Area Forecast Discussion

KEY MESSAGES

Updated at 619 AM CDT Sun Apr 19 2026

Key Messages:

* A cold front moving through Deep South Texas tonight will bring moderate to high (60-90%) chances for rain overnight. Widespread beneficial rainfall expected Sunday through Tuesday. * Most areas should receive between 1 and 2 inches of rain, but some areas could see locally heavier amounts of 3 to 4 inches. Isolated flash flooding is possible in low-lying or poor drainage areas that receive heavier rainfall. * A high risk of rip currents with elevated surf and minor coastal flooding near high tide cycles on Sunday. A High Surf and Coastal Flood Advisories and a High Rip Current Statement are in effect for Sunday morning starting at 6 AM.

* A Small Craft Advisory is in effect starting at 1 AM Sunday morning through 10 PM Sunday evening.

DISCUSSION

Issued at 1030 PM CDT Sat Apr 18 2026

Latest radar, satellite imagery, surface observations and surface analysis depicts a cold front extending from near Sarita to Weslaco. A coastal trough/low is expected to develop offshore, along the frontal boundary, Sunday morning and is expected to linger near the coast. The old frontal boundary and weak low should then lift back northward and stall over the Lower Rio Grande Valley Monday morning.

There is high (60-90%) chance of showers and a few thunderstorms with the passage of the cold front tonight. Rain chances have slightly decreased on Sunday, with still moderate to high (60 to 80%) rain chances. The combination of the lingering frontal boundary and a weak surface low will support beneficial rain as the moderate to high (60-70%) chance of rain Sunday night and Monday. A low to moderate (30-60%) chance of showers and a few thunderstorms will be possible Monday night and Tuesday. Drier conditions return Tuesday night through the end of the week as the surface/coastal through moves farther to the east.

Most likely rainfall amounts between tonight and Tuesday for most areas are expected to be between 1-2 inches, with some areas receiving closer to 3-4 inches in areas of locally heavy rainfall. Any slow moving heavier shower or thunderstorm has a small chance for nuisance and isolated flash flooding in low lying and poor- drainage areas.

Weather Prediction Center continues to maintain a marginal (level 1 of 4) risk of excessive rainfall across all of Deep South Texas for Sunday and Sunday night with a small portion over the northeast section of the CWA Monday into Monday night.

In the wake of the front, more noticeably cooler temperatures will occur on Sunday, especially across the ranchlands. Daytime highs on Sunday will range from the lower 60s across the west to the lower 70s near the coast. Lows Sunday night are expected to range from the mid 50s across the Rio Grande Plains to the mid to upper 60s near the coast. Monday will be mild with highs in the mainly in the 70s. Temperatures will recover to near normal on Tuesday and above normal by late week as drier conditions continue.

Hazardous coastal conditions are anticipated with the passage of the cold front, including life-threatening rip currents and elevated surf, as well as some potential beach run-up near high tide cycles, as astronomical tides begin to increase over the weekend. Therefore, A High Surf Advisory, a Coastal Flood Advisory, and a High Rip Current Statement have been issued, all starting at 6 AM Sunday morning.

AVIATION

(12Z TAFS) Issued at 619 AM CDT Sun Apr 19 2026

While generally MVFR conditions will persist for the majority of the period at all TAF sites. While showers and isolated thunderstorms are expected today, there could be some brief periods of IFR and LIFR due to the low ceilings and reduced visibilities associated with the heavy downpours. Northerly winds are forecasted for the rest of the period with some gusts up to 25 knots possible.

MARINE

Issued at 1030 PM CDT Sat Apr 18 2026

Light to moderate winds and seas of 3 to 5 feet prevail along the Lower Texas Coast late this evening. Hazardous conditions will develop overnight with the passage of a cold front. A Small Craft Advisory is in effect starting at 1 AM Sunday morning and will continue until 10 PM Sunday evening. Exercise Caution conditions are expected to continue on the Gulf waters Sunday night into Monday night. More favorable conditions will return late Tuesday before Exercise Caution conditions could then develop again later in the week.

PRELIMINARY POINT TEMPS/POPS

BRO WATCHES / WARNINGS / ADVISORIES

TX...Coastal Flood Advisory until 1 PM CDT this afternoon for TXZ451- 454-455.

High Rip Current Risk through Monday evening for TXZ451-454-455.

High Surf Advisory until 7 PM CDT this evening for TXZ451-454- 455.

GM...Small Craft Advisory until 10 PM CDT this evening for GMZ130-132- 135-150-155-170-175.