Area Forecast Discussion
Issued by NWS Shreveport, LA

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000
FXUS64 KSHV 212352
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
652 PM CDT THU MAY 21 2015

.AVIATION...
LOW CIGS WILL CONTINUE TO AFFECT THE TERMINALS FOR MUCH OF THE TAF
PD...WITH THE EXCEPTION OF KTXK...WHICH SHOULD RETURN TO VFR
WITHIN THE NEXT FEW HOURS. EXPECT NE TO ESELY WINDS AT 5-10 KTS
THROUGHOUT THE PD. /12/

&&

.PREV DISCUSSION... /ISSUED 350 PM CDT THU MAY 21 2015/

DISCUSSION...
WATER VAPOR IMAGERY CONTINUES TO SHOW A DISTURBANCE MOVING EAST
THIS AFTERNOON...OUT OF THE ARKLATEX REGION. HOWEVER...SCATTERED
SHOWERS CONTINUE ACROSS THE REGION...WITH THE BRUNT OF THE
SHOWERS EXTENDING FROM LUFKIN EAST TO LOUISIANA. THIS SHOWERS
ACTIVITY WILL GRADUALLY SHIFT SOUTH AND EAST THROUGH THE
EVENING..WITH JUST A FEW ISOLATED SHOWERS CONTINUING INTO THE
OVERNIGHT HOURS.

A TRANSITORY WEAK RIDGE WILL BUILD BACK ACROSS THE ARKLATEX FOR
FRIDAY. AT THIS POINT IN TIME...THINK THAT MOST OF THE REGION WILL
PROBABLY BE DRY...BUT HAVE LEFT IN A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS...MAINLY FOR WESTERN AREAS...AS SOME MOISTURE DOES
TRY TO SPREAD INTO THE AREA FROM TEXAS. THIS RIDGE WILL SHIFT EAST
ON SATURDAY...OPENING THE DOOR FOR A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THE WEEKEND.

THE PERIODS OF MOST CONCERN IN THE FORECAST ARE REALLY SUNDAY AND
MONDAY...AS THE NEXT WEST COAST LOW MOVES INTO THE CENTRAL PART OF
THE US BEFORE PUSHING EAST. SHOWERS AND THUNDERSTORMS WILL LIKELY
DEVELOP ACROSS THE REGION ON SUNDAY...WITH A DISTURBANCE AHEAD OF
THE MAIN TROUGH AIDS IN THE LIFT. THE MAIN TROUGH THEN SHIFTS EAST
ACROSS THE REGION LATE SUNDAY AND INTO MONDAY. PRECIPITABLE WATER
VALUES WILL INCREASE TO BETWEEN 1.6 AND 2.1 INCHES DURING THIS
TIME...MEANING THAT ANY THUNDERSTORMS THAT DEVELOP WILL BE VERY
EFFICIENT RAIN PRODUCERS...WITH PERIODS OF HEAVY RAIN LIKELY.
GIVEN HOW SATURATED THE GROUND IS WITH THE RECENT RAINS...BELIEVE
FLASH FLOODING WILL ALSO BE LIKELY THESE DAYS. HAVE HELD OFF
ISSUING A FLASH FLOOD WATCH FOR SUNDAY AND MONDAY AT THIS
TIME...JUST TO GIVE THE MODELS ANOTHER DAY TO FINE TUNE THE
TIMING...BUT BELIEVE ONE WILL BE NEEDED FOR THESE DAYS.

THE EXTENDED MODELS START TO VARY ON THE TIMING FOR TUESDAY
THROUGH THURSDAY...BUT FOR NOW IT APPEARS THAT THE REGION WILL
EITHER BE UNDER SOUTHWESTERLY FLOW ALOFT OR ANOTHER TROUGH.
THEREFORE...EXPECT THE THREAT OF UNSETTLED WEATHER TO CONTINUE
THROUGH AT LEAST THURSDAY.

HYDROLOGY...
THE POTENTIAL FOR A MAJOR FLOOD TO DEVELOP ALONG THE RED RIVER
CONTINUES TO BE A CONCERN. THE WEATHER PREDICTION CENTER IS
FORECASTING UPWARDS OF 8 INCHES OF PRECIPITATION FALLING OVER THE
RED RIVER BASIN UPSTREAM OF LAKE TEXOMA IN THE NEXT 7 DAYS. THIS
ADDITIONAL RAINFALL ON ALREADY SATURATED GROUND WILL INCREASE
THE LIKELIHOOD OF A MAJOR FLOOD EVENT ALONG THE RED RIVER...THE
FIRST TIME SINCE 1990. OUR MODELS ARE ALSO HINTING THAT A
SIGNIFICANT AMOUNT OF PRECIPITATION MAY FALL ALONG THE RED RIVER
AS THE CREST MOVES SOUTH TOWARDS SHREVEPORT. THIS ADDS AN
ADDITIONAL LEVEL OF CONCERN. NEEDLESS TO SAY...WE WILL CONTINUE
TO MONITOR THIS DEVELOPING SITUATION. FOR MORE INFORMATION ON THE
RED RIVER STAGES AND FORECASTS...PLEASE SEE NEWPNSSHV OR NOUS44
KSHV OR THE CURRENT AND FORECASTED RIVER LEVELS LINK ON OUR
WEBSITE AT WEATHER.GOV/SHV.

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  59  77  65  83 /  20  20  20  50
MLU  56  76  63  84 /  20  20  20  50
DEQ  55  72  60  79 /  10  40  20  50
TXK  56  73  61  81 /  20  30  20  50
ELD  55  74  61  82 /  20  20  20  50
TYR  61  76  66  82 /  20  40  20  40
GGG  61  77  66  83 /  20  30  20  40
LFK  65  80  69  84 /  30  40  20  40

&&

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

$$

12



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