textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 500 PM CST Wed Dec 31 2025

- There is a small chance that some patchy fog could develop in the late overnight hours, particularly along the I-69E/US77 corridor.

- Dry conditions are expected the rest of this week and next week, with temperatures warming to the upper 80s by Saturday.

- A weak cool front may reach the area Saturday night, dropping Sunday high temperatures to the low 80s. Temperatures will begin to warm again Monday. No rain is expected with this cool front.

DISCUSSION

Issued at 1120 AM CST Wed Dec 31 2025

A warming trend will continue through Saturday, as mid-to-upper level ridging remains dominant over Deep South Texas with clear skies and light to moderate winds that are expected to gradually veer from the north to the south throughout this afternoon. Tomorrow's highs should reach the upper 70s/lower 80s, and then warm up into the upper 80s for Friday and Saturday. Low temperatures are also expected to warm from the mid-40s tonight to the upper 50s by Saturday night. Conditions are also expected to remain rain-free the rest of this week into the middle of next week.

Confidence is very low, but there is a small potential for patchy fog development over the next few days, beginning tonight. Generally, fog formation is most likely to occur in the very late overnight/early morning hours at times of peak radiational cooling. However, if the temperatures decrease rapidly enough tonight, there is a small chance some patchy fog could form (particularly in the coastal counties) a few hours past midnight. Late night New Years travelers will want to exercise caution if they happen to encounter any areas of patchy fog, particularly along the I-69E/US77 corridor.

Latest model guidance suggests that a weak cool front may pass through Deep South Texas Saturday night into Sunday, associated with a small upper-level shortwave that is expected to move over the Southern Plains this weekend. Confidence is medium (but increasing) that this front will actually make it all the way to Deep South Texas. Model guidance has been consistently picking up on the shortwave moving over the Plains for a few days now, but the models are only now suggesting that any associated front could actually make it to our area. Guidance is trending the shortwave axis a little further south with slightly higher jet max winds aloft, which increases our area's odds of seeing a front.

If this weak front does make it to our area, it will be a dry front with no associated precipitation. However, high temperatures could be around 5 degrees cooler for Sunday than Saturday. Humidity could also be a bit less on Sunday as well due to the wind direction change. Any temperature relief we may see will be short-lived, though, since temperatures are expected to start warming from the lower 80s on Monday back to the mid-to-upper 80s again by Wednesday.

AVIATION

(00Z TAFS) Issued at 500 PM CST Wed Dec 31 2025

Gentle to moderate (8-12 knots) east-southeasterly winds and a few high clouds continue over the next few hours, becoming light to gentle, or calm, beyond sunset, becoming southerly overnight. VFR conditions are likely to continue, though there is a low possibility patchy fog near sunrise at KBRO and KHRL, which may briefly reduce visibility to MVFR. Confidence is too low to include in the TAF at this time. Any fog that develops should quickly dissipate beyond sunrise Thursday morning, with southerly winds becoming a moderate in the afternoon (5-10 knots, gusting to 15-20 knots).

MARINE

Issued at 1120 AM CST Wed Dec 31 2025

Winds could approach Small Craft Exercise Caution conditions on the Gulf waters tomorrow night, but other than this, marine conditions are expected to be favorable with low to moderate (2-4 feet) seas and light to moderate winds throughout the forecast period. Winds are expected to turn southerly by the end of tonight and remain so until at least Saturday, when a weak cool front may momentarily shift winds back to the north for Sunday. These winds will veer back to the south by Monday and remain southerly through the middle of the week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 54 79 64 84 / 0 0 0 0 HARLINGEN 49 80 61 87 / 0 0 0 0 MCALLEN 52 81 61 88 / 0 0 0 0 RIO GRANDE CITY 47 81 56 88 / 0 0 0 0 SOUTH PADRE ISLAND 61 74 68 78 / 0 0 0 0 BAYVIEW/PORT ISABEL 53 78 63 83 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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