textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1100 PM CST Wed Nov 26 2025

* Increasingly tranquil and mainly rain-free weather conditions with seasonable level temperatures are expected Thanksgiving Day and Black Friday with highs mostly in the 70s.

* A brief warm spike takes place on Saturday with highs in the 80s.

* A strong cold front Saturday night into Sunday will bring a notably cooler airmass (potentially the coldest since last February) to the region Sunday through early next week.

* Dangerous surf and boating conditions are expected to return Friday night and persist through at least Sunday in response to the strong cold front.

DISCUSSION

Issued at 1100 PM CST Wed Nov 26 2025

The main weather headline during the forecast period will focus on a strong cold front (Arctic origins) that will bring the coldest airmass of the season (since last February) to all of Deep South Texas and the Rio Grande Valley Saturday night/Sunday through next Tuesday night (~November 29/30-December 3 timeframe).

Tonight through Friday, dry, increasing tranquil, and mainly rain- free weather conditions will take place amid a 1030-1040 mb sfc high pressure system centered over the central and northern Plains and Midwest. Temperatures will remain cooler than prior days, but will still remain slight warmer than normal levels with highs topping out in the 70s most places (80s along the RGV) and overnight lows in the 50s and 60s.

Friday night through Saturday, a warm front associated with a developing mid-latitude cyclone over the central Rockies will result in a warming trend taking place. Overnight lows Friday night are progged to be in the 60s most places with some 70s along the RGV. On Saturday, this warm front will result in high temperatures climbing into the 80s across all of Deep South Texas. The warmup however will be brief as there is a growing consensus amongst global forecast models and ensembles that a major large-scale weather pattern shift will take place over the weekend into the early parts of next week. Numerous weather models/ensembles are advertising a highly amplified and active 500mb pattern featuring a mild West U.S. vs. a Cold Central and East U.S. developing late this week into the early parts of next week (~November 30-December 3 timeframe).

While this will bring plenty of wintry weather across the northern tier states, a strong cold front associated with the aforementioned mid-latitude cyclone (low pressure system) over the central Rockies will sweep through the state of Texas on Saturday. There still remains some discrepancies amongst forecast guidances on the precise timing of the cold fropa, which would impact high temperatures on Sunday. Typically, these cold shallow airmasses tend to have a faster timing than than what most global forecast models suggest. The hi- res, CAM North American Model (NAM) captures these trends better.

That said, it appears that sometime Saturday night into Sunday, this strong cold front with Arctic origins will sweep through all of Deep South Texas and the Rio Grande Valley. In it's wake will be the coldest airmass of the season (since last February). High temperatures on Sunday will likely be reached early in the day as temperatures are expected to fall through the day. High temperatures from Saturday to Sunday will be about 10F degrees cooler, but closer to seasonable norms with values on Sunday in the low to mid 70s along the RGV and 60s over the Northern Ranchlands.

Clearing skies amid additional cold and dry air advection will result in a markedly chilly Sunday night as overnight low temperatures are expected to plunge into the 40s most places and 50s along the mid to lower valley and towards South Padre Island (again some 10F degrees cooler than Saturday night). A full cold and dry air advection regime will be in place by Monday. This combined with a modified 1020-1025 mb sfc Arctic high pressure system over the region will result in cooler than normal temperatures with high temperatures failing to make it out of the 60s on both Monday and Tuesday. On Monday, highs could struggle to make it out of the 50s over the Northern Ranchlands. Clear skies and additional radiational cooling will result in overnight low temperatures holding in the 40s most places (50s along the immediate coast), which will be well below normal levels.

Stratiform rain showers are possible Saturday night through Monday night in response and connection to the cold frontal boundary. Currently, we have low to medium (20-50%) PoPs over Deep South Texas during this time period with the best chances being near the coast. Categorical PoPs are in place over the Gulf Waters during this time period. Rain showers are also possible over the Gulf Waters Friday night and Saturday in connection to the aforementioned warm front and again Tuesday through Thursday of next week. Hazardous coastal/marine conditions are expected to develop Friday night into the weekend in response to this strong cold front (see MARINE SECTION for more details).

Wednesday will make the onset of a warming trend as a return flow develops out of the southeast resulting in increase warm air advection. High temperatures on southerly winds will climb back into the 70s across much of Deep South Texas (closer to normal levels). By Thursday, additional warm air advection will result in high temperatures climbing into the 80s most places. Overnight lows Wednesday and Thursday nights will be in the 50s and 60s.

AVIATION

(06Z TAFS) Issued at 1100 PM CST Wed Nov 26 2025

Through 06z Friday....By and large, VFR conditions are expected to prevail through the 06z TAF period. There could be some MVFR ceilings around from time to time.

Winds will continue out of the north-northeast with speeds between 5- 15 kts through the 06z TAF period. Winds could gusts as high as 20- 25 kts, particularly during the afternoon hours.

MARINE

Issued at 1100 PM CST Wed Nov 26 2025

Adverse (i.e. Small Craft Exercise Caution) conditions will continue tonight through Friday in the wake of the first fropa. On the heels of the first fropa and still adverse marine conditons, a second, stronger cold front will sweep through the region Saturday night into Sunday. Ahead of this front, hazardous or dangerous marine conditions will develop Friday night into Saturday with Small Craft Advisory (SCA) conditions being likely. These conditions are likely to continue through at least Sunday before potentially improving early next week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 80 67 79 67 / 90 40 0 0 HARLINGEN 74 61 78 62 / 70 20 0 0 MCALLEN 75 63 79 64 / 60 20 0 0 RIO GRANDE CITY 73 58 78 62 / 70 10 0 10 SOUTH PADRE ISLAND 79 72 77 72 / 90 40 0 0 BAYVIEW/PORT ISABEL 76 66 78 66 / 80 30 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...High Rip Current Risk until 6 AM CST Thursday for TXZ451-454-455.

GM...Small Craft Advisory until midnight CST tonight for GMZ130-132- 135-150-155-170-175.