textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 539 AM CST Thu Nov 5 2026

- Active (wet/unsettled) weather pattern develops Thursday night through Sunday night; widespread categorical chances (50-80%) can be expected during this timeframe.

- The Weather Prediction Center (WPC) has our area under a Marginal Risk (Level 1 of 4) for Excessive Rainfall Saturday (Day 4) and Sunday (Day 5).

- Temperatures will run from seasonable to unseasonably cool Friday through next Thursday (i.e. high temperatures in the low 70s to mid 80s).

DISCUSSION

Issued at 1109 PM CST Wed Nov 4 2026

Forecast models/ensembles continue to advertise increasing prospects for a wet/unsettled weather pattern developing later this week through early next week. Ahead of this unsettled weather pattern, high temperatures on Thursday will quickly spike up into above normal levels with values in the mid 80s (Northern Ranchlands) to lower 90s (Rio Grande Valley). During the afternoon/evening hours on Thursday, warm air advection (WAA) and increased moisture influx could create enough instability for some isolated, diurnally-driven showers and thunderstorms (20-30% chances).

Thursday night into Friday, increased mid-upper troughing to our north and west coupled with increasing instability levels at the sfc, and an approaching cool front, will result in widespread showers and thunderstorms across Deep South Texas and the Rio Grande Valley. Currently, we have widespread categorical chances (50-90%) Thursday night into Friday.

A more robust/potent mid-upper trough further upstream across the Baja Peninsula of California and North-northwest Mexico will create diffluence aloft over Deep South Texas and the Rio Grande Valley Friday night into Saturday. A developing inverted trough near the sfc combined with multiple mid level impulses/perturbations tracking overhead from the aforementioned trough, and increased instability values will result in multiple rounds of showers and thunderstorms Saturday through Sunday night across the region. Again, we have widespread categorical (50-80% chances) for showers and thunderstorms during this time period.

Given the elevated atmospheric moisture content, with PWAT values ranging between 1.7- 2.0 inches, some 1-2 STDEVs above normal, heavy rainfall and therefore the potential for flooding is possible Saturday through Sunday. The Weather Prediction Center (WPC) has all of Deep South Texas and the Rio Grande Valley under a Marginal Risk (Level 1 of 4) for Excessive Rainfall Saturday (Day 4) and Sunday (Day 5). Rain chances decrease to 20-30% on Monday before things finally turn drier Monday night/Tuesday.

Rain-free conditions will then continue through next Thursday. During this unsettled timeframe and through the remainder of the forecast period, temperatures will be seasonable to unseasonably cool with highs ranging between the lower 70s to mid 80s and overnight lows in the 50s and 60s.

AVIATION

(12Z TAFS) Issued at 539 AM CST Thu Nov 5 2026

A mid level cloud deck around 6K ft and light winds prevail across Deep South Texas early this morning. Will included a TEMPO at MFE until 14Z for MVFR ceilings. Otherwise, VFR conditions are forecast today into early this evening. East to southeast winds 5 to 10 knots are expected today with light and variable winds this evening as weak cold front approaches the area. SHRA/TSRA and MVFR conditions will be possible later this evening into tonight along and ahead of the frontal boundary.

MARINE

Issued at 1109 PM CST Wed Nov 4 2026

Low to moderate winds and seas will prevail tonight through Friday night. SCEC conditions return Saturday with Small Craft Advisory conditions developing Saturday night into Sunday in response to our next cool front. Small Craft Advisory conditions could persist into Monday before conditions improve Monday night/Tuesday.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 89 73 82 70 / 10 50 90 40 HARLINGEN 89 70 81 67 / 30 70 70 30 MCALLEN 93 73 83 69 / 20 70 70 30 RIO GRANDE CITY 90 69 81 65 / 10 80 70 30 SOUTH PADRE ISLAND 83 74 78 73 / 10 60 80 50 BAYVIEW/PORT ISABEL 86 71 80 69 / 20 60 70 40

BRO WATCHES/WARNINGS/ADVISORIES

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