Area Forecast Discussion
Issued by NWS Shreveport, LA

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000
FXUS64 KSHV 231158
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
658 AM CDT SAT MAY 23 2015

.AVIATION...
FOR THE 23/12Z TAFS...A MIX OF VFR/MVFR CIGS TO BEGIN THIS TAF
PERIOD AS SELY WINDS RETURN LOW LEVEL MOISTURE NWRD ALONG AN
ADVANCING WARM FRONT. EXPECT THESE LOWER CIGS TO AFFECT MOST TAF
SITES EXCEPT ELD/MLU WHERE MOISTURE WILL BE SLOWER TO ADVECT.
THIS AIR MASS WILL USHER IN SOME LIGHT SHWRS LATER TODAY...AND
THESE WILL MAINLY AFFECT OUR E TX TERMINALS BUT GRADUALLY WORK
FARTHER EAST TO SHV/TXK WITH SOME ISOLD TSTMS ALSO POSSIBLE AS WE
SHIFT LATER INTO THE AFTERNOON AND EARLY EVENING. CIGS SHOULD LIFT
BACK TO AT LEAST LOW VFR AT MOST SITES BY EARLY AFTERNOON BUT
LOWER AGAIN OVERNIGHT WITH PATCHY FOG ALSO POSSIBLE WITH MOIST
SOILS. SFC WINDS WILL MAINTAIN A SELY COMPONENT THROUGH THE
PERIOD WITH SPEEDS INCREASING TO NEAR 10 KTS LATER TODAY. /19/

&&

.PREV DISCUSSION... /ISSUED 526 AM CDT SAT MAY 23 2015/

DISCUSSION...
ALL REMAINS QUIET THIS MORNING...ALTHOUGH LOW LEVEL MOISTURE RETURN
WILL COMMENCE IN EARNEST LATER THIS MORNING AS THE REMNANTS OF THE
STATIONARY FRONT STILL RESIDING FROM CNTRL AND SE TX ALONG THE LA
COAST SHOULD QUICKLY MIX N/WASH OUT AS SSE LOW LEVEL WINDS INCREASE
TODAY. THE MORNING WATER VAPOR IMAGERY INDICATES FLAT UPPER RIDGING
FROM E TX ACROSS THE LOWER MS VALLEY THIS MORNING...BUT THIS FEATURE
REMAINS PROGGED TO SHIFT E TODAY AS THE CLOSED LOW NEAR THE FOUR
CORNERS REGION DRIFTS NE INTO THE CNTRL ROCKIES/WRN PLAINS LATER THIS
AFTERNOON. THIS WILL RESULT IN A DEEPENING SRLY FLOW OVER MUCH OF THE
REGION TODAY...ENHANCING THE SEABREEZE AS IT WORKS INLAND FROM THE S
LA/SE TX COASTS. CHANCE POPS SHOULD SUFFICE THIS AFTERNOON FOR MUCH OF
THE REGION...ALTHOUGH SCT/NUMEROUS CONVECTION NOW ONGOING FROM ERN
NM/NW TX AS WELL AS S TX SHOULD SHIFT NNE INTO CNTRL TX/OK BY
AFTERNOON AS LARGE SCALE FORCING SPREADS E INTO THESE AREAS AHEAD OF
THE CLOSED LOW. WHILE BRIEF HEAVY RAINFALL CAN/T BE RULED OUT IN THE
STRONGER STORMS THIS AFTERNOON/EVENING...QPF AMOUNTS SHOULD NOT BE
EXCESSIVE...WITH THE GREATEST THREAT FOR FLOODING EXPECTED TO REMAIN W
OF THE REGION. TEMPS THIS AFTERNOON SHOULD CLIMB ANOTHER SEVERAL
DEGREES HIGHER THAN WHAT WAS OBSERVED FRIDAY...BACK TO NEAR CLIMO
VALUES OVER MUCH OF THE REGION.

THE SHORT TERM PROGS ARE IN GOOD AGREEMENT WITH THE PRIMARY TROUGH
AXIS BENEATH THE CLOSED LOW ENTERING W TX LATE TONIGHT...RESULTING IN
LARGE SCALE FORCING SLOWLY SPREADING ENE ACROSS CNTRL TX INTO
CNTRL/ERN OK. SHOULD SEE AN UPTICK IN SCT CONVECTION TONIGHT MAINLY NW
OF THE I-30 CORRIDOR OF NE TX/SW AR...WITH THE HEAVIER QPF/S WAITING
UNTIL AFTER 12Z SUNDAY BEFORE SPREADING INTO THE REGION. GIVEN THE
DEEP WARM LAYER AND LARGELY UNIDIRECTIONAL FLOW ENHANCING CELL
TRAINING...FLASH FLOODING IS A GOOD BET LATER TODAY AND TONIGHT JUST
W OF THE REGION...BEFORE THE HEAVY RAIN AXIS BEGINS TO SHIFT E INTO SE
OK/E TX AFTER DAYBREAK SUNDAY. GIVEN THE STILL SATURATED GROUNDS IN
WAKE OF WIDESPREAD 4-8+ INCHES OF RAIN THAT HAS FALLEN IN THE LAST
COUPLE OF WEEKS...HAVE HOISTED A FLASH FLOOD WATCH FOR SE OK/E TX/MUCH
OF SW AR AND NW LA FROM 09Z SUNDAY THROUGH 12Z MONDAY. THE SHORT TERM
PROGS DEPICT THE W TX SHORTWAVE AS RATHER PROGRESSIVE AS IT SHIFTS ENE
ACROSS CNTRL/ERN TX SUNDAY AFTERNOON...BUT STRONGLY DIFFLUENT FLOW
ALOFT ACROSS A STRONGLY UNIDIRECTIONLY SHEARED/UNSTABLE AND MOISTURE
LADEN AIR MASS WILL RESULT IN THE POTENTIAL FOR HIGH RAIN
RATES...DESPITE ITS STEADY ENE PROGRESSION THROUGH THE AREA.
WIDESPREAD QPF AMOUNTS OF 1-3 INCHES...WITH ISOLATED HIGHER
AMOUNTS...ARE POSSIBLE ACROSS THE WATCH AREA...ALTHOUGH THE PROGS DO
TAPER QPF AMOUNTS OFF CONSIDERABLY FARTHER E ACROSS SCNTRL AR/NCNTRL
LA.

THE HEAVY RAINFALL THREAT SHOULD DIMINISH SUNDAY NIGHT OVER NCNTRL LA
AS THIS TROUGH DAMPENS OUT/EXITS THE REGION TO THE NE. HOWEVER...THE
REPRIEVE IN RAINFALL WILL BE SHORT-LIVED AS ADDITIONAL SCT
REDEVELOPMENT OCCURS MONDAY AS ADDITIONAL RIPPLES IN THE SW FLOW ALOFT
SPREAD NE OVER THE AREA AHEAD OF THE OPENING LOW OVER THE NRN/CNTRL
PLAINS. UNFORTUNATELY...THE PROGS CONTINUE TO DEPICT ANOTHER SHORTWAVE
ROUNDING THE PLAINS UPPER TROUGH ACROSS TX/OK MONDAY AFTERNOON...AGAIN
LOADING UP WITH LARGE SCALE FORCING EXPECTED TO OVERSPREAD THE REGION
MONDAY NIGHT/TUESDAY MORNING. THUS...ANOTHER ROUND OF HEAVY
RAINFALL/FLASH FLOODING IS CERTAINLY POSSIBLE DURING THIS TIME FRAME
AS THE FIRST ROUND OF HEAVY RAINFALL WILL ONLY PRIME THE ALREADY MOIST
SOIL CONDITIONS. MODEST HEATING WITHIN A VERY MOIST AIR MASS SHOULD
OCCUR MONDAY AFTERNOON BEFORE THIS NEXT NEGATIVE TILT SHORTWAVE
TRAVERSES THE AREA...WITH THE THREAT FOR DAMAGING WINDS POSSIBLE IN
ADDITION TO THE HEAVY RAINFALL. GIVEN THE ALREADY SATURATED
GROUNDS...IT WILL NOT TAKE MUCH WIND TO DOWN TREES...EVEN FROM THE
SUB-SVR STORMS.

THE SVR/HEAVY RAINFALL THREAT SHOULD DIMINISH FROM W TO E TUESDAY
MORNING...ALTHOUGH A WSW FLOW ALOFT LOOKS TO PERSIST THROUGH THE
REMAINDER OF NEXT WEEK. HOWEVER...THE CONVECTION SHOULD BECOME MORE
WIDELY SCT AND DIURNAL EACH DAY. TEMPS SHOULD ALSO RETURN TO
NEAR/ABOVE CLIMO THROUGH THE REMAINDER OF THE PERIOD AS WELL.

PRELIMS TO FOLLOW BELOW...

15

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  84  71  81  69 /  30  40  80  80
MLU  85  70  86  70 /  20  30  60  80
DEQ  78  68  74  67 /  40  60  90  80
TXK  82  70  79  69 /  30  50  80  80
ELD  84  69  82  69 /  20  40  70  80
TYR  82  71  77  70 /  40  50  80  70
GGG  83  71  79  70 /  40  40  80  70
LFK  84  73  79  71 /  40  30  80  70

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR
     ARZ050-051-059>061-070>072.

LA...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR
     LAZ001>004-010>012-017-018.

OK...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR
     OKZ077.

TX...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR
     TXZ096-097-108>112-124>126-136>138-149>153-165>167.

&&

$$

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