textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Issued at 202 PM CST Sun Nov 15 2026

- Low to medium (20-40%) chances of rain are expected along a cold front passing through this afternoon into the early nighttime hours tonight.

- The chances of isolated strong to severe thunderstorms have reduced for today/tonight, though not been completely ruled out. - Adverse marine conditions become dangerous late tonight as a result of strong northerly winds behind the front, persisting into Tuesday.

- A moderate risk of rip currents becomes a high risk of life- threatening rip currents this evening through at least tomorrow afternoon.

- Low to medium (as much as 20-50%) chances of rain persist along/near the coast, spreading inland mid-to-late week.

DISCUSSION

Issued at 202 PM CST Sun Nov 15 2026

The mid/upper level cut-off trough and associated jet responsible for the cold front passing through this evening are expected to continue east across the Southern Plains and then southeastward to the Gulf, leaving semi- zonal flow aloft for much of the remainder of the forecast, into this upcoming weekend. Although the cold front is still just north of our County Warning Areas at this time, pre-frontal troughing has already began to shift winds further north and west while southerly flow continues across the RGV. Temperatures currently (1:06 PM CST) range from the upper 70s further north and west while remaining in the low to upper 80s across the RGV.

In comparison to forecast expectations from yesterday and last night, enhanced zonal flow aloft behind the departing trough has managed to entrain dry air aloft over deep south Texas, leading to drier than anticipated mid-levels. Despite all of the other convective parameters being sufficient for convection (adequate CAPE, shear, low-level moisture, divergence aloft and even a source of lift), most models are coming into agreement that this will hamper the development of convection and rain chances, thus reducing the odds of isolated to strong severe thunderstorms this afternoon and evening. For this reason, SPC has reduced the Marginal Risk of isolated severe thunderstorms down to a general risk of non-severe thunderstorms. However, there does still exist a low potential and confidence of a brief and isolated strong to severe storm, or two, discussed further below.

Chances of rain could still increase across the region, likely remaining east of Zapata County, to as much as a low to medium (20- 40%) just ahead of and along the cold front, passing through the northern ranchlands anywhere between 3-6 PM this afternoon and the RGV around 6-10 PM, perhaps a bit sooner or later. Despite lowered chances of severe cells, a bit of increased ascension aloft from troughing extending southwestward to the western Gulf and vorticity advection streaming off a trough approaching the southern US West Coast could be just enough to provide mid-level moisture for a strong to severe thunderstorm, or two, with the best signal across southern portions of the low and mid RGV this evening. Therefore, small to large (1+ inch) hail and strong to damaging (60+ mph) winds are not fully out of the question into tonight. Behind the front, strong northerly winds are likely to result in rough seas, dangerous surf, high risks of rip currents and minor coastal flooding of narrow beaches through Monday night. Additionally, cold air advection drops temperatures down to as low as the mid/upper 50s and 60s tomorrow morning and mostly 50s Tuesday morning, potentially as low as 50 F in the northern ranchlands.

Meanwhile, inland chances of rain are likely to diminish by the dawn hours tomorrow morning while coastal troughing could maintain as high as a low to medium (20-50%) chance of rain along/near the coast and, at times, approaching the I-69 E corridor through Tuesday afternoon. Following, broad troughing and easterly winds could resume low to medium chances across much of the region along the daytime seabreeze boundary on Wednesday and Thursday. Daytime high temperatures are expected to gradually warm from the 60s and 70s tomorrow and Tuesday back to the 80s by Thursday.

AVIATION

(18Z TAFS) Issued at 1124 AM CST Sun Nov 15 2026

VFR conditions have resumed across all terminals, with winds ranging from calm at KMFE to a 10-15 knot S-to-SSW breeze at KHRL and KBRO, potentially picking up at KMFE within an hour or two as well. VCSH and PROB30s have been added to the TAFS for late this afternoon/evening due to the possibility of isolated to scattered showers and thunderstorms developing ahead of, or along, a cold front arriving to the region. An isolated strong to severe thunderstorm, capable of producing small to large hail and/or strong to damaging winds, is possible during this timeframe. The greatest chances of thunderstorms resides at KBRO and just to the south of the international border, but overall confidence is low to medium at this time.

MVFR and/or IFR ceilings are anticipated to spread across all TAF sites by late tonight as winds tun northerly following the front's passage. Winds are likely to increase to near 15 knots with gusts to 20-25 knots by the dawn hours tomorrow morning, remaining out of the north.

MARINE

Issued at 202 PM CST Sun Nov 15 2026

Gentle to moderate easterly to southeasterly winds become strong northerly winds late tonight behind a cold front passing southward this evening into the early nighttime hours tonight, with gusts peaking at near-gale force early tomorrow morning into tomorrow night, when winds shift out of the northeast. This is expected to build moderate (4-6 ft) seas to rough (8+ ft) tomorrow morning into Tuesday afternoon. As such, a Small Craft Advisory remains in effect through the early Tuesday nighttime hours. Marine conditions continue improving throughout the remainder of Tuesday night, with gentle to moderate easterly winds and moderate (4-6 ft) seas resuming on Wednesday, becoming southeasterly later in the week.

Low to medium (30-60%) chances of rain return this evening ahead of and along the cold front, bringing another potential round of strong to isolated severe thunderstorms, which could produce small to large (1+ inch) hail, very strong to damaging (52+ knot) winds and isolated, but brief, waterspouts. Following, troughing over the Gulf and additional atmospheric disturbances could result in low to medium chances of rain persisting into late week, maximizing as high as a medium (40-60%) chance on Monday and Tuesday.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 65 71 62 72 / 40 20 30 40 HARLINGEN 61 68 58 70 / 30 10 20 30 MCALLEN 60 70 56 72 / 30 10 0 10 RIO GRANDE CITY 57 68 53 69 / 20 0 10 10 SOUTH PADRE ISLAND 68 71 67 72 / 40 50 40 50 BAYVIEW/PORT ISABEL 64 70 62 72 / 40 40 30 40

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 6 PM CST 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.