Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 050534
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1134 PM CST WED MAR 4 2015

.AVIATION...
PRECIP BEGINNING TO CHANGE OVER TO RAIN/SLEET MIX AT I-20 TERMINAL
SITES...WITH FRZG RAIN/SLEET MIX AT KTXK AND KELD. WITH INCREASING
POCKETS OF CONVECTIONS...CONCERN FOR RAPID ICE ACCUMULATIONS ONCE
SLOWLY FALLING TEMPS REACH FRZG MARK. PRECIP STILL VERY LGT AT
KMLU...AND PRECIP WILL REMAIN LIQUID RAIN MOST OR ALL NIGHT AT
KLFK WITH TEMPS STILL IN 40S. CIGS AND VSBYS TO REMAIN VRBL...AS
WILL PRECIP RATES...BUT WILL PREDOMINATE CIGS AT LOW MVFR CAT. NORTH
WINDS 15 TO 20 KTS OVERNIGHT ALL TERMINALS...AND WILL ONLY
DECREASE GRADUALLY DURG THE DAY THURSDAY... BEFORE BECMG LGT VRBL
AFTER 06/00Z. PRECIP ENDING 05/13-16Z AT MOST TERMINALS...ADN
BECMG VFR SKC BTWN 05/18-22Z./VII/.

&&

.PREV DISCUSSION... /ISSUED 954 PM CST WED MAR 4 2015/

DISCUSSION...

WILL NOT BE UPDATING THE FORECAST SINCE IT SEEMS TO BE IN LINE
WITH WHAT IS EXPECTED. HAVE REPORTS OF SLEET MIXED IN WITH THE
RAIN OVER MUCH OF SOUTHWEST AND SOUTH CENTRAL ARKANSAS...ALONG
WITH NORTHERN PARTS OF EAST AND NORTHEAST TEXAS...AND ALONG THE
ARKANSAS/LOUISIANA BORDER. SUSPECT A MIX OF FREEZING RAIN AND
SLEET OVER SOUTHEAST OKLAHOMA WITH TEMPERATURES NEAR AND BELOW
FREEZING. /06/

PREV DISCUSSION... /ISSUED 444 PM CST WED MAR 4 2015/

DISCUSSION...
THE ARCTIC COLD FRONT IS MOVING INTO DEEP EAST TEXAS AND NORTH
CENTRAL LOUISIANA. MOS WAS RIGHT ON AT MCALESTER AT 18Z...BUT NAM
WAS COLDER BY 2 DEGREES. IT IS HARD TO IGNORE ACTUAL OBS WHICH ARE
NOW FREEZING OVER ALL OF OKLAHOMA AND THE NORTHERN THIRD OF
ARKANSAS. SO KEEP AN EYE ON THE FRONT DOOR AND THE BACK DOOR. THE
SURFACE COLD FRONT WAS AHEAD OF MODEL GUIDANCE BY ALMOST TWO
HOURS. AS SUCH...THE ENTIRE SPECTRUM OF FALLING TEMPERATURES IS OR
MAYBE ON A SLIGHTLY FASTER PACE. ALSO...THE VAD WIND PROFILER AT
FORT SMITH AND NORMAN WAS UP TO 5KFT OF COLD AIR DEPTH A COUPLE OF
HOURS AGO. SO...NO CHANGES TO PREVIOUS WINTER STORM WARNING ASIDE FROM
EXTENDING OUT IN TIME TO NOON. THE WINTER WEATHER ADVISORY HAS A
TAIL SECTION NOW OVER NORTH CENTRAL LA FOR A BIT LONGER WITH
FREEZING TEMPERATURES POSSIBLE PAST NOON...TO NEAR MID AFTERNOON
WITH WHAT EVER REMAINS BACK TO JUST LIGHT RAIN.

ICE ACCUMULATIONS WILL VARY GREATLY OVER BOTH THE WARNING AND
ADVISORY IF POCKETS OF SLEET EMERGE ON TOP OF LIGHT FREEZING RAIN.
THE BIG QUESTION IS HOW LONG WILL IT TAKE FOR GROUND TEMPS TO
CHILL ENOUGH TO CAUSE PROBLEMS...THEY MAY NOT EVER SOUTH OF I-20. THE
RAIN TODAY WILL HELP THE COLD PENETRATE...BUT WE WENT FROM MID 40S
TWO DAYS AGO TO 55 THIS AFTERNOON AT LEAST FOR SHREVEPORT. SOIL
TEMPS NORTH OF I-30 ARE COLDER AND HAVE REMAINED COLDER WITH MUCH
LESS WARM AIR OVER THE LAST DAY OR TWO. ROADS MAY SEE ISSUES AND
ELEVATED STRUCTURE IS IN FOR IT WITH PERHAPS IMPOSSIBLE TRAVEL BY
DAYBREAK. HOWEVER...IT IS LIKELY THAT SOUTH OF I-30...MOST ROADS
MAY HAVE ENOUGH RESIDUAL HEAT TO MELT FROM BELOW KEEPING A SLUSH
PRESENT COMPARED TO FROZEN ICE. OF COURSE BRIDGES AND OVERPASSES
WILL ACCUMULATE ANYWHERE NORTH OF THE FREEZING LINE AS IT
PENETRATES SOUTHWARD ACROSS THE CWA. SLEET CAN FALL EVEN WITH AIR
TEMPERATURES ABOVE FREEZING...WHICH WILL HELP LOWER THAT AIR...AT
LEAST THAT IS WHAT THE NAM LIKES. AT THIS TIME...WE HAVE SEEN PATCHY
UP AND SNOW KNOCKING ON THE DOOR AT PARIS TX AND JUST NORTH OF
LITTLE ROCK AT THIS TIME. AS SUCH WE HAVE LEFT THE START TIMES ON
THE PRODUCTS AS IS WITH SUCH UNCERTAINTY. ALSO...KEEP IN MIND
NORTHERN PARTS OF COUNTIES AND PARISHES WILL BE AFFECTED PERHAPS
HOURS SOONER THAN SOUTHERN PARTS. AND CONDITIONS WILL BE WORSE
WITH ICE IN SHELTERED VALLEYS COMPARED TO UP ON WINDY RIDGES...SO
BETTER TO ERR ON THE SIDE OF CAUTION AND JUST HAVE A LOOK SEE IN
THE MORNING AND GET A GOOD CHECK OF THE ACTUAL AIR TEMPERATURE
BEFORE HEADING OUT.

LASTLY...KEEP IN MIND THE COLDEST AIR WILL ONLY REACH THE SOUTHERN
TIER OF OUR CWA AROUND DAYBREAK AND ESPECIALLY INTO THE MID
MORNING HOURS. RAIN MAY WILL TRANSITION LATE FOR THE SCHOOL DAY
ANYWHERE SOUTH OF I-20...IT IS JUST TOO UNPREDICTABLE CONSIDERING
EVAPORATIONAL COOLING THAT IS NOT MODELED WELL. TO NOTE...THIS
EVENT IS NOT LIKE THE LAST 3 DAY PERIOD OF ICE AND
SNOW...ESPECIALLY CONSIDERING A 15 DEGREE WARMER SOIL TO START.

AS IT TURNS OUT THIS MAY BE WINTERS LAST GASP FOR SUCH ON A WIDE
SPREAD SCALE WITH ICE. OF COURSE SNOW CAN HAPPEN UNDER ANY CLOSED
LOW EVEN INTO APRIL. IN THE SHORT TERM WE ARE IN FOR SOME MORE
VERY COLD AIR IN THE WAKE OF THE CLOUDS WITH A POSSIBLE HARD
FREEZE IN A SPOT OR TWO TOMORROW NIGHT AND STILL VERY COLD FOR
THIS TIME OF YEAR ON THE HIGH END AS WELL. LITTLE CHANGE TO THE
EXTENDED PORTION OF THE PERIOD WITH MODELS ON THE FENCE WITH QPF
HALF IN AND HALF OUT OF OUR CWA. /24/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  29  36  23  44  27 /  90  50  10  10  10
MLU  28  32  19  40  22 /  90  70  10  10  10
DEQ  25  37  19  44  19 /  90  10  10  10  10
TXK  25  34  20  43  25 /  90  20  10  10  10
ELD  25  35  17  40  21 /  90  50  10  10  10
TYR  30  37  24  46  28 /  90  20  10  10  10
GGG  29  37  23  45  25 /  90  50  10  10  10
LFK  32  39  25  50  30 /  90  50  10  10  10

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...LAKE WIND ADVISORY UNTIL 6 AM CST THURSDAY FOR THE FOLLOWING
     ZONES: ARZ050-051-059>061-070>073.

     WINTER STORM WARNING UNTIL NOON CST THURSDAY FOR THE FOLLOWING
     ZONES: ARZ050-051-059>061-070>073.

LA...LAKE WIND ADVISORY UNTIL 6 AM CST THURSDAY FOR THE FOLLOWING
     ZONES: LAZ001>006-010>014-017>022.

     WINTER STORM WARNING UNTIL NOON CST THURSDAY FOR THE FOLLOWING
     ZONES: LAZ001>006-014.

     WINTER WEATHER ADVISORY UNTIL 3 PM CST THURSDAY FOR THE
     FOLLOWING ZONES: LAZ013-019>022.

     WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR THE
     FOLLOWING ZONES: LAZ010>012-017-018.

OK...LAKE WIND ADVISORY UNTIL 6 AM CST THURSDAY FOR THE FOLLOWING
     ZONES: OKZ077.

     WINTER STORM WARNING UNTIL NOON CST THURSDAY FOR THE FOLLOWING
     ZONES: OKZ077.

TX...LAKE WIND ADVISORY UNTIL 6 AM CST THURSDAY FOR THE FOLLOWING
     ZONES: TXZ096-097-108>112-124>126-136>138-149>153-165>167.

     WINTER STORM WARNING UNTIL NOON CST THURSDAY FOR THE FOLLOWING
     ZONES: TXZ096-097-108>112-124>126-138.

     WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR THE
     FOLLOWING ZONES: TXZ136-137-149>153-165>167.

&&

$$






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