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National Weather Service Forecast Discussion

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670
FXUS64 KHGX 201957
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
257 PM CDT Mon Apr 20 2026

...New DISCUSSION, MARINE...

.KEY MESSAGES...

- Light showers/virga expected throughout the day on Monday,
  especially along and west of I-45.

- Chances for thunderstorms return Tuesday into Wednesday with the
  potential for another round of locally heavy rainfall.

- Gradual warming trend throughout the work week with shower/storm
  chances increasing again going into the weekend.

&&

.DISCUSSION...
Issued at 256 PM CDT Mon Apr 20 2026

Light showers are continuing this afternoon. The bulk of the
heaviest rainfall has remained to the west of our area. Expect
continued cloudiness through the remainder of the week as
disturbances impact SE Texas.

Tuesday and Wednesday will feature the wettest days of the week with
PW values exceeding the 90th percentile (~1.58"). This will
contribute to the potential for locally heavy rainfall. WPC has
outlined most of SE Texas in a marginal risk (level 1 of 4) of
excessive rainfall Tuesday and Wednesday. With soils already
saturated from previous rainfall, it would not take too much
rainfall for runoff to occur. Current QPF show generally 1-2";
however, locally higher amounts of 3+ inches will be possible.

There will be a decrease in moisture availability on Thursday,
but with embedded shortwaves passing overhead, may have enough to
see isolated to scattered activity during peak heating.

Temperature wise, expect a warm up trend to begin tomorrow and
continue through the end of the weekend. Highs will return to the
mid to upper 80s by the end of the week.

Another shot of rain will be possible this weekend as another upper-
level low moves across the Plains and another frontal boundary
approaches the area.

Bailey

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 614 AM CDT Mon Apr 20 2026

VFR conditions are expected through the next 12-18 hours. Cigs
will gradually lower through the day as moisture increases, but so
categorical degradations are expected. Chances for SHRA will
increase from SW to NE this afternoon into tonight. TSRA probs are
low enough to keep mention out of the TAFs this cycle, but will
continue to be monitored for tonight heading into Tuesday. Winds
will generally remain out of the east around 6-12 kt, except GLS
where gusts of 20-25 kt remain possible.

Young

&&

.MARINE...
Issued at 256 PM CDT Mon Apr 20 2026

Small craft will need to exercise caution through at least tonight.
Winds and seas are expected to take a while to subside below the
caution flag threshold. Wind speeds remain elevated, but will
gradually transition to easterly overnight and southeasterly by
tonight. An extended fetch of moderate southeasterly winds around
midweek will likely lead to another round of increased seas,
especially in the offshore Gulf waters. This may lead to another
period of caution flags on Wednesday into Thursday for the Gulf
waters. Scattered light rain is expected on Monday, but chances
for storms return Tuesday into Wednesday as an upper level
disturbance pushes through. Water levels are expected to remain
near 3.0 feet above Mean Lower Low Water during high tide cycles
through at least midweek.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  58  67  61  80 /  70  80  40  60
Houston (IAH)  62  71  65  79 /  50  80  50  80
Galveston (GLS)  69  76  72  78 /  50  60  60  80

&&

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

GM...Small Craft Should Exercise Caution until 1 AM CDT Tuesday for
     GMZ330-335-350-355-370-375.

&&

$$

DISCUSSION...Bailey
AVIATION...Young
MARINE...Bailey

NWS HGX Office Area Forecast Discussion