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National Weather Service Forecast Discussion

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406
FXUS64 KHGX 190608
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
108 AM CDT Tue May 19 2026

...New DISCUSSION...

.KEY MESSAGES...

- A wet, muggy weather pattern will continue through the rest of
  the week across southeast Texas, bringing temperatures slightly
  below normal (upper 80s) for this time of the year.

- Rain chances will continue through the week with 3-6 inch
  rainfall totals more likely (50-60% chance of 3+ inches) later
  this week and through the weekend.

- The threat of hazardous rip currents remains through at least
  midweek before marine hazards transition to thunderstorm-driven
  waves.

&&

.DISCUSSION...
Issued at 104 AM CDT Tue May 19 2026

Through most of the workweek into the weekend, the broader-scale
synoptic pattern of troughing across the Intermountain West and
ridging across the southeast U.S. will retain its position over
the CONUS with some amplifying evolutions/permutations to the
local southwesterly flows (and subtropical jet) aloft. As the
longwave trough delivers multiple ejections into the Great Plains,
it will maintain a moisture-rich southwesterly flow aloft (PWATs
near 2 inches, well above the 75% percentile of climatology).
This, combined with the advection of embedded vorticity maxima and
lift from an attendant frontal boundary, sets the stage for
multiple rounds of efficient rainfall producing convection (some
storms could produce 3 to 4 inches of rain per hour).

Forecast uncertainty remains with the expected evolution of
convective systems as they approach and proceed through southeast
Texas, however, the congruency that is emerging among short-term
model solutions at the moment favors MCS propagation. The first in
multiple rounds of MCSs is expected later tonight into the
overnight hours, while more concentrated convective rounds are
expected on Thursday and later this week. The cumulative concern
is for where the soils are primed the most from antecedent rains
by Friday and subsequent Flood Watch issuance can`t be ruled out
at this time. Long-range guidance continues the wet trend into
early next week with Day 1-7 QPF values of 5-7 inches becoming
likely.

Cassel

&&

.AVIATION...
(06Z TAF Issuance)
Issued at 1147 PM CDT Mon May 18 2026

MVFR cigs along with occasionally gusty SE winds expected
overnight into Monday morning. Cigs improve to VFR in most areas
by late morning. The primary weather concern will be the potential
for a line of heavy shra/tsra late afternoon and evening that
should approach the region from the north and west. A few widely
scattered thunderstorms could develop ahead of the line during the
afternoon hours as well. Storms could contain strong gusty winds.
We have TSRA TEMPO groups w/ gusts to 25 knots. However, these
gusts could be conservative given the potential for severe
thunderstorms.

&&

.MARINE...
Issued at 1242 AM CDT Tue May 19 2026

Gusty southeast flow and enhanced Gulf seas will continue into
Tuesday. However, the primary weather concern will be the
potential for strong thunderstorms overnight tonight and into
Tuesday. Thunderstorm winds could easily exceed gale force and
result in locally higher seas. It is important to note that
thunderstorm related winds can be felt tens of miles away from the
storm. Thunderstorms can also result in sudden changes in wind
direction.

As for the rest of the week, expect generally light to moderate
south to southeast winds and 3-4 ft seas. There will be a
continued daily risk of showers and thunderstorms, with locally
higher winds and seas in the vicinity of any thunderstorm.

&&

.HYDROLOGY...
Issued at 344 PM CDT Mon May 18 2026

Anticipating multiple rounds of moderate to heavy rainfall Tuesday
through at least Saturday. These rounds are expected to mostly be in
the form of Mesoscale Convective Systems (MCS`s). The exact timing
of these storms can be a bit tricky as mesoscale factors play a key
role (hence the name), but we anticipate the first round to come
late Tuesday. With PW values exceeding the 90th percentile (~1.7-2.1"),
rainfall rates will likely exceed 3-4"/hr in the heaviest downpours.
While these lines of storms are typically progressive,
the rainfall received early in the week is expected to prime the
soils for rounds later in the week. Saturated soils leads to a
quicker transition to runoff which brings an increased risk of
flooding. We continue to anticipate widespread rainfall
totals of 5-7" with isolated higher amounts. The highest rainfall
totals are still expected to occur north of I-10.

This rainfall will generate runoff and cause rises on area rivers
and watersheds. Action to minor stage flooding is the most likely
outcome, but cannot entirely rule out moderate to isolated major
stage flooding depending on where the most rainfall accumulates.
Remember that you can monitor updated river forecasts via the NWS
NWPS webpage (https://water.noaa.gov/).

Landry-Guyton

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  89  72  83  72 /  40  70  70  60
Houston (IAH)  89  76  86  75 /  10  60  60  40
Galveston (GLS)  86  79  85  79 /  10  50  30  20

&&

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

GM...Small Craft Advisory until 7 PM CDT Wednesday for GMZ330-335-350-
     355-370-375.

&&

$$

DISCUSSION...Cassel
AVIATION...Self
MARINE...Self

NWS HGX Office Area Forecast Discussion