000
FXUS64 KSHV 231001
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
501 AM CDT THU MAY 23 2013

.DISCUSSION...
THE 09Z SFC ANALYSIS THIS MORNING DEPICTS A WEAK/INVERTED SFC TROUGH
JUST S OF THE RED RIVER ACROSS N TX INTO EXTREME NE TX...EXTENDING
FROM THE PARENT SFC LOW OVER NE NM/WRN TX PANHANDLE. IN ADDITION...A
WEAK STATIONARY BNDRY THAT BARELY SHOWS UP IN THE PRESSURE FIELDS BUT
MORESO IN THE THETA-E ANALYSIS PERSISTS FROM SCNTRL AR NE ALONG THE MS
RIVER INTO THE OH VALLEY. THE LATTER BNDRY SHOULD CONTINUE TO WASH OUT
OVER OUR AREA TODAY...WITH THE SFC TROUGH TO OUR NW COMING INTO PLAY
TODAY AS IT MAY DRIFT A BIT FARTHER N AS THE AFOREMENTIONED SFC LOW
DRIFTS S INTO THE LOWER TX PANHANDLE. SATELLITE AND MOSAIC RADAR IMAGERY
THIS MORNING DEPICTS ELEVATED CONVECTION THAT HAS DEVELOPED THIS
MORNING OVER CNTRL/SE OK N OF THE SFC TROUGH...WHERE ELEVATED RETURN
MOISTURE HAS INTERACTED WITH WEAK VORTICITY ADVECTION THAT CONTINUES
TO SPILL SE IN THE NW FLOW ALOFT. THE 00Z PROGS FROM WEDNESDAY MORNING
HAVE DONE A MUCH BETTER JOB WITH THIS THAN THIS MORNING/S RUNS...BUT
AM EXPECTING THIS ELEVATED CONVECTION TO DIMINISH AS IT ENTERS EXTREME
SE OK/NE TX THIS MORNING AS THE 850MB FLOW BACKS MORE WRLY BY LATE
MORNING THUS WEAKENING ANY RESIDUAL ELEVATED MOISTURE CONVERGENCE. BUT
HAVING THIS SFC BNDRY FROM NEAR THE RED RIVER TO ALONG THE AR/LA LINE
DURING PEAK HEATING MAY ALLOW FOR ISOLATED CONVECTION TO REDEVELOP
ALONG/N OF THIS BNDRY NEAR THE VORTICITY ADVECTION. TEMPS TODAY SHOULD
REBOUND BACK TO NEAR 90 OVER MUCH OF THE AREA AS WE COULD SEE SOME
COMPRESSIONAL WARMING NEAR THIS SFC TROUGH...AND SFC RIDGING THAT WILL
EXPAND SE THIS AFTERNOON INTO THE MID-SOUTH AND LOWER MS VALLEY.

THIS SFC RIDGING WILL ALLOW A WEAK COOL FRONT TO BACKDOOR SW THROUGH
THE REGION TONIGHT...REACHING PORTIONS OF EXTREME NE TX INTO THE SRN
SECTIONS OF NCNTRL LA LATE. THE SHORT TERM PROGS ARE IN GENERAL
AGREEMENT IN DEVELOPING AN MCS THIS EVENING OVER THE ERN TX PANHANDLE
INTO NW TX...WITH ADDITIONAL VORTICITY ADVECTION SPILLING SE INTO THE
REGION ATOP THE BACKDOOR FRONT AFTER 06Z. HAVE MAINTAINED SLIGHT CHANCE
POPS OVER MUCH OF THE REGION TONIGHT...BUT HAVE ADDED LOW CHANCE POPS
TO THE NW SECTIONS OF NE TX AFTER 06Z TO ACCOMMODATE ANY ROGUE
CONVECTION THAT MAY DEVELOP ALONG THE SFC TROUGH WHERE LOW LEVEL
CONVERGENCE MAY BE A BIT STRONGER NEAR THE SRLY 20-25KT LLJ. THIS WEAK
FRONT MAY CONTINUE TO FOCUS ISOLATED CONVECTION OVER ALL BUT OUR
EXTREME ERN ZONES FRIDAY BEFORE DRIER AIR DEEPENS BEHIND THE FRONT.

THE WRN PLAINS UPPER RIDGING THIS MORNING SHOULD DRIFT E INTO THE
REGION FRIDAY NIGHT...WITH INCREASED SUBSIDENCE DIMINISHING THE MAINLY
DIURNALLY DRIVEN CONVECTION. SHOULD SEE SLIGHTLY COOLER AND DRIER
CONDITIONS IN WAKE OF THE SFC FRONT FRIDAY/SATURDAY...AS THE FRONT STALLS
FROM CNTRL OK INTO ECNTRL TX SATURDAY MORNING. THE PROGS REMAIN IN
REASONABLE AGREEMENT IN DEVELOPING A WEAK SHEAR AXIS FROM CONVECTION
OVER NW TX LATE TONIGHT...WHICH SHIFTS THIS FEATURE E INTO CNTRL
OK/WCNTRL TX SATURDAY MORNING...AND INTO ERN OK/N TX DURING THE
AFTERNOON. WILL KEEP SLIGHT CHANCE POPS GOING FROM THE WRN SECTIONS
OF E TX/SE OK/ADJACENT SW AR SATURDAY/SATURDAY NIGHT...WHERE THE SFC FRONT
BEGINS TO WASH OUT WHERE A SERLY LOW LEVEL FLOW ALLOWS FOR MOISTURE
ADVECTION TO RETURN BACK NWD. SLIGHT CHANCE POPS WILL SHIFT FARTHER E
INTO SW AR SUNDAY AS THIS SHEAR AXIS BEGINS TO FLATTEN OUT AND
ENCOUNTER DRIER AIR E OF THE RESIDUAL SFC FRONT.

WILL KEEP THE FORECAST DRY MEMORIAL DAY THROUGH THE REMAINDER OF THE
EXTENDED...AS RIDGING ALOFT SHOULD PERSISTS AND EVEN AMPLIFY FROM THE
GULF COAST N INTO THE MIDWEST /PER THE ECMWF AND CANADIAN BLEND/.
INCREASINGLY SRLY FLOW WILL ALSO ALLOW FOR WARMER AND MORE HUMID
CONDITIONS TO RETURN TO THE REGION AS WELL.

PRELIMS TO FOLLOW BELOW...

15

&&

.AVIATION...
MORE CLOUDS NOW...BUT FEW CIGS. WE ARE SEEING REDUCTIONS IN VSBY DUE
TO DAMP SOIL AND LIGHT WINDS. SOME BRIEF ISOLD MVFR CIGS POSSIBLE
UNTIL DAYBREAK WITH IFR/MVFR FOR VSBY EXPECTED TO RETURN TO VFR BY
13-15Z. SFC WINDS REMAIN LIGHT SOUTHERLY AS THE FRONT TURNS AROUND
AND LIFTS BACK TO THE NORTH. WE HAVE ALREADY SEEN NEARBY THUNDER
THIS MORNING IN OK WITH MORE COMING AND SCAT TSTMS MAY ACCOMPANY THE
FRONT/S PUSH BACK TO THE NORTH. EXPECT ELEVATED TSTM ACTIVITY WITH
SW FLOW AROUND 25 KTS FROM NEAR SFC TO 10KFT...THEN LIGHT NW FLOW.
/24/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  91  69  85  64  87 /  10  20  20   5  10
MLU  91  66  82  58  85 /  10  20  10   0   5
DEQ  87  64  80  59  83 /  20  20  20   5  20
TXK  88  66  80  61  84 /  20  20  20   5  10
ELD  89  64  79  57  84 /  20  20  10   0   5
TYR  90  71  87  68  86 /  10  20  20  10  20
GGG  91  70  86  67  87 /  10  20  20  10  10
LFK  91  70  90  67  89 /  10  10  20  10  10

&&

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

$$

15/24