516
FXUS64 KLIX 071738 AAC
AFDLIX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1138 AM CST TUE FEB 7 2023
..NEW AVIATION
UPDATE
ISSUED AT 938 AM CST TUE FEB 7 2023
A VERY WEAK SURFACE TROUGH IS HELPING IGNITE POCKETS OF LIGHT TO
MODERATE SHOWER ACTIVITY, GENERALLY ALONG AND EAST OF THE I55
CORRIDOR. THESE SHOWERS WILL BE POSSIBLE OFF AND ON THROUGH THE
AFTERNOON HOURS WITH THE MAIN FOCUS SHIFTING NORTHWARD INTO
INTERIOR SOUTH MISSISSIPPI. MADE A FEW CHANGES TO POPS FOR TODAY,
MOSTLY JUST EXTENDING THE MENTIONABLE POPS WEST TO INCLUDE MOST
OF THE METRO AND THE HAMMOND TO MCCOMB AREAS. WARM AIR ADVECTION
HAS DEVELOPED LEADING TO AN UPTICK IN SURFACE MOISTURE (DEWS NOW
IN THE 60S RESPECTIVELY) AND THE SOUTHERLY RETURN FLOW IS
CERTAINLY DOING ITS JOB IN TERMS OF KEEPING THE AREA A BIT ON THE
WARMER SIDE. FOR TODAY, DID NOT GO AS BULLISH WITH INCREASING
MAXTS ACROSS THE BOARD AS CLOUD COVER WILL LIKELY LIMIT EXCESSIVE
WARMING FROM INSOLATION. (FRYE)
SHORT TERM
(TODAY THROUGH WEDNESDAY)
ISSUED AT 340 AM CST TUE FEB 7 2023
ALOFT, THERE'S RIDGING FROM THE EASTERN GULF OF MEXICO TO NEW
ENGLAND. A NORTHERN STREAM TROUGH WAS MOVING INTO THE WESTERN
GREAT LAKES, WITH A SOUTHERN STREAM TROUGH NEAR THE FOUR CORNERS
REGION AND ANOTHER RIDGE ALONG THE PACIFIC COAST. AT THE SURFACE,
HIGH PRESSURE WAS ALONG THE ATLANTIC COAST. LOW PRESSURE OVER
WESTERN ONTARIO HAD A COLD FRONT TO NEAR CHICAGO, ST. LOUIS,
DALLAS AND ON TO THE TEXAS BIG BEND AREA. RADAR IS STARTING TO
DETECT A FEW VERY LIGHT PRECIPITATION ECHOES OVER THE LOUISIANA
COASTAL PARISHES. AT 3 AM CST, TEMPERATURES IN THE AREA WERE
GENERALLY IN THE 50S AND LOWER 60S, BUT GALLIANO AND BOOTHVILLE
WERE IN THE MID 60S.
AS ONSHORE FLOW CONTINUES TO BECOME BETTER ESTABLISHED TODAY,
ISOLATED SHOWERS WILL BE POSSIBLE IN THE MARINE REGIME. WARM
TEMPERATURES NEAR 700 MB WILL PROVIDE A CAP TO LIMIT DEEP
CONVECTION. ANY RAIN AMOUNTS TODAY WILL BE LIGHT AND BRIEF IN
DURATION. CONCERN OVERNIGHT WILL BE THE POTENTIAL FOR ADVECTION
FOG NEAR THE COAST WITH MID 60S DEW POINTS MOVING OVER WATER
TEMPERATURES IN THE UPPER 50S. QUESTION WILL BE WIND SPEED.
ON WEDNESDAY, THE FOUR CORNERS TROUGH WILL BE MOVING EASTWARD
ACROSS TEXAS AND TAKING ON A NEGATIVE TILT BEFORE IT LIFTS
NORTHEASTWARD. FORECAST SOUNDINGS SHOW VERY DRY MID LEVELS FOR
MUCH OF THE DAY ON WEDNESDAY, WITH PRECIPITABLE WATER VALUES IN
THE 1.0 TO 1.2 RANGE. INSTABILITY DOES INCREASE DURING THE
AFTERNOON, AND BEYOND 21Z THERE'LL BE SOMEWHAT BETTER POTENTIAL
FOR DEEP CONVECTION AS PRECIPITABLE WATER VALUES INCREASE TO
AROUND 1.5 INCHES. ANY ORGANIZED FORCING WILL STILL BE WEST OF THE
CWA THROUGH 00Z THURSDAY.
OVERALL, NBM TEMPERATURE GUIDANCE IS PRETTY CLOSE TO THE
OPERATIONAL DETERMINISTIC NUMBERS THROUGH WEDNESDAY, WITH A BIT OF
NOD TOWARD THE WARMER NUMBERS WHERE THERE IS A DIFFERENCE AWAY
FROM THE COAST.
LONG TERM
(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 340 AM CST TUE FEB 7 2023
MAIN CONCERN DURING THE FORECAST PACKAGE WILL BE DURING THE
OVERNIGHT HOURS WEDNESDAY NIGHT AS A NEGATIVE TILT TROUGH AND
DEEPENING SURFACE LOW LIFT FROM TEXAS TO LAKE MICHIGAN BY
THURSDAY MORNING. LOW LEVEL WINDS CRANK UP BRIEFLY WITH 45-50 KNOT
WINDS AS LOW AS 850-900 MB. GFS FORECAST SOUNDINGS DON'T REALLY
SHOW INSTABILITY AND SHEAR IN SYNC, WHILE THE NAM AND ECMWF SHOW
THEM BOTH AVAILABLE AT THE SAME TIME WEDNESDAY NIGHT. GFS HAS THE
BEST INSTABILITY DURING THE DAY WEDNESDAY, DIMINISHING AFTER
SUNSET, BUT MOST OF THE CONVECTION ALLOWING MODELS HOLD ONTO
ORGANIZED CONVECTION FOR MOST OF THE OVERNIGHT HOURS. WIND FIELDS
BECOME NEARLY UNIDIRECTIONAL, WHICH WOULD FAVOR A QLCS SETUP,
MAINLY FROM INTERSTATE 10 NORTHWARD. THREAT PROBABLY WON'T REACH
WESTERN PORTIONS OF THE AREA UNTIL ABOUT 8 PM WEDNESDAY, REACHING
THE MISSISSIPPI COASTAL COUNTIES IN THE EARLY MORNING HOURS. STILL
SOME QUESTION WHETHER THE FRONT GETS HUNG UP IN THE FAR EASTERN
PORTION OF THE AREA THURSDAY MORNING, AS THE MAIN IMPETUS IS
REMOVED WELL NORTH AND NORTHEAST OF THE AREA. AT THIS TIME, FEEL
ANY SIGNIFICANT THREAT OF THUNDERSTORMS/HEAVY RAIN BEYOND SUNRISE
THURSDAY WILL BE EITHER EAST OF THE AREA OR LIMITED TO THE COASTAL
WATERS AND PERHAPS LOWER PLAQUEMINES PARISH.
A SECOND STRONG NORTHERN STREAM SHORTWAVE WILL FOLLOW RAPIDLY ON
THE HEELS OF THE WEDNESDAY NIGHT SYSTEM, SWEEPING EVERYTHING
EASTWARD THURSDAY NIGHT AND FRIDAY. CAN'T RULE OUT SHOWERS WITH
THAT SYSTEM, BUT STRONG CONVECTION AND HEAVY RAIN ARE NOT
ANTICIPATED OVER OUR AREA. BEHIND THAT SYSTEM, MUCH COOLER/COLDER
AND DRIER AIR FOR THE WEEKEND. SATURDAY/SATURDAY NIGHT WILL SEE
TEMPERATURES WELL BELOW NORMAL, WITH ANOTHER LIGHT FREEZE POSSIBLE
NORTH OF LAKE PONTCHARTRAIN. TEMPERATURES MODERATE QUICKLY EARLY
NEXT WEEK, WITH ANOTHER SOUTHERN STREAM TROUGH POTENTIALLY
BRINGING ANOTHER ROUND OF SHOWERS/STORMS SOMEWHERE AROUND
TUESDAY/WEDNESDAY OF NEXT WEEK.
BEYOND FRIDAY, GFS/ECMWF/NBM DETERMINISTIC NUMBERS ARE IN
SURPRISINGLY GOOD AGREEMENT FOR THE MOST PART. DID HAVE TO SHADE
LOW TEMPERATURES DOWN SOMEWHAT ON SATURDAY/SUNDAY MORNINGS IN THE
USUALLY COOLER LOCATIONS IN THE EASTERN PORTIONS OF THE AREA.
AVIATION
(18Z TAFS)
ISSUED AT 1135 AM CST TUE FEB 7 2023
MOSTLY MVFR THIS AFTERNOON ACROSS THE REGION. A FEW SHOWERS WILL
BE POSSIBLE MAINLY ALONG AND EAST OF THE I55 CORRIDOR. THE
HEAVIEST ACTIVITY MAY BRINGS VIS/CIGS DOWN A CATEGORY FROM THERE.
OVERNIGHT LOW CIGS AND VIS WILL BE POSSIBLE AGAIN AS ADVECTION FOG
BEGINS TO DEVELOP (ESPECIALLY TERMINALS CLOSEST TO THE WATER).
IFR OR PERHAPS LOWER WILL BE POSSIBLE AROUND OR SHORTLY AFTER 06Z
TONIGHT. OTHERWISE, SOUTHEASTERLY WINDS WILL GRADUALLY BE
INCREASING THROUGH THE CYCLE. SOME GRADUAL IMPROVEMENT AT LEAST IN
VIS IS ANTICIPATED BY MID TO LATE MORNING ON WEDNESDAY. (FRYE)
MARINE
ISSUED AT 340 AM CST TUE FEB 7 2023
WILL ALLOW SMALL CRAFT EXERCISE CAUTION HEADLINES TO WIND DOWN
THIS MORNING ON SCHEDULE. ABOUT AN 18-24 HOUR LULL BEFORE GRADIENT
TIGHTENS DURING THE DAY ON WEDNESDAY. QUESTION WILL BE WHETHER
WE'LL NEED AN ADVISORY WEDNESDAY NIGHT OR JUST EXERCISE CAUTION
HEADLINES. DON'T REALLY GET INTO A STRONG COLD ADVECTION SITUATION
UNTIL THE SECOND SHORTWAVE PASSES ON FRIDAY, WITH ADVISORIES
LIKELY TO BE NECESSARY FRIDAY NIGHT INTO SATURDAY.
PRELIMINARY POINT TEMPS/POPS
MCB 72 58 75 54 / 40 20 50 90
BTR 79 61 80 56 / 20 20 50 90
ASD 75 61 76 59 / 30 40 50 80
MSY 77 63 77 59 / 20 30 50 80
GPT 71 60 71 61 / 40 30 40 60
PQL 74 60 75 60 / 30 20 30 50
LIX WATCHES/WARNINGS/ADVISORIES
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
UPDATE...RDF
SHORT TERM...RW
LONG TERM....RW
AVIATION...RDF
MARINE...RW
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