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National Weather Service Forecast Discussion

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323
FXUS64 KHGX 311811
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
111 PM CDT Mon Aug 31 2026

...New DISCUSSION, AVIATION, MARINE...

.KEY MESSAGES...

- Tropical Depression Five has developed in the north central
  Gulf. It is expected to become a Tropical Storm before it makes
  landfall along the Upper Texas coast on Tuesday.

- Tropical Storm Warnings are in effect for Chambers County, the
  Bolivar Peninsula, and the adjacent Gulf waters.

- The primary threat is rainfall with widespread 3-5" amounts and
  isolated 6-9" amounts with the highest totals east of I-45. A
  Flood Watch is in effect from 1AM Tuesday thru 7AM Wednesday.

- Daily chances for scattered showers/storms continues beyond
  midweek.

&&

.DISCUSSION and TROPICAL...
Issued at 111 PM CDT Mon Aug 31 2026

With Tropical Depression (TD) Five bringing imminent impacts to
portions of Southeast Texas within the next 24-36 hours, we`ll keep
the discussion tailored mainly to what`s going on and how it may
impact you.

TD Five continues to sit off the coast of Louisiana with maximum
sustained winds of 35 mph (as of the 1pm advisory). It will
continue gradually moving west-northwestward and may become
Tropical Storm Edouard as early as later today. Current model
guidance continues to point towards a landfall location generally
between Sabine Pass and High Island, but this could definitely
shift depending on trends. Hurricane Hunter aircraft flew into the
disturbance this morning and did not find the data needed to call
this a tropical depression/storm as of yet. However, the
expectation is for this system to strengthen to a tropical storm
by Tuesday morning. As a result, Tropical Storm Warnings are in
effect for Chambers County, the Bolivar Peninsula, and the
adjacent Gulf waters through Wednesday morning.

While tropical storm force winds are possible (40-50 mph at most
based on the higher envelope of intensity guidance) in the warned
areas, the main concern from TD Five will be periods of moderate
to heavy rainfall. Periods of moderate to heavy rainfall
associated with TD Five are expected to begin as early as late
tonight and lasting into late Tuesday night/early Wednesday
morning. Although if you are in Galveston County, then you already
experienced an early round of scattered showers/storms with a
little added flavor of tropical moisture. Our latest forecast
reflects 3-5 inches with isolated amounts of 6-9 inches. The
highest rainfall totals are expected to occur mainly east of I-45.
Since we`re dealing with a tropical airmass, rainfall rates will
exceed 3-4 inches per hour at times in the heaviest downpours.
This can lead to flash flooding especially in urban and vulnerable
areas (low-lying areas and areas with poor drainage).

The Weather Prediction Center has outlined areas generally east of
the Brazos River in a slight risk (level 2 of 4) of excessive
rainfall for both Tuesday and Wednesday. A marginal risk (level 1 of
4) of excessive rainfall is in place elsewhere in Southeast Texas
for Tuesday and Wednesday. As a result, a Flood Watch has been
issued for counties generally along and east of I-45 early Tuesday
morning through Wednesday morning. It`s important to note that if TD
Five is able to sufficiently organize and have the precipitation
become more focused around the center, then we could have a scenario
where there is a tighter gradient of rainfall amounts. In this
scenario, the rainfall amounts would be highly dependent where TD
Five makes landfall. So, if it where to become organized and make
landfall further east (closer to Sabine Pass), then the rainfall
threat would be decreased...and vice versa.

Keeping the rainfall/flooding theme going, we are not currently
expecting any widespread or significant issues along area rivers,
streams, or bayous. We`ll continue to monitor for any potential
impacts, especially along the Trinity and San Jacinto River basins.
Keep in mind that extended periods of high rainfall rates could
cause issues as well, so impacts may be limited right along the axis
of the heaviest rainfall.

Since this is a rather small and compact system, we are not
expecting storm surge to be a major threat. Strong rip currents,
minor coastal flooding, and wave run-up are the most likely
outcomes especially along Gulf facing beaches north of San Luis
Pass during times of high tide. As a result, a Beach Hazards
Statement is in effect from late tonight through Wednesday
morning.

This elevated moisture looks to sticks around going into at least
Thursday. Increased chances for scattered showers/storms will
persist through the end of the work week as a result, especially
during the afternoon hours. Some lingering moderate to heavy
rainfall is possible on Wednesday with deeper tropical moisture
remaining in place for most of the day. Ridging aloft moves back in
towards the end of the work week and going into the weekend leading
to a return to high temperatures generally in the mid to upper 90s
and heat indices peaking above 100 degrees. Daily chances for
scattered showers/storms continues into the weekend with the highest
chances generally along and south of I-10 along the sea breeze.

Batiste

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 111 PM CDT Mon Aug 31 2026

VFR conditions expected to prevail throughout the day. A moist air
mass over our southern TAF sites interacting with the afternoon sea
breeze may lead to isolated SH, warranting the use of VCSH. Winds go
calm and VRB overnight before ramping back up tomorrow morning,
coinciding with the approach of the tropical system. As this system
moves onshore along the TX/LA coast, rain bands could bring
conditions below MVFR, especially for our coastal sites along and
east of I-45. TEMPOs with gusty winds, TSRA, and MVFR cigs/vis
were included in the 15Z to 18Z time frame for our southern TAF
sites to account for the current window of greatest impacts. GLS
has these conditions starting earlier to account for its more
coastal position. We will continue to monitor storm trends and
their aviation impacts as we get closer to tomorrow.

JMG

&&

.MARINE...
Issued at 111 PM CDT Mon Aug 31 2026

...A Tropical Storm Warning is in effect for the coastal waters from
High Island to Freeport from 0 to 60 NM, including Galveston Bay
through Wednesday morning...

Tropical Depression Five is currently off the coast of Louisiana and
is slowly moving west-northwest across the northwestern Gulf. This
system is expected to move over the Upper Texas coast as a weak
Tropical Storm on Tuesday. Given the small size of this system,
impacts on navigation should generally remain over the coastal
waters from High Island to Freeport, including Galveston Bay.
Potential marine impacts include tropical storm-force wind gusts
around 30 to 40 knots over the coastal waters, and 15 to 25 knots
over Galveston Bay, and building seas of 3 to 5 ft (occasionally
higher seas possible). Overall, periods of showers and thunderstorms
can be expected this evening into Wednesday morning. Some of these
showers could become moderate to heavy at times.

Beach conditions are expected to deteriorate later tonight into at
least Wednesday. A Beach Hazards Statement is in effect for all Gulf-
facing beaches including Galveston Island and the Bolivar Peninsula.
While significant coastal flooding is not anticipated, minor coastal
flooding and wave run-up at the beach are possible, especially
during times of high tide. The highest probabilities of these
conditions are expected to be north of Port Bolivar.

Conditions are expected to improve once the system makes landfall
late Tuesday afternoon and evening. However, intermittent scattered
thunderstorms are possible throughout the week. Please continue
to monitor the latest forecast updates and be prepared.

JM

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  77  97  75  95 /  10  30  50  60
Houston (IAH)  80  91  78  93 /  10  80  60  70
Galveston (GLS)  81  90  83  91 /  60  70  60  50

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Tropical Storm Warning for TXZ214-439.

     Flood Watch from 1 AM CDT Tuesday through Wednesday morning for
     TXZ178-179-199-200-213-214-238-300-313-338-438-439.

     Beach Hazards Statement from 1 AM CDT Tuesday through Wednesday
     morning for TXZ438-439.

GM...Small Craft Advisory until 9 AM CDT Wednesday for GMZ335.

     Tropical Storm Warning for GMZ355-375.

&&

$$

DISCUSSION...Batiste
AVIATION...JMG
MARINE...JM

NWS HGX Office Area Forecast Discussion