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National Weather Service Forecast Discussion

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480
FXUS64 KHGX 281947
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
247 PM CDT Mon Sep 28 2026

...New DISCUSSION, MARINE...

.KEY MESSAGES...

-  Hot and slightly more humid conditions continue Tuesday with
   isolated coastal showers/storms.

-  Periods of showers and storms are expected each day, peaking
   from Wednesday to Saturday. Locally heavy rain will be
   possible.

- Rain chances and increased cloud cover will keep temperatures
  near seasonal levels through most of the forecast period.


&&

.DISCUSSION...
Issued at 145 PM CDT Mon Sep 28 2026

One more day of hot and humid weather is on tap before the pattern
transitions to become more cloudy, rainy, and slightly cooler...

Looking at where things are today...we have the ridge axis
bisecting the state this afternoon with an amplified trough
moving into California from the Pacific. As this trough continues
to move inland through the day and into the overnight hours it
will continue to nudge the ridge axis eastward. Once the trough
approaches the Four Corners, it is expected to be met by what will
then be the remnants of Polo from the Baja California area
(Hurricane Polo is expected to move inland into Mexico early
Tuesday morning and quickly weaken as it moves NE and interacts
with the high terrain). Polo`s remnants will merge into the
overall flow of this trough and continue a slow eastward
progression through the rest of the week.

So, for Tuesday, expecting southeast Texas to still have influence
from the ridge as the axis moves across our area during that time.
Highs across the area will still be in the 90s, and with
increasing humidity, expect to see heat indices in the upper 90s
to around 105F. Our coastal locations and southern most locations
may see some isolated to scattered development in the afternoon,
particularly as the sea breeze moves in and begins to interact
with the moisture in the area.

Wednesday, the mid- upper level trough moves into New Mexico and
extends into the central portion of Texas. Models continue to show
the eastward progression of the trough and its associated cold
front slowing down on approach to North/Central Texas as high
pressure builds across the eastern CONUS. This trough, along with
Polo`s remnants will pull moisture into the mid-upper levels from
the Pacific. At the surface, persistent onshore flow will bring
moisture into the area from the Gulf of America. As a result we
will see PWAT values increase to around 2.0". Weak impulses in the
eastern periphery of the trough will move across the area
Wednesday and interact with the moisture, bringing isolated to
scattered showers and thunderstorms through Southeast Texas.

Thursday into Friday appears to be the peak rainfall days for this
event. At this point models show a pre-frontal surface trough
developing in the vicinity of southeast Texas. This will
provide moisture convergence in the lower levels. The moisture
convergence from the pre- frontal trough combined with the
arrival of the mid-upper level plume of moisture from the Pacific
will consequently result in PWAT values increasing to around 2.5"
(as mentioned by previous forecaster this is around 2 to 3
standard deviations above normal). This setup will be favorable
for heavy rainfall and instances of flash flooding.

WPC has maintained a slight risk for portions of the Brazos Valley
on Wednesday, and for most of the area (including the City of
Houston) on Thursday. This continues to be an evolving forecast,
and will be largely dependent on how much the trough slows down,
where the frontal boundary stalls, and for how long as well as how
any outflow boundaries from the Hill Country area behave.
Guidance has gradually shifted the axis of highest rainfall
westward (Hill Country NEward into Dallas receiving the highest
amounts); however, Hi-Res guidance will provide more insight and
confidence in the next day or two.

At this time, confidence is increasing in most of the area seeing
at least 1-2" of rainfall through the latter part of the week with
locations across the Brazos Valley and Piney Woods seeing around
3-4". Confidence on details pertaining to the frontal boundary and
where any of the heavier convective showers may occur remain low.


Continue to monitor the forecast over the coming days for updates.

Rain chances are projected to continue into the weekend as
moisture lingers and the front gradually moves through.
Temperatures during the day will be in the 80s this weekend
through early next week. Nighttime lows will generally be in the
70s with a few locations in the Brazos Valley/Piney Woods dipping
into the upper 60s.

Bailey



&&

.AVIATION...
(18Z TAF Issuance)
Issued at 102 PM CDT Mon Sep 28 2026

VFR conditions prevail today despite a few isol showers along the
coast. A SE breeze between 5-10kts will continue throughout the day
before relaxing overnight. During the sunrise hours a brief period
of MVFR VIS and BR is possible within low-lying areas. Tomorrow
winds pick back up in the early afternoon with the chance for gusts
up to 20kts and continue to remain out of the SE.

CMW

&&

.MARINE...
Issued at 145 PM CDT Mon Sep 28 2026

A gentle to moderate (BF 3-4) east to southeasterly flow is expected
to persist, along with seas between 2-3 feet, through Tuesday
afternoon. Winds are forecast to increase to fresh to strong (BF 5-
6) by Tuesday night as low pressure deepens over West Texas. Small
Craft Advisories may be needed as early as Tuesday night with
advisory conditions continuing through Thursday. Isolated to
scattered showers and thunderstorms expected Tuesday, increasing
to scattered to numerous by Thursday and Friday. Rain chances
continue through the weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  96  71  96  75 /  10   0  10  10
Houston (IAH)  94  75  93  78 /   0   0  10  20
Galveston (GLS)  89  82  88  83 /  20   0  30  40

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

DISCUSSION...Bailey
AVIATION...CMW
MARINE...Bailey

NWS HGX Office Area Forecast Discussion