903
FXUS64 KLCH 171129
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
629 AM CDT FRI APR 17 2026
..NEW AVIATION
KEY MESSAGES
- WARM, HUMID CONDITIONS WILL CONTINUE THROUGH SATURDAY AFTERNOON
WITH HIGHS IN THE MID TO UPPER 80S.
- A COLD FRONT WILL MOVE THROUGH THE REGION SATURDAY EVENING INTO EARLY
SUNDAY MORNING ACCOMPANIED BY SHOWERS AND THUNDERSTORMS. SOME
STORMS WILL HAVE THE POTENTIAL FOR LOCALIZED HEAVY RAINFALL.
- STRONG NORTHERLY WINDS ARE EXPECTED FOR THE COASTAL WATERS
BEHIND T HE FRONT SATURDAY NIGHT THROUGH MONDAY WITH THE
POTENTIAL FOR GALE FORCE GUSTS EARLY SUNDAY MORNING.
- COOLER, DRIER AIR WILL MOVE INTO THE REGION SUNDAY THROUGH
TUESDAY WITH GRADUAL WARMING EXPECTED BEGINNING WEDNESDAY.
DISCUSSION
(TODAY THROUGH THURSDAY)
ISSUED AT 1210 AM CDT FRI APR 17 2026
A SURFACE HIGH PRESSURE SYSTEM OVER THE ATLANTIC OCEAN EAST OF THE
FLORIDA COAST WILL CONTINUE TO RIDGE WESTWARD ALONG THE NORTHERN
GULF COAST AND INTO THE FORECAST AREA THROUGH EARLY SATURDAY. THIS
WILL KEEP A WARM AND MUGGY AIR MASS IN PLACE. BOTH HIGH AND LOW
TEMPERATURES WILL BE AROUND 5 DEGREES ABOVE CLIMO NORMS.
A MAINLY DRY WEST-SOUTHWEST WIND ALOFT WILL BE OVER THE FORECAST
AREA THROUGH EARLY SATURDAY THAT WILL HELP KEEP A CAP IN PLACE.
COOLING OF THE BOUNDARY LAYER AT NIGHT WILL HELP FORM CLOUDS IN THE
LOW LEVEL MOISTURE UNDER THE CAP. HOWEVER, BOUNDARY LAYER WINDS ARE
EXPECTED TO STAY UP ENOUGH TO CREATE MIXING TO KEEP ANY WIDESPREAD
FOG FROM FORMING WITH MAINLY A LOW STRATUS CLOUD DECK. DURING THE
DAYTIME, HEATING WILL ALSO PRODUCE SOME CLOUD DECKS, HOWEVER THE CAP
WILL KEEP ANY SIGNIFICANT SHOWER ACTIVITY FROM FORMING.
ON SATURDAY, THE UPPER LEVEL RIDGE OVER THE GULF WILL FLATTEN AND
WEAKEN AS IT SHIFTS TO THE SOUTH. MEANWHILE, A SIGNIFICANT UPPER
LEVEL STORM SYSTEM ORIGINATING FROM THE PACIFIC NORTHWEST WILL
CONTINUE TO MOVE EASTWARD AND DEEPEN INTO A SHARP UPPER LEVEL TROUGH
FROM THE CANADIAN PRAIRIES TO THE SOUTHERN PLAINS. AS IT MOVES
FURTHER EASTWARD, THIS SYSTEM WILL HELP MOVE A SURFACE COLD FRONT
ACROSS THE FORECAST AREA SATURDAY EVENING INTO THE OVERNIGHT.
BOTH EAST PAC AND WESTERN GULF MOISTURE WILL BE PICKED UP AHEAD OF
THE UPPER LEVEL TROUGH AND POOL AHEAD OF THE FRONTAL SYSTEM. THE
MOISTENING AIRMASS WILL HELP ERODE THE CAP AND ALONG WITH FRONTAL
LIFT HELP INITIATE SHOWERS AHEAD OF THE FRONT BY LATE SATURDAY
AFTERNOON. INSTABILITY IS ENOUGH DURING THE LATE AFTERNOON AND EARLY
EVENING HOURS THAT A FEW THUNDERSTORMS SHOULD MIX IN WITH THE SHOWER
ACTIVITY.
NOT MUCH HAS CHANGED IN THE GUIDANCE WITH THIS SYSTEM FROM LOOKING
AT IT YESTERDAY. ANOMALOUSLY HIGH MOISTURE VALUES ARE EXPECTED BY
LATE SATURDAY AFTERNOON INTO SATURDAY NIGHT WITH PWAT VALUES ABOVE
THE 90TH PERCENTILE OF 1.6 INCHES AND NEAR THE MAX MOVING VALUE OF
1.9 INCHES. MEANWHILE, MEAN LAYER RELATIVE HUMIDITY VALUES ARE
PROGGED TO BE ABOVE 80 PERCENT. WHICH MEANS ANY STORMS THAT FORM
COULD BE EFFICIENT PRECIPITATION PRODUCERS. AS THE FRONT MOVES
EASTWARD DURING THE OVERNIGHT, INSTABILITY WILL DECREASE AND
INTENSITY OF THE SHOWER ACTIVITY SHOULD ALSO DECREASE AS THE
ACTIVITY MOVES TOWARD ACADIANA AND THE ATCHAFALAYA BASIN.
FORECAST RAINFALL AMOUNTS WILL FOLLOW THAT SCENARIO WITH HIGHEST
RAINFALL AMOUNTS EXPECTED NORTHWEST OF A BEAUMONT/PORT ARTHUR TO
LAFAYETTE LINE WITH AVERAGE RAINFALL AMOUNTS BETWEEN 0.50 AND 1.25
INCHES. THE PROBABILITY OF A "WETTING" RAIN OR AMOUNTS GREATER THAN
0.25 INCHES IS BETWEEN 50 AND 80 PERCENT IN THAT AREA, AND
PROBABILITY OF OVER 1 INCH IS 30 TO 50 PERCENT IN THAT AREA.
REASONABLY HIGHEST RAINFALL AMOUNTS OR THE 90TH PERCENTILE FROM THE
NBM IS BETWEEN 2 AND 3 INCHES, AGAIN NORTHWEST OF A PORT ARTHUR TO
LAFAYETTE LINE. THESE AMOUNTS COULD BE REACHED IN LOCALIZED AREAS AS
PROGS SHOW THE MEAN WIND SPEED DECREASES AND WINDS BECOME PARALLEL
TO THE THETA-E RIDGE ALONG THE FRONT IN THE EVENING HOURS.
THEREFORE, THERE IS SOME POTENTIAL THAT THE STRONGER CONVECTION WITH
HIGH RAINFALL RATES MAY FALL FOR A LENGTH OF TIME OVER THE SAME
LOCATIONS. THUS, A MARGINAL EXCESSIVE RAINFALL OUTLOOK (LEVEL 1 OUT
OF 4) DURING THE SATURDAY NIGHT TIME PERIOD IS OUTLINED FOR MUCH OF
SOUTHEAST TEXAS, CENTRAL AND SOUTHWEST LOUISIANA.
BEHIND THE FRONT, HIGH PRESSURE RIDGING DOWN FROM THE UPPER MIDWEST
WILL BRING A CONTINENTAL AIR MASS FROM THE CANADIAN PRAIRIES INTO
THE REGION WITH COOLER TEMPERATURES AND DRIER CONDITIONS. THROUGH
MONDAY LOWS AND HIGHS WILL BE SOME 5 TO 10 DEGREES BELOW CLIMO
NORMS.
ALSO, AS THIS AIR MASS MOVES IN, GUSTY NORTHERLY WINDS WILL DEVELOP,
ESPECIALLY OVER THE COASTAL WATERS. THIS WILL BRING ABOUT THE
POTENTIAL FOR SOME MARINE HAZARDS. LREF IS SHOWING BETWEEN A 50 AND
70 PERCENT CHANCE OF GUSTS OVER GALE FORCE ON SUNDAY MORNING, WITH
THE NBM SHOWING BETWEEN A 20 TO 30 PERCENT CHANCE DURING THE SAME
TIME PERIOD, WITH THE HIGHER PROBABILITIES WEST OF CAMERON.
THEREFORE, A GALE WATCH OR WARNING FOR FREQUENT GUSTS OVER 34 KNOTS
WILL BE POSSIBLE.
ALSO, ON SUNDAY AFTERNOON, LOW RELATIVE HUMIDITY VALUES BETWEEN 25
AND 35 PERCENT AND 20 FOOT NORTHEAST WINDS AROUND 15 MPH WITH SOME
HIGHER GUSTS MAY BRING ABOUT SOME DEGREE OF FIRE DANGER, HOWEVER A
LOT WILL DEPEND ON HOW MUCH RAIN FALLS ON SATURDAY NIGHT.
BY MID WEEK, TEMPERATURES BEGIN TO WARM UP AGAIN. A MORE ACTIVE
SOUTHWEST FLOW WILL ALSO ALLOW FOR A CHANCE OF SHOWERS.
07/RUA
AVIATION
(12Z TAFS)
ISSUED AT 605 AM CDT FRI APR 17 2026
PATCHY FOG IS CAUSING MVFR CONDITIONS ALONG THE COAST BUT IFR
CONDITIONS INLAND. AFTER SUNRISE CONDITIONS WILL IMPROVE TO VFR
WITH WINDS FROM THE SOUTH AROUND 10 KNOTS. OVERNIGHT MORE FOG IS
EXPECTED.
MARINE
ISSUED AT 1210 AM CDT FRI APR 17 2026
SURFACE HIGH PRESSURE WILL RIDGE ACROSS THE NORTHERN GULF FROM OFF
THE FLORIDA COAST THROUGH SATURDAY WITH LOW PRESSURE FORMING OVER
THE PLAINS. THIS WILL ALLOW FOR A PERSISTENT MODEST SOUTHERLY FLOW.
A COLD FRONT IS FORECAST TO MOVE THROUGH ON SATURDAY NIGHT WITH
STRONG AND GUSTY NORTHERLY WINDS ALONG WITH BUILDING SEAS BEHIND IT.
THERE IS THE POTENTIAL FOR FREQUENT GUSTS OVER 34 KNOTS AND GALE
FORCE CONDITIONS ON SUNDAY MORNING, ESPECIALLY WEST OF CAMERON AND A
GALE WATCH/WARNING MAY BE NEEDED.
FIRE WEATHER
ISSUED AT 1210 AM CDT FRI APR 17 2026
ALTHOUGH FUELS REMAIN DRY ACROSS THE REGION WITH VARIOUS DEGREES OF
DROUGHT CONTINUES, PERSISTENT SOUTHERLY FLOW FOR INTO SATURDAY WILL
BRING IN LOW LEVEL MOISTURE THAT WILL ALLOW FOR MINIMUM AFTERNOON
RELATIVE HUMIDITY VALUES TO RANGE FROM 40 TO 60 PERCENT, THIS WILL
HELP KEEP THE FIRE DANGER SOMEWHAT IN CHECK THROUGH SATURDAY. A COLD
FRONT WILL MOVE ACROSS SATURDAY NIGHT THAT MAY BRING SOME PORTIONS
OF THE AREA A WETTING RAIN. STRONG NORTHERLY WINDS AND LOW RELATIVE
HUMIDITY VALUES ARE EXPECTED BEHIND THE FRONT ON SUNDAY THAT MAY
BRING ABOUT A FIRE DANGER DEPENDING ON HOW MUCH RAIN FALLS ON
SATURDAY NIGHT. THE LOW RELATIVE HUMIDITY AND DRY CONDITIONS WILL
PERSIST INTO MONDAY WITH SOME POTENTIAL FIRE DANGER, ALTHOUGH WINDS
ARE EXPECTED TO BE LIGHTER.
LCH WATCHES/WARNINGS/ADVISORIES
LA...NONE.
TX...NONE.
GM...NONE.
PUBLIC/FIRE/MARINE...07
AVIATION...14
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