textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1035 PM CST Wed Dec 3 2025

* A cool fropa will result in scattered showers and maybe a thundershower during the day on Thursday along with falling temperatures; best chances near the coast and over the Gulf Waters.

* Lingering post-frontal, stratiform showers are expected to persist through Friday.

* Fluctuating (roller-coaster) temperature regime expected through next week.

* Small Craft Advisory is in effect from 5 PM CST Thursday to Noon CST Friday in response to the cool fropa.

DISCUSSION

Issued at 1035 PM CST Wed Dec 3 2025

The forecast period will consist of unsettled weather conditions initially (Thursday through Friday) followed by rain-free weather through the remainder of the period. Cloud coverage will range between mostly cloudy to partly cloudy with mostly cloudy skies early in the period and partly cloudy skies developing next week. A fluctuating temperature pattern will also take place, though temperature anomalies will overall run near normal levels for the balance of the forecast period.

Latest satellite and MSAS sfc observations depicted the eastern half of Texas socked under a scattered to overcast deck of stratus to strato-cumulus clouds with some areas of fog with a nearby frontal boundary and weak shortwave trough over Deep South Texas. Here across Deep South Texas, particularly over the mid to lower Rio Grande Valley, there is a lull in cloud coverage. However, satellite trends are suggesting that clouds will begin to increase over these areas over the next 3-6 hours. Dewpoint depressions are low as well ranging between 2-4 at the local terminals, so may have to watch for the potential for mist/fog later. Expect a quiet night ahead with at least periods of clouds and maybe some mist as the frontal boundary remains to our north.

During the late morning to early afternoon hours, the aforementioned frontal boundary to our north will pass to our south as a cool front. Showers and maybe a few thunderstorms are expected to develop late morning and especially during the afternoon hours on Thursday in response to this frontal boundary. High temperatures (lower 80s along the Rio Grande Valley; 70s elsewhere) will likely be reached during the early afternoon hours as temperatures will fall throughout the remainder of the day. As cold air advection (CAA) on northerly winds continues to build into the region, overnight low temperatures will fall to below normal levels with values in the 50s along the RGV and coastal area, and 40s over the Northern Ranchlands. Lingering post-frontal stratiform type rain showers will take place on Friday. High temperatures will struggle to make it out of the 60s across the region on Friday due to rain chances and abundant cloud cover. Overnight low temperatures Friday night will be near seasonable levels with values in the 50s areawide with any lingering rain showers ending.

Rainf-free or tranquil weather conditions returns Saturday and will persist through the remainder of the forecast period or through next Thursday. Cloud coverage is expected to improve in time as well transitioning from mostly cloudy to partly cloudy. A warming trend takes place Saturday and Sunday before cooling down again on Monday and finally warming up again Tuesday through Thursday.

AVIATION

(06Z TAFS) Issued at 1035 PM CST Wed Dec 3 2025

Through 06z Friday....Latest satellite and sfc observations depicted a SCT-OVC deck of MVFR-IFR stratus to strato-cumulus clouds over the terminals with ceilings ranging between 900-2,500 feet AGL with some mist around.

Narrow dewpoint depressions could result in some mist at times, particularly at KBRO and KHRL tonight. Have TEMPO headlines for KBRO and KHRL to reflect the potential for some mist tonight. MVFR-LIFR ceilings are expected to persist through the 06z TAF period amid a nearby frontal boundary and weak shortwave trough.

Some showers and maybe a thundershower is possible on Thursday amid the nearby cool frontal boundary. Have Prob30 groups to account for the potential for showers or thunderstorms on Thursday.

Light and variable winds will persist through tonight. Following the cool fropa, winds on Thursday will shift out of the north- northwest with speeds between 10-15 kts and gusts as high as 15-20 kts or so.

MARINE

Issued at 1035 PM CST Wed Dec 3 2025

Small Craft Advisory (SCA) conditions are expected to develop Thursday afternoon through Thursday night in response to a cool fropa. Marine conditions improve on Friday with low to moderate winds and seas persisting into Sunday. Sunday night into Monday, an enhanced pressure gradient will result in the potential for adverse marine conditions developing. Marine conditions look to improve once again Monday night through the remainder of the forecast period or through Thursday with low to moderate winds and seas.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 76 68 78 53 / 10 10 40 40 HARLINGEN 75 63 75 49 / 10 10 40 30 MCALLEN 75 66 75 52 / 0 10 20 20 RIO GRANDE CITY 74 61 72 50 / 0 10 10 20 SOUTH PADRE ISLAND 73 71 75 59 / 10 10 60 60 BAYVIEW/PORT ISABEL 74 66 76 51 / 10 10 50 40

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Small Craft Advisory from 5 PM Thursday to noon CST Friday for GMZ130-132-135-150-155-170-175.