textproduct: Corpus Christi

KEY MESSAGES

Updated at 635 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

(12Z TAFS) Issued at 635 AM CDT Thu May 21 2026

Showers and storms are ongoing across the eastern half of the area this morning but will gradually move out. Mainly VFR conditions are noted behind the convection with MVFR to IFR within it. Once this moves out, expect VFR conditions everywhere during the day. Will have another chance for convection late this afternoon into the overnight.

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.