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National Weather Service Forecast Discussion

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400
FXUS64 KHGX 040540
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1240 AM CDT Sat Jul 4 2026

...New DISCUSSION, MARINE...

.KEY MESSAGES...

- Dangerously hot conditions expected today. A Heat Advisory is
  now in effect for Harris County for heat indices between
  105-109F (41- 43C).

- Elsewhere, widespread heat indices of 105-107F (41-42C) with locally
  higher values over 108F (43C +) are likely this weekend.

- Isolated showers/thunderstorms are possible today and on Sunday.
  Chance of isolated to scattered sea breeze showers/storms
  increases early next week.

&&

.DISCUSSION...
Issued at 1232 AM CDT Sat Jul 4 2026

The dominant mid-level ridge that setup across the eastern U.S over
the last several days has begun to slowly break down. As the
atmosphere reshuffles from the massive ridge, mid-level heights look
to briefly increase across our region this weekend. This will help
promote slightly drier and slightly warmer conditions across the
area. Currently, quiet weather conditions is seen across our area.
Winds are generally light at 5 mph out of the south.

The biggest change with this forecast package was the issuance of a
Heat Advisory for inland and coastal Harris County. A combination of
slightly higher temperatures and lower shower/thunderstorm coverage
placed a majority of Harris County in a range of max heat indices
between 107-109F (42-43C). With several events ongoing today and
greater than fifty percent of the county exceeding Heat Advisory
Criteria, it was prudent that a Heat Advisory was issued. Heat
indices of 108F (43C) or higher will be more isolated in
occurrence outside of Harris County and thus a Heat Advisory was
not considered elsewhere. Heat indices look to remain just under
the 108F threshold on Sunday as well, although it could be close
once again in Harris County. A brief decrease in maximum
temperatures will be possible on Monday and Tuesday as ridging
relaxes some. However, maximum heat indices look to remain
elevated as increased moisture moves into the region. Tuesday in
particular could be close to reaching Heat Advisory criteria
depending on shower/thunderstorm coverage in the afternoon.
Guidance shows ridging building back into the region towards the
latter half of next week, which will keep the heat threat around
for the foreseeable future.

Isolated seabreeze showers/thunderstorms will continue today and
Sunday, but slightly drier conditions should limit coverage
compared to the past couple of days. Models show a mid to upper-
level impulse swing down the eastern Southern Plains early next
week. This will help lower mid-level heights Monday and Tuesday.
It remains unlikely that we will see any direct effects from the
mid to upper-level impulse, but it should allow for an increase in
seabreeze showers/thunderstorms each afternoon. Ran chances look
to diminish once again towards the latter half of next week.

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 616 PM CDT Fri Jul 3 2026

Chances for shower/storm activity diminishes this evening as
outflows from earlier storms have stabilized the atmosphere. VFR
conditions will prevail through TAF period with the low
probabilities of VIS concerns for most terminals between the coast
and KCXO from 10-13Z. Winds will then become mostly S/SSW`ly near
5-7 kt before switching to mostly S`ly winds at 7-9 kts with the
seabreeze moving through from 17-20Z. Hi-res model wants to keep
most of any seabreeze convection closer to the coastal areas
between KLVJ and KGLS, but confidence is low enough to add any
TEMPO groups to KHOU, but this will be something that will be
carefully monitored with the overnight forecast trends and radar
Saturday morning.

&&

.MARINE...
Issued at 1232 AM CDT Sat Jul 4 2026

Light onshore flow will continue over the next several days. Gulf
seas are expected to average 1 to 3 feet. Isolated coastal and Gulf
showers will be possible each morning, with a chance of isolated
thunderstorms along the sea breeze in the afternoon.
By the middle to later part of next week, a gradually steepening
pressure gradient may allow for an increase in south to southeast
winds, along with a corresponding increase in the seas. For now, the
forecast shows onshore winds increasing to 10-15 knots by
Tuesday/Wednesday, before increasing further to the 15-20 knot range
by Thursday. Seas may increase to 3-4 feet by week`s end.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  77  95  77  95 /   0   0   0   0
Houston (IAH)  79  96  79  95 /  10  10   0  20
Galveston (GLS)  83  90  83  89 /   0   0   0  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 11 AM this morning to 7 PM CDT this evening
     for TXZ213-313.

GM...None.
&&

$$

DISCUSSION...Williams
AVIATION...Enriquez
MARINE...Williams

NWS HGX Office Area Forecast Discussion