565  
FXUS64 KLIX 162122  
AFDLIX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW ORLEANS LA  
422 PM CDT MON JUL 16 2018  
   
SHORT TERM
 
 
THIS TRANSITION TO A MORE TYPICAL TO WETTER THAN NORMAL PATTERN  
OCCURRED AS EXPECTED TODAY, BUT THUS FAR MAINLY OVER EASTERN  
PORTIONS OF THE FORECAST AREA. AM STILL EXPECTING AN INCREASE IN  
CONVECTIVE ACTIVITY IN THE CENTRAL TO SOME WESTERN LOCATIONS  
THROUGH THE EARLY EVENING HOURS AS THE NUMEROUS OUTFLOW  
BOUNDARIES INTERACT AND COLLIDE. A FEW LARGE CLUSTERS AND SLOW  
MOVING THUNDERSTORMS HAVE DUMPED TORRENTIAL DOWNPOURS AND FREQUENT  
TO CONTINUOUS LIGHTNING AT TIMES THIS AFTERNOON ACROSS MUCH OF  
THE MISSISSIPPI GULF COAST, AND SOME OTHER LOCATIONS ARE EXPECTED  
TO SEE THIS THROUGH EARLY EVENING.  
 
A MID/UPPER LEVEL HIGH WILL BE BUILDING OVER THE SOUTHWEST CONUS  
INTO THE SOUTHERN PLAINS WHILE TROUGHING DEVELOPS OVER THE GREAT  
LAKES INTO THE MUCH OF THE EASTERN THIRD OF THE CONUS THROUGH  
WEDNESDAY. THIS SUPPRESSION OF THE RIDGE ALOFT IN OUR REGION WILL  
BE COINCIDENT WITH DEEP MOISTURE CONTINUING TO STREAM INTO THE  
REGION. LIKE THIS AFTERNOON, SOME AREAS OVER THE NEXT FEW DAYS  
MAY RECEIVE LOCALLY HEAVY RAINFALL AMOUNTS FROM SLOW MOVING  
THUNDERSTORMS CAPABLE OF PRODUCING PONDING OF WATER IN LOW LYING,  
POORLY DRAINED AREAS AND SOME STREETS. ALSO, AREAS THAT SEE LATER  
CONVECTIVE DEVELOPMENT, WHICH IS OFTEN TYPICAL WHEN THERE IS  
NORTHERLY FLOW ALOFT, WILL HAVE GREATER INSTABILITY AND SOME  
POTENTIAL FOR STRONGER THUNDERSTORMS. THE HIGHER RAIN CHANCES AND  
RESULTANT CLOUD COVER SHOULD TEMPER THE HEAT OVER THE NEXT FEW  
DAYS, BUT CANNOT RULE OUT SOME HEAT INDICES UP IN THE 100 TO 105  
DEGREE RANGE IN SOME DRIER LOCATIONS OR LOCATIONS SEEING RAIN  
DEVELOP LATER IN THE DAY. HOWEVER, NIGHTTIME RAIN CHANCES WILL  
ALSO BE BIT HIGHER THAN NORMAL WHICH COULD SPILL OVER INTO THE  
MORNING HOURS (MAINLY IN THE SOUTHEAST/COASTAL AREAS), SO THAT  
SHOULD ALSO HELP WITH HOLDING DOWN THE HIGH TEMPERATURES. THE  
MODELS ARE IN DECENT AGREEMENT, SO USED A BLEND WHICH ALSO HAS  
GOOD CONTINUITY FROM THE PREVIOUS FORECAST.  
   
LONG TERM
 
 
THE INITIAL SHORTWAVE TROUGH OVER THE EASTERN CONUS WILL MOVE  
EAST INTO THE ATLANTIC OCEAN WHILE ANOTHER DIGGING AND POTENT  
SHORTWAVE TROUGH MOVES INTO THE UPPER MISSISSIPPI VALLEY/GREAT  
LAKES AND OHIO VALLEY TO SOUTHEAST STATES LATE IN THE WEEK INTO  
NEXT WEEKEND. USING A GENERAL BLEND OF THE GLOBAL MODELS, HAVE  
CONTINUED THE HIGHER RAIN CHANCES INTO THURSDAY, AND WOULD EXPECT  
A CONTINUED THREAT OF SOME STRONGER THUNDERSTORMS AND HEAVY  
RAINFALL AMOUNTS.  
 
AN EXPANSION/EXTENSION OF THE SOUTHERN PLAINS HIGH ALOFT INTO THE  
FORECAST AREA SHOULD BRING LESS RAINFALL AND ABOVE NORMAL  
TEMPERATURES WELL INTO THE MID 90S OVER MUCH OF THE FORECAST AREA  
FRIDAY THROUGH NEXT SUNDAY, SO HEAT INDICES ARE STILL FORECAST TO  
REACH 105 TO 110 IN MANY LOCATIONS. WILL HAVE TO MONITOR THIS AS  
THE RAINY PATTERN TRANSITIONS BACK TO DRIER. 22/TD  
 

 
   
AVIATION
 
 
STRONGER TSRA WITH PERIODIC MUCH LOWER VSBY AND LOWER CIG ALONG  
WITH FREQUENT LIGHTNING MAY CONTINUE TO IMPACT A FEW AIRPORTS  
THROUGH EARLY EVENING, OTHERWISE VFR CONDITIONS SHOULD PREVAIL  
THROUGH TUESDAY MORNING. CONVECTIVE DEVELOPMENT ON TUESDAY LIKELY  
TO BE A BIT EARLIER, AND MORE WIDESPREAD. WILL CARRY PROB30 FOR  
MORNING ACTIVITY FOR NOW, BUT THAT MAY NEED TO BE BEEFED UP IN  
LATER FORECASTS. ANY STORMS TODAY OR TUESDAY POTENTIALLY COULD  
PRODUCE MVFR TO IFR CONDITIONS BRIEFLY. 35  
 

 
   
MARINE
 
 
A LARGE RIDGE OF HIGH PRESSURE COVERING MOST OF THE GULF OF MEXICO  
WILL DOMINATE WITH GENERALLY LIGHT WESTERLY WINDS OF AROUND 10  
KNOTS OR LESS AND SEAS/WAVES OF 2 FEET OR LESS THROUGH MOST OF  
NEXT WEEK. THE EXCEPTION IS SOME PERIODIC 10 TO 15 KNOT WIND  
SPEEDS OVER CHANDELEUR SOUND AND SOME MAINLY EASTERN COASTAL  
WATERS AT TIMES DURING LATE AFTERNOON AND NIGHTTIME HOURS THROUGH  
TUESDAY. AN APPROACHING COLD FRONT THAT WILL DISSIPATE WELL NORTH  
OF THE COAST WILL TIGHTEN THE PRESSURE GRADIENT ENOUGH TO PRODUCE  
MORE WIDESPREAD 10 TO 15 KNOT WIND SPEEDS LATE TUESDAY NIGHT INTO  
WEDNESDAY AND THURSDAY AND THURSDAY NIGHT. MORE NUMEROUS  
THUNDERSTORMS WILL CONTINUE TO PRODUCE PERIODIC HIGHER WINDS AND  
SEAS NOT REFLECTED IN THE GENERAL FORECAST DURING LATE NIGHT INTO  
MORNING HOURS THROUGH FRIDAY. 22/TD  
 

 
   
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 73 91 73 90 / 50 50 40 60  
BTR 75 92 76 91 / 30 40 30 50  
ASD 75 91 76 91 / 30 60 50 70  
MSY 78 92 77 91 / 20 50 40 60  
GPT 76 91 77 90 / 30 60 60 70  
PQL 75 90 74 92 / 40 70 60 70  
 

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

 
 

 
 
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