textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Issued at 123 PM CST Sat Nov 14 2026

- Low to medium (20-40%) chances of rain near the coast tomorrow morning/early afternoon spread inland and increase from north- to-south along a cold front either late tomorrow afternoon or evening to as much as a medium to likely (40-90%) chance of rain tomorrow night.

- The Storm Prediction Center (SPC) maintains a Marginal Risk (Level 1 of 5) of isolated severe thunderstorms within the elevated chances of rain across almost all of deep south Texas and the RGV tomorrow through tomorrow night.

- Adverse marine conditions continue into tomorrow afternoon, deteriorating to dangerous conditions late tomorrow night behind the front, persisting into Tuesday.

- A moderate risk of rip currents becomes a high risk tomorrow morning as a result of winds increasing this evening.

- Strong northerly winds behind the front are expected to result in dangerous surf and an elevated risk of minor coastal flooding of narrow beaches on Monday.

DISCUSSION

Issued at 123 PM CST Sat Nov 14 2026

Despite a fair amount of uncertainty, SPC continues to highlight a Marginal Risk (level 1 of 5) of isolated severe thunderstorms across nearly all of deep south Texas and the RGV tomorrow, Sunday, through tomorrow night in association with a cold front expected to pass through the entire region by Monday morning. These storms carry a greater than 5%, but less than 15%, chance of both damaging (60+ mph) winds and large (1+ inch) diameter hail as well as a greater than 2%, but less than 5%, chance of a brief and isolated tornado and/or waterspout. This remains a conditional risk, dependent on several factors, though any storm that develops is likely to produce frequent/dangerous lightning and heavy rain.

Low (15-30%) chances of rain have been added along/east of US-281 and forecast winds have been weakened by just a bit through this afternoon into the early evening hours today to reflect the areas of brief and spotty showers, isolated in nature, developing in association with a weak mid-level shortwave moving over the region. Mainly dry conditions and breezier conditions should resume by the early nighttime hours tonight.

Behind the shortwave, a mid/upper level trough/potential cut-off low and associated 60-70+ kt jet translate eastward from the Desert Southwest to the Southern Plains by late tonight, tightening a pressure gradient and enhancing southeasterly wind gusts to 20-25+ mph later tonight into tomorrow afternoon as the attendant surface low pressure system and cold front slide southeastward to the northwestern Gulf by tomorrow evening. As increasing cold front- induced surface lift and more favorable upper level mechanics interact with daytime heating/instability and elevated moisture content via onshore southeasterly flow, generally low to medium (20-40%) chances of rain from passing showers and perhaps a few non-severe thunderstorms are anticipated to develop along/near the coast tomorrow morning. Following, there is a slight potential for an isolated strong to severe thunderstorm, or two, to develop tomorrow afternoon along the seabreeze boundary over the northern ranchlands along/east US-281 and possibly the adjacent coastal waters as low (15-30%) chances of rain spread inland. However, confidence is low at this time.

Otherwise, depending on the forward speed and arrival time of the cold front, the secondary round of potential strong to isolated severe thunderstorms arrives to the northern ranchlands by either late tomorrow afternoon or tomorrow evening, possibly a bit sooner or later, progressively shifting southward to the RGV by either early or late tomorrow night; with the exception of Zapata County, chances of rain are anticipated to increase north-to-south to as high as a medium to likely (40-90%) chance tomorrow night, highest along/east of I-69 E, where there is a likely (70-90%) chance of rain. Although the chances of rain are mostly east of the Rio Grande Plains, SPC still includes all, but the northwestern tip, of Zapata County within the Marginal Risk as well.

This remains a conditional risk for isolated severe thunderstorms. Over the past 24-48+ hours, models have struggled to come into agreement in the most likely strong to isolated severe convection scenario, featuring and ranging from: isolated/ discrete supercells to scattered strong to isolated severe cells ahead of a squall line/cold front (still suggested by the RAP) or just along the front (without a squall line) as well as the potential for convection being limited to the coastal counties (recently suggested by the GFS, ECMWF, HRRR and RRFS). In yet another scenario, as indicated by this morning's 12Z RRFS run, deconstructive thunderstorm- produced outflow interference along the front to the north could limit the isolated severe threat to the northern ranchlands during the afternoon hours. Perhaps the most concerning, but least likely, possibility continues to be the elevated SigTor values, creeping upwards of at least 1 to as high as 3, tomorrow afternoon into tomorrow night, resulting from deep layer (40 knot) shear and a bit of low-level turning evident in soundings; SPC has limited the brief and isolated tornado threat (greater than 2% but less than 5% chance) to northeastern Kenedy County.

Following, coastal troughing could maintain a low to medium (15-40%) chance of rain from intermittent light showers along/near the coast Monday afternoon through Tuesday afternoon, diminishing throughout Tuesday night. Weak troughing could resume low chances of rain later in the week.

Otherwise, due to warm air advection ahead of the front, high temperatures are expected to increase from the upper 70s/low 80s this afternoon to the mid/upper 80s tomorrow while falling to the upper 60s/low 70s tonight. Breezy northerly winds follow in wake of the cold front are expected to drop overnight low temperatures from the 50s/60s Monday morning to mostly 50s Tuesday morning while temperatures only maximize in the mid/upper 60s to low 70s Monday and Tuesday afternoons. Following, a warming trend ensues as winds gradually become easterly and/or southeasterly, resulting in low/mid 80s by possibly Thursday.

AVIATION

(00Z TAFS) Issued at 528 PM CST Sat Nov 14 2026

VFR conditions prevail through the period. Occasionally gusty to 20 kt easterly winds this evening lessen, becoming southeasterly overnight as clouds remain socked over the RGV. Winds strengthen and turn more southerly Sunday morning, with occasional gusts to 20-25 kts possible. There is a low (<30% chance) of MVFR ceilings at MFE and HRL between 09-13Z.

MARINE

Issued at 123 PM CST Sat Nov 14 2026

A Small Craft Advisory goes into effect across Lower Texas coastal waters at 5 PM this evening, lasting through early Tuesday night; a tightening pressure gradient results in frequent gusts of 20-25 knots into tomorrow afternoon, stronger further away from shore, building seas to moderate (4-7 ft) by late tonight. Winds briefly subside late tomorrow afternoon ahead of a cold front. The front passes through tomorrow night, transitioning winds to northerly and increasing to strong with as high as near-gale gusts from Monday morning into Tuesday morning, building seas to as high as 7-10+ feet by Monday afternoon, persisting into Tuesday night. Conditions continue improving throughout the remainder of Tuesday into Wednesday, with much more favorable marine conditions expected later in the week.

Chances of rain gradually increase late tonight into tomorrow to a low to medium (20-60%) chance by tomorrow afternoon before briefly diminishing into the late afternoon hours. Chances begin to increase tomorrow evening ahead of the front to as high as a likely (75-95%) chance by early tomorrow night into early Monday morning. There is the potential for strong to isolated severe thunderstorms tomorrow afternoon and most especially along the front tomorrow night, capable of producing damaging (52+ knots) winds, large (1+ inch) hail as well as isolated waterspouts. Additional chances of rain follow into Friday, perhaps as high as a 50-80% chance Monday night, resulting from troughing behind the cold front.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 72 84 66 70 / 10 20 60 20 HARLINGEN 69 84 62 68 / 0 10 60 10 MCALLEN 70 88 62 69 / 0 0 50 10 RIO GRANDE CITY 67 87 60 67 / 0 0 40 0 SOUTH PADRE ISLAND 74 78 67 70 / 10 30 70 40 BAYVIEW/PORT ISABEL 71 82 65 70 / 10 30 70 30

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Small Craft Advisory until midnight CST Tuesday night for GMZ130- 132-135-150-155-170-175.