Thompsons, Texas Weather Forecast Discussion

258
FXUS64 KHGX 211709
AFDHGX
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1209 PM CDT Sun Sep 21 2025
...New DISCUSSION, MARINE...
.KEY MESSAGES...
Issued at 1209 PM CDT Sun Sep 21 2025
- Chances for isolated to scattered showers/storms continue into
  the new week with the highest rain chances closer to the coast.
- Slight warming trend going into midweek with high temperatures
  approaching the mid 90s.
- A midweek cold front looks to bring drier air and slightly
  cooler temperatures prevailing into the end of the week.
&&
.DISCUSSION...
Issued at 1209 PM CDT Sun Sep 21 2025
Do you remember...the 21st night of September?
The last night of summer as we venture
Into the season of fall, let`s enterrrrr!
Be glad you couldn`t hear me rehearsing that...but anyway let`s talk
about these showers/storms! We started out the day with scattered
showers mainly along the coast as PW values ranged between 1.7-1.9"
south of I-10. With plenty of PVA from embedded shortwaves in the
increasingly amplifying northwesterly flow aloft acting as a lifting
source for the influx of moisture, we see showers and storms
reaching well past the I-10 corridor. Rain chances will be higher
the closer you are to the coast though. The amplification of the
northwesterly flow aloft comes from a mid level high over northern
Mexico that gradually nudges eastward going into the early part of
the work week. That means that we`ll go on a slight warming trend
at least through Tuesday. High temperatures today will be mainly
in the low 90s and we`ll see a 1-2F increase each day through
Tuesday. Overnight temperatures will be above normal as well with
lows in the low to mid 70s tonight and in the mid to upper 70s by
Tuesday night.
Southeast Texas remains east enough of the mid level high to
maintain northwesterly flow aloft, which means we`ll still have some
embedded shortwaves passing through intermittently. As a result,
chances for showers/storms remain in the forecast. Around midweek
is when things get a bit interesting! Although the Autumnal
Equinox occurs Monday afternoon at 1:19 PM CDT, it won`t feel like
the season of fall has begun...at least not yet. A cold front
pushing through around the middle of the work week looks to bring
us some drier air and slightly cooler temperatures...along with
an even better chance of rain. This front is the result of an
elongated upper level trough sweeping through the Central Plains
towards the Mississippi River Valley.
Let`s preface this by mentioning that FROPA timing remains quite a
bit uncertain. The front is within range of the latest 12km NAM run,
which shows the front pushing through Wednesday morning and offshore
by Wednesday afternoon. Compare that to the GFS/Euro, which has the
front pushing through Wednesday afternoon/evening and offshore by
Wednesday night. A line of showers/storms is expected to accompany
the frontal boundary, but there are some signs that these storms
could be associated with a prefrontal trough rather than the front
itself. Drier air moves in late Wednesday night into Thursday
leading to pleasant conditions prevailing going into next weekend.
High temperatures on Wednesday will be highly dependent on FROPA
timing, but beyond midweek expect high temperatures to mainly top
out in the upper 80s. Low temperatures beyond midweek (starting
Thursday night once drier air is in place) are expected to be mainly
in the 60s. Deterministic model guidance shows PW values dropping
near or below the 10th percentile (~0.89"), and the ensemble mean
for both the GEFS and Euro are generally around or below the 25th
percentile (~1.14"). As a result, we can expect rain chances to
drastically decrease going into the end of the week. Trended PoPs
to end a bit quicker behind the influx of drier air and kept the
rain chances to a minimum Friday and onward into the weekend.
Batiste
&&
.AVIATION...
(12Z TAF Issuance)
Issued at 604 AM CDT Sun Sep 21 2025
Scattered showers and isolated thunderstorms have developed over
the coastal waters, and this activity will be expanding inland
through the late morning/early afternoon. Coverage will be highest
south of I-10, so went with VCSH with PROB30 of TS for any
terminal south of I-10. Did include a PROB30 of TS at IAH for this
afternoon as an isolated storm may reach north enough to pass near
IAH. Activity is expected to diminish with sunset, but isolated
coastal showers will begin again near sunrise tomorrow.
VFR conditions will prevail with south-southeasterly winds around
7-12kt through the period. Patchy fog may impact CXO and LBX like
the past few days.
Fowler
&&
.MARINE...
Issued at 1209 PM CDT Sun Sep 21 2025
Light to occasionally moderate southeasterly winds and 2 to 4 foot
seas will prevail going into midweek. Chances for shower/storms will
persist as well with higher chances in the early morning to
afternoon hours over the waters. Winds become southwesterly to
westerly around the middle of the work week as a frontal boundary
approaches. Exact timing of the front is still a bit uncertain, but
expecting northerly flow to become prevalent by early Thursday and
prevail going into the weekend. Showers/storms will accompany the
frontal boundary as it pushes offshore, but expect drier air in its
wake.
Batiste
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  72  93  74  95 /   0  10   0  20
Houston (IAH)  76  90  77  92 /  10  40  10  50
Galveston (GLS)  80  88  81  89 /  40  40  20  50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
DISCUSSION...Batiste
AVIATION...Fowler
MARINE...Batiste

NWS HGX Office Area Forecast Discussion