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National Weather Service Forecast Discussion

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840
FXUS64 KHGX 151854
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
154 PM CDT Sat Aug 15 2026

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

.KEY MESSAGES...

- High pressure will intensify through the weekend, reducing
  chances of rain to near zero this weekend well into next week.

- Slightly above average summertime heat (upper 90s/lower 100s)
  will persist through most of the rest of the month across
  Southeast Texas. The potential for Heat Advisory issuance
  remains elevated as a result.

- Without adequate precautions outdoors, cumulative impacts of
  heat and heat stress will remain a significant risk factor to
  health (especially for heat-sensitive populations).

&&

.DISCUSSION...
Issued at 147 PM CDT Sat Aug 15 2026

The weather pattern will continue to be dominated by a mid-level
area of high pressure that is expected to shift westward and become
centered over Texas through early next week. This will continue our
"rinse and repeat" pattern of hot and dry weather through the next
several days. Highs will be in the low to mid 90s along the coast,
with inland areas seeing highs climb to the upper 90s to around
100F.

The probabilities of of heat advisories (using an input of MaxT
>102F) through next week are around 30-60% (GEFS is the more closely
aligned ensemble with today`s temperatures, so using this as
baseline). Highest probabilities exist across the Brazos
Valley/Northern Piney Woods, and across the easternmost counties
(Trinity, Polk, San Jacinto, Liberty) where temperatures could reach
the Advisory threshold of 103F.

Looking at the heat index side of things, deterministic guidance
seems to be coming in a bit warm compared to what is being observed
today, particularly the NBM (which is known to bring in higher
dew points for our area). I`m hesitant to rule out heat indices
getting into the Advisory range (>=108F); however, probabilities
of this were lower than reaching the Advisory criteria on MaxT
alone. Current thought, after looking at sounding data, is that we
appear to have good mixing each day, dry air in the lower levels,
and high 850mb temperatures, so this could be the reason why
probabilities of reaching Advisory with MaxT are higher than
reaching it with the heat index.

Scientific analysis aside, it`s going to be HOT. Nighttime
temperatures will not provide much relief as lows remain in the 70s
to low 80s. Winds will be on the lighter side and out of the SE.

To echo the previous forecaster, continue to use caution and
protect yourself from dangerously hot temperatures. Do not
underestimate the effects of heat stress when working or spending
time outdoors, especially with little relief expected during the
nighttime hours (heat stress compounds over time). Stay hydrated,
wear loose-fitting and light-colored clothing, and LOOK BEFORE YOU
LOCK; never leave kids or pets unattended in vehicles. For pet
owners, if the pavement is too hot for your palm, it is too hot
for their paws!

As we get into the latter part of the week, closer to the weekend,
rain chances increase to around 15% (decent rain chances for it
being in the long-term). High pressure will continue to retrograde
west into the Four Corners, and a trough across the Great lakes will
deepen over the SE CONUS, putting SE Texas in the proximity of NW
flow aloft. NW flow aloft has been known to trigger showers and
storms over our area, and with energy moving through the 500 mb
level around the same time frame, this may result in some rainfall
for portions of the area. In any case, it is pretty far out in the
long-term, but will continue to monitor how it evolves in the coming
days.

Bailey

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 147 PM CDT Sat Aug 15 2026

For the 15/18Z TAF update, ridging continues to control and suppress
the development of much impactful convection (other than very
isolated -SHRA). Typical VFR vis/cig diurnal trends will prevail
outside of a window of MVFR/IFR cigs for inland KCLL/KUTS terminals
by 15/10Z-15/15Z with VRB04 winds maximizing to a southerly 10 to 15
kts this afternoon and by the end of the period.

Cassel

&&

.MARINE...
Issued at 147 PM CDT Sat Aug 15 2026

Light onshore winds and seas of 2-3 feet expected to continue
over the next several days. Otherwise, hot and dry conditions
persist.

Bailey

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  99  74  99  74 /   0   0   0   0
Houston (IAH)  97  77  97  77 /   0   0   0   0
Galveston (GLS)  90  82  89  81 /   0   0   0   0

&&

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

$$

DISCUSSION...Bailey
AVIATION...Cassel
MARINE...Bailey

NWS HGX Office Area Forecast Discussion