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National Weather Service Forecast Discussion

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685
FXUS64 KHGX 171845
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
145 PM CDT Sun May 17 2026

...New DISCUSSION, MARINE...

.KEY MESSAGES...

- Warm, breezy, and muggy conditions will continue for the next
  several days.

- Isolated light showers possible tonight, scattered activity on
  Monday, followed by increasing shower and thunderstorm chances
  for the rest of the week.

- Elevated winds, seas, tides, and rip current risk in the marine
  water and beaches at least into mid week.

&&

.DISCUSSION...
Issued at 129 PM CDT Sun May 17 2026

Warm and humid out there, with scattered light showers spreading
across the region. Latest observations indicate ample southeast to
northeast 925mb moisture transport on top of a broad area of
increased theta-e advection. In other words, plenty of moisture is
filtering in, enough to support the scattered activity radar is
showing this afternoon. This activity should remain low in intensity
and is forecast to persist this evening and overnight. Will continue
with 15 to 20 percent PoPs during this time frame.

Unsettled weather is expected this work week with multiple chances
for rain and storms. A deepening and broad longwave trough will be
moving over the west CONUS/Rockies tonight into Monday. Ahead of
this system, several shortwaves/vort maxes embedded in the
southwesterly flow aloft will move over Southeast TX throughout
the week. The combination of deep moisture (PWAT values near the
daily climatological max) with passing shortwaves (increasing
potential vorticity advection) will support scattered showers and
isolated storms on Monday, particularly during the peak of
daytime heating.

The atmosphere becomes more favorable for scattered to widespread
activity late Tuesday into the end of the week as multiple mesoscale
convective systems (MCS) attempt to move through the region. In
addition to the parade of shortwaves aloft, a surface front will
attempt to make its way southward across north-central TX sometime
in the late Tuesday to Wednesday time-frame. Wherever this boundary
sets up will be the main focus for shower and storm activity.
Uncertainty remains moderate to high on how far south this
boundary will move and where it will likely stall. Latest guidance
keeps this front just north of Southeast TX by midweek, stalling
somewhere between the Dallas/Fort Worth area and the Brazos Valley
through the end of the week. Overall, with plenty of moisture and
convergence at the surface, and enough forcing aloft, showers and
thunderstorms are expected along of and ahead of this boundary.
Localized heavy rain and/or training rain/storms cannot be ruled
out, especially along the frontal boundary. At the moment, the
highest PoPs are expected on Wednesday with the passage of one of
the strongest MCSs. WPC highlights the risk of excessive rainfall
with a Slight risk (level 2 of 4) mainly for areas along and north
of a line from Brenham to Conroe to Livingston.

The mid to upper level pattern continues to look "messy" with
several disturbances moving over the region, potentially keeping
rain and storm chances in the forecast into next weekend. Forecast
rainfall totals from Monday through Friday of 2 to 4+ inches will be
possible mainly north of I-10, with isolated higher amounts. Of
course, as we have been saying over the past discussions, do not
focus on specific rainfall amounts but rather on the potential. It
is still early for specific details on the location of the heaviest
rain, coverage and total amounts. We will continue to update the
forecast as the systems evolve and more Hi-Res guidance comes in.

JM

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 633 AM CDT Sun May 17 2026

MVFR cigs this morning should improve to VFR by afternoon.
However, low cigs may linger at the coast all day. MVFR cigs
should push inland, impacting most/all terminals by evening and
overnight. Winds will be gusty and from the southeast. Gusts are
expected to be 20-25 knots. In some areas, gusts could exceed 25
knots.

&&

.MARINE...
Issued at 129 PM CDT Sun May 17 2026

Moderate to strong onshore winds and seas from 4 to 7ft
(occasionally higher well offhsore) are the main weather story
across the Upper TX coast this evening/tonight. A Small Craft
Advisory remains in effect through mid Monday morning and could
potentially be extended through the evening. Light to moderate
onshore winds resume late Monday. Multiple disturbances will be
moving across the region through the week; therefore, a daily risk
of showers and thunderstorms is expected. The best rain and storm
chances will be after mid-week.

We will continue to monitor coastal conditions as there remains a
high risk of rip currents along all Gulf-facing beaches, as well as
a localized risk of minor coastal flooding, particularly during
times of high tide. Model guidance now indicates water levels
between 3.0 and 3.8 ft MLLW during high tides along the Bolivar
Peninsula and Galveston Island through early Monday. A Beach Hazards
Statement remains in effect through at least Monday morning.

JM

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  89  77  89  76 /  20  20  20  20
Houston (IAH)  89  78  88  77 /  20  20  20  10
Galveston (GLS)  85  79  86  79 /  20  10  20  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Beach Hazards Statement through Monday morning for TXZ436>439.

GM...Small Craft Advisory until 10 AM CDT Monday for GMZ330-335-350-
     355-370-375.

&&

$$

DISCUSSION...JM
AVIATION...Self
MARINE...JM

NWS HGX Office Area Forecast Discussion