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National Weather Service Forecast Discussion

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786
FXUS64 KHGX 011037
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
537 AM CDT Sat Aug 1 2026

...New AVIATION...

.KEY MESSAGES...

- Heat Advisory in effect for our southern counties (including the
  City of Houston) this afternoon.

- Frontal boundary may bring isolated to widely scattered showers/
  storms later today / this evening, though a morning shower is
  possible in our northern counties.

- Forecast has trended hotter for Sunday and especially Monday.

&&

.DISCUSSION...
Issued at 1220 AM CDT Sat Aug 1 2026

As of 12AM CDT, there are few things that catch my eye as I write
this AFD. Water vapor imagery is currently telling a story of a
flow pattern in flux. The ridge that has dominated Texas weather
over the last weak is shifting west, with the center of its ridge
axis firmly over W CONUS. Meanwhile, a deep low over the Midwest
is diving east to southeast, while its trailing cold front extends
all the way down into SE Oklahoma and N Texas. The airmass behind
the front is also of interest, featuring decreasing dew points
and cooler temperatures. Me thinks the falling dew points are in
SE TX`s future....the cooler temps not so much.

The HRRR continues to insist on a band of showers that develops
over our northern counties early this morning. The showers push
southward, fizzling out before reaching the I-10 corridor. Some of
the other CAMs suggest the presence of an isolated shower or two.
There does appear to be plenty of dry air in the 900-700 MB zone.
But ML water vapor imagery suggests there is slightly less ML dry
air in our northern zones. So I kept some PoPs in the forecast
north of I-10 this morning to give the HRRR a little weight in the
forecast. We shall see...

This aforementioned front should continue its southward push,
reaching our neck of the woods by later today or tonight. There`s
still some question regarding the timing of the front. Will the
front be able to interact with peak daytime heating? Latest
guidance suggest it won`t arrive in SE TX until the evening, when
daytime heating is being lost. Therefore, the chance of seeing
showers/thunderstorms has decreased but has not been eliminated
for later today. A veering wind profile ahead of the front will
support a modest WAA regime when the air is already quite hot.
Forecast peak heat indices from the I-10 counties to the coast are
generally 107-110 degrees, warranting the issuance of a Heat
Advisory from 1PM to 7PM CDT in our southern zones. There could be
a sweet spot that`s just inland enough to limit Gulf influence
but also just coastal enough to limit mixing that manages to reach
111-112F.

Sunday may feature some showers and isolated storms near the coast
and offshore in the morning. Otherwise, much drier air
infiltrates the area in the front`s wake. Mid/upper heights will
be at their lowest on Sunday, generally supporting a cooler
temperature profile. But drier air and the August sun should boost
temperatures into the upper 90s to around 100 (low 90s coast).
Inland dew points are expected to be well down into the 60s, which
should keep heat indices below advisory criteria. The dry air may
not make it to the coast. So if you`re in a coastal county, you
may remain in the humid soup. But on Monday, the ridge builds
back into the region, warming the temperatures profile. With a
similar dry LL regime remaining in place, Monday`s actual
temperatures cold get quite hot. Right now, we have high
temperatures ~100 degrees across most inland areas. But this is
technically a little "cooler" than most of the guidance. If
forecast temperatures trend another 2-3 degree higher, then we
could be approaching Heat Advisory criteria for actual
temperatures (103+). The high heat may linger into Tuesday before
temperatures attempt to modify down to normal by mid/late week.

Self

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 537 AM CDT Sat Aug 1 2026

Cluster of showers is currently moving southward towards our
northern terminals ahead of an approaching frontal boundary. This
band of showers is expected to dissipate before it makes it to the
Houston metro terminals. Additionally, low-end MVFR ceilings are
ongoing across the northern terminals (CXO and northward) and will
likely persist through 15Z. Can`t rule out brief MVFR ceilings at
IAH this morning.

High resolution model guidance has trended drier for this
afternoon. However, given that showers are already developing up
north, have decided to keep the PROB30`s for showers in the
afternoon for IAH and northward. Further south, confidence remains
too low to include any SH mentions. A stray thunderstorm cannot be
ruled out either for sites with the PROB30`s. Winds will start out
southwesterly this morning around 8-12 kt with occasional gusts of
15-20 kt possible this afternoon. Winds will become light and
northerly behind the front.

Batiste

&&

.MARINE...
Issued at 1136 PM CDT Fri Jul 31 2026

Southwest winds 10-15 knots should gradually increase to 15-20
knots later today into tonight. For Galveston Bay and our eastern
Gulf zones, winds may gust to around 25 knots at times. Small
vessels should exercise caution later today into tonight. A
frontal boundary approaches the area this evening into tonight,
possibly resulting in a few showers and thunderstorms tonight into
Sunday morning. Westerly winds are expected on Sunday, followed
by continued light to moderate south to southwest winds through
much of the upcoming week. Winds may become more south-southeast
late in the week. Seas should primarily be 2-3 feet, but could
build to 4 feet (locally 5ft) Saturday night in our eastern Gulf
zones.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  97  75  99  73 /  30  10   0   0
Houston (IAH)  99  79 100  78 /  20  20   0   0
Galveston (GLS)  94  82  92  82 /  10  20  10   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 1 PM this afternoon to 7 PM CDT this evening
     for TXZ200-213-214-226-227-235>238-300-313-335>338-436>439.

GM...Small Craft Should Exercise Caution from 1 PM to 4 PM CDT this
     afternoon for GMZ335-355.

     Small Craft Advisory from 4 PM this afternoon to 7 AM CDT Sunday
     for GMZ335-355.

     Small Craft Should Exercise Caution from 1 PM CDT this afternoon
     through Sunday morning for GMZ375.

&&

$$

DISCUSSION...Self
AVIATION...Batiste
MARINE...Self

NWS HGX Office Area Forecast Discussion