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000
FXUS64 KSHV 090418
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1018 PM CST SUN DEC 8 2013

.DISCUSSION...

MADE A FEW CHANGES TO THE ZONES FOR TONIGHT BY ADDING PATCHY FOG
AND PATCHY FREEZING FOG WHERE TEMPERATURES MAY DIP TO NEAR
FREEZING THROUGH TONIGHT AND INTO THE EARLY MORNING HOURS ON
MONDAY. MODIFIED THE WINDS AND DEW POINTS BASED ON CURRENT TRENDS. /06/

&&

.AVIATION...

IFR AND OCCASIONAL LIFR CONDITIONS ARE EXPECTED THROUGH THE
OVERNIGHT AND EARLY MORNING HOURS. VARIABLE WINDS SHOULD BECOME NLY
AROUND 5 KTS AS A COLD FRONT MOVES ACROSS THE AREA EARLY IN THE TAF
PERIOD. FREEZING FOG IS LIKELY ACROSS MUCH OF THE AREA BUT THE
SLIGHT INCREASE IN WIND SPEEDS BEHIND THE FRONT SHOULD KEEP THE
BOUNDARY LAYER MIXED ENOUGH TO KEEP VSBYS FROM FALLING BELOW 2SM.
CIGS SHOULD SLOWLY IMPROVE DURING THE DAY MONDAY AS LOW LVL DRY AIR
FILTERS IN FROM THE N BEFORE LOWERING BACK INTO MVFR/IFR AFTER
10/00Z. /09/

&&

.PREV DISCUSSION... /ISSUED 358 PM CST SUN DEC 8 2013/

DISCUSSION...
SCATTERED AREAS OF -RA/-DZ CONTINUE ACROSS PORTIONS OF EXTREME ERN
TX/N LA/SCNTRL AR...AS STRONG OVERRUNING CONTINUES ATOP THE
SHALLOW ARCTIC AIR MASS IN PLACE. DRIER AIR NOTED ON THE WATER
VAPOR IMAGERY HAS BEGUN TO ENTRAIN ENE INTO THE LOWER MS VALLEY
THIS AFTERNOON...AND WILL CONTINUE TONIGHT AS THE WEAK PVA ALOFT
SHIFTS E AWAY FROM THE REGION. THE OVERRUNNING SHOULD ALSO WEAKEN
THIS EVENING AS LOW LEVEL DRY AIR BEGINS TO SPREAD E ATOP THIS
SHALLOW AIR MASS. THE SHORT TERM PROGS HAVE BEEN A LITTLE
AMBITIOUS IN THE EWD EROSION OF THE STRATUS BAK GENERALLY ALONG/E
OF THE I-35 CORRIDOR VIA RECENT VISIBLE SATELLITE IMAGERY...BUT
THE PROGS DO INDICATE A WEAK SFC TROUGH TRAVERSING SE INTO THE
REGION AFTER 06Z MONDAY WHICH MAY ALLOW FOR SOME BREAKS IN THE
STRATUS. SHOULD THIS OCCUR...AND GIVEN THE LOW TEMP/DEWPOINT
DEPRESSIONS...CAN/T RULE OUT PATCHY FZFG DEVELOPING OVER PORTIONS
OF E TX/SE OK/SW AR LATE. HAVE MADE MENTION OF THIS IN THE
FORECAST...ALTHOUGH WINDS BEHIND THE SFC TROUGH MAY KEEP THE AIR
MIXED ENOUGH THAT MAY DETER ANY FZFG DEVELOPMENT.

SOME AREAS OF THE REGION MAY ACTUALLY SEE SUN MONDAY IF THE LOW
STRATUS CLEARS BY MIDDAY...BUT OVERRUNNING WILL INCREASE ONCE
AGAIN BY LATE AFTERNOON WELL AHEAD OF THE NEXT SHORTWAVE...NOW
DIGGING INTO NV/UT...AS IT BEGINS TO TRANSLATE E INTO THE
CNTRL/SRN PLAINS. COULD SEE AREAS OF -RA DEVELOP DURING THE
AFTERNOON OVER MUCH OF THE REGION...WITH THE COLUMN BEGINNING TO
SATURATE QUICKLY BY EARLY EVENING AS LARGE SCALE FORCING INCREASES
AHEAD OF THE TROUGH. AS WAS THE CASE TODAY...MOST OF THE -RA
SHOULD BE CONFINED TO EXTREME ERN TX/N LA...ALTHOUGH THERE WILL BE
A PERIOD OF A WINTRY MIX AGAIN MONDAY NIGHT MAINLY ALONG AND N OF
THE I-30 CORRIDOR. NOT EXPECTING ANY ICE ACCUMULATION AS WHAT
AVAILABLE MOISTURE IS QUICKLY ERODED AS LOW LEVEL RIDGING BEGINS
TO BUILD S AHEAD OF CANADIAN HIGH PRESSURE OVER THE SRN PLAINS.

SHOULD ACTUALLY SEE A LITTLE MORE OF THAT BRIGHT BALL OF FIRE IN
THE SKY BY TUESDAY AS THE DEEP LEVEL DRIER AIR IS ADVECTED SE INTO
THE REGION. TEMPS SHOULD REMAIN BELOW NORMAL THOUGH THROUGH LATE
WEEK AS THIS COLD AIR REINFORCEMENT IS ENHANCED BY ANY RESIDUAL
ICE/SNOW STILL IN PLACE OVER OK/AR. DRY CONDITIONS WILL CONTINUE
THROUGH LATE WEEK...BEFORE MORE RAIN MOVES BACK INTO THE REGION BY
FRIDAY AS A CLOSED LOW IS NUDGED E ACROSS THE DESERT SW AND
ABSORBED INTO THE WRLY FLOW AHEAD OF A SECOND UPPER TROUGH THAT
WILL DIG SE INTO THE INTERMOUNTAIN W. GIVEN CONSISTENCY IN THE
GFS/ECMWF THE LAST FEW DAYS...HAVE INCREASED POPS TO HIGH CHANCE
FRIDAY/FRIDAY NIGHT...ALTHOUGH THE GFS HAS BECOME MUCH WETTER FOR
THE ERN HALF OF THE AREA SATURDAY AS IT IS FARTHER S WITH THE
TROUGH DIGGING INTO NRN MX SATURDAY...MAINTAINING SW FLOW ALOFT
FROM SE TX INTO THE LOWER/MID MS VALLEY. ATTM...PREFER THE MORE
PROGRESSIVE ECMWF AS THIS HAS BEEN CONSISTENT IN RECENT
DAYS...DIMINISHING POPS FROM W TO E SATURDAY.

PRELIMS TO FOLLOW BELOW...

15

AVIATION...
POCKETS OF LIGHT RAIN AND DRIZZLE CONTINUE TO AFFECT THE SHV/ELD
TERMINALS THIS AFTERNOON...LIKELY SEEING SOME OF THE PRECIPITATION
FREEZING ON CONTACT AT ELD. VSBYS HAVE ALSO BEEN REDUCED TO MVFR/IFR
AT TIMES WITH THIS VERY LIGHT PRECIPITATION WHICH WILL CONTINUE TO
WORK EWRD AND EVENTUALLY AFFECT MLU EARLY IN THE 00Z TAF PERIOD BUT
WILL QUICKLY EXIT BY AROUND 03Z. ELSEWHERE...MVFR/IFR CIGS HAVE HELD
ON ALL AFTERNOON AND WILL PERSIST THROUGH THE OVERNIGHT HOURS AND
MOST OF MONDAY MORNING...RANGING FROM A FEW HND FEET TO NEAR 1KFT.
LIGHT AND VARIABLE WINDS THIS AFTERNOON WILL SHIFT BACK NORTH WITH
THE PASSAGE OF A SHORT WAVE LATER THIS EVENING WITH SPEEDS RANGING
FROM 3-8 KTS. IMPROVING CIGS WILL FINALLY COME BY MIDDAY ON MONDAY
WITH VFR CONDITIONS LIKELY RETURNING AREA WIDE BY 09/18Z. /19/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  32  48  33  45  29 /  10  20  40  10   0
MLU  35  47  35  44  28 /  40  20  50  10   0
DEQ  26  43  26  42  24 /  10  10  20  10   0
TXK  28  44  29  43  27 /  10  20  30  10   0
ELD  28  45  29  43  25 /  10  20  40  10   0
TYR  28  45  29  44  28 /  10  20  20  10   0
GGG  29  47  30  45  28 /  10  20  30  10   0
LFK  33  49  35  47  31 /  20  20  30  10  10

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&

$$

06/09