S OF A OCH...TO IER AND OLLA LINE. COULD
EVEN SEE A DUSTING OF SNOW ALONG THE I-20 CORRIDOR OF E TX/N
LA...WITH AREAS S OF THE INTERSTATE POSSIBLE SEEING BLACK ICE
CONDITIONS OVERNIGHT AS ANY RESIDUAL MOISTURE QUICKLY FREEZES AS
TEMPS FALL BELOW FREEZING BY MID/LATE EVENING.
SNOWFALL SHOULD QUICKLY END FROM W TO E FRIDAY EVENING...WITH
SKIES CLEARING OVERNIGHT...RESULTING IN THE COLDEST TEMPS OF THE
SEASON SATURDAY MORNING. ADDITIONAL FREEZE WARNINGS WILL BE NEEDED
TO COVER THE REMAINDER OF THE AREA THAT HAS YET TO FREEZE...AND
WILL ALLOW THE MID SHIFT TO COVER THIS WITH THE MORNING ZONE
ISSUANCE.
UPDATE SUITE OF PRODUCTS ARE ALREADY AVAILABLE...GRIDS WILL BE
AVAILABLE SHORTLY.
15
&&
.AVIATION...
VFR CONDITIONS ACROSS THE REGION THIS EVENING WITH A LOW SC DECK
STILL OBSERVED AT THE MLU TERMINAL BUT THIS SHOULD BE TEMPORARY. OF
MORE IMPORTANCE IS THE AC DECK OBSERVED ACROSS SE OK EXTENDING INTO
NORTH CENTRAL AND CENTRAL TEXAS. THIS DECK PRECEDES THE DEVELOPING
UPPER LEVEL TROUGH AXIS THAT WILL BE QUICKLY COMING OUR WAY DURING
THE DAY FRIDAY. HAVE CEILINGS COMING IN AT 8-10KFT THROUGH THE NIGHT
ACROSS OUR NE TX TERMINALS AND PREVAILING THIS CEILING THROUGH MUCH
OF THE DAY ON FRIDAY. COLUMN WILL LIKELY SATURATE FROM THE TOP DOWN
AS LIFT BEGINS IN EARNEST ACROSS CENTRAL TEXAS FRIDAY AFTERNOON.
EXPECTING SNOW TO BEGIN MOVING INTO SE/EAST CENTRAL TEXAS BY LATE
FRIDAY AFTERNOON INTO FRIDAY EVENING AND HAVE MADE MENTION OF THIS
AT THE LFK TERMINAL. CANNOT RULE OUT SOME FLURRIES NEAR THE I-20
CORRIDOR WHICH WOULD INCLUDE THE TYR/GGG/SHV AND EVENTUALLY...THE
MLU TERMINALS BUT DO NOT THINK CHANCES WARRANT A TAF MENTION ATTM. /13/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 32 42 25 50 32 / 10 30 20 0 10
MLU 32 44 26 49 27 / 10 30 40 0 10
DEQ 26 42 18 50 25 / 10 10 10 0 10
TXK 28 42 25 51 34 / 10 20 10 0 10
ELD 28 40 24 51 25 / 10 20 20 0 10
TYR 31 40 24 52 37 / 10 30 20 0 10
GGG 30 40 24 52 35 / 10 30 20 0 10
LFK 34 41 24 52 35 / 10 60 40 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FREEZE WARNING UNTIL 8 AM CST FRIDAY FOR THE FOLLOWING ZONES:
ARZ070.
LA...FREEZE WARNING UNTIL 8 AM CST FRIDAY FOR THE FOLLOWING ZONES:
LAZ001>006-010>014.
WINTER WEATHER ADVISORY FROM 3 PM FRIDAY TO MIDNIGHT CST FRIDAY
NIGHT FOR THE FOLLOWING ZONES: LAZ018>022.
WINTER WEATHER ADVISORY FROM NOON TO 9 PM CST FRIDAY FOR THE
FOLLOWING ZONES: LAZ017.
OK...NONE.
TX...FREEZE WARNING UNTIL 8 AM CST FRIDAY FOR THE FOLLOWING ZONES:
TXZ097-112-126-136>138-149>153.
WINTER WEATHER ADVISORY FROM NOON TO 9 PM CST FRIDAY FOR THE
FOLLOWING ZONES: TXZ149-152-153-165>167.
&&
$$
15/13
