textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Issued at 539 AM CST Sun Nov 15 2026

- A cold front arriving late this afternoon/overnight brings showers and thunderstorms.

- The Storm Prediction Center (SPC) maintains a Marginal Risk (Level 1 of 5) of isolated severe thunderstorms along the front.

- Marine conditions continue to deteriorate as the front approaches. A Small Craft Advisory is in effect through early this week.

- There is a High Risk of life-threatening rip currents Sunday, and dangerous surf and minor coastal flooding is possible Monday.

- Cool temperatures and gusty winds Monday in the wake of the front.

DISCUSSION

Issued at 948 PM CST Sat Nov 14 2026

Tonight, any showers should remain mostly offshore, with a low chance of isolated showers along the immediate coast. A cold front will move through the region Sunday, with latest guidance supporting a round of showers and thunderstorms Sunday evening into early Monday morning. SSE surface winds will allow low- level moisture to build during the day Sunday, with PWATs climbing to 1.4-1.7" (75-90th percentile for mid-Nov). Strong westerly flow aloft will maintain relatively dry mid and upper levels, which should allow for mostly clear skies and daytime sfc heating with highs in the mid-80s. The combination of instability, moisture, and lift will bring conditions favorable for showers and thunderstorms, with greatest potential along and east of US-281.

This is a supportive environment for organized convection, with a few strong to severe storms possible. Convection is expected to initially develop in a clustered mode ahead of the front, potentially congealing into a line along the front overnight. Any storms could capable of producing damaging winds and hail, with a brief tornado also possible. Most favorable conditions for severe storms exist east of US-281, particularly along the coast, with lapse rates around 6degC/km and effective SRH values of 100-150 m2s2 anticipated. However, storms my struggle with dry air entrainment, given dry mid and upper levels. SPC maintains a Marginal Risk (level 1 of 5) for severe thunderstorms.

There remains uncertainty regarding the timing and inland extent of convection with continued disagreement in short range guidance. Some solutions keep activity largely confined to east of US-77, while others support scattered thunderstorms extending into the upper RGV - kept NBM PoPs, supporting activity reaching inland to US-281. Current thinking is precip most likely arriving in the NE Ranchlands around 5 PM, pushing southeasterly into the RGV through midnight, with activity moving out of the Valley before sunrise Monday.

Behind the front, gusty northerly winds to 20-30 mph develop, lasting into the evening. Cooler temperatures follow, with Monday highs around 60 (upper 50s in N Ranchlands). Opted to bump NBM temperatures down given cloud cover and CAA. Tuesday morning will be chillier with lows in the 50s (60s near the coast), followed by afternoon highs generally in the 70s (though this may need to be adjusted down on future shifts as cloud cover and northerly flow persists..). Isolated showers near the coast are possible Monday and Tuesday in the wake of the front.

Conditions at local beaches deteriorate Sunday, with elevated seas and increasing swell bringing a High risk of life-threatening rip currents. Minor coastal flooding is possible early this week behind the front.

AVIATION

(12Z TAFS) Issued at 539 AM CST Sun Nov 15 2026

Light east to southeast winds with areas of low stratus prevail across Deep South Texas early this morning. Brief MVFR ceilings may be possible at MFE through around 14Z. Otherwise, VFR conditions are expected through early evening. Winds will increase later this morning with some gusts around 20 kts, especially at BRO. Winds are forecast to decrease later this afternoon into early evening ahead of a frontal boundary. A cold front will move through the area late this evening into tonight. Breezy north winds with gusts around 25 kts and MVFR/IFR conditions will be possible later tonight. Rain chances will increase late today into tonight along and ahead of the cold front.

MARINE

Issued at 948 PM CST Sat Nov 14 2026

A Small Craft Advisory remains in effect through early this week. Sunday, an enhanced pressure gradient ahead of a cold front will maintain moderate winds and seas with gusts greater than 20 kts. Rain chances increase to moderate in the northern waters Sunday evening ahead of the cold front, bringing showers and thunderstorms from north to south overnight. Thunderstorms can to bring elevated seas, strong winds, and possible waterspouts. Behind the front early Monday morning, expect strong northerly winds, with near-gale gusts possible, Monday through Monday night as seas build to 9-11 ft. Lingering showers and thunderstorms are expected to continue over the waters through Tuesday. Winds and seas gradually subside Tuesday. Small Craft Exercise Caution conditions will likely last through midweek.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 84 63 64 59 / 10 60 20 30 HARLINGEN 85 60 61 56 / 20 60 20 20 MCALLEN 88 59 62 57 / 0 60 10 10 RIO GRANDE CITY 88 59 64 55 / 0 30 10 10 SOUTH PADRE ISLAND 78 68 69 63 / 20 70 40 60 BAYVIEW/PORT ISABEL 82 64 65 60 / 10 70 30 50

BRO WATCHES/WARNINGS/ADVISORIES

TX...Coastal Flood Advisory from 6 PM this evening to 6 AM CST Tuesday for TXZ451-454-455.

High Rip Current Risk from this evening through late Monday night for TXZ451-454-455.

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

GM...Small Craft Advisory until midnight CST Tuesday night for GMZ130- 132-135-150-155-170-175.