textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1218 AM CDT Mon Mar 9 2026

Key Messages:

- There is a low to medium (30-40%) chance of rain tonight along/west of US-281 and the Northern Ranchlands as isolated to scattered showers pass through as well as a low (15-20%) chance Tuesday night across the Northern Ranchlands and Rio Grande Plains.

- Mainly dry and breezy conditions return Monday, becoming windy Tuesday, with a potential for a Wind Advisory as gusts up to 40+ mph are possible along/east of US-281 by mid-morning Tuesday, continuing through the late afternoon hours. A Fire Danger Statement (RFD) is also possible on Tuesday.

- Breezy to gusty conditions and much drier air behind a cold front on Wednesday are likely to result in elevated to critical fire weather conditions each afternoon, especially on Wednesday and Thursday, when Red Flag Warnings are possible.

- Above average temperatures continue through the day Wednesday, briefly falling to near/below normal into the later parts of the week before rising back to above average next weekend.

- A medium risk of rip currents continues through Monday afternoon, likely increasing to a High Risk of Rip Currents by the middle of the week as winds increase.

DISCUSSION

Issued at 1040 PM CDT Sun Mar 8 2026

A stationary boundary remains situated along I-69 E this evening, with southeasterly winds and warmer temperature to the east and northeasterly to northwesterly winds and cooler temperatures to the west. Convergence along this boundary resulted in area of thunderstorms with heavy rain this afternoon, producing rainfall amounts up to near 1.0-2.5 inches, extending southward from just southeast of Raymondville to Harlingen. This frontal boundary is expected to lift northward overnight as a tightening pressure gradient enhances lower level south-southeasterly winds. Meanwhile, southwesterly winds aloft continue over Deep South Texas, downstream of a mid/upper level low pressure and trough situated over near the Baja Peninsula. Embedded within this flow is a mid-level impulse translating northeastward across the region tonight bringing a low to medium (30-40%) chance of brief light rain showers, mostly along/west of US-281, though could reach further east across the Northern Ranchlands. Temperatures minimize in the 60s/70s by Monday morning.

As the low pressure and trough aloft begin to progress east- northeastward over northern Mexico, mainly dry and breezy conditions return Monday, becoming windy on Tuesday as a pressure gradient tightens; high pressure over the Gulf interacts with both a strong low pressure system developing over the Central Plains as well as with lowering heights over the Sierra Madre. The highest wind speeds are likely to be along/east of US-281, where south-southeasterly wind gusts up to 30+ mph during the day on Monday afternoon increase to 40+ mph by mid-morning Tuesday, continuing through the late afternoon hours. The NBM currently suggests up to a 30-50% chance of wind gusts exceeding reaching and exceeding 40 mph across the Lower and Middle RGV, where a Wind Advisory is certainly possible. Following, there is a low (15-20%) chance of rain Tuesday night across portions of the Rio Grande Plains and the Northern Ranchlands, as convection develops ahead of the approaching trough aloft and its associated surface low's cold front. Additionally, a Fire Danger Statement (RFD) is possible for Tuesday afternoon. In the meantime, temperatures remain above average, maximizing in the 80s/90s, with the warmest day anticipated to be on Wednesday, in which 90s are likely across all of inland Deep South Texas, even into the coastal areas while temperatures remain in the 70s along the immediate coast. Overnight temperatures minimize in the 60s/70s through Tuesday night.

The next focus of the forecast will be the fire danger threat behind the cold front, which is currently anticpated to arrive during the day on Wednesday as the low pressure and trough aloft move over central Texas. On the backside of the low, an upstream northwesterly 30-40 kt 925 mb LLJ brings downslope-compressed air into our CWA from the Sierra Madre, crashing relative humidity values Wednesday afternoon. The combination of breezy conditions and much drier air advecting into the region from northwesterly winds on Wednesday and northerly winds on Thursday may to lead to fire products, with RFDs or Red Flag Warnings possible, dependent on wind speeds. Otherwise, southeasterly winds return by Friday, becoming breezier over the weekend, along with fire weather concerns prevailing each afternoon. Highs in the 70s/80s on Thursday increase back to the 80s/90s over the weekend with overnight lows warming from the 50s/60s to mainly 60s. A medium risk of rip currents continues through Monday afternoon, likely increasing to a High Risk of Rip Currents by the middle of the week as winds increase.

AVIATION

(06Z TAFS) Issued at 1218 AM CDT Mon Mar 9 2026

MVFR conditions are expected to persist over the next several hours through the duration of the overnight period at all TAF sites. While generally light southerly winds will continue through the period as well, those winds should become gusty up to 25 knots around the late morning and early afternoon time period. Around this time, the ceilings should life to VFR and continue through the daytime and evening hours.

MARINE

Issued at 1040 PM CDT Sun Mar 8 2026

Gentle southeasterly winds and moderate (3-4 feet) seas tonight increase to moderate to fresh south-southbeasterly winds with Small Craft Exercise Caution (SCEC) conditions by Monday afternoon as a pressure gradient tightens across the Lower Texas coastal waters. SCEC and/or a Small Craft Advisory (SCA) are likely Tuesday as fresh to strong south-southeasterly winds lead to moderate (5-6 feet, or greater) seas. Winds and seas temporarily improve on Wednesday as a cold front moves through, possibly during the afternoon and evening hours, followed strong northerly winds Wednesday into Thursday with additional SCA headlines likely as seas become rough. Winds and seas improve Thursday night into Friday, with gentle to moderate southeasterly winds resuming Friday and into the weekend. There is a low (15-20%) chance of rain tonight and again Tuesday night into Wednesday morning.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 87 71 86 72 / 0 0 0 0 HARLINGEN 90 69 89 71 / 10 0 0 10 MCALLEN 93 74 93 74 / 10 0 0 10 RIO GRANDE CITY 93 71 95 69 / 10 10 0 20 SOUTH PADRE ISLAND 79 72 79 72 / 0 0 0 0 BAYVIEW/PORT ISABEL 86 69 85 70 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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