Flash Flood Warning 4, NWS Corpus Christi, TX

Area Forecast Discussion
National Weather Service Corpus Christi TX
148 AM CDT Thu May 21 2026

...New DISCUSSION, AVIATION, MARINE, FIRE WEATHER...

.KEY MESSAGES...
Updated at 119 AM CDT Thu May 21 2026

-Flood Watch in effect area-wide through Monday as multiple rounds
of storms bring a marginal to slight risk of flash flooding each
day.

-Increasing risk of river flooding by this weekend due to
 continued rounds of heavy rainfall.

&&

.DISCUSSION...
Issued at 119 AM CDT Thu May 21 2026

At the time of writing this discussion, yet another nocturnal MCS is
slowly progressing through South Texas (this is the third night
in a row). This morning's MCS is more of the prototypical late
spring eastward propagating system from Mexico, riding just ahead
of a convectively-enhanced shortwave. Instability is less
impressive than last night (MLCAPE around 2000 J/kg, DCAPE 900 to
1000 J/kg), but should be enough to support MCS maintenance as it
treks through the area. If the system is able to form and sustain
a robust cold pool, strong winds would be a convective hazard,
otherwise as mentioned in previous discussions hydro will likely
be the biggest concerns. One hour FFGs are as low as 2-2.5 inches
(and 3 hour FFG < 3 inches) over portions of the Brush Country and
Coastal Plains, so those in particular will be areas to monitor
early this morning.

Although the CAM suite has had a lot of issues timing the
progression of this system, based on current radar trends and
assumed system propagation, would expect precipitation to more or
less have cleared the area by 11-14Z. Similar to the last couple
days, the combination of post MCS low-lvl stabilization and weak
subsidence will somewhat limit precipitation chances during the
daytime hours. However, there is some signal for another trailing
wave during the afternoon hours, so will retain some low-medium
range PoPs (20-40%), but am pretty skeptical of the widespread
coverage some of the CAMs and the GFS depict (the storms would
likely have to initiate north of the area which is less worked
over). We will potentially have to contend with additional
overnight convection tonight into Friday morning as more storms
developing over Mexico and the West Texas dryline and gradually
propagate towards our area. There is a more muted convective
signal compared to the last couple nights, so will retain only
Chc (generally 40-50%) PoPs for now, but any additional convective
rainfall would trigger renewed hydro concerns given antecedent
conditions.

The most-amplified mid-lvl wave is still progged to move over the
area on Saturday, likely bringing fairly widespread rainfall to
the area. Hydro will likely be the greatest concern by that
point, and beyond the localized flash and urban flooding threat,
river flooding will also bear increasing monitoring. The
aforementioned mid-lvl low looks to amplify/close off near the
area on Sunday and then lift slowly to the north/northeast on
Monday/Tuesday. This could provide a setup to give us a brief
respite from the active weather as drier air filters down its
western flank from the north. Any break in precipitation looks to
be short-lived as another mid-lvl system makes it way towards the
area mid to late next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 119 AM CDT Thu May 21 2026

An ongoing cluster of showers and thunderstorms over the Rio Grande
Plains will continue to slowly shift eastward through the early
morning hours. We'll likely have a mix of VFR/MVFR ceilings through
15-16Z as convection throws a wrench in the forecast. Heavy
thunderstorms directly impacting terminals will cause reduced
visibility and potentially strong variable winds. VFR conditions
prevail by midday with variable winds becoming predominately out of
the southeast at around 10 knots in the afternoon.

&&

.MARINE...
Issued at 119 AM CDT Thu May 21 2026

Generally gentle to moderate E-SE winds will prevail through the
weekend over the waters. The main exception to this will be brief
periods of erratic and gusty winds (and elevated seas) in the
vicinity of thunderstorms. Thunderstorm chances remain high
(60-80%) today, Saturday and Sunday, with Friday have somewhat
lower rain chances (20-40%).

&&

.FIRE WEATHER...
Issued at 119 AM CDT Thu May 21 2026

No fire weather concerns through the week as moisture increases
and minimum RHs remain over 50% area-wide. Medium to high rain
chances (50-80%) are expected each day through Saturday. These
should be solid wetting rains with aerial totals in the 2 to 4
inch range through the weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi    84  73  88  76 /  70  40  30  30
Victoria          81  70  86  72 /  70  40  50  20
Laredo            86  71  92  73 /  40  40  10  40
Alice             84  71  89  73 /  50  40  40  30
Rockport          86  77  89  78 /  80  40  30  20
Cotulla           84  69  90  72 /  40  40  10  40
Kingsville        83  72  88  74 /  60  30  40  30
Navy Corpus       84  77  87  79 /  70  40  30  30

&&

.CRP WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch through Monday evening for TXZ229>234-239>247-
     342>347-442-443-447.

GM...None.
&&

DISCUSSION...NC/91
AVIATION...EMF/94

Special Weather Statement
National Weather Service Corpus Christi TX
1220 AM CDT Thu May 21 2026

TXZ229-239-210545-
Webb TX-La Salle TX-
1220 AM CDT Thu May 21 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN LA SALLE AND
NORTHEASTERN WEBB COUNTIES THROUGH 1245 AM CDT...

At 1220 AM CDT, Doppler radar was tracking a strong thunderstorm 14
miles north of Ranchitos Las Lomas, or 17 miles southeast of Encinal,
moving north at 30 mph.

HAZARD...Wind gusts up to 40 mph and nickel size 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...
Encinal.

This includes Interstate 35 between mile markers 31 and 40.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 2775 9895 2773 9933 2806 9943 2809 9903
TIME...MOT...LOC 0520Z 168DEG 26KT 2785 9917

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

EMF

Special Weather Statement
National Weather Service Corpus Christi TX
239 AM CDT Thu May 21 2026

TXZ239>241-210815-
Jim Wells TX-Webb TX-Duval TX-
239 AM CDT Thu May 21 2026

...STRONG THUNDERSTORMS WILL IMPACT SOUTHERN DUVAL...SOUTHEASTERN
WEBB AND SOUTHWESTERN JIM WELLS COUNTIES THROUGH 315 AM CDT...

At 239 AM CDT, Doppler radar was tracking a cluster of strong
thunderstorms along a line extending from 11 miles northeast of
Oilton to 8 miles northeast of Bruni to 6 miles north of Jim Hogg
County Airport to South Fork Estates to 6 miles east of
Thompsonville. Movement was east at 50 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Concepcion, Ramirez, Realitos, Rios, Cruz Calle, and Bruni.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 2726 9851 2727 9852 2734 9852 2734 9855
      2736 9856 2736 9859 2734 9859 2734 9862
      2736 9863 2735 9880 2727 9880 2727 9890
      2743 9886 2754 9889 2768 9900 2762 9849
      2739 9822 2726 9819
TIME...MOT...LOC 0739Z 291DEG 42KT 2762 9888 2754 9876 2743 9870 2726
9870 2721 9882

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

EMF

Special Weather Statement
National Weather Service Corpus Christi TX
451 AM CDT Thu May 21 2026

TXZ241>244-342-343-442-211045-
Jim Wells TX-Inland Nueces TX-Inland San Patricio TX-
Kleberg Islands TX-Coastal Nueces TX-Coastal Kleberg TX-
Inland Kleberg TX-
451 AM CDT Thu May 21 2026

...STRONG THUNDERSTORMS WILL IMPACT NUECES...SOUTHWESTERN SAN
PATRICIO...NORTHERN JIM WELLS AND CENTRAL KLEBERG COUNTIES THROUGH
545 AM CDT...

At 450 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from Alfred to near Bishop to 7 miles southeast of
Riviera Beach. Movement was east at 20 mph.

HAZARD...Wind gusts up to 50 mph and pea size 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...
Corpus Christi, Kingsville, Alice, Robstown, Driscoll, Corpus Christi
International Airport, Bishop, Orange Grove, San Patricio, Edroy,
Banquete, Tecalote, Clarkwood, Annaville, Calallen, Kingsville Naval
Air Station, Riviera Beach, South Texas Botanical Gardens,
Alfred-South La Paloma, and Bluntzer.

This includes the following highways...
 Interstate 37 between mile markers 10 and 31.
 US Highway 281 between mile markers 662 and 668.
 US Highway 77 between mile markers 658 and 694.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 2724 9763 2728 9765 2726 9772 2752 9788
      2790 9815 2807 9774 2766 9740 2732 9725
      2724 9728 2724 9735 2728 9735 2727 9737
      2724 9737 2724 9740 2726 9745 2725 9749
      2724 9749 2724 9750 2723 9754
TIME...MOT...LOC 0950Z 255DEG 19KT 2788 9797 2757 9775 2724 9757

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

EMF