243  
FXUS64 KLIX 122117  
AFDLIX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW ORLEANS LA  
ISSUED BY NATIONAL WEATHER SERVICE MOBILE AL  
417 PM CDT WED AUG 12 2020  
   
SHORT TERM
 
ONGOING SHOWERS AND THUNDERSTORMS ARE PRIMARILY  
FOCUSED ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE AREA,  
INCLUDING THE COASTAL MISSISSIPPI ZONES ALONG A SEABREEZE PUSHING  
INLAND. THE WET MICROBURST POTENTIAL IS MODERATE, SO A FEW OF THE  
STRONGER THUNDERSTORMS STILL HAVE THE CAPABILITY OF PRODUCING  
LOCALIZED WIND GUSTS UP TO 40 MPH INTO EARLY EVENING. CONVECTION  
WILL DIMINISH BY MID EVENING ACROSS THE ENTIRE AREA, ALTHOUGH  
THERE COULD BE A LINGERING LIGHT RAIN SHOWER OR TWO INTO LATE  
EVENING. ISOLATED TO LOW-END SCATTERED CONVECTION WILL AGAIN BE  
POSSIBLE LATE TONIGHT INTO EARLY THURSDAY MORNING ALONG THE  
COASTAL SECTIONS OF SOUTHEAST LOUISIANA AND SOUTHEAST MISSISSIPPI.  
 
THE SYNOPTIC PATTERN CHANGES SLIGHTLY AS THE AXIS OF AN UPPER  
SHORTWAVE OVER THE AREA TONIGHT SHIFTS EASTWARD OVER ALABAMA BY  
MIDNIGHT THURSDAY, WHILE WEAK UPPER RIDGING BUILDS IN FROM THE  
WEST. DESPITE THIS PATTERN CHANGE, THERE WILL BE AMPLE  
INSTABILITY FOR CONVECTION AGAIN ON THURSDAY DESPITE THE LACK OF A  
FORCING MECHANISM AS THE TROUGH IS LIKELY NOT TO HAVE MUCH OF AN  
INFLUENCE. HOWEVER, WILL ADVERTISE SCATTERED TO NUMEROUS COVERAGE  
OF STORMS FOR TOMORROW AFTERNOON MAINLY DUE TO DECREASING  
STABILITY. THE DEEP LAYER STEERING FLOW WILL BE VERY LIGHT AND  
PRECIPITABLE WATERS WILL BE AT OR ABOVE 2". THEREFORE, ANY  
STRONGER STORMS THAT DEVELOP WILL CONTAIN STRONG, GUSTY WINDS AND  
THE POTENTIAL FOR LOCALLY HEAVY RAINFALL DUE TO THE SLOW MOVEMENT  
OF STORMS. HEAT INDICES WILL CLIMB TO 104-107 DEGREES ACROSS THE  
REGION ON THURSDAY. THIS IS JUST SHY OF HEAT ADVISORY CRITERIA  
(108 DEGREES) BUT WILL CONTINUE TO MONITOR. /22  
   
LONG TERM
 
FOR THE LONG TERM PERIOD (THIS FRIDAY THROUGH NEXT  
TUESDAY), THE LOCAL AREA WILL GENERALLY BE UNDER AN AREA OF UPPER  
LEVEL WEAKNESS AS A RIDGE MAINTAINS ITS HOLD ALOFT OVER THE  
SOUTHWESTERN CONUS AND AN UPPER LEVEL TROUGH PERSISTS OVER THE OHIO  
AND TENNESSEE VALLEYS DOWN THROUGH MISSISSIPPI AND ALABAMA. HOWEVER,  
BY EARLY NEXT WEEK THE UPPER TROUGH TO THE EAST WILL BEGIN TO BUILD  
BACK WEST OVER LOUISIANA AND EVENTUALLY OVER THE ARKLATEX REGION AS  
WELL. AT THE SURFACE, HIGH PRESSURE WILL LARGELY BE MAINTAINED OVER  
THE GULF OF MEXICO THROUGH THE WEEKEND. MEANWHILE, A SURFACE  
BOUNDARY WILL BE DRAPED OVER THE ARKLATEX AND TENNESSEE VALLEY  
REGIONS THROUGH THE DAY FRIDAY. BY SATURDAY, THIS BOUNDARY WILL  
PROGRESS BACK NORTH SLIGHTLY, BECOMING A COLD FRONT OVER SOUTHERN  
MISSOURI, KENTUCKY, AND DOWN INTO NORTH CAROLINA. THIS FRONT WILL  
THEN BEGIN TO BE PUSHED SOUTHEAST BY ANOTHER COLD FRONT TO THE  
NORTHWEST OVER THE UPPER MISSISSIPPI VALLEY. THE FIRST COLD FRONT  
WILL PROGRESS OVER THE EAST COAST OF THE CAROLINAS, SOUTHERN  
GEORGIA, AND THE FLORIDA PANHANDLE BY EARLY MONDAY. THE SECOND COLD  
FRONT IS THEN EXPECTED TO MAKE ITS WAY OVER THE ARKLATEX AND  
TENNESSEE VALLEY REGIONS DURING THIS TIME, EVENTUALLY MOVING OVER  
THE NORTHERN GULF COAST THROUGH THE DAY TUESDAY.  
 
AS FOR SENSIBLE WEATHER, A DIURNAL PATTERN WILL CONTINUE THROUGH AT  
LEAST THE WEEKEND. MLCAPE VALUES WILL BE RIGHT AROUND 1000 J/KG  
THROUGH SATURDAY, WITH AN INCREASE IN INSTABILITY TO BETWEEN 1000-  
2500 J/KG FOR SUNDAY THROUGH TUESDAY AFTERNOONS. THUS, EXPECTING  
SCATTERED SHOWERS AND STORMS TO BEGIN DURING THE LATE NIGHT/EARLY  
MORNING HOURS OVER THE GULF WATERS AND THEN TRANSITION OVER LAND  
THROUGH THE DAY. SHOWERS AND STORMS WILL DWINDLE TO BE FAIRLY  
ISOLATED THROUGH THE EVENING. IN GENERAL, PWATS WILL RANGE BETWEEN  
1.7-2.0 INCHES FOR THE LOCAL AREA THROUGH MONDAY, WITH THE HIGHEST  
VALUES EXPECTED AREA-WIDE ON FRIDAY. PWATS WILL THEN DECREASE TO BE  
AROUND 1.4 INCHES OVER THE INLAND AREAS AND AROUND 1.8-2.0 INCHES  
NEAR THE LOUISIANA AND MISSISSIPPI COASTS ON TUESDAY. THIS IS DUE TO  
DRIER AIR BEING BROUGHT IN FROM THE NORTH WITH COLD FRONTAL PASSAGE.  
AT THIS TIME, WENT WITH LIKELY POPS FOR FRIDAY AND SATURDAY  
AFTERNOONS BECAUSE OF HIGHER DEEP LAYER MOISTURE AND SOUTHWEST TO  
WESTERLY WIND FLOW. ALSO, CAPPED POPS AT CHANCE FOR SUNDAY THROUGH  
TUESDAY AFTERNOONS DUE TO DECLINING PWATS, A SHIFT TO MORE  
NORTHWESTERLY FLOW, AS WELL AS MODEL UNCERTAINTY.  
 
HIGH TEMPERATURES WILL BE IN THE UPPER 80S TO LOWER 90S ON FRIDAY  
(DUE TO HIGHER CLOUD COVER AND POPS), THEN TEMPERATURES WILL  
INCREASE TO GENERALLY BE IN THE LOWER TO MID 90S THROUGH THE  
WEEKEND. HIGHS WILL SLIGHTLY DECREASE TO BE IN THE UPPER 80S TO  
LOWER 90S ONCE AGAIN BY TUESDAY. LOW TEMPERATURES WILL MAINLY BE IN  
THE LOWER TO UPPER 70S THROUGH SUNDAY NIGHT, WITH AREAS RIGHT ALONG  
THE LOUISIANA COAST NEAR 80 DEGREES. LOWS MONDAY AND TUESDAY NIGHTS  
WILL THEN BE IN THE LOWER TO MID 70S FOR MOST INLAND AREAS, WITH  
AREAS RIGHT ALONG THE LOUISIANA COAST IN THE UPPER 70S; ALTHOUGH, A  
FEW SPOTS OVER FAR SOUTHWEST MISSISSIPPI COULD SEE LOWS IN THE UPPER  
60S. /26  
 

 
   
AVIATION
 
NOT MUCH OF A CHANGE TO THE AVIATION FORECAST THIS  
AFTERNOON AS ONGOING SCATTERED TO NUMEROUS SHOWERS AND STORMS THIS  
AFTERNOON WILL GRADUALLY DIMINISH INTO EARLY EVENING. VFR  
CONDITIONS WILL PREVAIL THROUGH MUCH OF THE FORECAST, EXCEPT NEAR  
THUNDERSTORMS WHEN VISIBILITIES AND CEILINGS COULD DROP TO MVFR OR  
IFR CRITERIA. WIND GUSTS OF 15-25 KNOTS ARE POSSIBLE NEAR  
THUNDERSTORMS. /22  
 

 
   
MARINE
 
SHOWER AND THUNDERSTORM ACTIVITY HAS WANED OVER THE  
COASTAL WATERS THIS AFTERNOON AND GENERALLY LIGHT WINDS AND SEAS  
ARE EXPECTED OUTSIDE OF ANY CONVECTION. WINDS WILL CONTINUE TO BE  
LIGHT AS HIGH PRESSURE REMAINS OVER THE COASTAL WATERS.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
MCB 76 90 75 89 / 40 60 20 60  
BTR 77 94 77 91 / 30 60 20 60  
ASD 76 93 76 91 / 30 60 20 70  
MSY 78 92 79 91 / 30 60 20 60  
GPT 78 89 77 88 / 30 60 30 70  
PQL 75 92 75 90 / 30 60 40 70  
 

 
   
LIX WATCHES/WARNINGS/ADVISORIES
 
 
LA...NONE.  
GM...NONE.  
MS...NONE.  
GM...NONE.  

 
 

 
 
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