549  
FXUS64 KSHV 210356  
AFDSHV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SHREVEPORT LA  
1056 PM CDT SUN SEP 20 2020  
   
UPDATE
 
 
FOR THIS UPDATE, DECIDED TO ADJUST POPS DOWN TO 20 PERCENT FOR  
AREAS SOUTH OF INTERSTATE 20 DURING THE REMAINDER OF THE EVENING  
HOURS. ALSO, DECIDED TO TREND POPS DOWN A TAD DURING THE  
OVERNIGHT HOURS AS SHORT-TERM MODELS HOLD OFF PRECIP UNTIL AFTER  
3 AM. OTHERWISE, THE REMAINDER OF THE FORECAST REMAINS ON TRACK.  
 

 
   
PREV DISCUSSION
 
/ISSUED 842 PM CDT SUN SEP 20 2020/  
 
AVIATION...  
 
FOR THE 21/00Z TAF PERIOD, VFR CONDITIONS WILL CONTINUE FOR THE  
FIRST HALF OF THE TAF PERIOD. HOWEVER, THE EFFECTS FROM TROPICAL  
STORM BETA WILL BEGIN TO BE FELT ACROSS THE REGION AS LOW CLOUDS  
BEGIN TO MOVE INLAND AND RESULT IN MVFR/IFR CIGS SPREADING NORTH  
THROUGH THE OVERNIGHT AND EARLY MORNING HOURS. SHOWERS AND SOME  
ISOLATED THUNDERSTORMS WILL ALSO GRADUALLY SPREAD NORTH THROUGH  
THE LATTER HALF OF THE PERIOD AS OUTER BANDS FROM BETA ADVANCE  
INTO OUR REGION. EXPECT CONVECTION TO INCREASE THROUGHOUT MONDAY  
WITH CIGS DROPPING EVEN FURTHER THROUGH THE END OF THE PERIOD.  
WINDS WILL ALSO BE INCREASING FROM THE E/NE BETWEEN 10-15 KTS  
ALONG WITH SOME HIGHER GUSTS NEAR 20 KTS POSSIBLE, ESPECIALLY  
DURING THE DAYTIME HOURS.  
 
PREV DISCUSSION... /ISSUED 341 PM CDT SUN SEP 20 2020/  
 
SHORT TERM.../TONIGHT THROUGH MONDAY NIGHT/  
 
WE HAVE MANAGED TO MAINTAIN DRY CONDITIONS OVER THE VAST MAJORITY  
OF THE REGION TODAY WITH ONLY A FEW VERY LIGHT SHOWERS ASSOCIATED  
WITH TROPICAL STORM BETA GRAZING OUR EXTREME SOUTHERN ZONES THIS  
AFTERNOON. MOISTURE HAS HAD A DIFFICULT TIME OVERCOMING THE VERY  
DRY AIR MASS IN PLACE, BUT EXPECT INCREASING MOISTURE ADVECTION  
OVERNIGHT WITH SHOWERS GRADUALLY INCREASING AND EXPANDING FROM  
SOUTH TO NORTH. HOWEVER, IT STILL APPEARS THAT COVERAGE MAY NOT BE  
ALL THAT IMPRESSIVE BASED ON THE LATEST HI-RES GUIDANCE BECAUSE OF  
THE DEPTH OF THIS DRY AIR IN PLACE. HOWEVER, HAVE GONE AS HIGH AS  
LIKELY POPS ACROSS OUR SOUTHERNMOST ZONES AND TAPERED THEM BACK AS  
YOU GO FARTHER NORTH. THE GENERAL THINKING IS MOST OF THE SHOWERS  
THAT DO DEVELOP SHOULD REMAIN ALONG AND SOUTH OF I-20 THROUGH THE  
OVERNIGHT HOURS AND GRADUALLY EXPAND FARTHER NORTH ACROSS THE REST  
OF THE REGION THROUGH THE DAY ON MONDAY. TEMPERATURES WILL BE HELD  
WELL BELOW NORMAL DUE TO THE EXTENT OF CLOUD COVER AND INCREASING  
CONVECTION WITH AFTERNOON HIGHS ONLY MANAGING THE LOWER TO MID 70S  
ON MONDAY.  
 
CONVECTION WILL REMAIN ONGOING INTO MONDAY NIGHT AS TROPICAL STORM  
BETA NEARS LANDFALL ALONG THE MIDDLE TEXAS COAST. THERE MAY SOME  
OCCASIONAL PERIODS OF HEAVY RAINFALL, BUT OVERALL DON'T ANTICIPATE  
A SIGNIFICANT FLOODING THREAT AT THIS TIME GIVEN THE EXTENDED DRY  
PERIOD WE HAVE EXPERIENCED THROUGH THE MIDDLE THIRD OF THIS MONTH.  
THEREFORE, NO FLOOD HEADLINES ARE PLANNED FOR THE SHORT TERM BUT  
THAT COULD CHANGE AS WE MOVE LATER IN THE WEEK DURING THE LONGER  
TERM PART OF THE FORECAST.  
 
LONG TERM.../TUESDAY THROUGH SATURDAY NIGHT/  
 
A PROLONGED PERIOD OF INCLEMENT WEATHER IS STILL ANTICIPATED ACROSS  
THE ENTIRE FOUR STATE REGION TUESDAY AND WEDNESDAY AS THE REMNANTS  
OF TROPICAL STORM BETA AND A STRENGTHENING UPPER LEVEL TROUGH TO OUR  
WEST FOCUS LIFT, MOISTURE ADVECTION, AND MARGINAL INSTABILITY OVER  
THE AREA. SOME GRADUAL DECREASE IN RAIN COVER FROM WEST TO EAST IS  
EXPECTED THURSDAY AND FRIDAY, ALTHOUGH A GENERALLY UNSETTLED PATTERN  
SHOULD REMAIN IN OUR REGION THROUGH THE WEEKEND AND THIS WILL  
CONTINUE 20 TO 40 PERCENT RAIN CHANCES.  
 
DETAILS IN THE TIMING AND FOCUS OF HEAVY RAINFALL POTENTIAL TUESDAY  
AND WEDNESDAY ARE STILL VERY UNCERTAIN GIVEN MANY DIFFERENT MODEL  
IDEAS OF HOW THE REMNANTS OF BETA WILL REACT WITH THE AFOREMENTIONED  
UPPER LEVEL TROUGH. THE MOST RECENT RAINFALL GUIDANCE FROM THE  
WEATHER PREDICTION CENTER HAS REACTED TO THE UNCERTAINTY (AND  
POTENTIAL FOR HEAVIER CONVECTION TO GET ANCHORED NEAR THE COAST) BY  
LOWERING EXPECTED PEAK TOTALS IN OUR REGION A GREAT DEAL THROUGH  
FRIDAY. OF COURSE THIS IS GOOD NEWS, AS IT REPRESENTS LESS POTENTIAL  
FOR EVENTUAL FLOODING IMPACTS (ESPECIALLY IN LA SOUTH OF I-20). OUR  
LATEST GRAPHICS REPRESENT A STRONG TREND TOWARD THIS ADJUSTMENT.  
HOWEVER, IT IS WORTH POINTING OUT THAT THERE IS STILL CONSIDERABLE  
UNCERTAINTY WITH HOW THE INLAND RAINFALL WILL PAN OUT IN OUR  
VICINITY AND WE CANNOT YET COMPLETELY LET OUR GUARD DOWN FOR THE  
THREAT OF FLOODING.  
 
OTHERWISE, EXPECT LOW TEMPERATURES TO BE NEAR NORMAL THROUGH THE  
PERIOD WITH HIGH TEMPERATURES AT LEAST SLIGHTLY BELOW NORMAL MOST  
DAYS THANKS TO AN ABUNDANCE OF CLOUDS AND PRECIPITATION BEING  
AROUND. HUMIDITY WILL DEFINITELY BE HIGHER THAN HAS BEEN THE CASE  
THE LAST FEW DAYS. DECENT MODEL CONSENSUS ON A POSSIBLY BIG COLD  
FRONT COMING DOWN VERY EARLY NEXT WEEK, BUT THIS IS PAST THE  
OFFICIAL LONG TERM PERIOD. /50/  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SHV 64 73 64 74 / 40 80 80 70  
MLU 65 75 64 74 / 30 60 60 70  
DEQ 63 76 62 70 / 10 50 70 70  
TXK 63 72 63 68 / 20 60 80 80  
ELD 62 74 61 70 / 20 50 70 70  
TYR 64 70 64 74 / 40 80 80 70  
GGG 64 72 64 76 / 40 80 80 70  
LFK 65 76 67 79 / 60 80 80 70  
 

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

 
 

 
 
20  
 
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