Flash Flood Warning 70, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
710 AM CDT Mon Sep 2 2024

...New AVIATION...

.SHORT TERM...
(Today through Tuesday Night)
Issued at 333 AM CDT Mon Sep 2 2024

With the axis of the deepest moisture having shifted a bit more to
the west (now between Galveston and Matagorda Bays), the best POPs
should also be shifting in this direction. So far this morning, we
are seeing this trend as bands of moderate (to occasionally heavy)
rains have fallen through the overnight/early morning hours...with
radar estimates from 0.5 to 1.5 inches in spots.

So, based on this, WPC has included coastal portions of SE TX in a
Slight Risk for Excessive Rainfall (level 2 out of 4)...stretching
from Galveston Island going southwest along the coast to Matagorda
Bay (and then further down the coast). A Marginal Risk (level 1 of
4) will be in place for much of the rest of the CWA for Day 1 (to-
day and tonight). Rainfall totals over the coastal counties should
range from 1-3" but localized totals from 3-6" can't be ruled out.
This could lead to issues with street flooding and flooding in low
lying areas. Elsewhere, further inland, rainfall totals should av-
erage from 0.5-1".

This wet/unsettled pattern, all courtesy of that broad area of low
pressure that has been lingering just off the Upper TX coast, will
eventually track inland by late tonight/tomorrow. However, this is
not going to end rain chances for SE TX. A steady E/SE flow at the
lower and mid levels will help to keep high PWs (2.2-2.6") in over
much of the CWA through tomorrow. So, with daytime heating and the
possibility of weak shortwave energy or even the seabreeze will be
enough for the development of scattered mainly diurnal activity on
Tues. 41

&&

.LONG TERM...
(Wednesday through Sunday)
Issued at 333 AM CDT Mon Sep 2 2024

The rainy pattern of late will continue as we move through the
middle of the week, with the synoptic pattern remaining favorable
for the development of scattered showers and storms. Global models
still show the approach of a fairly robust midlevel trough/low from
the NW by Wednesday. This feature, combined with the presence of
deep Gulf moisture as well as diurnal heating, will support the
development of scattered storms that should impact most of the area
on Wednesday and Thursday. While a significant flooding threat is
not anticipated at this time, the possibility of a locally heavy
downpour still cannot be ruled out. High temperatures will remain
confined to the upper 80s given the expected rainfall and associated
cloud cover, while lows remain in the 70s.

What will likely be a welcomed pattern shift arrives on Friday as a
surface front associated with low pressure over the Great Lakes
moves through the Southern Plains and into the area. While a
significant drop off in temperatures is not expected, global
deterministic models and ensemble solutions remain supportive of
drier air working its way into the area over the course of the
weekend. In addition to stifling rainfall chances for inland areas,
we should see dew points dropping below 70 on Friday and into the
lower 60s/upper 50s for most of the area by Sunday. This drop off in
humidity should be noticeable, giving the area its first taste of
"fall-like" weather (for SE TX standards) that should prevail into
early next week. Highs remain in the upper 80s/near 90 despite the
decrease in moisture. Lows may dip into the 60s as early as Saturday
night.

Cady

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 657 AM CDT Mon Sep 2 2024

Will be continuing with the messy unsettled forecast with the bulk of
the showers and thunderstorms likely south of the I-10 corridor. CIGs
have been problematic overnight as the widespread LIFR/IFR conditions
have only been spotty at best so far this morning. Otherwise, will be
keeping with TSRA in prevailing/TEMPO groups for mainly the southern-
most terminals through this afternoon. VCSH for the northern sites by
this afternoon for now. Expecting this coverage to decrease/dissipate
by this evening for most of the CWA...but development should be pick-
ing back up over the coastal waters/southern terminals overnight once
again. 41

&&

.MARINE...
Issued at 333 AM CDT Mon Sep 2 2024

Daily rainfall chances prevail throughout the upcoming week, with a
few stronger storms having the potential to produce isolated
downpours and/or stronger wind gusts. Wind speeds otherwise remain
below caution thresholds, while seas will continue to sit in the 2
to 3 foot range. Rain chances remain the most likely in the early
morning to afternoon hours.

Cady

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)	  91  75  89  73 /  40  50  40  20
Houston (IAH)			  90  77  90  76 /  40  30  50  40
Galveston (GLS)			  86  80  87  78 /  70  40  60  60

&&

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

SHORT TERM...41
LONG TERM....Cady
AVIATION...41
MARINE...Cady