textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 110 PM CST Sun Jan 25 2026

* First Arctic airmass of the 2025/2026 winter season has arrived.

* The coldest air (record to near record-breaking low temperatures) will occur tonight into Monday morning and again Monday night into Tuesday morning with widespread freezing/hard freezing temperatures and extreme wind chills.

* A Freeze Warning and Extreme Cold Warning remains in effect for tonight into Monday morning. Another Freeze Warning and Extreme Cold Warning will likely be needed for Monday night into Tuesday. Plan to protect people, pets, plants, and pipes and limit exposure to all for multiple days. Please refer to www.weather.gov/safety/cold for tips on how to protect yourself and others.

* A Small Craft Advisory remains in effect through Monday. A High Risk for Rip Currents and High Surf Advisory are also in effect.

* Rain chances increase Thursday night through Saturday ahead and in response to yet another potentially strong cold front that's set to arrive late next week into next weekend.

DISCUSSION

Issued at 110 PM CST Sun Jan 25 2026

The first Arctic airmass of the 2025/2026 winter season, and the coldest since January 21-22, 2025 has arrived across Deep South Texas and the Rio Grande Valley. This makes it the 4th consecutive winter season of having at least one Arctic Blast or significant cold snap (2022/23, 2023/24, 2024/25). A highly amplified large- scale pattern in the middle to upper levels of the atmosphere, driven by a negative Arctic Oscillation (-AO) and a positive Pacific North American Oscillation (+PNA) has resulted in the collapse of a Polar Vortex (PV) lobe, which explains this significant cold air outbreak/winter storm that encompasses much of the nation at this time. Moving forward towards the tail end of January/first part of February, medium range computer models and ensembles are suggesting that this pattern will remain in place meaning that there could be additional cold air intrusions taking place over the next week at least. In fact, we're closely monitoring the potential for another (second) cold shot taking place late next week into the following weekend (Jan 30-Feb 2 timeframe).

We start off the forecast period today where I lowered temperatures slightly due to the combination of clouds this morning hanging tough under a cold air advection (CAA) regime in place. A rather steep inversion just above the sfc to about 890 mb seen from this morning's 12z BRO sounding, supports the stubborn OVC low level stratus deck this morning. In time, as the day progresses, expect for cloud coverage and heights to gradually improve as the aforementioned inversion gradually erodes/breaks down and additional dry air continues to advect into the region. With additional cold air advection (CAA) streaming into the region on blustery north-northwest winds 10-20 mph with gusts up to 30 mph, little warming will result in well below normal temperatures today with highs not making it out in the upper 40s to lower 50s.

By tonight, the 1030-1040 mb Arctic high will be centered over the southern Plains (near the OK/TX Panhandles). Adequate radiational cooling on clearing skies on top of additional cold air advection (CAA) will result in record to near record breaking overnight low temperatures (see CLIMATE SECTION for more details). Widespread sub-freezing (temperatures <32F degrees) are expected across Deep South Texas and the Rio Grande valley tonight. In fact, widespread hard freeze (temperatures <28F for 2+ hours) are expected to take place tonight. NBM has near 100% chance for temperatures falling below 32F tonight across the Northern Ranchlands. NBM has a medium-high (50-80%) chance for temperatures to fall below 32F across the Rio Grande Plains into the Rio Grande Valley. The NBM has a medium-high (30-70%) chance for a hard freeze to take place tonight from northern Cameron, northern Hidalgo, northern Starr, and Willacy counties and points north. There is a low chance south of that corridor.

Monday and Monday night will be similar to today and tonight, respectively with the full cold and dry air advection regime locked into place over the region. With similar highs and lows expected Monday and Monday night, there will be another shot at record to near record breaking overnight low temperatures (see CLIMATE SECTION for more details). Finally, with winds not fully subsiding tonight or Monday night, wind chill values (real feel temperatures) are expected to be in the teens on both nights across much of Deep South Texas. 20s along the coast and the Rio Grande Valley. A second Freeze Warning will likely be needed and another hard freeze is possible. Another Extreme Cold Warning and/or Cold Weather Advisory may be needed as well.

Tuesday through Thursday, we'll see temperatures moderate as the aforementioned 1030-1040 mb sfc high and anomalously strong central/east U.S. trough departs further to our east and before retreating northward. Despite the moderation or brief reprieve from the Arctic airmass, temperatures Tuesday through Thursday will still be below normal levels for this time of year. High temps on Tuesday are progged to climb into the lower 60s along the RGV and 50s elsewhere. Wednesday and Thursday, we'll see high temps mainly in the 60s across Deep South Texas. Overnight low temps Tuesday and Wednesday nights will be in the 30s/40s. By Thursday night, lows are projected to be in the 40s/50s.

Thursday night into Friday, ahead of yet another potentially strong cold front, rain chances (PoPs) are expected to increase. Some weak moisture influx and warm air advection (WAA) on east-southeasterly winds coupled with a developing weak shortwave trough nearby could drive up the chances for showers Thursday night into Friday. Currently, we have 20-30% PoPs Thursday night confined along and east of IH-69C. On Friday, these PoPs increase to 30-50% areawide in conjunction with another strong cold front. Finally, by Saturday, PoPs decrease back to 20-30% as the cold front is expected to sweep through the area and push to our south. During this time, we will be in a low CAPE/high shear environment. However, due to low CAPE values and overall weak instability values, we're not anticipating any thunderstorm development (just some much needed rain/rain showers). We'll keep watch on convective trends and see if there is enough sfc convergence with the incoming cold front to trigger enough buoyancy for thunder.

As touched on earlier with the description of the large-scale pattern regime (i.e. -AO/+PNA) we're in, forecast models and ensembles are indicating yet another (second) cold front to sweep through the region Friday night into Saturday. Based on some computer projections and synoptic analysis, this cold front could yield another round of freezing temperatures to at least parts of Deep South Texas as Arctic air envelopes much of the central/east U.S. Greatest uncertainties at this point is just how far south the cold air will penetrate and the eastward placement of the full fetch of Arctic cold air (i.e. over the Plains vs. east of the Mississippi River). That said, temperatures will remain below normal late next week through next weekend.

AVIATION

(18Z TAFS) Issued at 1104 AM CST Sun Jan 25 2026

Through 18z Monday....Latest sfc and satellite obs showed an OVC MVFR stratus deck in place with ceilings ranging between 1,000- 1,600 feet AGL and unrestricted visibilities. This morning's 12z BRO sounding indicated an inversion just above the sfc up to about 890 mb, which supports the presence of the low (MVFR) stratus this morning. Given how steep the low level inversion is, these clouds may stick around for a few more hours before scouring out later this afternoon.

The expectation is for cloud coverage and heights to show some improvements as the day wears on and the inversion weakens. This will give way to an eventual return to VFR conditions this afternoon. With cool and dry air still advecting into the region, expect for clouds to remain mostly to partly clear later this evening/tonight with VFR conditions continuing through the remainder of the forecast period.

North-northwest winds will continue blustery through the day today with speeds between 10-20 kts and gusts up to 25 kts or so. Later this evening/tonight, it will still be blustery at times, but the gusts are expected to subside. Blustery north-northwest winds will continue on Monday with gusts returning during the day as mixing heights increase. Peak gusts are expected to be up to 20-25 kts.

MARINE

Issued at 110 PM CST Sun Jan 25 2026

Hazardous marine conditions will continue into Monday night. A Small Craft Advisory remains in effect till 6 PM CST Monday evening. Marine conditions improve on Tuesday with conditions becoming favorable with light to moderate winds and seas. Favorable marine conditions will persist into Thursday evening. Marine conditions could yet again become adverse/hazardous in response to another cold frontal passage late next week into next weekend.

CLIMATE

Issued at 110 PM CST Sun Jan 25 2026

The first Arctic airmass of the 2025/2026 winter season, and the coldest since January 21-22, 2025 has arrived across Deep South Texas and the Rio Grande Valley. Adequate radiational cooling on clearer skies on top of additional cold air advection (CAA) will result in record to near record-breaking overnight low temps tonight and possibly again Monday night into Tuesday. Below are the all-time record low temperatures for Brownsville, Harlingen, and McAllen.

Record Low Temperatures for January 26, 2026:

Brownsville: 32F degrees in 1940 Harlingen: 32F degrees in 1938 & 1940 McAllen: 35F degrees in 1966

Record Low Temperatures for January 27, 2026:

Brownsville: 32F degrees in 1948 Harlingen: 30F degrees in 1966 McAllen: 30F degrees in 1966

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 30 49 32 61 / 0 0 0 0 HARLINGEN 26 50 28 61 / 0 0 0 0 MCALLEN 32 52 32 61 / 0 0 0 0 RIO GRANDE CITY 27 52 25 59 / 0 0 0 0 SOUTH PADRE ISLAND 38 50 44 61 / 0 10 10 0 BAYVIEW/PORT ISABEL 29 49 34 61 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...Freeze Warning from 9 PM this evening to 10 AM CST Monday for TXZ248>255-351-353>355.

Extreme Cold Warning from 3 AM to 8 AM CST Monday for TXZ248>255- 351-353>355-451-454-455.

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

High Surf Advisory until 6 PM CST Monday for TXZ451-454-455.

GM...Small Craft Advisory until 6 PM CST Monday for GMZ130-132-135- 150-155-170-175.