542
FXUS64 KHGX 231158
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
558 AM CST Sun Nov 23 2025

...New AVIATION...

.KEY MESSAGES...

- Brief dry period overnight through Sunday following the passage
  of a weak cold front. Rain chances return on Monday as a warm
  front lifts north.

- The next round of showers and thunderstorms will be late Monday
  into Tuesday. Isolated strong to severe storms and locally heavy
  rainfall will be possible.

- A stronger, reinforcing front pushes through early Wednesday
  bringing cooler and drier conditions just in time for
  Thanksgiving.

&&

.DISCUSSION...
Issued at 1115 PM CST Sat Nov 22 2025

As of late Saturday night (~11pm), a weak frontal boundary is
lingering just offshore in the nearshore Gulf waters. As a result,
drier conditions will prevail for the area going into Sunday as a
brief period of ridging aloft builds in. Temperatures tonight will
be seasonal-ish with lows in the upper 40s to upper 50s. Late in the
day on Sunday (most likely early evening), the weak frontal boundary
will push back northeastward as a warm front bringing on the advent
of warm air advection to Southeast TX going into Monday. With
northeasterly to easterly winds through peak heating, high
temperatures on Sunday will mainly top out in the mid 70s to near
80. Rain chances gradually re-enter the picture late Sunday night as
an upper level low traverses the Four Corners region and into the
Southern Plains.

Onshore flow strengthens Sunday night into Monday as lee
cyclogenesis results in surface low pressure development near the
TX/OK panhandles. So, there will be a frontal boundary approaching
Southeast TX on Monday...but it won`t begin to push into the area
till the evening/nighttime hours. So what does this mean? Well for
one, compressional heating ahead of the front will allow for
Monday`s high temperatures to peak in the low to mid 80s. Mostly
cloudy skies will be a saving grace to keep temperatures from
getting higher than that...and also that the wind direction doesn`t
transition to southwesterly till after sunset. The front begins to
push through the Brazos Valley/Piney Woods late Monday
afternoon/early evening. Moisture convergence along the frontal
boundary leads to PW values peaking in the 1.6-1.8" range, which is
above the 90th percentile (~1.52"). Locally heavy rainfall will be
possible in any of the stronger storms and could lead to localized
instances of minor/street flooding if high rainfall rates occur over
a particular area for an extended period of time. WPC has outlined
all of Southeast TX in a marginal risk (level 1 of 4) for excessive
rainfall for late Monday into Tuesday.

Now I did mention "stronger" storms, so let`s take a look into the
potential for strong to severe storms. We`ll do a quick Weather 101
first. The four ingredients for severe weather are: moisture, lift,
instability, and shear. We already know from the paragraph above
that moisture is readily available, so we won`t talk about that any
further. We`ll also have 40-50 kt of bulk shear as the frontal
boundary pushes in, so we have shear and lift. We can also throw in
PVA, a 30-40 kt LLJ, and being in the right entrance region of a jet
streak (upper level divergence) as additional sources of lift. That
leaves one ingredient...instability. We`ll spend the majority of
Monday in the warm sector of the approaching disturbance, so there
will be some instability. The main questions are will it be enough
and will it overlap well with all of the previous ingredients. The
latest model guidance has the greater amounts of instability both
west of the Brazos River and along the coast on Monday night while
the peak in bulk shear remains generally north of I-10. There is
some general overlap of ~40kt bulk shear and 1000-1500 J/kg MUCAPE,
which can certainly lead to some storms becoming strong to severe.
This is most likely over in the Brazos Valley/Piney Woods. SPC (as
of ~11pm Saturday) currently has areas generally north of I-10 in a
slight risk (level 2 of 5) of severe weather for Monday night into
early Tuesday. The remainder of Southeast TX is in a marginal risk
(level 1 of 5). I wouldn`t be surprised to see the slight risk
trimmed back a bit based on what we discussed above.

While there is potential for spotty showers late Monday morning into
the afternoon, the main window for heavy rain/strong storms will be
Monday evening into Tuesday morning. The front will linger near the
coast throughout the day on Tuesday leading to rain chances
persisting south of I-10 going into Tuesday night. A stronger
reinforcing cold front will push through early Wednesday bringing an
end to the rain chances for a bit and ushering in cooler, drier air.
PW values by Thanksgiving will be essentially around the 10th
(~0.38") to 25th (~0.54") percentiles to give you an idea of how dry
it`ll be. This bodes well for the Thanksgiving forecast! High
temperatures for Thanksgiving will be mainly in the mid to upper 60s
with low temperatures in the 40s/50s. This gives us more flexibility
in outfit planning! The morning of Thanksgiving (Wednesday
night/Thursday morning) will be the coldest period of the forecast
with temperatures at dawn in the low 40s to upper 40s. Keep that in
mind if you`re planning on standing outside for outdoor festivities.

Onshore flow returns on Black Friday leading to a gradual warming
trend going into the end of the week. Rain chances will also be on
the rise as another upper level disturbance approaches. For now, I`m
just going to be thankful that Mother Nature is treating us to a
cool, dry Thanksgiving. We`ll worry about next weekend`s rain
chances after the third round of dessert...hey don`t judge!

Batiste

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 544 AM CST Sun Nov 23 2025

VFR conditions are expected to prevail for much of the TAF period.
NNE winds at 5-10KT this morning will become ESE by mid morning
and then SE around midnight. High clouds will gradually move
across SE TX today and lower during the overnight hours on Sunday
into early Monday morning. Iso showers may begin over CLL/UTS
around sunrise timeframe on Monday.

Cotto

&&

.MARINE...
Issued at 1115 PM CST Sat Nov 22 2025

A weak frontal boundary is located over the nearshore Gulf waters
currently and will linger going into Sunday morning/early afternoon.
As a result, easterly winds generally in the 10-15 kt range will
prevail through Sunday afternoon before southeasterly winds return
late Sunday afternoon. Winds will gradually strengthen going into
Sunday night/Monday morning and likely necessitate caution flags
throughout the day on Monday. The elevated onshore flow is expected
to lead an increased risk of rip currents Monday into Tuesday. The
next round of showers/storms will be late Monday night into Tuesday
as another frontal boundary pushes towards the coast. Rain chances
linger going into Tuesday night/Wednesday morning as the initial
front lingers near the coast.

A stronger reinforcing front will help push the cold front off the
coast Wednesday morning with moderate to strong northeasterly winds
prevailing in its wake. This will likely necessitate a Small Craft
Advisory through early Thursday. The moderate to strong offshore
flow may lead to abnormally low water levels during Wednesday`s low
tide cycle in Galveston Bay. Tail-end of Saturday afternoon`s model
run of PETSS guidance shows water levels trending towards being
around -0.5 ft MLLW on Wednesday afternoon in the upper part of
Galveston Bay.

Batiste

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  75  63  81  59 /   0  20  80  70
Houston (IAH)  78  65  84  66 /   0  10  40  80
Galveston (GLS)  75  70  80  70 /   0  10  30  70

&&

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

$$

DISCUSSION...Batiste
AVIATION...Cotto
MARINE...Batiste