659  
FXUS64 KLCH 160848  
AFDLCH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LAKE CHARLES LA  
348 AM CDT THU AUG 16 2018  
   
DISCUSSION
 
 
REGIONAL RADAR REFLECTIVITY SHOWS A GREATER AMOUNT OF CONVECTION  
ONGOING ACROSS THE NORTHERN GULF OF MEXICO COMPARED TO THIS TIME  
YESTERDAY. AN OVERALL TREND OF CONVECTION BECOMING MORE WIDESPREAD  
EACH DAY IS EXPECTED TO CONTINUE THROUGH THE WEEKEND AS AN UPPER  
LEVEL RIDGE THAT WAS OVER THE AREA SHIFTS WESTWARD AND DEEP LAYER  
MOISTURE INCREASES ACROSS THE REGION. THE 00Z KLCH SOUNDING SHOWS  
THIS INCREASE WITH A PWAT NEAR 2 INCHES COMPARED TO LESS THAN 1.5  
INCHES JUST 24 HOURS EARLIER.  
 
PWATS ARE FORECAST TO REMAIN NEAR OR ABOVE 2 INCHES (WHICH  
CORRESPONDS TO THE 75TH PERCENTILE OF CLIMATOLOGY FOR AUGUST)  
THROUGH THE MIDDLE PART OF NEXT WEEK. AS A RESULT, POPS ARE  
EXPECTED TO GRADUALLY INCREASE OVER THE NEXT TWO DAYS AND REMAIN  
ABOVE CLIMATOLOGICAL NORMALS THROUGH EARLY NEXT WEEK. CONVECTION  
TODAY THROUGH SUNDAY WILL BE PRIMARILY DRIVEN BY THE DEVELOPMENT  
OF THE GULF BREEZE/MESOSCALE BOUNDARIES DUE TO DIFFERENTIAL  
HEATING OF THE LAND/WATER SURFACES. A FAIRLY TYPICAL DIURNAL  
PATTERN IS EXPECTED WITH SHOWERS AND THUNDERSTORMS DEVELOPING OVER  
THE COASTAL WATERS DURING THE EARLY MORNING HOURS BEFORE MOVING  
INLAND BY THE MIDDLE TO LATE MORNING AND DIMINISHING WITH THE LOSS  
OF DAYTIME HEATING AT SUNSET.  
 
MODEL GUIDANCE CONTINUES TO INDICATE A LONG WAVE TROUGH WILL  
DEVELOP ACROSS THE EASTERN TWO-THIRDS OF THE CONUS THIS WEEKEND  
INTO EARLY NEXT WEEK. A SHORTWAVE TROUGH EMBEDDED WITHIN THIS  
FEATURE IS FORECAST TO DIG INTO THE LOWER MISSISSIPPI VALLEY EARLY  
NEXT WEEK. THIS WILL CONTRIBUTE TO A MORE FAVORABLE ENVIRONMENT  
FOR ASCENT ACROSS THE CWA AND SHOWERS/THUNDERSTORMS WILL BE LIKELY  
ON MONDAY AND TUESDAY AS A SURFACE LOW PRESSURE AND ITS  
ASSOCIATED "COLD" FRONT APPROACH FROM THE NORTHWEST. THE SURFACE  
FRONT IS FORECAST TO REACH COAST LATE TUESDAY AND IS THEN EXPECTED  
INTO LATE WEDNESDAY/EARLY THURSDAY. THEREFORE, POPS CURRENTLY  
REMAIN AROUND 30%-50% THROUGH THE END OF THE FORECAST PERIOD.  
 

 
   
MARINE
 
 
LIGHT SOUTHERLY WINDS OF 5-10 KNOTS AND ACCOMPANIED BY SEAS OF 1-2  
FEET WILL CONTINUE THROUGH THE WEEKEND. SHOWER AND THUNDERSTORM  
ACTIVITY WILL GRADUALLY INCREASE THROUGH THE WEEKEND AS HIGH  
PRESSURE SUBSIDES. AN AREA OF LOW PRESSURE APPROACHING FROM THE  
NORTHWEST IS EXPECTED TO RESULT IN AN INCREASING PRESSURE GRADIENT  
OVER THE COASTAL WATERS. THIS WILL PRODUCE SLIGHTLY HIGHER WINDS  
AND SEAS ON SUNDAY AND MONDAY. A SURFACE FRONT ASSOCIATED WITH  
THIS LOW IS EXPECTED TO STALL SOMEWHERE IN THE VICINITY OF THE  
COAST WHICH WILL RESULT IN WINDS TAKING ON A MORE WESTERLY  
COMPONENT ON TUESDAY AND WEDNESDAY. THE FRONT WILL ALSO RESULT IN  
ELEVATED CHANCES FOR SHOWERS AND THUNDERSTORMS LINGERING INTO THE  
MIDDLE OF NEXT WEEK.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
AEX 95 72 94 72 / 30 10 30 10  
LCH 91 76 91 76 / 30 10 30 10  
LFT 92 75 92 75 / 50 10 50 10  
BPT 91 77 91 77 / 20 10 20 10  
 

 
   
LCH WATCHES/WARNINGS/ADVISORIES
 
 
LA...NONE.  
TX...NONE.  
GM...NONE.  

 
 

 
 
PUBLIC...26  
 
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