528  
FXUS64 KLIX 180917  
AFDLIX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW ORLEANS LA  
417 AM CDT WED SEP 18 2019  
   
SHORT TERM
 
 
WITH A VERY SLOW FORWARD PACE BY IMELDA, THERE WILL ALMOST BE A  
STATUS QUO IN THE FCAST TODAY. THE MOISTURE GRADIENT STILL EXISTS  
ALONG THE MISS RIVER AND A WELL ESTABLISHED UPPER OUTFLOW FROM  
IMELDA WILL HELP SH/TS GET LIFT ONCE INITIATED TODAY. A WEAK  
CONVERGENT SFC FLOW STILL EXISTS AS WELL WHICH HELPS WITH WHERE  
THE CONVERGENT BAND WILL SET UP TODAY. THIS IS SHOWN WELL IN SFC  
OBS WITH SE FLOW OVER THE WESTERN ATCHAFALAYA AND EAST FLOW ALONG  
AND EAST OF THE MISS RIVER. THE INITIATING PERIOD WILL BE AFTER  
THE SUN RISES AS IT WILL TAKE SOME HEATING TO GET THINGS GOING,  
BUT SHOULD BE IN ROUGHLY THE SAME GENERAL PLACES AS THEY WERE  
YESTERDAY. FORTNATELY, AREAS OVER THE WESTERN MOST PORTION OF THE  
CWA ARE GETTING SOME MUCH NEEDED RAINFALL WHILE THE REMAINDER IS  
BAKING AND DRY. A BACKDOOR FRONT WILL MOVE INTO THE AREA THURSDAY  
INTO FRIDAY. SOME SH/TS ARE BEING ADVERTISED WITH THIS FRONT AS IT  
MOVES THROUGH DURING THE DAY THURSDAY. SUPRESSION AHEAD OF THIS  
FRONT WILL COUPLE WITH THE SUPRESSION ON THE OUTER PERIPHERY OF  
OLD IMELDA TO CAUSE A VERY STRONG SUPRESSION INVERSION WHICH COULD  
PRODUCE SOME STRONG HEATING. IF ENOUGH HEATING CAN BE ACHIEVED  
THURSDAY, THERE COULD BE A FEW STRONG OR SEVERE THUNDERSTORMS  
ALONG THE FRONT WHEN IT COMES IN AND WEAKENS THE INVERSION. THE  
OTHER POSSIBILITY IS THAT THE INVERSION IS ABLE TO BRIDGE THE  
FRONT KEEPING ANY THUNDERSTORM FROM GETTING OUT OF HAND. BUT THIS  
WILL NEED TO BE LOOKED AT LATER TODAY INTO THE OVERNIGHT. THERE IS  
SOME DRY AIR WITH THIS FRONT BUT DON'T SEE ANY COOL AIR. BUT WHEN  
SOME OF THIS DRY AIR FILTERS INTO THE EASTERN MOST PORTION OF THE  
AREA, EVENINGS AND MORNINGS SHOULD FEEL A LITTLE MORE COMFORTABLE  
FRIDAY INTO THE WEEKEND. MODELS DISAGREE ON HOW LONG THE DRY AIR  
WILL STAY AND AM MORE INCLINED TO FOLLOW THE GFS ON THIS BRINGING  
MOISTURE BACK TO THE AREA ONCE THE IMELDA REMNANTS HAVE DEPARTED.  
 

 
   
AVIATION
 
 
EXPECT VFR CONDITIONS FOR ALL AREA TERMINALS THROUGH THE EARLY  
MORNING HOURS TODAY. A FEW BANDS OF TROPICAL SHOWERS AND STORMS MAY  
PRESS EAST ENOUGH ACROSS THE ATCHAFALAYA BASIN TO REACH NEAR KBTR AND  
KHUM TERMINALS, BUT WILL BE MORE ISOLATED IN COVERAGE. HOWEVER, ANY  
ONE BAND/STRONGER STORM MAY CONTAIN GUSTY ERRATIC DOWNDRAFT WINDS  
AND LOCALLY HEAVY RAINFALL LEADING TO PERIODIC LOWER FLIGHT  
CATEGORIES IN THIS REGION. OTHERWISE, VFR CONDITIONS CAN BE EXPECTED  
ELSEWHERE THROUGH THE TAF PERIOD. KLG  
 

 
   
MARINE
 
 
WINDS WILL REMAIN RATHER WEAK UNTIL THURSDAY WHEN A BACK DOOR  
FRONT WILL MOVE INTO THE COASTAL WATERS CAUSING EASTERLY WINDS TO  
RISE TO AROUND 20KT THROUGH THE WEEKEND. BY THE EARLY PART OF  
NEXT WEEK, HIGH PRESSURE SETTLES BACK INTO THE AREA AND WINDS  
AGAIN GO LIGHT.  
 

 
   
DECISION SUPPORT
 
 
DSS CODE: GREEN.  
DEPLOYED: NONE.  
ACTIVATION: NONE.  
ACTIVITIES: NONE.  
 
DECISION SUPPORT SERVICES (DSS) CODE LEGEND  
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION.  
BLUE = LONG-FUSED WATCH, WARNING, OR ADVISORY IN EFFECT OR HIGH  
VISIBILITY EVENT; MARGINAL RISK SEVERE OR EXCESSIVE RAIN.  
YELLOW = HEIGHTENED IMPACTS WITH SHORT-FUSED WATCH, WARNING OR  
ADVISORY ISSUANCES; RADAR SUPPORT FOR SLIGHT RISK SEVERE  
OR EXCESSIVE RAIN.  
ORANGE = HIGH IMPACTS; ENHANCED RISK SEVERE; NEARBY TROPICAL EVENTS;  
HAZMAT OR OTHER LARGE EPISODES.  
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK OF SEVERE AND/OR  
EXCESSIVE RAINFALL, OR DIRECT TROPICAL THREATS; EVENTS OF  
NATIONAL SIGNIFICANCE.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
MCB 94 72 91 70 / 20 10 50 20  
BTR 91 73 90 73 / 60 10 40 20  
ASD 94 73 91 72 / 10 10 50 20  
MSY 92 77 91 77 / 40 10 40 20  
GPT 92 74 89 72 / 10 0 50 30  
PQL 97 73 90 70 / 10 10 50 20  
 

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

 
 

 
 
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