497
FXUS64 KLCH 201317
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
817 AM CDT WED MAY 20 2026
..NEW AVIATION
KEY MESSAGES
- AN UNSETTLED PATTERN WILL BE IN PLACE INTO THE MEMORIAL DAY
HOLIDAY WEEKEND AS THE SOUTHERN JET STREAM BRINGS A SERIES OF
UPPER LEVEL DISTURBANCES TO WORK WITH A VERY MOIST AIR MASS.
- THE SHOWERS AND THUNDERSTORMS THAT DEVELOP WILL HAVE THE
POTENTIAL TO PRODUCE HIGH RAIN RATES AND THERE IS A RISK OF
HEAVY RAINFALL AND A RISK FOR FLOODING INTO EARLY NEXT WEEK.
- ALL INTERESTS IN FLOOD PRONE LOW-LYING AREAS OR FLOOD PRONE
URBAN POOR DRAINAGE AREA, ALONG WITH THOSE ALONG STREAM AND
RIVER BASINS SHOULD KEEP AWARE OF THE LATEST FLOOD RISK
FORECASTS.
- TEMPERATURES WILL REMAIN ON THE WARM AND HUMID SIDE THROUGH THE
PERIOD.
DISCUSSION
(TODAY THROUGH TUESDAY)
ISSUED AT 100 AM CDT WED MAY 20 2026
A COMPLEX OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO MOVE
EASTWARD ACROSS THE FORECAST AREA INTO ACADIANA AND THEN GRADUALLY
WEAKEN BY DAYBREAK. SHOWERS AND OCCASIONAL THUNDERSTORMS WILL
CONTINUE BEHIND THE LINE BEFORE ALSO GRADUALLY DECREASING BY
MORNING. SOME HIGH RAIN FALL RATES, BRIEF GUSTY WINDS, AND
FREQUENT LIGHTNING WILL BE THE MAIN CONCERNS FOR THE NEXT FEW
HOURS.
THE ONGOING CONVECTION IS EXPECTED TO WORK OVER THE ATMOSPHERE
ENOUGH THAT IT IS EXPECTED TO TAKE A WHILE ON WEDNESDAY TO
ACTIVITY GOING AGAIN. WITH A VERY MOIST AIR MASS AND DAYTIME
HEATING, SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY EARLY TO
MID AFTERNOON WITH THE HIGHER CHANCES WHERE THE OLD BOUNDARY WILL
BE LOCATED ACROSS THE FORECAST AREA.
NO REAL CHANGES ARE SEEN IN THE ONGOING FORECAST FOR THE REMAINDER
OF THE WEEK AND INTO THE HOLIDAY WEEKEND, AS GENERALLY AN UPPER
LEVEL TROUGH WILL BE FOUND ACROSS THE WESTERN US INTO THE ROCKIES
WITH AN UPPER LEVEL RIDGE OVER THE EASTERN GULF AND NORTHWEST
CARIBBEAN. IN BETWEEN THE SUB-TROPICAL JET WILL STREAM OVER THE
FORECAST AREA BRINGING MID AND UPPER LEVEL MOISTURE FROM THE
TROPICAL PACIFIC TO GO ALONG WITH THE LOW LEVEL GULF MOISTURE FROM
THE SOUTHERLY FLOW AROUND A SURFACE HIGH EAST OF THE REGION. THIS
WILL ALLOW THE FORECAST AREA TO SEE A HIGHLY ANOMALOUS MOIST AIR
MASS WITH DAILY PWAT VALUES OVER THE 90TH PERCENTILE OF 1.79
INCHES AND NEAR THE MAX MOVING AVERAGE OF 2+ INCHES. MEANWHILE,
MEAN LAYER RELATIVE HUMIDITY BETWEEN 100H-50H WILL BE OVER 80
PERCENT. WARM CLOUD PRECIPITATION PROCESSES WILL ALSO BE NOTED AS
THE WARM CLOUD LAYER IS PROJECTED TO BE FROM 11K TO 15K FEET,
NOTING AN ALMOST TROPICAL LIKE AIR MASS.
SO, WE DO KNOW THAT THERE WILL BE SEVERAL DAYS OF HIGH RAIN CHANCES
WITH POSSIBLE LOCALLY HEAVY RAINFALL AND A FLOOD RISK. WPC HAS
OUTLINED A MAJORITY OF THE FORECAST AREA IN A MARGINAL (1 OUT OF
4) TO SLIGHT (2 OUT OF 4) RISK OR AT LEAST A 5 TO 25 PERCENT
CHANCE OF EXCESSIVE RAINFALL LEADING TO FLOODING FOR EACH DAY
THROUGH SUNDAY, AND EXTENDED WPC HAZARDS KEEP A RISK OF HEAVY
RAINFALL WITH FLOODING POSSIBLE ALL THE WAY THROUGH MAY 27.
WHAT IS OF A LOWER CONFIDENCE IS THE TIMING EACH DAY OF WHEN THE
PRECIPITATION WILL BE THE MOST WIDESPREAD AND AT ITS HEAVIEST. IT
WILL NOT RAIN ALL THE TIME, BUT THE TIMING OF EACH UPPER LEVEL
DISTURBANCE AND IF IT COMES DURING MAX DAYTIME HEATING, WILL BE THE
STORY OF WHEN THE RAIN CHANCES WILL BE THE HIGHEST. SO EACH DAY WILL
BE MORE FINE TUNED THE CLOSER IN TIME WE GET TO EACH DAY.
ALSO, AS THE ANTECEDENT CONDITIONS BECOME MORE MOIST WITH WET
GROUNDS, AND HYDRO FLOW BEGIN TO INCREASE, THE RISK FOR FLOODING
MAY INCREASE IN TIME.
OTHERWISE, TEMPERATURES WILL REMAIN RATHER WARM WITH HUMID
CONDITIONS THROUGH THE PERIOD.
07/RUA
AVIATION
(12Z TAFS)
ISSUED AT 812 AM CDT WED MAY 20 2026
A MIXTURE OF BROKEN TO OVERCAST SKIES AT DIFFERENT LEVELS
(RANGING FROM VFR TO LIFR) WILL PERSIST THROUGH THE MORNING, WITH
ALL SITES BECOMING VFR BY THE MIDDAY. LIGHT AND VARIABLE WINDS
WILL PREVAIL TODAY AS WELL. LATER THIS AFTERNOON INTO TONIGHT,
ANOTHER ROUND OF SHOWERS AND STORMS IS EXPECTED TO AFFECT ALL
SITES, COMING TO AN END BY MIDNIGHT. THESE STORMS WILL HAVE THE
POTENTIAL TO PRODUCE ISOLATED GUSTY WINDS, REDUCTIONS IN VIS,
FREQUENT LIGHTNING, AND LOWER CEILINGS (MVFR TO IFR). CONDITIONS
IMPROVE BACK TO VFR POST-CONVECTION THROUGH TOMORROW MORNING.
MARINE
ISSUED AT 100 AM CDT WED MAY 20 2026
SURFACE HIGH PRESSURE ACROSS THE NORTHERN GULF WITH A STALLED FRONTAL
BOUNDARY TO THE NORTH. THIS WILL ALLOW FOR A PERSISTENT LIGHT TO
MODERATE SOUTHEAST FLOW AND LIGHT TO MODEST SEAS THROUGH THE
WEEK. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL ALSO CONTINUE
THROUGH THE WEEK AND REMAIN HIGH INTO THE WEEKEND AS A SERIES OF
UPPER LEVEL DISTURBANCES PRODUCE SEVERAL WAVES OF PRECIPITATION.
FIRE WEATHER
ISSUED AT 100 AM CDT WED MAY 20 2026
EXPECT MODEST SOUTHERLY WINDS TO CONTINUE THROUGH THE NEXT SEVERAL
DAYS BRINGING IN RICH AMOUNTS OF GULF MOISTURE. AFTERNOON MINIMUM RH
VALUES WILL BE ABOVE 70 PERCENT THROUGH THE WEEK INTO THE WEEKEND.
HIGH CHANCES FOR DAILY SHOWERS AND THUNDERSTORMS ARE ALSO EXPECTED
THROUGH THE WEEK INTO EARLY NEXT WEEK AS A STALLED FRONTAL
BOUNDARY AND A SERIES OF UPPER LEVEL DISTURBANCES PROVIDE WAVES OF
PRECIPITATION EACH DAY. SOME LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE. THE HIGH MINIMUM RELATIVE HUMIDITY VALUES AND EXPECTED
WET ANTECEDENT CONDITIONS IS EXPECTED TO KEEP FIRE WEATHER IN
CHECK.
LCH WATCHES/WARNINGS/ADVISORIES
LA...NONE.
TX...NONE.
GM...NONE.
PUBLIC/FIRE/MARINE...07
AVIATION...17
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