561
FXUS64 KLIX 121044
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
544 AM CDT SAT SEP 12 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 542 AM CDT SAT SEP 12 2026
- AN ELEVATED RISK FOR LOCALIZED HEAVY RAINFALL LEADING TO STREET
FLOODING AND OVERFLOWING OF POOR DRAINAGE WILL CONTINUE TODAY.
- LOWER RAIN CHANCES AND WARMER TEMPS RETURN NEXT WEEK.
SHORT TERM
(NOW THROUGH TUESDAY)
ISSUED AT 1238 AM CDT SAT SEP 12 2026
A SHORTWAVE TROUGH AXIS MOVING TROUGH THE REGION WILL CONTINUE TO
BRING INCREASED RAIN CHANCES TO THE AREA TODAY. THIS TROUGH WILL
INTERACT WITH A VERY MOIST ENVIRONMENT AS NOTED BY PWATS OF 2 TO
2.2 INCHES WHICH ARE IN EXCESS OF THE 75TH PERCENTILE FOR THIS
TIME OF YEAR. AS TEMPERATURES WARM INTO THE 80S, UPDRAFT
DEVELOPMENT WILL BEGIN IN THE MID- MORNING HOURS AND SCATTERED TO
NUMEROUS SHOWERS AND STORMS WILL START TO FIRE UP BY THE LATE
MORNING HOURS. THESE SHOWERS AND STORMS WILL CONTINUE TO FIRE UP
THROUGH THE MID TO LATE AFTERNOON HOURS BEFORE BEGINNING DISSIPATE
IN THE EVENING HOURS WITH THE LOSS OF DAYTIME HEATING. STORM
MOTION WILL REMAIN AROUND 10 MPH AND RAINFALL RATES OF 2 TO 3
INCHES PER HOUR CAN BE EXPECTED WITH THE STRONGEST STORMS. AS A
RESULT, ANOTHER DAY OF LOCALIZED FLOODING CONCERNS, ESPECIALLY FOR
LOW LYING AND POORLY DRAINED URBAN AREAS, WILL BE IN PLAY. THE
REGION REMAINS IN A LEVEL 1 OUT OF 5, MARGINAL, RISK OF FLOODING
FOR TODAY.
THE TROUGH AXIS WILL BEGIN TO PULL EAST OF THE AREA TOMORROW AND A
BROAD UPPER LEVEL RIDGE OVER TEXAS WILL START TO EXPAND EASTWARD.
AS THE INFLUENCE OF THE RIDGE INCREASES, THE MID AND UPPER LEVELS
OF THE ATMOSPHERE WILL BEGIN TO BOTH WARM AND DRY IN RESPONSE TO
INCREASING SUBSIDENCE ON SUNDAY AND MONDAY. THIS WILL ALLOW PWATS
TO FALL TO BETWEEN 1.8 AND 2 INCHES. THESE VALUES ARE STILL
ELEVATED FOR THIS OF YEAR AT BETWEEN THE MEDIAN AND 75TH
PERCENTILE, BUT THE INCREASING RIDGING ALOFT WILL HELP TO SOMEWHAT
LIMIT UPDRAFT DEVELOPMENT. CONVECTIVE ACTIVITY WILL STRUGGLE TO
MAINTAIN ITSELF UNTIL TEMPERATURES WARM INTO THE LOWER 90S AND THE
WEAK MID- LEVEL CAPPING INVERSION IS OVERCOME. OVERALL, SHOWER
AND STORM COVERAGE WILL BE LOWER AND WILL BE MORE CONFINED TO THE
SEA BREEZE AND LAKE BREEZE BOUNDARIES WHERE LOW LEVEL FORCING IS
MAXIMIZED. POP WILL BE CLOSER TO AVERAGE IN THE 30 TO 50 PERCENT
RANGE. ANOTHER CONCERN WILL THE THREAT OF STRONGER WIND GUSTS WITH
THE MOST INTENSE STORMS THAT FORM. DRIER AIR WILL EASILY ENTRAIN
IN THE TALLEST UPDRAFTS AND THIS COULD LEAD TO WINDS OF 40 TO 50
MPH WITH THESE MORE INTENSE STORMS. AN ISOLATED SEVERE WIND GUST
OF 60 MPH CANNOT BE RULED OUT FOR SUNDAY AND MONDAY. THIS IS
SUPPORTED BY DCAPE VALUES OF AROUND 1100 J/KG AND FAVORABLE MODEL
SOUNDING PROFILES EXHIBITING VERY STEEP LAPSE RATES BELOW 3KM IN
EXCESS OF 8.0C/KM.
BY TUESDAY, CONTINUED DRYING AND WARMING ALOFT AS THE RIDGE
BECOMES CENTERED OVER THE TENNESSEE VALLEY WILL PUSH PWATS DOWN TO
AROUND THE MEDIAN VALUES FOR THIS TIME OF YEAR. CONVECTION WILL
FIRE UP LATER IN THE DAY, MORE TOWARD THE MID TO LATE AFTERNOON,
WHEN THE CONVECTIVE TEMPERATURES IN THE LOW TO MID 90S ARE
REACHED. THE END RESULT WILL BE MORE ISOLATED TO WIDELY SCATTERED
SHOWERS AND STORMS AND POP OF 20 TO 40 PERCENT. ONCE AGAIN, STORMS
WILL FIRE UP FIRST ALONG THE SEA BREEZE AND LAKE BREEZE
BOUNDARIES AND THEN FIRE UP ALONG OUTFLOW FROM THE PREVIOUS
CONVECTION AS THOSE FIRST STORMS COLLAPSE SHORTLY AFTER FORMING.
ALTHOUGH THE SEVERE THREAT WILL BE LOWER ON TUESDAY, ONE OR TWO
STORMS COULD TURN STRONG ENOUGH TO PULL IN SOME DRIER AIR ALOFT
AND PRODUCE DAMAGING WIND GUSTS.
LONG TERM
(TUESDAY NIGHT THROUGH FRIDAY)
ISSUED AT 1238 AM CDT SAT SEP 12 2026
BY TUESDAY NIGHT, UPPER LEVEL RIDGING IS EXPECTED TO BE CENTERED
(598DM) NEAR CHATTANOOGA, TENNESSEE. MEANWHILE, AN UPPER TROUGH THAT
MOVES OFF THE MID-ATLANTIC COAST MONDAY NIGHT AND TUESDAY IS
EXPECTED TO CLOSE OFF A LOW OFF THE COAST OF THE CAROLINAS WEDNESDAY
AND HEAD SOUTHWESTWARD AROUND THE UPPER RIDGE, CROSSING FLORIDA AND
ENTERING THE EASTERN GULF THURSDAY NIGHT INTO FRIDAY. THERE'S
ACTUALLY PRETTY DECENT AGREEMENT ON THE MID LEVEL FEATURE BETWEEN
THE GFS AND ECMWF OPERATIONAL RUNS FROM THE DAYTIME HOURS FRIDAY,
AT LEAST THROUGH THE END OF THE WORKWEEK NEXT WEEK.
AT THIS TIME, NEITHER OF THE MEDIUM RANGE MODELS DEVELOPS A SURFACE
LOW OVER THE GULF WITH THIS MID LEVEL FEATURE. THE DRYING OF THE
AIRMASS THAT IS ANTICIPATED FROM THE RIDGING ON SUNDAY AND MONDAY
ACTUALLY CONTINUES THROUGH MOST OF THE WORKWEEK, WITH PRECIPITABLE
WATER VALUES EVEN ON FRIDAY FORECAST TO REMAIN BETWEEN THE 50TH AND
75TH PERCENTILES IN MOST OF THE AREA (1.5 TO 1.8 INCHES).
IF THE MOISTURE DEPICTED IN THE FORECAST SOUNDINGS IS IN THE
BALLPARK, WE MAY NOT SEE A LOT OF THUNDERSTORMS DURING THE WORKWEEK.
THAT WOULD ALSO MEAN THE HOT WEATHER CONTINUES FOR MOST OF NEXT WEEK
WITH TEMPERATURES IN THE MID 90S LOOKING REASONABLE. MAY NOT BE
ENOUGH HUMIDITY TO JUSTIFY HEAT ADVISORIES THOUGH.
BEYOND NEXT FRIDAY, THE GLOBAL OPERATIONAL MODELS FALL OUT OF
AGREEMENT WITH EACH OTHER. THE ECMWF CONTINUES TO TAKE THE MID LEVEL
SYSTEM WESTWARD TO THE TEXAS COAST WITHOUT A LOT OF IMPACT. THE 18Z
GFS BRINGS IT TO ABOUT 90W BEFORE STARTING TO DRIFT IT EAST NEXT
WEEKEND. WE'LL WORRY ABOUT THOSE DIFFERENCES WHEN NEXT WEEKEND FALLS
WITHIN THE RANGE OF THE FORECAST.
AVIATION
(12Z TAFS)
ISSUED AT 542 AM CDT SAT SEP 12 2026
A WEAK INVERSION HAS FORMED OVER SOUTHWEST MISSISSIPPI THIS
MORNING IN RELATION TO LIGHT BOUNDARY LAYER WINDS AND CONTINUED
HIGH RELATIVE HUMIDITY. THIS HAS RESULTED IN LIFR LOW STRATUS AND
FOG DEVELOPMENT AT MCB. THESE CONDITIONS WILL PERSIST THROUGH
AROUND 13Z BEFORE QUICKLY MIXING OUT AS TEMPERATURES BEGIN TO WARM
AND INVERSION LIFTS. PREVAILING VFR CONDITIONS WILL THEN BE FOUND
AT ALL OF THE TERMINALS FROM 13-14Z ONWARD. AFTER 16-17Z,
SCATTERED SHOWERS AND STORMS WILL BEGIN TO DEVELOP AND COULD
IMPACT ANY OF THE TERMINALS. PROB30 WORDING IS IN PLACE FROM 17Z
TO 23Z AT THE MAJORITY OF THE TERMINALS FOR THUNDERSTORM IMPACTS
WITH GUSTY WINDS OF 20 TO 25 KNOTS, LIGHTNING, AND BRIEF
REDUCTIONS IN VISIBILITY. TOWARD THE END OF THE FORECAST PERIOD,
ANOTHER ROUND OF FOG AND STRATUS HAS A DECENT PROBABILITY OF
IMPACTING MCB ONCE AGAIN, AND IFR STRATUS AND FOG IS IN THE
FORECAST FROM 10Z TO 12Z.
MARINE
ISSUED AT 1238 AM CDT SAT SEP 12 2026
WINDS WILL TURN MORE SOUTH-SOUTHWESTERLY BUT WITH THE BERMUDA RIDGE
CENTERED WELL EAST OF THE AREA, WIND SPEEDS SHOULD BE LIGHT AT 10
KNOTS OR LESS TODAY. THE HIGH WILL BECOME MORE CENTERED OVER THE
NORTH-CENTRAL GULF SUNDAY INTO NEXT WEEK. THIS WILL CAUSE WINDS TO
TURN MORE SOUTH-SOUTHEASTERLY AND EVEN LIGHT/VARIABLE AT TIMES. SEAS
WILL GENERALLY REMAIN IN THE 2 FEET OR LESS RANGE. ADDITIONALLY,
THUNDERSTORM ACTIVITY WILL DEVELOP EACH DAY, PEAKING IN THE EARLY TO
MID-MORNING HOURS, AND THESE STORMS WILL PRODUCE HIGHER WIND GUSTS,
WATERSPOUTS, AND LIGHTNING CONCERNS.
LIX WATCHES/WARNINGS/ADVISORIES
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
SHORT TERM...PG
LONG TERM....RW
AVIATION...PG
MARINE...PG
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