Skip to main content.

National Weather Service Forecast Discussion

Related quick links> 5 Day Forecast, Local Advisories, Drought Monitor, UV Forecast, Air Quality Forecast 
914
FXUS64 KHGX 201929
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
229 PM CDT Mon Jul 20 2026

...New DISCUSSION, MARINE, TROPICAL...

.KEY MESSAGES...

- Hot conditions persist through the week with the hottest days
  Tuesday and Wednesday.

- A Heat Advisory is in effect from 11 AM - 8 PM Tuesday.

- NHC is monitoring the development of Tropical Depression Two,
  currently in the northeast Gulf. While forecast uncertainty
  remains fairly high, residents should monitor the latest
  forecasts and evolution of this system as it eventually tracks
  westward toward Texas late Thursday and Friday.

- Corresponding rain and temperature forecasts for the local area
  are subject to changes later in the week and highly dependent on
  the tropics.

&&

.DISCUSSION...
Issued at 225 PM CDT Mon Jul 20 2026

Hot and humid conditions continue this afternoon as high pressure
remains anchored over the region. Water vapor and visible satellite
imagery depict  a prevailing drier airmass and broad subsidence
dominant across the area. Afternoon temperatures will climb into the
mid 90s. When combined with sfc dewpoints in the 70s, heat indices
will reach up to  107F, close to advisory levels. Be sure to
practice heat safety if spending extended periods outdoors!

The main weather story for the first half of the week continues to
be the heat. A robust ridge of high pressure will remain anchored
across the central and western CONUS, providing sufficient
subsidence locally to keep highs on a steady upward trend. Some
inland locations will likely see their first 100-degree day of the
year by Tuesday or Wednesday. Simultaneously, low to mid-level
moisture filtering inland from the Gulf will keep humidity levels
elevated. The combination of hot and humid conditions will push peak
heat index values into the 107 to 112F range Tuesday and Wednesday.
A Heat Advisory has been issued for all of southeast Texas for
Tuesday from 11 AM - 8 PM. Wednesday is shaping up to be even hotter
(likely due to the approaching tropical system over the Gulf).
Therefore, advisories will likely be extended in future forecast
updates.

Heading into Thursday - Saturday, attention turns toward the Gulf
regarding the evolution of Tropical Depression (TD)Two. The mid to
upper level ridge positioned to our northwest will serve as the
primary steering focus, nudging the system on a general westward to
west-northwestward track toward the northwestern Gulf. However,
environmental factors including dry air entrainment and shear
could influence the system`s track and intensity. Please, see the
Tropical discussion below for further details on this system and
potential impacts for Southeast Texas.

Forecast beyond Saturday remains sensitive to the final track and
strength of TD Two. Well-above normal temperatures will be possible.
Will continue to monitor for heat headlines through the weekend.

JM

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 117 PM CDT Mon Jul 20 2026

Mostly VFR conditions and light winds are expected through the
forecast period. There is a chance for MVFR vis/cigs tomorrow
morning. This has been hinted at via the 6SM BR SCT015 prevailing
lines in most of the TAFs during the morning hours tomorrow.

&&

.MARINE...
Issued at 225 PM CDT Mon Jul 20 2026

Surface high pressure will continue to bring light to occasionally
moderate west to southwest winds and low seas across the Upper TX
coast. Mariners should continue to monitor weather conditions,
especially toward the end of the week as Tropical Depression Two
moves westward along the northern Gulf. This system is forecast to
strengthen into a tropical storm later today as it approaches
southeast Louisiana, before weakening again into a tropical
depression as it moves toward the Upper Texas coast Thursday and
Friday. While forecast confidence remains low, given high
uncertainty in track and intensity; significant impacts are not
anticipated across our coastal waters. However, Small Craft
Advisories could potentially be issued during this period with
elevated winds and seas up to 6 ft (offshore).

JM

&&

.TROPICAL...
Issued at 225 PM CDT Mon Jul 20 2026

The National Hurricane Center has initiated advisories on Tropical
Depression Two in the northeast Gulf of America. The system is
gradually becoming better organized, producing a broad region of
squally weather across the eastern and central Gulf. The system is
expected to become a tropical storm as it drifts northwestward over
the next couple of days. Beyond then, the forecast becomes quite
tricky. However, there is a growing risk that the system will take a
westerly turn, possibly bringing the system to SE Texas by Thursday.

The forecast is tricky for a few reasons. First, the system remains
in its early developmental stages. This stage is notorious for
computer model errors. In addition, we are waiting for Hurricane
Hunter aircraft data that will be crucial in assessing the system`s
future potential. There is also uncertainty regarding how much of a
west versus southwest steering component will be provided by a
building ridge to the north of the system later this week. A
stronger ridge could keep the storm south of Louisiana and over the
open Gulf, allowing the system more room for further organization.
But a track farther north could place the system over Louisiana,
limiting intensification.

Regarding timing of possible impacts, we cannot rule out tropical
storm conditions in outer rainbands as early as Wednesday evening
over the Gulf waters, with a better chance of seeing more widespread
rains, and potentially increased winds, by Thursday. But the scale
and timing of the impacts will be very difficult to pin point so
long as the uncertainty remains high. We will be able to assess
these potential future impacts better as more data is obtained and
as the system becomes a little better organized.

Please stay tuned to forecast updates as this is an evolving
situation.

Self

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  72  98  78 100 /   0   0   0   0
Houston (IAH)  75 100  80 102 /   0   0   0  10
Galveston (GLS)  79  94  81  95 /   0   0   0  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 11 AM to 8 PM CDT Tuesday for TXZ163-164-
     176>179-195>200-210>214-226-227-235>238-300-313-335>338-
     436>439.

GM...None.
&&

$$

DISCUSSION...JM
AVIATION...Self
MARINE...JM
TROPICAL...Self

NWS HGX Office Area Forecast Discussion