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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