169
FXUS64 KHGX 242258
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
558 PM CDT Sat May 24 2025

...New AVIATION...

.SYNOPSIS...
Issued at 223 PM CDT Sat May 24 2025

Meteorological summer isn`t until June 1, but if you ascribe to
the idea that Memorial Day begins summer, the atmosphere agrees
with you. Summery conditions, with temperatures near record highs
and isolated to scattered showers and storms will be the rule this
weekend, giving way to a pattern with more widespread showers and
storms in the middle of the week.

Some of the key things for the week to come:
- Near-record temperatures prevail today and tomorrow. With all of
  the outdoor holiday happenings, be sure to also keep heat safety
  in mind, with plenty of shade, lots of water, and quick access
  to AC if needed. (Buildings with AC are also handy if you end up
  under one of the isolated to scattered afternoon showers).
- Monday into Tuesday will see temperatures back off slightly as a
  pattern with more coverage of showers and storms for the middle
  of the week. Conditions will still be summer-like, but trading
  record high potential for higher rain potential.
- We`ll also want to look at the potential for some severe storms
  and locally heavy rain. For Monday through Wednesday, there is a
  marginal risk for excessive rain (threat level 1 of 4) north of
  I-10. Severe potential is highest on Monday, where there is a
  slight risk (threat level 2 of 5) from Huntsville northward, and
  a marginal risk (threat level 1 of 5) north a line roughly from
  Columbus to Livingston.

&&

.SHORT TERM...
(This evening through Sunday Night)
Issued at 223 PM CDT Sat May 24 2025

Memorial Day weekend, and the atmosphere is ready to give us
summer right off the bat (okay, it really started solidly earlier
in the month, but let`s just ignore that for now). For today and
tomorrow, the high temperatures will be the stars of the show with
daily records under threat both today and tomorrow.

However, we are gradually making our way towards a shift in the
weather pattern as the ridging in place aloft helping fuel this
heat slides off to the east. It will be replaced by a parade of
shortwave troughs giving us plenty of opportunities for showers
and clouds that will take a bit of edge of the heat, but we`re not
there quite yet. Read on to the long term section for more on
that.

Sunday will be more of a transition day, as we end up on the back
end of the departing upper ridge. There are indications that a
small vort max will ride through the area, which will give us
another afternoon of isolated to widely scattered showers and
thunderstorms. The best potential, like today, mostly appear to be
for the eastern bulk of the area. If you win the shower/storm
lottery, that will also help keep Sunday`s high temp tamped down a
bit. But elsewhere, look for another day with high temps in
roughly the middle 90s.

&&

.LONG TERM...
(Monday through next Friday)
Issued at 223 PM CDT Sat May 24 2025

Monday is going to be a challenging day to forecast, as there is
currently still quite a bit of uncertainty as to the progress of a
weak cold front blobbing its way down through the state. A more
slowly blobbing front likely makes Monday quite a bit like Sunday.
Warmer, with scattered showers and storms that fade off with
sunset, while heavier rain happens north of our area, more for
North Texas to Northeast Texas. The slowest scenario in the LREF
clustering is cluster 2 (26 percent of ensemble members), and this
even holds the axis of heaviest rain back over the Red River!

On the flip side, a faster front would start to push showers and
storms developing near the front down into our area more on
Monday. The fastest scenario brings the front and some heavier
rain into the northern parts of our area by Monday evening. Given
that the LREF is an ensemble of global ensembles, there are some
mesoscale features that could impact timing as well, so there may
even be a bit more southward potential for heavier rain if it runs
out ahead of the front some, but this probably makes a pretty
rough window for how Monday goes.

Cluster 1 in the LREF is not terribly different from the grand
ensemble mean, and tends to be a little bit slower, and so the
most substantial rain along and near the front looks to make its
way into the area more Tuesday afternoon. Because of this, the
trend for both the severe and excessive rain outlooks from SPC and
WPC, respectively, have tightened up and focus more just to the
north of our area. With the uncertainty though, we still have some
threat of severe weather (slight risk from Huntsville north,
marginal risk from roughly I-10 north) and excessive rain
(marginal risk roughly north of I-10).

From Tuesday onward, the story becomes that of a weak, diffuse
front-like substance continuing to slowly blob its way towards the
coast. It will continue to be a focus for convection, though
intensity should be diminished some as the supporting upper trough
and its accompanying surface low on Tuesday stays up in the mid-
Mississippi Valley, well north of the area. Still, we`ll have
roughly 90th percentile precipitable water values progged in the
NAEFS and EPS ensemble means. As a result, marginal risk areas for
excessive rain continue for a couple more days in the "frontal"
zone. While SPC does not delineate marginal risk areas out that
far, that`s another potential outcome, though it would entirely be
for one or two pulse severe storms fueled entirely by large
instability, as the broader environment supportive of severe
weather looks to fade as the upper support ejects away from the
area.

We may be keeping an eye on the severe potential modestly nudging
back up as the remnant front doesn`t look to go anywhere (indeed,
another weak "reinforcing" "front" may pile up on it) and the next
upper trough swings through late in the week. However, there is
considerable uncertainty as to how strong this upper trough will
be, so I don`t want to promise too much - or anything, really -
about that this far out. But it can be something to keep checking
on these discussions for through the week, and confidence should
increase and allow us to better describe the late week scenario
with more definition.

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 556 PM CDT Sat May 24 2025

Spotty shra/tsra will diminish this evening. MVFR cigs expected
to return overnight as winds decrease. Winds will increase from
the S to SE by mid/late morning tomorrow. Cigs are expected to
improve to VFR by 15-16Z tomorrow.

&&

.MARINE...
Issued at 1222 PM CDT Sat May 24 2025

Light to moderate onshore winds and seas into the 3 to 4 ft range
will continue this afternoon and evening. Gusts up to 25 knots are
possible at times; therefore, Small Craft Should Exercise Caution
conditions are in effect for all Bays and Gulf waters. Winds and
seas could reach advisory levels, at least through late Monday.
Onshore winds will prevail through most of the week. In terms of
precipitation, a few showers are possible this afternoon; however,
the best rain and storm chances arrive late Monday afternoon, and
will continue through most of the work-week.

Beach conditions will become hazardous over the Memorial Day weekend
with an increasing risk of rip currents. The risk gradually increase
late today and will continue through the week. A High Rip Current
Risk Statement is in effect.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  76  96  77  94 /   0  10  20  40
Houston (IAH)  79  94  79  92 /   0  10  10  20
Galveston (GLS)  80  87  80  87 /   0  10   0  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Tuesday morning for TXZ436>439.

GM...Small Craft Should Exercise Caution through Sunday morning for
     GMZ330-335-350-355-370-375.

&&

$$

SHORT TERM...Luchs
LONG TERM....Luchs
AVIATION...Self
MARINE...JM