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National Weather Service Forecast Discussion

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559
FXUS64 KHGX 220508
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1208 AM CDT Wed Apr 22 2026

...New DISCUSSION, MARINE...

.KEY MESSAGES...

- Scattered afternoon showers and storms may bring locally heavy
  rainfall Today.

- Gradual warming trend with temperatures reaching the upper 80s
  by the end of the work week.

- Lower rain chances Thursday through the weekend. Cannot rule out
  some stronger or severe storms on these days either.

&&

.DISCUSSION...
Issued at 1158 PM CDT Tue Apr 21 2026

A midlevel ridge is expected to pass over SE Texas today, putting
our areas in a northeasterly flow pattern aloft. Subsidence from
the ridge should result in a noticeable decrease in overall
rainfall coverage for today. However, embedded impulses passing
through the ridge, along with daytime heating, should still be
sufficient to bring showers to the area. They`ll initially start
as light, sporadic showers this morning, increasing in coverage as
the day progresses. Daytime heating should slowly kick in,
producing some scattered thunderstorms during the afternoon. With
deep moisture over the region, the strongest storms could end up
producing heavy downpours, which may result in some locally heavy
rainfall. Generally rainfall totals are forecasted to be around an
inch or less, though models show that those isolated higher-end
totals could reach upwards of 3-5 inches. WPC has portions of SE
Texas under a Marginal (level 1/4) Risk of heavy rainfall for
Today, though this is a fairly common scenario for our area, where
one or two spots may see a heavy amount of rainfall while others
see relatively little by comparison. Any of those stronger
downpours could result in some ponding on roadways and minor
street flooding, especially in urban areas. Either way, showers
and storms should taper off into the evening with quieter weather
overnight.

Thursday will see rising mid level heights and generally less
shortwave impulses passing overhead in this semi-zonal flow pattern.
While there should be some better instability and shear, showers and
storms should largely be isolated in nature. Otherwise, conditions
should be warm with highs in the mid/lower 80 and lows in the upper
60s/lower 70s.

Friday through the weekend will be a rather interesting period of
the forecast to watch. SE Texas will remain in a predominantly zonal
flow pattern throughout this period of the forecast as temperatures
rise. Long range ensembles show ample shear and instability in place
across portions of the Southern Plains/Lower Mississippi River
Valley during this period. Over SE Texas specifically, SFC CAPE is
forecasted to range from around 1700-2800 J/KG with 500mb shear
around 30-45 knots. Several troughs/disturbances are forecasted to
pass to the north of our area around this time, though as a result,
much of the best lift and forcing will keep north of our area as
well. This explains why models are producing low PoPs through the
weekend. Still, if any storms can get started, this environment does
appear conducive for severe weather. SPC currently has a Slight
(level 2/5) Risk of severe weather up against our northern boarder
on Friday, Saturday, and Sunday as well. While it`s not directly in
our CWA for all of these days, we`re still several days out, and any
southerly shift in the shortwaves/impulses could result in this risk
shifting into our area. Given the WNW flow aloft as well, it`ll be
worth monitoring as we draw closer to the end of the week.

On Monday, a much more robust shortwave trough is anticipated to
fill north across the Plains, sending a cold front towards SE Texas.
Decent shear and instability remain present, though models suggest
the front may slow/stall around the Brazos Valley/Piney Woods area.
A subtropical mid-level high then builds in from the south on
Tuesday, allowing low rain chances and warmer weather to continue.

03

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 613 PM CDT Tue Apr 21 2026

Showers should taper off this evening with only sparse rain
chances overnight. MVFR to IFR CIGs are anticipated to scatter out
in may areas for a brief period in the evening, then fill back in
early Wednesday morning. Scattered showers start to develop across
the region again early on Wednesday with coverage slowly rising
into the late morning as CIGs scatter/lift in most spots.
Scattered thunderstorms may develop over portions of SE Texas
Wednesday afternoon. Showers and storms should taper off during
the late afternoon, with only light and very sparse showers
anticipated Wednesday night.

03

&&

.MARINE...
Issued at 1158 PM CDT Tue Apr 21 2026

Elevated winds of around 15 to 20 knots are anticipated across the
nearshore coastal waters from High Island to Freeport early this
morning. Small craft should exercise caution to allow winds to
subside. Light to moderate southeasterly winds should continue
through the later half of the work week. A long fetch of these
southeasterly winds may bring increased seas at times. This with,
periodically higher winds may warrant caution flags at times.
Scattered showers and thunderstorms will be possible today with rain
chances decreasing into Thursday. Above normal water levels near 3.0
feet MLLW are still expect at each high tide cycle through the end
of the work week.

03

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  61  77  66  83 /  30  50  20   0
Houston (IAH)  63  80  68  84 /  40  70  20  10
Galveston (GLS)  70  79  73  80 /  40  60  20  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 1 AM CDT Wednesday for TXZ436>439.

GM...Small Craft Should Exercise Caution until 1 AM CDT Wednesday for
     GMZ335.

     Small Craft Should Exercise Caution until 7 AM CDT Wednesday for
     GMZ355.

&&

$$

DISCUSSION...03
AVIATION...03
MARINE...03

NWS HGX Office Area Forecast Discussion