textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1245 PM CST Fri Jan 2 2026

* Unseasonably warm, record to near record-breaking temperatures are expected this afternoon and again on Saturday.

* Patchy mist/fog/low stratus is possible tonight. * Breezy southerly winds could result in small craft exercise caution (SCEC) conditions later this evening through tonight; Rip Current Risk will be Moderate through tonight.

* A weak cool front pushes through Saturday night into Sunday little airmass change.

* Overall, warmer than normal, rain-free, and at times breezy conditons with chances for patchy mist/fog at night will prevail through next week.

DISCUSSION

Issued at 1245 PM CST Fri Jan 2 2026

Low amplitude, zonal to semi-zonal (west-southwest aloft) 500 mb regime with plenty of subsidence will foster warmer than normal temperatures, mostly sunny skies, and at time breezy conditions with patchy mist/fog possible at night across Deep South Texas and the Rio Grande Valley through the forecast period or through the first full week of January 2026.

Ahead of a weak cool front, increased moisture and warm air advection (WAA) amid breezy southerly winds, compressional heating (downsloping) off the Sierra Madre, coupled with a flat, yet anomalously strong 582-585 mb ridge overhead will drive record to near record-breaking temperatures today and on Saturday across the region (see CLIMATE SECTION for more details). High temperatures this afternoon and on Saturday are progged to top out in the mid 80s to around 90F degrees, some 12-17F degrees above normal for early January standards.

For tonight, radiational cooling amid mainly clear skies, light winds, coupled with some low level moisture could result in the development of mist, low stratus, and maybe even fog across parts of Deep South Texas and the Rio Grande Valley. A classic "field goal post signature" shown in the BUFKIT soundings as well as NBM probabilities supports the potential for mist, low stratus, and maybe even some fog developing later tonight. Currently, there is a medium (30-50%) chance for this happening with the best chance being in the form of mist/low stratus. The greatest uncertainties regarding fog development is focused on how weak the winds get and how much radiational cooling takes place. Have applied some patchy fog in the grids to take into account the potential for some mist/fog overnight tonight. Otherwise, expect a tranquil night with warmer than normal temperatures.

A weak cool front will push through the region late Saturday into Sunday. However, given the magnitude of the cool front, a notable airmass change is not anticipated. In fact, temperatures will remain above average Saturday night and on Sunday with overnight lows in the 50s most places and daytime highs in the upper 70s to lower 80s, respectively. No rain is expected with the ridge axis overhead.

A return flow develops out of the south-southeast Sunday night into Monday, yielding a quick return to well above normal temperatures. Rain-free, unseasonably warm, and at times breezy conditons will prevail through the remainder of the forecast period or through next Friday amid the continuation of flat ridging (zonal to semi-zonal flow aloft pattern) over the region. There may be some weak shortwave troughs around next week. However, subsidence overhead will be more than sufficient to cancel out any rainfall risks.

After Sunday and through the remainder of the forecast period, daytime high temperatures will top out in the mid to upper 80s inland (70s along South Padre Island). Meanwhile, overnight lows will be in the 50s/60s across the region (mostly 60s).

Happy New Year!!

AVIATION

(18Z TAFS) Issued at 1245 PM CST Fri Jan 2 2026

Through 18z Saturday....VFR conditions will persist through the remainder of the day today with SKC to mainly clear skies. However, tonight, there is the potential for some mist, low stratus, and maybe even some fog developing at the terminals and across parts of Deep South Texas.

Radiational cooling amid mainly clear skies, light winds, and some low level moisture around could promote the development of some mist, low stratus, and/or fog developing. NAM3KM and RAP BUFKIT soundings show a classic "field goal post signature" developing later this evening/tonight. This combined with support from NBM probabilities suggest the potential for some mist, fog, and/or low stratus developing. Confidence at this time is greatest for mist/low stratus developing overnight.

Any mist, fog, or low stratus that develops will have the capabilities of reducing flight categories (cigs/vsbys) down to MVFR-LIFR levels. Have included TEMPO groups to acknowledge the potential for mist/fog/low stratus developing at all of the terminals later tonight.

After daybreak or around 15z, expect for any fog, mist, or low stratus to lift or scour out giving way to a return to VFR conditions on Saturday.

Southerly winds will remain breezy through the day today with speeds 10-15 kts gusting as high as 20 kts or so. Winds will wane later this evening/tonight as mixing heights decrease with speeds up to or around 5 kts.

MARINE

Issued at 1245 PM CST Fri Jan 2 2026

Breezy south-southwest winds could result in Small Craft Exercise Caution (SCEC) conditions over the outer Gulf Waters later this evening through tonight. Otherwise, favorable marine conditions will persist through the remainder of the forecast period with light to moderate winds and low to moderate seas (wave heights mainly between 2-4 ft).

CLIMATE

Issued at 1245 PM CST Fri Jan 2 2026

A low amplitude, yet anomalously strong 582-585 dam ridge overhead coupled with strong sfc based differential heating under mainly sunny skies and breezy southerly winds at the sfc will support record to near record-breaking temperatures this afternoon and again on Saturday. This will be ahead of a weak cool front that will move into the region Saturday night.

Friday, January 2, 2026 Record High Temperatures Brownsville: 87F in 2006 Harlingen: 89F in 2017 McAllen: 93F in 2017

Saturday, January 3, 2026 Record High Temperatures Brownsville: 91F in 1982 Harlingen: 86F in 2023 McAllen: 94F in 1971

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 64 87 57 80 / 0 0 0 0 HARLINGEN 60 89 53 78 / 0 0 0 0 MCALLEN 62 91 56 81 / 0 0 0 0 RIO GRANDE CITY 56 89 52 82 / 0 0 0 0 SOUTH PADRE ISLAND 66 77 65 73 / 0 0 0 0 BAYVIEW/PORT ISABEL 62 84 59 77 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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