861  
FXUS64 KLIX 281808  
AFDLIX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW ORLEANS LA  
1208 PM CST SUN FEB 28 2021  
   
UPDATE
 
 
AN UNSEASONABLY WARM AND MOSTLY DRY DAY IS SHAPING UP AS FORECAST  
FROM EARLIER. THE ONLY CHANGE MADE TO THE FORECAST WAS TO TRIM  
BACK ON THE AREA WITH MENTION OF THUNDERSTORMS TO THE FAR  
NORTH/NORTHWEST WHERE THE CAP FROM THE MID LEVEL WARM NOSE MAY  
COOL JUST ENOUGH FOR SOME DEEPER CONVECTION. FOG IS EXPECTED TO  
REDEVELOP OVER THE MARINE AREA EARLY THIS EVENING TONIGHT AND  
OVER NEARSHORE/LAKESHORE AREAS AND SPREADING INLAND A BIT LATER IN  
THE EVENING AND OVERNIGHT. WILL LIKELY BE ISSUING A DENSE FOG  
ADVISORY WITH THE AFTERNOON FORECAST PACKAGE. 22/TD  
 

 
   
AVIATION
 
 
MVFR TO VFR CONDITIONS WITH SOME LINGERING LOWER CIGS SHOULD  
IMPROVE TO MOSTLY VFR AFTER 19Z. A FEW SHRA MAY DEVELOP AFTER  
20-21Z, BUT PROBABILITY WAS TOO LOW TO INCLUDE IN THE TAFS.  
ANOTHER NIGHT OR LOWERING CIGS AND THEN LOWER VISIBILITY IS  
EXPECTED TO BRING WIDESPREAD IFR TO LIFR LATE EVENING, OVERNIGHT  
AND INTO MONDAY MORNING. CONDITIONS WILL GRADUALLY IMPROVE DURING  
MID TO LATE MORNING, HOWEVER THERE WILL ALSO BE INCREASING CHANCES  
OF SHRA AND SOME TS. SOUTHERLY WINDS WILL REMAIN GUSTY TODAY  
BEFORE BECOMING LIGHTER DURING THE LATE AFTERNOON AND EARLY  
EVENING. 22/TD  
 

 
   
PREV DISCUSSION
 
/ISSUED 359 AM CST SUN FEB 28 2021/  
 
SYNOPSIS...  
 
LOW PRESSURE OVER IOWA THIS MORNING WITH A COLD FRONT INTO NORTH  
TEXAS. ALOFT, RIDGING IS CENTERED OVER THE EASTERN GULF OF MEXICO,  
WITH A TROUGH FROM THE CANADIAN PRAIRIE PROVINCES TO THE FOUR  
CORNERS AREA OF THE US SOUTHWEST. SOUTHERLY FLOW CONTINUES TO  
TRANSPORT WARM, MOIST AIR NORTHWARD ACROSS THE AREA. LOW CLOUDS  
AND MARINE BASED ADVECTION FOG CONTINUE TO BE ISSUES ACROSS THE  
AREA. TEMPERATURES AT 3 AM CST WERE MAINLY IN THE UPPER 60S AND  
LOWER 70S. NO SIGNIFICANT PRECIPITATION NOTED ON RADAR AT THIS  
TIME ACROSS THE AREA.  
 
SHORT TERM...  
 
TODAY SHOULD PRETTY MUCH BE A REPEAT OF SATURDAY'S WEATHER WITH  
MARINE BASED ADVECTION FOG BURNING OFF OVER LAND DURING THE  
MORNING HOURS. COULD BE SOME ISOLATED SHOWERS IN THE MARINE LAYER  
BELOW THE INVERSION NEAR 700 MB, BUT DON'T SEE ANYTHING STRONG  
ENOUGH TO PUNCH THROUGH FOR THUNDERSTORMS TODAY. NORTHERN STREAM  
SHORTWAVE MOVING THROUGH THE GREAT LAKES ON MONDAY WILL SLOWLY  
PUSH THE COLD FRONT INTO AND THROUGH THE AREA DURING THE DAYTIME  
HOURS ON MONDAY INTO THE NORTHERN GULF MONDAY NIGHT. THE CURRENT  
FOUR CORNERS SHORTWAVE WILL MOVE EASTWARD TO NORTHERN ALABAMA BY  
WEDNESDAY MORNING. LOW PRESSURE WILL DEVELOP ALONG THE FRONT AND  
MOVE ACROSS THE AREA TUESDAY AFTERNOON AND TUESDAY NIGHT. WHERE  
THERE HAD BEEN DISAGREEMENT BETWEEN MODELS OVER THE LAST SEVERAL  
DAYS, THE LAST COUPLE RUNS OF THE GFS HAVE SLOWED DOWN, AND NOW  
HAVE SIMILAR TIMING TO MOST OF THE OTHER MODELS, INCREASING  
CONFIDENCE IN THE FORECAST SCENARIO.  
 
AS THE FRONT MOVES INTO THE AREA ON MONDAY, MOST OF THE  
PRECIPITATION WILL BE NORTH OF THE FRONT, AFTER THE 700 MB  
TEMPERATURES COOL ENOUGH TO ELIMINATE THE INVERSION. COULD BE A  
BRIEF WINDOW AHEAD OF THE FRONT WHERE THE INHIBITION IS WEAK  
ENOUGH TO ALLOW A THUNDERSTORM OR TWO MONDAY AFTERNOON, BUT A  
SOMEWHAT BETTER CHANCE OF THUNDER IS EXPECTED LATE MONDAY NIGHT  
AND TUESDAY AS THE CURRENT FOUR CORNERS SHORTWAVE PUSHES TOWARD  
AND THROUGH THE AREA. THIS CONVECTION WILL NOT BE SURFACE BASED.  
CAN'T RULE OUT A LITTLE SMALL HAIL WITH A FEW OF THE STORMS, BUT  
SEVERE POTENTIAL LOOKS PRETTY LOW. AT THIS POINT, WIDESPREAD HEAVY  
RAIN ACROSS THE AREA DOESN'T LOOK TO BE MUCH OF A THREAT.  
 
EXPECT TEMPERATURES TODAY TO BE FAIRLY CLOSE TO WHAT WE SAW ON  
SATURDAY, AND DEFINITELY ABOVE THE NBM NUMBERS. TONIGHT AND  
MONDAY'S TEMPERATURES WILL BE PREDICATED ON THE LOCATION OF THE  
FRONTAL BOUNDARY, WITH TEMPERATURES LIKELY TO DROP OFF DURING THE  
AFTERNOON BEHIND THE FRONT. FIFTY MILES COULD MAKE A SIGNIFICANT  
DIFFERENCE IN THE SENSIBLE WEATHER ON MONDAY. TUESDAY HIGHS WILL  
BE GENERALLY 15-20 DEGREES COOLER THAN TODAY, AND MAY STILL NEED  
LOWERED A COUPLE MORE DEGREES IN LATER FORECASTS, AS WE ARE STILL  
RUNNING ABOVE THE MAV NUMBERS. THERE'S AT LEAST A LITTLE POTENTIAL  
FOR A BUST IF THE SURFACE LOW MOVES INLAND AND PORTIONS OF THE  
AREA GET IN THE WARM SECTOR BEFORE THE LOW GETS EAST OF THE AREA  
TUESDAY EVENING. 35  
 
LONG TERM (WEDNESDAY AND BEYOND)...  
 
WEDNESDAY WILL START OFF WITH HIGH PRESSURE BUILDING IN BEHIND A  
DEPARTING STORM SYSTEM TO OUR EAST, WITH CLEARING SKIES AND  
RELATIVELY MILD AFTERNOON TEMPERATURES. THIS HIGH SETTLES IN ACROSS  
THE NORTHERN GULF COAST WEDNESDAY NIGHT AND INTO EARLY THURSDAY,  
HELPING TO SUPPORT RADIATIONAL COOLING FROM CALM WINDS, CLEAR SKIES  
AND AMPLE TROPOSPHERIC SUBSIDENCE AT PLAY. LOOK FOR MORNING LOWS IN  
THE MID TO A FEW LOWER 40'S, ESPECIALLY ALONG AND NORTH OF I-10/12  
COME DAYBREAK THURSDAY. MAY HAVE TO MONITOR TRENDS HERE, AS BLENDS  
SOMETIMES SUFFER ON TEMPERATURES ANOMALIES CHARACTERIZED BY SMALL-  
SCALE PROCESSES (RADIATIONAL COOLING/COLD AIR DRAINAGE) WHICH MAY  
LEAD TO TEMPERATURES ATLEAST A FEW DEGREES COOLER THAN WHAT IS  
ALREADY FORECAST, BUT WILL WATCH TRENDS FOR ANY FUTURE ADJUSTMENTS.  
 
BEYOND THIS TIME FRAME, FOCUS BEGINS TO SHIFT BACK TO THE WEST YET  
AGAIN AS A DEEP, CLOSED OFF UPPER-LEVEL LOW TRACKS EAST ACROSS THE  
FOUR CORNERS REGION. SOMETHING TO MONITOR HERE THAT IS TYPICAL WITH  
THIS TYPE OF SYNOPTIC SET UP IS THE PROXIMITY OF THIS LOW SOUTH OF A  
VERY DEEP RIDGE AXIS ACROSS THE WESTERN US THAT CAN LEAD TO A SLOWER  
EASTWARD PROGRESSION. SOMETHING THAT THE GFS APPEARS TO HAVE BEEN  
STARTING TO PICK UP ON AND IS NOW BECOMING BETTER IN LINE WITH ECMWF  
SOLUTIONS. BECAUSE OF THIS TREND, HAVE PULLED BACK POP'S ON THURSDAY  
WITH A MOSTLY DRY DAY FOR MANY. BUT THIS SYSTEM WILL STILL  
EVENTUALLY DIVE MORE ESE WITH TIME AS DEEPER TROUGHING DEVELOPS  
ACROSS THE NE US, SENDING THE DEEP UPPER-LOW/TRANSITIONING SHORTWAVE  
TROUGH AND SURFACE LOW TOWARDS THE NORTHERN GULF COAST. NOT GOING TO  
DIVE INTO SPECIFICS YET, AS MODELS HAVE BEEN HANDLING THIS TIME  
PERIOD POORLY IN THE PAST FEW DAYS AND WANT TO STAY ON TRENDS AND  
GET CLOSER INTO EARLY NEXT WEEK BEFORE MENTIONING SPECIFIC HAZARDS  
THAT MAY BE POSSIBLE ON FRIDAY. THE GOOD NEWS IS THIS SYSTEM  
QUICKLY IS OUT OF HERE JUST IN TIME FOR NEXT WEEKEND, WITH TRENDS  
LEANING TOWARDS AROUND BELOW NORMAL TEMPERATURES (5-10 DEGREES OR  
SO BELOW NORMAL) AND STAYING DRY. KLG  
 
AVIATION (VALID THROUGH 18Z MONDAY)...  
 
MAIN FOCUS FOR EARLY THIS MORNING WILL BE AREAS OF LOW CIG'S AND  
SURFACE FOG LIKELY IN AND AROUND COASTAL TAF SITE LOCATIONS. AT  
THIS TIME, THE HIGHEST CONFIDENCE FOR DENSE SURFACE FOG WILL  
CONTINUE TO BE ALONG THE MISSISSIPPI COASTLINE, WEST TO AROUND  
INTERSTATE 55 AND SOUTH ALONG COASTAL SE LA. FOR TAF SITES IN THIS  
REGION, EXPECT IFR TO PERIODIC LIFR FLIGHT CATEGORIES THROUGH  
ATLEAST 12-14Z. BEYOND THIS TIME FRAME, ANY LINGERING FOG WILL  
LIKELY BE FOR NEAR COASTAL MARINE AREAS ALONG THE MS COAST, ANY  
TIDAL LAKES/SOUNDS AND ACROSS COASTAL SE LA THROUGH AROUND NOON TO  
POSSIBLY EARLY AFTERNOON. HOWEVER, CONDITIONS ARE EXPECTED TO  
IMPROVE FOR INLAND AREAS AFTER MID/LATE MORNING WITH VFR FLIGHT  
CATEGORIES EXPECTED FOR ALL TERMINAL SITES THEREAFTER. A FEW  
ISOLATED SHOWERS OR THUNDERSTORMS MAY BE POSSIBLE WEST OF I-55 IN  
THE AFTERNOON, BUT SHOULD REFRAIN FROM BECOMING A SIGNIFICANT  
HAZARD AT THIS TIME. ANTICIPATE MARINE FOG WILL AGAIN MOVE INLAND  
OVERNIGHT, PRIMARILY BEYOND 06Z MONDAY, WITH IFR OR LOWER  
CONDITIONS AGAIN EXPECTED.  
 
COLD FRONT LIKELY WILL NOT MOVE SOUTHWARD THROUGH KMCB UNTIL  
BEYOND 12Z MONDAY, GRADUALLY WORKING SOUTHWARD DURING THE DAYLIGHT  
HOURS. IT MAY REACH KMSY JUST BEFORE THE END OF THE 30 HOUR TAF  
WINDOW FOR THAT TERMINAL IN THE UPCOMING 12Z PACKAGE. KLG/35  
 
MARINE...  
 
WINDS WILL PICK UP A BIT TODAY, BUT REMAIN NEAR OR BELOW 15 KNOTS.  
FOG CONTINUES TO BE AN ISSUE OVER THE NEARSHORE AND PROTECTED  
WATERS. DENSE FOG ADVISORY WILL CONTINUE THROUGH MID-DAY, AND WILL  
LIKELY BE REISSUED AT SOME POINT FOR OVERNIGHT INTO MONDAY.  
TONIGHT SHOULD BE THE LAST NIGHT FOR THE FOG AS A FRONT SLIDES  
SOUTHWARD INTO THE NORTHERN GULF OF MEXICO DURING THE DAY ON  
MONDAY, WITH OFFSHORE FLOW DEVELOPING. IF ANY WIND RELATED  
HEADLINES ARE NECESSARY OVER THE NEXT 5 DAYS, IT WOULD PROBABLY BE  
LATE MONDAY NIGHT OR TUESDAY, AS OFFSHORE WINDS MAY CREEP ABOVE 15  
KNOTS FOR 6-12 HOURS. 35  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
MCB 82 63 71 50 / 30 40 70 70  
BTR 84 66 75 55 / 20 20 70 70  
ASD 83 66 76 54 / 20 20 70 60  
MSY 83 66 78 57 / 20 10 70 60  
GPT 78 63 75 54 / 20 20 70 60  
PQL 80 65 76 54 / 20 20 60 50  
 

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

 
 

 
 
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