textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1032 PM CST Sun Dec 28 2025

- A strong cold front will bring much cooler temperatures, strong northerly winds, and increased rain chances late tonight into Monday. A Wind Advisory is in effect for all of Deep South Texas from 3 AM Monday morning until 6 PM Monday evening. - Very strong winds over the Gulf will lead to dangerous marine conditions and coastal hazards. A Coastal Flood Statement is in effect from 4 AM Monday morning until 6 PM Monday evening while a High Risk of Rip Currents and a High Surf Advisory go into effect from 6 AM Monday morning until 6 PM Tuesday evening.

- Elevated fire weather concerns across most of Deep South Texas on Monday due to the combination of low humidity and breezy winds. A Fire Danger Statement is in effect for most of Deep South Texas from 6 AM Monday morning until 6 PM Monday evening.

- Hazardous marine conditions are likely Monday into Tuesday. A Gale Warning is in effect from 3 AM to 6 PM Monday.

DISCUSSION

Issued at 1032 PM CST Sun Dec 28 2025

A strong and potent mid/upper level trough and mid-level low over the Northern Plains and Upper Midwest this evening remains on track to send a powerful cold front, diving through Deep South Texas and the Rio Grande Valley late tonight into early Monday morning. Meanwhile, areas of patchy fog have began to form due to enhanced moisture pooling, which could continue over the next few hours. Ahead of and along the front, a broken line of scattered to numerous showers and isolated thunderstorms brings a medium to likely (60-80%) chance of rain to the entire region, with brief periods of moderate to heavy rain, gusty winds and lightning possible. The front itself is currently anticipated to begin to enter the northern ranchlands between Midnight and 3 AM tonight, possibly passing through the entire RGV between roughly 3-6 AM Monday morning, bringing strong north-northeasterly winds of around 20-30 mph, with gusts of 45 mph or higher, along and behind the front's leading edge, persisting through the late afternoon hours. As such, a Wind Advisory goes into effect across all the County Warning Area (CWA) from 3 AM late tonight to 6 PM Monday evening. Gusts of 50 mph, or greater, are not out of the question in some spots, especially within the first couple of hours behind the front's arrival. Meanwhile, chances of rain decrease fairly quickly for most locations throughout the morning hours on Monday, though some pop-up showers could occur into the early afternoon hours. As the winds usher in much cooler and drier air, Monday morning lows could fall to the upper 40s and lower 50s across the northern ranchlands, mid 50s across most of the RGV and upper 50s to lower across southeastern and eastern portions of the Lower RGV. Due to the strong cold air advection (CAA) continuing throughout the day Monday, the morning lows may also be very similar to the daytime's high temperatures, potentially only warming by 5 degrees, into the 50s and 60s. Additionally, as the strong winds coincide with lower relative humidity values, there is concern for fire weather conditions. Please see the FIRE WEATHER section below for more details. Otherwise, thick stratus cloud cover continues in wake of the front.

Winds shift out of the north and begin to subside Monday evening into Monday night. Along and west of I-69 C/US 281, winds drop from around 10-15 mph, gusting to 20-25 mph, to 5-15 mph, gusting to 15-20 mph overnight. Further east, winds decrease from 15-20 mph, gusting to 25-30 mph, in the evening down to 10-15 mph with gusts up to 20 mph by Tuesday morning. Meanwhile, along the coast, winds decrease from 25-30 mph, gusting to 30-35 mph, in the evening to 20-25 mph, gusting up to 30 mph by the morning hours. Stratus cloud cover continues into Monday night, preventing full nighttime radiational cooling, keeping lows in the 40s across the region, which is around 10 degrees below average. Following, winds improve further throughout Tuesday, becoming light to gentle winds by Tuesday evening along with clearing skies. CAA keeps high temperatures in the 50s and 60s during the day on Tuesday, falling to the upper 30s and low to mid 40s by Wednesday morning.

As very strong winds over the Gulf roughen seas late tonight into Tuesday, dangerous conditions are expected in and near the shore. A Coastal Flood Statement goes into effect from 4 AM tonight/Monday morning until 6 PM Monday evening as winds build water levels, leading to minor coastal flooding of narrow beaches through several hours following high tide, which is at 2:12 PM Monday afternoon. A High Risk of Rip Currents and a High Surf Advisory go into effect Monday morning through late Tuesday afternoon as waves of at least 5 to 8 feet crash within the surf zone. Combined with long wave periods of 7-9 seconds, dangerous rip currents are expected.

Surface high pressure transitions from the Southern Plains to the northern Gulf Tuesday into Wednesday, returning winds from the southeast on Wednesday back to southerly by Thursday. This will start a warming trend into the later parts of this week, with 80s again over the weekend. Another, much weaker, front is possible Friday or Saturday as a mid-level shortwave could pass north of the region.

AVIATION

(06Z TAFS) Issued at 1032 PM CST Sun Dec 28 2025

Winds have become light and variable across all terminals at the time of this writing. Enhanced moisture across the region has started to develop patchy areas of fog and or low ceilings, which has led to IFR visibility (1 SM) with scattered clouds at KHRL, MVFR at KMFE (ceilings around 1,700 ft) and VFR at KBRO. Late tonight and early tomorrow morning, perhaps by around 11/12 Z, chances of rain from scattered showers and isolated thunderstorms increase ahead of a strong cold front, bringing the possibility for brief periods of moderate to heavy rain, lightning and MVFR ceilings (or lower) at all terminals along the leading edge of precipitation. As the front passes through, perhaps by 12/13 Z Monday, strong northerly winds bring sustained winds to around 19-22 knots, gusting up to 40 knots, or higher, into mid- morning. Meanwhile, brief showers may bring light to moderate rain. Airport Weather Warnings (AWWs) are likely at KHRL and KBRO for non-convective winds of 35 knots or greater as well as for possible lightning at KBRO. By the afternoon, overcast MVFR or VFR ceilings persist and windy conditions continue around 15-20 knots, gusting to 30-34 knots, or higher, along with mainly dry conditions. Additional AWWs are possible for winds.

MARINE

Issued at 1032 PM CST Sun Dec 28 2025

Late tonight into early tomorrow morning, a strong cold front blasts southward through the Lower Texas coastal waters bringing a broken line of scattered to numerous showers and isolated thunderstorms, briefly increasing chances of rain to a medium to likely (60-80%) chance. Meanwhile, rapidly deteriorating marine conditions are expected as the front brings gale force northeasterly to northerly winds, strong gale force gusts and rough to very rough (9-14 foot) Monday morning into Monday afternoon. A Gale Warning goes into effect for the Laguna Madre and the Gulf waters (0-60 nm) from 3 AM Monday morning until 6 PM Monday evening. Near gale force northerly winds, gale force gusts and rough (9-12 foot) seas continue overnight Monday. Northerly winds continue and improve on Tuesday, becoming gentle to moderate overnight with moderate (3-4 foot) seas possibly by Wednesday morning. Winds gradually become southerly by Wednesday, with gentle to moderate southeasterly or southerly winds and slight to moderate (2-4 foot) seas continuing through this upcoming weekend. Conditions remain dry with less than a 10% chance of rain.

FIRE WEATHER

Issued at 1032 PM CST Sun Dec 28 2025

Several factors will come together for elevated fire weather concerns on Monday as strong northerly to northeasterly winds filter in much drier and colder air throughout Monday along and behind a strong cold front expected to move through the region late tonight into early Monday morning. Northerly to northeasterly 20 foot winds, gusting to 45 mph or greater will coincide with minimum relative humidity values ranging as low as around 20% west of US 281/I-69 C to as high as 35% east of I-69 E. Additionally, a D2 Severe to D3 Extreme drought continues with dry to cured fuels. All of this considered, a Fire Danger Statement goes into effect for the northern ranchlands (Jim Hogg, Brooks, Inland and Coastal Kenedy) and the RGV (Starr, Hidalgo, Inland Willacy and Inland Cameron) from 6 AM Monday morning until 6 PM Monday evening.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 60 61 47 60 / 60 50 0 0 HARLINGEN 57 58 45 59 / 50 30 0 0 MCALLEN 54 55 47 61 / 60 40 0 0 RIO GRANDE CITY 51 53 47 61 / 60 40 0 0 SOUTH PADRE ISLAND 64 64 48 60 / 60 50 0 0 BAYVIEW/PORT ISABEL 60 61 46 60 / 60 40 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...Wind Advisory from 3 AM to 6 PM CST Monday for TXZ248>255-351- 353>355-451-454-455.

High Rip Current Risk from 6 AM CST Monday through Tuesday afternoon for TXZ451-454-455.

High Surf Advisory from 6 AM Monday to 6 PM CST Tuesday for TXZ451-454-455.

GM...Gale Warning from 3 AM to 6 PM CST Monday for GMZ130-132-135-150- 155-170-175.