Flash Flood Warning 1, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
257 PM CDT Sun Apr 12 2026

...New DISCUSSION, MARINE...

.KEY MESSAGES...

- A Flood Watch is in effect through early Monday morning for
  portions of the Brazos Valley where slow-moving, training
  thunderstorms are expected to develop. A few instances of flash
  flooding will be possible.

- Isolated strong to severe thunderstorms capable of producing
  strong winds, hail, and localized downpours will be possible
  through this evening.

- Increasingly summer-like weather by the second half the week.

&&

.DISCUSSION...
Issued at 102 PM CDT Sun Apr 12 2026

Scattered showers and thunderstorms have moved into SE Texas as a
weak upper level disturbance moves overhead. Isolated strong to
severe thunderstorms will remain possible through this evening.
Damaging wind gusts and hail remain to be the primary concerns
with regards to severe thunderstorms, but a brief, isolated
tornado cannot be ruled out. The primary impact from the
thunderstorms today will be the potential for locally heavy
rainfall leading to a few instances of flash flooding as the
storms will be slow-moving and potentially train over the same
areas. Rainfall rates of 3-4" per hour have already been reported
in areas to our west, and these rainfall rates will remain
possible as the storms enter into SE Texas. 1-hr and 3-hr FFG
across the area is generally 2-4", so the chance for flash
flooding will be there for any slow-moving downpours. A Flood
Watch has been issued this afternoon through early Monday morning
for Burleson, Brazos, Madison, Grimes, Washington, Austin, and
Colorado counties. Generally expecting up to 1-3" of rain for most
areas along and north of I-10, but locally higher amounts of
3-6"+ will be possible within the Watch area. Locally higher
amounts will still be possible outside the Watch area, but the
chances are greater within the Watch. Coverage of the showers and
thunderstorms will begin to wane late this evening, but isolated
showers and thunderstorms will linger into the overnight hours
before this event ends.

Overall the remainder of the week looks to be mostly rainfree, but
weak shortwaves embedded in the southwesterly flow aloft will lead
to continued slight rain chances through midweek for our northern
zones. The best dynamics for thunderstorms will be northwest of
our region, but may see some storms skirt the Brazos Valley and
Piney Woods region. Otherwise, moist onshore flow and daytime
heating could lead to isolated afternoon streamer showers by the
end of the week.

Speaking of daytime heating, we will be on the warming trend
through the week thanks to that southwesterly flow aloft and
southerly flow at the surface. High temperatures will rise into
the low 80s on Monday, mid-80s on Tuesday, then upper 80s by
Thursday (with some isolated areas potentially hitting the 90
degree mark).

Fowler

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 615 AM CDT Sun Apr 12 2026

CIGs are anticipated to remain around MVFR levels early this
morning as light showers develop over the region. Maintaining a
wide timing window for thunderstorms today given the differences
between wx models and uncertainty present. Still, the bulk of
guidance suggests better thunderstorm chances/coverage north of
the Houston Metro area today while areas further south have more
sparse coverage for showers/storms. Could see some areas scatter
out to VFR FLs for some time during the afternoon, though this
too is contingent of shower/storm coverage, thus VFR appears more
feasible at KIAH and southward. Rain chances decrease tonight with
CIGs lowering once again to MVFR-IFR levels overnight.

03

&&

.MARINE...
Issued at 102 PM CDT Sun Apr 12 2026

Small craft should continue to exercise caution through Monday
morning as moderate southeasterly winds continue (around 15kt with
gusts to 20kt) and seas around 4-6ft. Scattered showers and
thunderstorms will be possible through this evening, but the
majority of this activity will remain inland.

Light to moderate onshore flow will prevail through the remainder
of the week with 3-5ft seas and low rain chances. This persistent
onshore flow will lead to elevated tides (high tides around
2.5-3.0ft above MLLW) and moderate to strong rip currents through
most of this week.

Fowler

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)	  69  83  68  85 /  60  20   0   0
Houston (IAH)			  71  83  70  85 /  30  20   0   0
Galveston (GLS)			  72  78  72  79 /  20  10   0  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch through Monday morning for TXZ176-195>198-210-211.

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

&&

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

Special Weather Statement
National Weather Service Houston/Galveston TX
1235 PM CDT Sun Apr 12 2026

TXZ210-121815-
Colorado TX-
1235 PM CDT Sun Apr 12 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN COLORADO AND
WESTERN AUSTIN COUNTIES THROUGH 115 PM CDT...

At 1235 PM CDT, Doppler radar was tracking a strong thunderstorm over
Schulenburg, moving northeast at 25 mph.

HAZARD...Wind gusts up to 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Weimar and Frelsburg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 2978 9672 2989 9663 2996 9657 2995 9656
      2990 9653 2987 9648 2987 9647 2986 9646
      2985 9644 2983 9641 2961 9684 2963 9687
TIME...MOT...LOC 1735Z 231DEG 20KT 2969 9688

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Special Weather Statement
National Weather Service Houston/Galveston TX
259 PM CDT Sun Apr 12 2026

TXZ210>212-122045-
Waller TX-Colorado TX-Austin TX-
259 PM CDT Sun Apr 12 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN COLORADO...EASTERN
AUSTIN AND CENTRAL WALLER COUNTIES THROUGH 345 PM CDT...

At 259 PM CDT, Doppler radar was tracking a strong thunderstorm 9
miles west of Sealy, moving northeast at 35 mph.

HAZARD...Wind gusts up to 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Sealy, Hempstead, Bellville, Pine Island, San Felipe, Pattison,
Monaville, and Cat Spring.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 2975 9648 3010 9610 2990 9587 2963 9636
TIME...MOT...LOC 1959Z 232DEG 29KT 2978 9632

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Special Weather Statement
National Weather Service Houston/Galveston TX
341 PM CDT Sun Apr 12 2026

TXZ211>213-227-122130-
Waller TX-Inland Harris TX-Fort Bend TX-Austin TX-
341 PM CDT Sun Apr 12 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN AUSTIN...
NORTHWESTERN FORT BEND...SOUTHWESTERN MONTGOMERY...SOUTHERN WALLER
AND NORTHWESTERN HARRIS COUNTIES THROUGH 430 PM CDT...

At 340 PM CDT, Doppler radar was tracking a strong thunderstorm over
San Felipe, or near Sealy, moving northeast at 30 mph.

HAZARD...Wind gusts up to 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Katy, Sealy, Brookshire, Hockley, Waller, Simonton, San Felipe,
Pattison, Cypress, and Monaville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 2983 9621 3014 9584 3011 9580 3009 9580
      3009 9579 2992 9559 2963 9612 2967 9622
TIME...MOT...LOC 2040Z 231DEG 28KT 2982 9607

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH