Funnel Cloud in Texas, October 4, 2023

Area Forecast Discussion
National Weather Service Houston/Galveston TX
644 AM CDT Wed Oct 4 2023

...New AVIATION...

.SYNOPSIS...
Issued at 358 AM CDT Wed Oct 4 2023

Another day of messy weather at the coast and on the Gulf today.
Indeed, hi-res guidance is indicating a potential for another day
with locally heavy rain falling on locations that saw heavy rain
yesterday. Due to this potential threat, a flood watch is in
effect until this evening. If you're in a spot that saw heavy rain
yesterday, be alert to conditions today, as these locations will
be much more sensitive to heavy rainfall today.

Beyond the flood watch, we also see a continuing threat of
dangerous rip currents on Gulf-facing beaches, as well as a
lingering threat of minor coastal flooding as we come out of high
tide early this morning. A small craft advisory is in place on a
portion of the Gulf waters for this morning, while small craft
will still need to exercise caution on the rest of the Gulf and on
Galveston Bay thanks to gusty winds and elevated seas.

All in all, not a great day to make your way to the Gulf. If you
have plans down there and can postpone to a better weather day,
that may be a good option. Otherwise, please keep alert to all of
the potential threats from wind, rain, and elevated seas today.

&&

.SHORT TERM...
(Today through Thursday Night)
Issued at 358 AM CDT Wed Oct 4 2023

Another cloudy and stormy day is on tap today for portions of
Southeast Texas with periods of showers and thunderstorms to be
expected through much of the day. The mid level high is to remain
situated over the Gulf waters while shortwaves push over our local
area and an upper level trough moves eastward across the Southern
Plains. Abundant low level moisture transported from the Gulf of
Mexico will continue to push in PWs of 2.0-2.3 inches over much of
the region, which could result in some areas receiving moderate to
heavy rainfall. The latest Hi-Res solutions have a swath of storms
lining up again from Brazoria/Matagorda region northward into
Western Harris and Montgomery this morning into the mid afternoon
hours. Given the amount of rainfall received yesterday around this
same area, it was decided to issue a Flood Watch for Brazoria, Fort
Bend, Matagorda, Wharton, and inland Galveston counties from 7 AM
through 7 PM today. Modifications to the Flood Watch could occur
later this morning, so stay tuned on the latest updates.

We will have a bit of a break from the storms during the evening and
early night hours, however, a few more rounds of showers and
thunderstorms starting around midnight and continuing into Thursday
are expected as a cold front pushes across Southeast Texas. Thus,
the risk for minor flooding and ponding of water in low-lying and
poor drainage areas could continue. WPC has placed a Slight Risk of
excessive rainfall for much of Southeast Texas from 7 AM today
through 7 AM Thursday.

The high temperatures today will be in the mid to upper 80s, with
some spots possibly reaching 90 degrees. The lows tonight into early
Thursday morning will once again be in the low to mid 70s for much
of the inland portions and in the upper 70s to low 80s along the
immediate coast and Barrier Islands. Temperatures finally will begin
to cool on Thursday...woohoo! There will be a bit of a temperature
gradient with the Brazos Valley and Piney Woods region having highs
in the upper 70s to low 80s while areas south of I-10 could still
have highs in the upper 80s. It will ultimately depend on how quick
the front moves through and the coverage of clouds and rain.

&&

.LONG TERM...
(Friday through Tuesday)
Issued at 358 AM CDT Wed Oct 4 2023

The forecast from Friday is instantly challenged by the potential
influence of mesoscale factors on Thursday. A strong line of
thunderstorms developing on the approaching front could
dramatically change the anticipated timing of that front passing
through the area, putting us in a situation where we could be
looking at anything from a somewhat rainy situation waiting for a
reinforcing front to move in, to having seen everything scoured
out by a more vigorous change forced by strong thunderstorms.

So, in this case, I go with a conservative, albeit somewhat
unsatisfying choice: I take something pretty much in line with the
consensus of guidance. Which may not end up verifying all that
well depending on how today and Thursday play out...but without a
ton of confidence in that, it's hard to say much with confidence
for Friday. In collaboration with neighboring offices, I did
choose to lean a little more towards a "cleaner" Friday, pulling
rain chances A little below NBM, while still allowing for a slight
chance/chance of lingering showers or an isolated storm, mainly
Friday morning.

By evening, the action should be offshore, setting us up for
relatively fair weather into early next week. For those who are
fans of fall weather, this weekend should be it. Friday night and
Saturday look a bit breezy as a decently strong surface high plops
into the Great Plains, tightening up the pressure gradient. But
strong winds look to mainly be a marine concern (more on that
below) while winds over land look to be a bit more muted.

Despite a partly cloudy sky allowing ample sun through, we'll see
decent enough cold advection and a low enough October sun angle
that temperatures will be below average - a rare occurrence these
past several months! Expect highs to be held below 80 degrees for
most of the area Saturday and Sunday, and perhaps some of the
cooler spots on Monday, though we'll start to see most of the area
have highs drift to around or just above 80 by then. A surge of
cooler, drier air will also provide delightfully cool weekend
nights. Up around Madison and Houston County, both Sunday and
Monday morning may see temps slip below 50 degrees for a brief bit
in the pre-dawn hours! Most of the area, though, should still see
lows in the 50s, and even into the lower half of the 60s right on
the Gulf Coast.

While a nice change of pace, this is also just a brief visit from
cooler, drier conditions. Expect onshore flow to return sometime
on Monday, which will bring warmer, more humid Gulf air back into
the picture pretty quickly. Look for temperatures to be back
around seasonal averages (or warmer) from Monday night onward, and
we may even manage some isolated rains at the coast again Tuesday
afternoon. There may be more to say about higher rain chances from
a weak Gulf low for the middle of next week, but fortunately for
me, that lies just beyond the scope of this forecast discussion.

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 614 AM CDT Wed Oct 4 2023

Mix of MVFR to VFR conditions expected for much of the TAF period,
although, there may be brief periods of IFR vis/cigs at times. A
few rounds of SH/TS expected through this evening and some strong
storms will be capable of producing +SHRA, lightning, and strong
VRB winds with gusts. SE winds at around 10 KTS with gusts up to
around 20 KTS for today, relaxing to around 5 KTS in the evening.
A lull in wx activity is anticipated from around 01-05Z. After
06Z, SH/TS will begin to develop over the northern portions of SE
TX and gradually expand southward as the night and early morning
progresses. A cold front will push through the region on Thu
keeping our chance for SH/TS for much of the day.

&&

.MARINE...
Issued at 358 AM CDT Wed Oct 4 2023

Another messy day on the waters and coastal areas today with
strong onshore winds this morning moderating later in the day,
elevated seas and tides, and periods of showers and thunderstorms.
A quick summary of threats for the day: a flood watch is in effect
for portions of the coast today, mainly for those who saw heavy
rain yesterday. Though not a direct marine concern, it could be of
importance to anyone headed to the coast from inland. Dangerous
rip currents remain a threat at Gulf-facing beaches, and are
likely to remain so until the persistent onshore fetch is changed.
A coastal flood statement is also in place this morning as we come
down from an abnormally high tide cycle. Though future high tides
do look to be lower, they will still be fairly elevated due to the
onshore winds and a high baseline from astronomical tides.

This general setup can be expected for a portion of tomorrow as
well. A cold front is forecast to push off the coast Thursday, and
is expected to be followed by moderate to strong offshore winds
Friday night as cooler air moves over the warmer water. Advisory-
level winds are very likely Friday night, and some gusts may even
reach to around gale force. A gale itself, though unlikely, cannot
yet be ruled out.

&&

.HYDROLOGY...
Issued at 358 AM CDT Wed Oct 4 2023

A flood watch is in effect today for Matagorda, Wharton, Brazoria, Fort
Bend, and mainland portions of Galveston counties due to the
potential for training, locally heavy rain moving south to north
from the Gulf of Mexico. The highest threat will exist in
locations that saw heavy rain yesterday, as they will be much more
sensitive to any further rain today. Elsewhere in the area,
including farther inland, lighter antecedent rainfall will make
rain from storms today more manageable. Still, be cautious around
low-lying and/or poor drainage locations as intense rain rates
from a strong storm can overwhelm their drainage abilities and
result in localized flooding.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)	  89  72  81  69 /  70  70  90  30
Houston (IAH)			  88  74  86  72 /  70  30  80  40
Galveston (GLS)			  88  79  88  75 /  60  20  40  50

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch through this evening for TXZ226-227-236>238-336>338.

     High Rip Current Risk through Thursday morning for TXZ436>439.

GM...Small Craft Should Exercise Caution until 10 AM CDT this morning
     for GMZ335-350-370.

     Small Craft Advisory until 10 AM CDT this morning for GMZ355-375.

&&

SHORT TERM...24
LONG TERM....Luchs
AVIATION...24
MARINE...Luchs