557
FXUS64 KLIX 291803
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
103 PM CDT TUE SEP 29 2026
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1250 PM CDT TUE SEP 29 2026
- SCATTERED TO LOCALLY NUMEROUS SHOWERS AND A FEW STORMS WILL
RETURN TO THE AREA THURSDAY AFTERNOON. ONE OR TWO STORMS COULD
BECOME STRONG, PRODUCING GUSTY WINDS, FREQUENT LIGHTNING AND
BRIEF PERIODS OF HEAVY RAINFALL.
- CONFIDENCE IS INCREASING THAT WIDESPREAD RAIN AND EMBEDDED
THUNDERSTORMS WILL AFFECT THE AREA FRIDAY THROUGH AT LEAST
SUNDAY. WHILE SPECIFIC RAINFALL TOTALS ARE STILL UNCERTAIN,
HEAVY RAIN AND AT LEAST LOCALIZED FLASH FLOODING WILL BE A
THREAT. RESIDENTS SHOULD CONTINUE TO MONITOR THE FORECAST FOR
UPDATES REGARDING THIS THREAT.
SHORT TERM
(NOW THROUGH THURSDAY)
ISSUED AT 1250 PM CDT TUE SEP 29 2026
WEATHER WILL REMAIN FAIRLY QUIET THROUGH TOMORROW AS MID/UPPER
RIDGING CONTINUES TO SUPPRESS CONVECTION.
EXPECT TO SEE A RATHER QUICK INCREASE IN ATMOSPHERIC MOISTURE
BEGINNING THURSDAY AS DEEPER TROPICAL MOISTURE BEGINS TO MOVE
INTO THE AREA. AT THE SAME TIME, THE MID/UPPER RIDGING WILL BEGIN
TO BREAK DOWN AS AN UPPER TROUGH MOVES THROUGH THE PLAINS STATES
TOWARD THE MISSISSIPPI VALLEY.
THIS WILL ALLOW FOR SCATTERED TO LOCALLY NUMEROUS SHOWERS TO
DEVELOP MAINLY DURING THE AFTERNOON HOURS AS DAYTIME HEATING WILL
BE NECESSARY TO BREAK THROUGH THE REMAINING CAP. THAT BEING SAID,
WE CAN'T RULE OUT A COUPLE THUNDERSTORMS, AND ANY STORMS THAT DO
BREAK THROUGH THE CAP WILL BE CAPABLE OF PRODUCING GUSTY WINDS,
LIGHTNING AND AND BRIEF PERIODS OF HEAVY RAINFALL.
TEMPERATURES WILL REMAIN WARMER THAN NORMAL THROUGH THE PERIOD.
LONG TERM
(FRIDAY THROUGH MONDAY)
ISSUED AT 1250 PM CDT TUE SEP 29 2026
FRIDAY THROUGH MONDAY LOOK TO BE QUITE ACTIVE WEATHER-WISE.
GENERALLY SPEAKING, A TROPICAL WAVE WILL BE MOVING NORTHWESTWARD
OUT OF THE CARIBBEAN AND TOWARD THE NORTHERN GULF COAST. AT THE
SAME TIME, THE PREVIOUSLY MENTIONED UPPER TROUGH WILL MOVE INTO
THE MIDDLE MISSISSIPPI VALLEY BEFORE FLATTENING AND LIFTING
NORTHEASTWARD. THIS WILL FORCE A SLOW-MOVING COLD FRONT TOWARD
THE AREA AS WELL. THESE TWO SYSTEMS WILL INTERACT RESULTING IN
WIDESPREAD RAINFALL WITH EMBEDDED THUNDERSTORMS ACROSS THE LOCAL
AREA MAINLY FROM LATE FRIDAY THROUGH SUNDAY, WITH THE MOST INTENSE
RAIN TAPERING OFF BY MONDAY.
TO PUT THE FORECAST MOISTURE AVAILABILITY IN PERSPECTIVE, MOST
GUIDANCE INDICATES PRECIPITABLE WATER VALUES WILL BE APPROACHING
2.5 INCHES ACROSS MUCH OF THE AREA BY LATE FRIDAY WITH SIMILAR
VALUES SATURDAY AND SUNDAY. PW VALUES LIKE THESE ARE WELL ABOVE
THE 90TH PERCENTILE FOR THIS TIME OF YEAR AND NEARING THE DAILY
MAXIMUM OBSERVED VALUES FOR THE OCT 2-4 TIME FRAME. THIS WILL
RESULT IN PRIME CONDITIONS FOR EFFICIENT RAINFALL PROCESSES, AND
IN FACT THE MODEL FORECAST SOUNDING PROFILES ARE BASICALLY MOIST
ADIABATIC FROM THE SURFACE TO THE TROPOPAUSE.
HEAVIEST RAIN WILL LIKELY OCCUR SATURDAY INTO SUNDAY WHEN
INSTANTANEOUS RATES OF OVER 4 INCHES PER HOUR WILL BE POSSIBLE IN
THE HEAVIEST STORMS. RAINFALL RATES LIKE THESE, EVEN OVER SHORT
PERIODS CAN EASILY OVERWHELM DRAINAGE CAPACITY IN URBAN AND OTHER
POOR DRAINAGE AREAS. CURRENTLY WE ARE HIGHLIGHTING A SLIGHT RISK
OF EXCESSIVE RAINFALL/FLASH FLOODING FOR SATURDAY, BUT IF
CONFIDENCE CONTINUES TO INCREASE IN THIS THREAT, WOULD NOT BE
OVERLY SURPRISED TO SEE THAT THREAT LEVEL INCREASE TO MODERATE.
EXPECT TO SEE A SLIGHT RISK INTRODUCED FOR SUNDAY WHEN SUNDAY
BECOMES "DAY 5" TOMORROW AS WELL.
CURRENT STORM TOTALS FOR THE FRIDAY THROUGH SUNDAY PERIOD ARE
FORECAST IN THE 3-6" RANGE, BUT THIS COMES WITH A BIG CAVEAT THAT
THERE WILL LIKELY BE POCKETS OF HIGHER TOTALS. THE UPPER END
POTENTIAL IS REALLY TOUGH TO NAIL DOWN AT THIS POINT GIVEN THE
SEVERAL DAYS LEAD TIME, BUT IT CERTAINLY WOULDN'T BE OUT OF THE
QUESTION FOR A COUPLE PLACES TO BE APPROACHING THE 10" MARK OVER
THE THREE-DAY PERIOD.
IF THERE'S ANY GOOD NEWS TO GLEAM, IT'S THAT RIVERS ACROSS THE
REGION ARE AT BASE FLOW OR LOWER RIGHT NOW AND THUS STORAGE
CAPACITY IS HIGH. CURRENT ENSEMBLE GUIDANCE IS GENERALLY INDICATING
A 10% OR LOWER CHANCE OF REACHING MINOR FLOOD STAGE AT ANY GIVEN
RIVER FORECAST POINT. WOULDN'T BE SURPRISED TO SEE THOSE
PROBABILITIES COME UP IN A FEW PLACES AS THE FORECAST ITSELF
BECOMES CLEARER AND THE RANGE OF POSSIBILITIES THEREFORE
DECREASES. BUT FOR NOW, THIS APPEARS TO BE MORE OF A FLASH FLOOD
CONCERN THAN A SIGNIFICANT RIVER FLOOD CONCERN.
AVIATION
(18Z TAFS)
ISSUED AT 1250 PM CDT TUE SEP 29 2026
UNDER THE INFLUENCE OF CONTINUED HIGH PRESSURE, VFR CONDITIONS
WILL PREVAIL THROUGH THE PERIOD. THE PRESSURE GRADIENT WILL BEGIN
TO TIGHTEN WEDNESDAY, LEADING TO A SLIGHT INCREASE IN WIND SPEEDS
TO AROUND 10 KNOTS AT MOST TERMINALS.
MARINE
ISSUED AT 1250 PM CDT TUE SEP 29 2026
ONSHORE FLOW WILL BECOME DOMINANT AGAIN TODAY AROUND AROUND 10
KNOTS. AS THE WEEK PROGRESSES, THE PRESSURE GRADIENT WILL TIGHTEN
CAUSING WINDS TO BEGIN STRENGTHENING TO 15 TO 20 KNOTS BY THURSDAY
OR THURSDAY NIGHT. SHOWERS AND SOME THUNDERSTORMS WILL BEGIN TO
INCREASE IN COVERAGE TOWARD THE END OF THE WEEK AS WELL AS A
TROPICAL WAVE MOVES THROUGH THE NORTHERN GULF AND INTERACTS WITH AN
APPROACHING WEAK COLD FRONT.
LIX WATCHES/WARNINGS/ADVISORIES
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
SHORT TERM...DM
LONG TERM....DM
AVIATION...DM
MARINE...DM
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