FXUS64 KSHV 011003
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
403 AM CST TUE DEC 1 2009
.DISCUSSION...
SIGNIFICANTLY COOLER TEMPS ON THE WAY...AS COLD CORE UPPER
LOW SPINS OVER NRN MEXICO...SRN AZ/NM EARLY THIS MORNING. WV
IMAGERY SHOWS MID/UPPER LEVELS OF THE ATMOSPHERE WITH ABUNDANT
PACIFIC MOISTURE PIPING IN ACROSS SRN AND ERN TX...INTO LA...S
AR...AND SE OK. FRONT THAT MOVED THROUGH THE REGION EARLIER IN THE
WEEK NOW DRAPED ACROSS THE NRN GULF COAST. WITH WINDS AT THE SFC
REMAINING OUT OF THE NE...AND THE UPPER LOW APPROACHING FROM THE
W...THIS SCENARIO IS SHAPING UP AS A CLASSIC ISENTROPIC/OVERRUNNING
EVENT. MODELS SEEM A BIT SLUGGISH TO BEGIN PRECIP OVER THE
REGION...SO WENT AHEAD OF GUIDANCE BY 3-6 HRS. ONE TO THREE INCHES
OF RAIN WILL BE POSSIBLE ALONG THE TRACK OF THE UPPER LOW...AS
FORECAST PW VALUES ARE NEAR 1.5 INCHES. FLOODING OF LOW LYING AND
FLOOD PRONE AREAS MAY BE POSSIBLE...ESPECIALLY CONSIDERING THE ONE
TO TWO INCHES THAT FELL SUNDAY NIGHT ACROSS PARTS OF THE AREA.
SOME UNCERTAINTY EXISTS AS TO JUST HOW COLD THIS LOW WILL BE AS IT
PASSES THROUGH THE REGION. WITH THIS IN MIND...THE POSSIBILITY
EXISTS FOR SOME SNOW FLURRIES MAINLY ALONG AND NORTH OF I-30
DURING THE WEDNESDAY AFTERNOON TIMEFRAME. HOWEVER IF FLURRIES DO
OCCUR...NO ACCUMULATIONS ARE EXPECTED...AS SFC/GROUND TEMPS SHOULD
REMAIN ABOVE FREEZING. LEFT MENTION OF SNOW OUT OF THE GRIDS FOR
NOW...AND WILL LET SUBSEQUENT SHIFTS RE- EVALUATE AS THE EVENT
NEARS.
PRECIP WILL FINALLY PUSH OUT OF THE REGION BY THURSDAY
MORNING...AS STRONG SFC HIGH PRESSURE AND ARCTIC AIR MASS BEGINS
TO BUILD IN. TEMPS THU NIGHT/FRI MORN WILL PLUMMET...WITH CLEAR
SKIES...LIGHT WINDS...AND DRY HIGH PRESSURE OVERHEAD.
BY FRIDAY MORNING...A WEAK UPPER LEVEL DISTURBANCE BEGINS TO PUSH
THROUGH THE REGION. MOISTURE RETURN IS QUESTIONABLE WITH THIS
SYSTEM...BUT ALL INDICATIONS ARE THAT A SUFFICIENTLY COLD AIR MASS
WILL BE IN PLACE FOR SNOW. AS WITH THE POTENTIAL FLURRIES FOR
WEDNESDAY AFTERNOON...WILL LEAVE MENTION OF SNOW OUT OF THE GRIDS
FOR FRIDAY AFTERNOON/EVENING. AS SATURDAY MORNING ROLLS
AROUND...SFC HIGH PRESSURE ONCE AGAIN REGAINS ITS STRONGHOLD
THROUGH THE REMAINDER OF THE WEEKEND. MODELS SUGGESTING A WEAK
DISTURBANCE ON TAP FOR THE FIRST PART OF NEXT WORK WEEK...BUT AS
THE TREND HAS BEEN...MODELS SOMEWHAT OUT OF SYNC WITH EACH OTHER. /12/
&&
.AVIATION...
AN UPPER-LEVEL LOW CONTINUES SPINNING ACROSS NORTHERN MEXICO THIS
MORNING AND HAS BEGUN TO EDGE OVER WEST TX. WATER VAPOR IMAGERY SHOWS
ABUNDANT MID AND UPPER LEVEL MOISTURE FROM THE RIO GRANDE...ACROSS
THE COASTAL BEND AND OVER THE MID SOUTH. VFR CIGS WILL PERSIST MUCH
IF NOT ALL DAY WITH MVFR BCMG LIKELY SOON AFTER SUNSET FROM SW TO NE
ACROSS THE CWA AS THE RAIN INCREASES IN COVERAGE AND INTENSITY. OUR
NE SFC WINDS WILL VEER A BIT TO EAST KEEPING LESS THAN 10 KTS. THE
NE FLOW EXTENDS FROM THE SFC TO ABOUT 9KFT...10-20 KTS ATTM...BUT
WILL QUICKLY SHALLOW AND VEER TO SE BY 18Z. WE WILL KEEP OVERRUNNING
NE FLOW ON THE SFC...BUT BCMG SW ALOFT BY THIS TIME TOMORROW. A
STRONG SFC COLD FRONT WILL SCOUR THE WEATHER DURING WEDNESDAY. /24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 52 43 50 33 50 / 40 80 60 10 0
MLU 50 42 48 35 50 / 30 80 80 20 0
DEQ 53 39 44 29 47 / 20 80 80 20 0
TXK 52 42 47 32 48 / 20 80 80 10 0
ELD 51 41 46 32 49 / 20 80 80 20 0
TYR 51 40 50 32 49 / 50 90 50 10 0
GGG 51 40 50 33 50 / 50 80 50 10 0
LFK 50 41 51 35 53 / 60 90 40 10 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
12/24
