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000
FXUS64 KSHV 042352
AFDSHV

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


.AVIATION...
VERY STG BUT SHALLOW ARCTIC COLD FRONT HAS JUST FINISHED MOVG
ACROSS KMLU AND KLFK TERMINALS...WITH WINDS ABRUPLY SHIFTING TO
NORTH. THESE NORTH WINDS OF 15 TO 25 KTS...WITH GUSTS TO OVER 30
KTS AT TIMES...WILL CONTINUE OVERNIGHT...ALONG WITH IFR TO LOW
MVFR CIG...AND WIDESPREAD RAIN....WITHIN A 2 TO 4 HOUR PERIOD OF TIME
AFT FROPA. EMBEDDED THUNDER WITH ELEVATED INSTABILITY ABOVE SHARP
LOW LAYER INVERSION POSSIBLE UNTIL AROUND 05/06Z. PRECIP WILL
CONTINUE INTO MID/LATE MORNING THUR...WITH FRZG LINE REACHING
KTXK AND KELD AROUND 05/09Z...I-20 TERMINALS AROUND 05/12Z. FRZG
RAIN...POSSIBLY MIXED WITH IP WITH CHANGOVER TO FRZG...AND
POSSIBLE BRIEF -SN BEFORE PRECIP ENDING. NORTH WINDS TO DECREASE
TO 10 TO 15 KTS MOSTLY DURG THIS PERIOD OF TIME...BUT WILL
MAINTAIN SPEED INTO AFTN AS SKIES PARTIALLY CLEAR TO HIGH MVFR OR
SCT DECKS ACROSS AREA./VII/.

&&

.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 FROM 9 PM THIS EVENING TO 3 PM CST
     THURSDAY FOR THE FOLLOWING ZONES: LAZ013-019>022.

     WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 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 FROM 9 PM THIS EVENING TO NOON CST
     THURSDAY FOR THE FOLLOWING ZONES:
     TXZ136-137-149>153-165>167.

&&

$$