FXUS64 KSHV 100924
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
324 AM CST THU DEC 10 2009
.SHORT TERM /TODAY THROUGH SATURDAY NIGHT/...
HIGH PRESSURE /CENTERED OVER EASTERN OKLAHOMA/ WAS IN CONTROL OF OUR
WEATHER EARLY THIS MORNING. EVEN WITH SOME CIRRUS ON THE
ANTICYCLONIC SIDE OF THE UPPER JET...TEMPERATURES WERE QUITE COLD.
READINGS RANGED FROM THE MIDDLE TEENS IN NORTHERN MCCURTAIN COUNTY
TO THE LOWER 30S IN AND AROUND LASALLE PARISH.
DRY WEATHER CONDITIONS ARE EXPECTED TO CONTINUE THROUGH TONIGHT
ACROSS MUCH OF THE FORECAST AREA. THE NEARLY ZONAL FLOW ALOFT
SHOULD BECOME INCREASINGLY SOUTHWEST OVER THE NEXT 24 HOURS...AS A
WEAK SHORTWAVE TROUGH MOVES ONSHORE THE CALIFORNIA COAST. THIS
SHOULD ALLOW WEAK PERTURBATIONS START TRAVERSING OUR AREA AS THE
SURFACE HIGH GRADUALLY SHIFTS EAST TOWARD THE TENNESSEE VALLEY.
ISENTROPIC UPGLIDE WILL LIKELY COMMECE AGAIN TONIGHT...MAINLY OVER
SOUTHWEST LOUISIANA AND SOUTHEAST TEXAS. THE UPGLIDE AREA IS
EXPECTED TO INCREASE ITS AREA OF INFLUENCE FRIDAY AS LOWER
CONDENSATION PRESSURE DEFICITS EXPAND NORTHWARD. SINCE IT SHOULD
TAKE SOME TIME TO OVERCOME THE REALLY DRY AIRMASS IN PLACE OVER THE
REGION...I FEEL THE RESULTING /SO-CALLED/ OVERRUNNING RAIN SHOULD
LARGELY HOLD OFF UNTIL FRIDAY AFTERNOON IN MANY PLACES. AT ANY
RATE...THE GREATEST COVERAGE OF PRECIPITATION SHOULD BE OVER MY
SOUTHERN TIER OF COUNTIES AND PARISHES...IN VICINITY OF SLIGHTLY
DEEPER MOISTURE.
THERE HAS BEEN SOME BRIEF DISCUSSION ON THE POSSIBILITY OF WINTRY
PRECIPITATION AT THE ONSET OF THIS EVENT...MAINLY OVER OUR NORTHERN
COUNTIES. BASED ON PARTIAL THICKNESS VALUES...IT APPEARS THE LAYERS
SHOULD WARM ABOVE CRITICAL VALUES FRIDAY MORNING /BEFORE
PRECIPITATION MOVES INTO THIS REGION. AS SUCH...AN ALL-LIQUID
FORECAST WILL BE MAINTAINED WITH THIS FORECAST PACKAGE.
THE POSSIBILITY FOR RAIN OVER THE FORECAST AREA WILL LIKELY CONTINUE
INTO SATURDAY...AS A WAVE OF LOW PRESSURE DEVELOPS AND MOVES ALONG A
BOUNDARY IN THE NORTHERN GULF OF MEXICO. RAIN SHOULD GRADUALLY END
FROM THE WEST SATURDAY NIGHT AS THE SURFACE LOW WEAKENS AND HEADS
TOWARD THE SOUTHEAST LOUISIANA COAST.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A BRIEF RETURN TO A SLIGHTLY DRIER AIRMASS IS EXPECTED TO RETURN
SUNDAY IN WAKE OF SATURDAY'S WAVE OF LOW PRESSURE. OUR EYES WILL
THEN SHIFT TO THE NEXT STORM SYSTEM SLATED TO AFFECT THE REGION. BY
SUNDAY...THIS SYSTEM SHOULD BE DEEPENING OVER THE WESTERN UNITED
STATES.
SURFACE HIGH PRESSURE SHOULD MOVE INTO THE WESTERN ATLANTIC AS THIS
SYSTEM QUICKLY MOVES EAST...AND PUSHES A COLD FRONT INTO THE CENTRAL
PLAINS. THE FRONT SHOULD MOVE INTO MY NORTHWESTERN COUNTIES BY
MONDAY MORNING...THEN SLOW AS IT MOVES ACROSS OUR AREA. A SECOND
SHORTWAVE TROUGH /EMBEDDED IN MORE OF THE SOUTHERN STREAM/ IS
FORECAST TO GIVE THE FRONT ANOTHER SHOVE...PUSHING THE FRONT OUR OF
OUR AREA EITHER LATE MONDAY NIGHT OR EARLY TUESDAY MORNING.
HIGH PRESSURE SHOULD RATHER QUICKLY BUILD INTO THE REGION FROM THE
NORTHWEST TUESDAY IN WAKE OF THE FRONT. RIGHT NOW...IT LOOKS LIKE
WE MAY EXPERIENCE VERY BREEZY CONDITIONS DUE TO A TIGHT PRESSURE
GRADIENT. IN ADDITION...STRONG LOW-LEVEL COLD AIR ADVECTION SHOULD
RESULT IN NOTICEABLY COOLER TEMPERATURES OVER THE REGION BEHIND THE
FRONT. THESE COOL TEMPERATUERS ARE EXPECTED TO CONTINUE INTO
MID-WEEK...AS HIGH PRESSURE SETTLES OVER THE FORECAST AREA. /21/
&&
.AVIATION...
NO AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HRS...AS VFR
CONDITIONS IN THIS POST-FRONTAL ARCTIC AIR MASS WILL CONTINUE WITH
MOST TERMINALS WITH A 10 DEGREE T/TD SPREAD ATTM. EXTENSIVE CIRRUS
CANOPY TIED TO SOUTHERN BRANCH JET EXTENDS FROM BAJA...RIDGING OVER
CENTRAL TEXAS...THEN FLATTENING INTO THE BASE OF THE LONG WAVE
TROUGH BASE...CROSSING THE MS RIVER ATTM. I-30 MAY KEEP SKC FOR THE
DAY AHEAD...BUT IN ADDITION TO THE CIRRUS ELSEWHERE...THERE IS
ALREADY SOME SCT MID DECK OVER KATT/KCLL/AND KDKR. SFC WINDS WILL
BE VEERING FROM NORTH TO NE...LESS THAN 10 KTS. OUTLOOK IS FOR VFR
TO CONTINUE BEYOND THIS CYCLE BEFORE STRONG OVERRUNNING BEGINS FROM
THE SW FRIDAY AFTERNOON...WITH CIGS LOWERING DURING THE OVERNIGHT.
/24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 44 32 46 38 50 / 0 10 20 60 50
MLU 44 30 45 38 47 / 0 10 20 60 70
DEQ 39 25 46 34 49 / 0 0 10 20 30
TXK 41 28 45 35 49 / 0 10 20 40 40
ELD 43 29 46 35 47 / 0 10 20 40 60
TYR 45 32 46 39 53 / 0 10 20 60 40
GGG 45 32 47 38 52 / 0 10 20 60 50
LFK 48 34 48 42 53 / 0 10 40 70 50
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
PUBLIC FORECASTER... D. BUTTS
AVIATION/FIRE WEATHER FORECASTER... CHATELAIN
