699
FXUS64 KHGX 271852
AFDHGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
152 PM CDT SUN SEP 27 2026
..NEW DISCUSSION, AVIATION, MARINE
KEY MESSAGES
- PATTERN CHANGE WILL OCCUR MID-WEEK THIS WEEK, WITH INCREASING
POTENTIAL FOR SHOWERS AND THUNDERSTORMS
- SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF SE TEXAS ON
WEDNESDAY AND ALL OF SE TEXAS ON THURSDAY
DISCUSSION
ISSUED AT 1230 PM CDT SUN SEP 27 2026
THE AXIS OF THE MID-UPPER LEVEL RIDGE WILL CONTINUE TO SHIFT EAST
DURING THE MONDAY, AS REMNANTS OF POLO MERGE WITH AN AMPLIFIED
TROUGH MOVING IN FROM THE CALIFORNIA AREA. OVER THE NEXT COUPLE OF
DAYS A SERIES OF WEAK IMPULSES ALOFT WILL MOVE THROUGH AND
INTERACT WITH THE WARM AIR ADVECTION FROM THE GULF, RESULTING IN
ISOLATED SHOWERS AND STORMS ALONG THE COAST AND GULF WATERS MONDAY
AND TUESDAY.
THE AFOREMENTIONED TROUGH WILL SLOW DOWN UPON ARRIVAL INTO TEXAS,
BY WHICH POINT THE REMNANTS OF POLO ARE EXPECTED TO HAVE BECOME
ENGULFED WITHIN THE OVERALL FLOW. POLO'S REMNANTS WILL BRING AN
EXTRA SURGE OF TROPICAL MOISTURE INTO THE REGION AS IT MERGES WITH
THE TROUGH. AT THE SAME TIME, SOUTHEASTERLY FLOW IN THE LOWER
LEVELS WILL PULL IN MOISTURE FROM THE GULF. AS A RESULT, PWAT
VALUES WILL INCREASE INTO THE 2.3-2.5" RANGE (>99TH PERCENTILE FOR
THIS TIME OF YEAR).
THE AMOUNT OF RAINFALL SOUTHEAST TEXAS WILL EXPERIENCE WILL DEPEND
HEAVILY ON:
1) WHERE THE TROUGH AXIS SETS UP
2) HOW MUCH THE TROUGH SLOWS DOWN ONCE IT ARRIVES IN TEXAS
RIGHT NOW IT LOOKS LIKE A BATTLE BETWEEN PRESSURE SYSTEMS...TO
START, AS THE TROUGH ARRIVES IN TEXAS, A SECOND AREA OF LOW
PRESSURE LOOKS TO DEVELOP OVER THE GULF OF AMERICA, IMPACTING THE
FLOW OF THE WESTERNMOST TROUGH (SLOWING THE PROGRESSION). BY
THURSDAY, HIGH PRESSURE OFF THE EAST CONUS EXPANDS OVER THE
SOUTHEASTERN CONUS, PUSHING THE LOW PRESSURE IN THE GULF SOUTHWARD
AND PUSHING AGAINST THE TROUGH OVER TEXAS (CONTINUING TO SLOW THE
PROGRESSION).
MODELS BEGIN TO DIVERGE ON WHAT HAPPENS THURSDAY THROUGH THE
WEEKEND. GFS REMAINS MORE PROGRESSIVE AND THE TROUGH BECOMES
ABSORBED INTO WHAT IS CURRENTLY TD 18-E IN THE PACIFIC. ECMWF
REMAINS THE SLOWER SOLUTION AND KEEPS THE PACIFIC TROPICAL SYSTEM
OFFSHORE, ALLOWING THE TROUGH OVER TEXAS TO HANG AROUND THROUGH
MOST OF THE WEEKEND.
SO WHAT DOES THIS MEAN FOR SOUTHEAST TEXAS? RIGHT NOW WE ARE
SEEING INCREASING POTENTIAL FOR SHOWERS AND THUNDERSTORMS FOR THE
LATTER HALF OF THE WEEK, WITH HEAVY RAINFALL POTENTIAL ALSO
INCREASING. ENSEMBLE GUIDANCE HAS CONSISTENTLY SHOWN 99TH
PERCENTILE RANGE FOR MOISTURE. PROBABILISTIC GUIDANCE HAS BEEN
STEADILY INCREASING THE CHANCE OF MOST OF THE AREA SEEING AT LEAST
AN INCH OF RAINFALL (60-80% CHANCE THIS FORECAST PERIOD) AND THERE
HAS BEEN A SLIGHT UPTICK IN THE CHANCE OF SOME LOCATIONS WITHIN
THE OVERALL AREA SEEING GREATER THAN 2" OF RAINFALL (30-45%).
THE THING WE WILL WANT TO KEEP AN EYE ON OVER THE NEXT COUPLE OF
DAYS IS HOW THE TROUGH EVOLVES, WHERE THE AXIS SETS UP, AND IF THE
AFOREMENTIONED PRESSURE SYSTEMS OVER THE EASTERN CONUS/GULF
STRENGTHEN OR WEAKEN. IF THE AXIS SHIFTS MORE EAST THAN WHAT IS
CURRENTLY FORECAST AND THE SYSTEM SLOWS DOWN/STALLS, THAT WOULD
CERTAINLY INCREASE THE QPF FOR SOUTHEAST TEXAS, AS WELL AS THE
POTENTIAL FOR FLASH FLOODING.
CURRENTLY, WPC HAS MOST OF THE AREA IN A SLIGHT RISK FOR EXCESSIVE
RAINFALL FOR WEDNESDAY, AND FOR THE ENTIRE AREA ON THURSDAY. QPF
FOR WEDNESDAY THROUGH THE WEEKEND IS AROUND 3-5". I WOULD LIKE TO
POINT OUT, AGAIN, TO NOT FOCUS ON EXACT AMOUNTS, AND INSTEAD ON
POTENTIAL IMPACTS. THIS FORECAST CONTINUES TO EVOLVE, AND WILL
LIKELY CONTINUE TO EVOLVE OVER THE COMING DAYS, ESPECIALLY WHEN
HI-RES GUIDANCE COMES IN.
AS FAR AS TEMPERATURES ARE CONCERNED, HIGHS WILL BE IN THE 90S FOR
A FEW MORE DAYS, WITH RAINFALL EXPECTED TO BRING HIGHS DOWN INTO
THE 80S DURING THE LATTER PART OF THE WEEK. LOWS WILL BE IN THE
70S THROUGH THE WEEK. A FRONTAL BOUNDARY IS PROJECTED TO MOVE
THROUGH THE AREA DURING THE DAY SATURDAY, BRINGING DRIER AIR AND
SLIGHTLY COOLER TEMPERATURES. HIGHS SATURDAY AND SUNDAY ARE
FORECAST TO BE IN THE LOW TO MID 80S.
BAILEY
AVIATION
(18Z TAF ISSUANCE)
ISSUED AT 1230 PM CDT SUN SEP 27 2026
VFR CONDITIONS PERSIST FOR THE ENTIRE FORECAST PERIOD. ANY POPCORN
CONVECTION OR SHOWERS ARE ANTICIPATED TO REMAIN CONFINED TO THE EAST
OF GLS AND OFF SHORE. THE LIGHT SE CONTINUES BEFORE RELAXING
OVERNIGHT. LOW-LYING AREAS AROUND CXO HAVE THE CHANCE AROUND SUNRISE
FOR BR TO DEVELOP AND BRIEFLY REDUCE VIS TO MVFR. THIS CLEARS AS
WINDS PICK BACK UP, ONCE AGAIN, OUT THE SE. THE MAIN DIFFERENCE FOR
TOMORROW WILL BE THE INCREASED WINDS AND GUSTS PERIODICALLY IN THE
AFTERNOON/EVENING.
CMW
MARINE
ISSUED AT 1230 PM CDT SUN SEP 27 2026
LIGHT EAST TO SOUTHEAST WINDS AND LOW SEAS WILL PREVAIL TODAY.
UNSETTLED WEATHER IS EXPECTED AS EARLY AS TUESDAY AND CONTINUING
THROUGH THE WEEKEND. THIS WILL BE THE RESULT OF A DISTURBANCE
MOVING THROUGH THE PLAINS AND EJECTING A FRONTAL BOUNDARY INTO
SOUTHEAST TEXAS. PERIODS OF SHOWERS AND THUNDERSTORMS WILL PEAK
THURSDAY AND FRIDAY, WITH ELEVATED WINDS AND BUILDING SEAS UP TO 8
FEET. SMALL CRAFT ADVISORIES WILL LIKELY BE IN EFFECT AFTER
MIDWEEK
BAILEY
PRELIMINARY POINT TEMPS/POPS
COLLEGE STATION (CLL) 97 73 96 72 / 0 0 0 0
HOUSTON (IAH) 94 76 94 76 / 10 0 10 0
GALVESTON (GLS) 88 82 88 82 / 20 0 20 0
HGX WATCHES/WARNINGS/ADVISORIES
TX...NONE.
GM...NONE.
DISCUSSION...BAILEY
AVIATION...CMW
MARINE...BAILEY
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