textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Issued at 1206 PM CST Fri Nov 13 2026

- Rain chances have lowered for Saturday (around 30%), but have increased for Sunday into Sunday night (20 to 60%).

- The Storm Prediction Center has all of Deep South Texas in a Marginal Risk (level 1 of 5) for severe weather on Sunday. This is a conditional threat depending on the timing of the frontal passage.

- Temperatures will gradually warm through Sunday before the second stronger cold front lowers highs into upper 60s/lower 70s for next week.

- Marine hazards and beach are expected late this weekend into early next week following the frontal passage.

DISCUSSION

Issued at 1206 PM CST Fri Nov 13 2026

Rain-free conditions are expected to persist this evening through tonight, as a weak cold front that passed through the area has brought drier air to Deep South Texas. It was initially thought that this cold front would stall just to our south, with a surface low developing just south of our area. However, it appears that this front is going to stall further south than originally expected. Therefore, any surface disturbances that develop along this boundary are going to be further away from the area, which will keep the atmosphere slightly more stable for Saturday. For this reason, precipitation chances have trended lower for Saturday, and are expected to be no greater than 30%.

A second stronger cold front is expected to move through the area late this weekend/early next week, but there is some uncertainty on the exact timing. Some guidance favors the front coming through the area earlier Sunday afternoon, whereas other guidance has the front moving in a bit slower and not reaching the area until Monday morning. Despite the lack of confidence in exact timing, there is a conditional threat for convective thunderstorm development ahead of and along the frontal boundary. It will largely depend on timing; if the front passes through more slowly Sunday evening into Monday morning, conditions will be more favorable for development because diurnal heating will help destabilize the warm sector. If the front moves through earlier on Sunday afternoon, then thunderstorms will be less likely.

If thunderstorms do happen to form, some of these thunderstorms could be strong to severe. The Storm Prediction Center has placed all of Deep South Texas under a Marginal Risk (level 1 of 5) for severe weather for Sunday. A strong moisture return is expected ahead of this front in the warm sector with favorable wind profiles to support potential supercell development. If this occurs, the main hazards will be damaging winds and hail. As of now, the NBM has the best rain chances overnight Sunday into Monday morning, with POPs ranging between 20-60% (higher chances closest to the coast). There is also a low to moderate (20-40%) chance along the coastal counties Sunday afternoon as well. As certainty regarding the cold front's exact timing increases, the timing of these rain chances may shift as well.

Due to robust warm air advection, temperatures are expected to warm into the mid-80s Sunday before the frontal passage brings temperatures back down into upper 60s/lower 70s for Monday and Tuesday. Low temperatures will be coolest Monday night into Tuesday, with lows getting down into the mid 50s and lower 60s. A northerly wind shift is expected with the front, with overall dry conditions following the frontal passage. Beach hazards are also expected to increase this weekend following the frontal passage.

AVIATION

(18Z TAFS) Issued at 1206 PM CST Fri Nov 13 2026

VFR conditions with clear skies are expected this afternoon and evening. A southeasterly wind shift is expected this afternoon, with winds expected to remain light to moderate.

MARINE

Issued at 1206 PM CST Fri Nov 13 2026

Conditions should be favorable the rest of today and tonight, but winds are expected to increase to Small Craft Exercise Caution conditions as the pressure gradient tightens ahead of an approaching cold front. Conditions will further deteriorate Saturday night into Sunday and Small Craft Advisories will likely be needed starting Saturday night. Adverse conditions are expected to continue through Tuesday following the arrival of a strong cold front, and will begin to improve again by mid-week next week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 67 80 72 84 / 0 10 10 20 HARLINGEN 63 79 68 84 / 0 20 0 20 MCALLEN 62 80 69 86 / 0 20 0 10 RIO GRANDE CITY 61 80 67 85 / 0 20 10 0 SOUTH PADRE ISLAND 73 78 74 80 / 0 10 20 30 BAYVIEW/PORT ISABEL 67 79 70 82 / 0 10 10 30

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...None.