textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1239 PM CDT Fri Mar 13 2026

Key Messages:

- Elevated fire weather conditions continue each afternoon with Fire Danger Statements (RFDs) possible beginning tomorrow.

- Near record to record-breaking heat is possible on Sunday with highs near 100 possible further west.

- A Fire Weather Watch may be issued over the weekend ahead of potential Red Flag Warnings on Monday as a cold front, passing through Sunday night, advects significantly drier air via strong northerly winds. There could be a Wind Advisory Sunday night and Monday as well.

- Temperatures fall below average on Monday but warm back to above average by the middle or later part of next week.

DISCUSSION

Issued at 1239 PM CDT Fri Mar 13 2026

By Sunday morning, a strong mid/upper level ridge pushes a digging trough aloft over the Northern and Central Plains, where a strengthening low pressure system and trailing cold front are exptected to develop. Pressure falls interacting with a surface high pressure over the Gulf lead to a tightening pressure gradient and breezy conditions for Deep South Texas this weekend. Beginning tomorrow, Fire Danger Statements (RFDs) are certainly possible for the counties along/east of US-281 during the afternoon hours as minimizing relative humidity values coincide with southeasterly winds gusting up to 20-25 mph on Saturday, increasing to 30-35 mph, or higher, on Sunday. Outdoor burning is not recommended this weekend, particularly on Sunday when northwesterly downsloping winds and/or a dry line further lowers relative humidity.

Yet, the bigger fire weather concern may actually begin late Sunday night as the cold front pushes through Deep South Texas. At this time, the latest probabilistic guidance indicates a low to medium chance for critical fire weather conditions, possibly by Monday morning, as strong northerly winds (potentially gusting up to 30-40 mph, or higher) in wake of the front result in crashing relative humidity values into the afternoon hours. A Fire Weather Watch may be issued over the weekend ahead of potential Red Flag Warnings on Monday. A Wind Advisory may be issued for Sunday night and Monday as well. The latest global deterministic model runs suggest PWAT values minimizing as low as around 0.30-0.50 in. Monday afternoon, which is lower than the lowest 10th percentile for this time of the year. Even as return flow begins to elevate lower level moisture by the middle of next week, lower relative humidity and breezy conditions maintain an elevated fire weather concern each afternoon, with additional RFDs possible as ridging persists overhead. Considering that our region remains in a D2-D4 (Severe to Exceptional) Drought with abundant cured fuels, outdoor burning continues to be not advised. A warming trend ahead of the front warms highs (lows) from mainly the 80s (50s/60s) today (tonight) to 80s/90s (60s) tomorrow (tomorrow night), which is near 5-10 degrees above average. As downslope-induced compressional heating occurs on Sunday, highs could soar into the 90s across all of inland Deep South Texas, possibly reaching 100 degrees in areas along/west of US-281, which is near 10-20 degrees above average. Although we currently anticipate temperatures reaching around 5 degrees shy of record- breaking, record tying or record breaking heat still remains possible on Sunday. Behind the front Sunday night, highs could drop 20-30 degrees, only rising into the 60s during the day Monday and falling to the 40s/50s Monday night, which is around 10-15 degrees below average. Yet, the return of southeasterly winds brings temperatures back to above average by the middle or later parts of next week.

A low risk of rip currents prevails through tomorrow afternoon.

AVIATION

(18Z TAFS) Issued at 1239 PM CDT Fri Mar 13 2026

Gentle to moderate southeasterly winds return across all terminals this afternoon, around 5-10 knots, gusting to 15-20 knots, before becoming light to gentle beyond sunset this evening. Gentle to moderate southeasterly winds return throughout Saturday morning. VFR conditions prevail.

MARINE

Issued at 1239 PM CDT Fri Mar 13 2026

Gentle to moderate south-southeasterly winds and slight to moderate (2-3 feet) seas prevail through tonight, increasing to moderate to fresh with moderate (3-4 feet) seas tomorrow as a pressure gradient begins to tighten. Small Craft Exercise Caution (SCEC) headlines are likely on Sunday as fresh to strong southerly winds enhances seas to 3-5 feet. A cold front passes through Sunday night, ushering in near gale to possibly gale force winds and rough to very rough seas on Monday. Conditions improve Monday night into Tuesday with gentle to moderate southeasterly winds and slight to moderate seas returning into the middle and later parts of next week. There is a low to medium (20-60%) chance of brief showers Sunday night ahead of and along the cold front.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 62 85 69 89 / 0 0 0 0 HARLINGEN 58 89 65 95 / 0 0 0 0 MCALLEN 63 93 69 100 / 0 0 0 0 RIO GRANDE CITY 59 95 65 100 / 0 0 0 0 SOUTH PADRE ISLAND 67 78 71 81 / 0 0 0 0 BAYVIEW/PORT ISABEL 62 85 68 90 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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