textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1238 PM CDT Sat Jul 18 2026

* Hot, dry, and at times breezy conditions will continue through next week.

* Widespread Moderate (Level 2 of 4) can be expected over Deep South Texas with pockets of Major (Level 3 of 4) Heat Risk possible.

* A Fire Danger Statement (RFD) has been issued for all of Deep South Texas, excluding the coastal and island counties for Sunday. Additional Fire Statements may be needed through next week.

* A Special Weather Statement (SPS) remains in effect for the inland portions of Cameron, Willacy and Kenedy counties till 7 PM this evening as heat indices peak around 108-111F.

* Additional SPSs and a potential heat advisory, or two, are possible each day through next week.

* A moderate risk of life-threatening rip currents continues through Sunday afternoon.

DISCUSSION

Issued at 1238 PM CDT Sat Jul 18 2026

Hot, dry, and at times breezy conditions will continue over Deep South Texas through next week. After plaguing the northern Rockies and Plains, and Upper Midwest with a massive heat wave including numerous record-breaking temperatures, an anomalously strong and broad heat dome will retreat and shift into the 4-Corners Region and Southern Plains next week. With a strong 594-597 dam sub-tropical heat dome or ridge over the region and encompassing much if not all of Texas, the heat in the days to come will be slightly more intense compared to prior days. For Deep South Texas and the Rio Grande Valley, 850 mb temps between 20-26C will translate to widespread ambient temperatures near the sfc ranging between 100-107F degrees across much of the region (including the inland coastal counties) through next week. Not only are these values slightly above climate normals, but some of these values on some days could be record to near record-breaking (see CLIMATE SECTION for more details).

Strong compressional heating via strong subsidence from the aforementioned heat dome will help to lower the dewpoint and relative humidity values across the region through next week. As a result, maximum heat indices or "feel-like" temperatures will not be as strong as what it typically could be. That said, peak heat indices through next week will generally range between 100-115F degrees with the lower values far west or inland and the higher values near the coast. Additional Special Weather Statements (SPSs) or borderline Heat Advisories may be needed in the days ahead, particularly for the coastal counties as there could be days where heat indices are ranging between 108-113F degrees. While the strong compressional heating is good in keeping the heat in check, it does raise the risk for fires through next week (see FIRE WEATHER SECTION for more details).

These temperatures will continue to result in widespread Moderate (Level 2 of 4) Heat Risk across Deep South Texas with pockets of Major (Level 3 of 4) Heat Risk over the major population centers and towns along the Rio Grande Valley through next week.

AVIATION

(18Z TAFS) Issued at 1238 PM CDT Sat Jul 18 2026

Through 18z Sunday....VFR conditions will prevail through the 18z TAF cycle, though there could be a few MVFR clouds around from time to time, especially at night.

Winds will continue out of the southeast with speeds between 10-15 kts. Winds could gusts up to 25 kts, especially during the afternoon hours.

MARINE

Issued at 1238 PM CDT Sat Jul 18 2026

Generally favorable marine conditions can be expected through next week with low to moderate seas. A modest pressure gradient will at times produce moderate winds along the Lower Texas Coast through the forecast period. Although Small Craft Advisory is not likely to be needed, periodic Small Craft Should Exercise Caution is possible, especially for the Laguna Madre.

FIRE WEATHER

Issued at 1238 PM CDT Sat Jul 18 2026

Strong subsidence or compressional heating from the heat dome overhead will result in reduced relative humidity values through next week. In fact, Sunday through Friday, minimum relative humidity values are expected to meet Fire Danger Statement (RFD) criteria. Winds will also be breezy at times through next week with values also reaching Fire Danger Statement (RFD) criteria through next week.

Strong evaporation rates combined with a lack of widespread and meaningful rainfall has resulted in normal to dry fuels across the region. Given the situation, we need to keep close watch on observations and forecast trends for the potential of Fire Danger Statements, particularly in the Sunday through Friday timeframe. We have decided to issue a Fire Danger Statement (RFD) for most of Deep South Texas on Sunday. This includes all of the counties of Deep South Texas with the exception of the coastal and island counties.

CLIMATE

Issued at 1238 PM CDT Sat Jul 18 2026

An anomalously strong 594-597 dam heat dome over the region will result in a perpetual state of hot and dry conditions that includes record to near record-breaking temperatures through next week.

Record High Temperatures for Saturday July 18:

Brownsville: 101F (2023) Harlingen: 102F (1956) McAllen: 105F (2018, 2009)

Record High Temperatures for Sunday July 19:

Brownsville: 100F (2023, 2009, 1918) Harlingen: 102F (1938) McAllen: 106F (2009)

Record High Temperatures for Monday July 20:

Brownsville: 100F (1980) Harlingen: 103F (1947) McAllen: 107F (2009)

Record High Temperatures for Tuesday July 21:

Brownsville: 99F (2023, 1980, 1909) Harlingen: 102F (2012, 1924) McAllen: 105F (1980)

Record High Temperatures for Wednesday July 22:

Brownsville: 100F (2023) Harlingen: 102F (1913) McAllen: 105F (2018, 2009, 1980)

Record High Temperatures for Thursday July 23:

Brownsville: 101F (2018) Harlingen: 104F (1943) McAllen: 107F (2018)

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 80 96 79 97 / 0 0 0 0 HARLINGEN 77 99 75 101 / 0 0 0 0 MCALLEN 79 103 77 104 / 0 0 0 0 RIO GRANDE CITY 78 104 76 105 / 0 0 0 0 SOUTH PADRE ISLAND 81 88 80 88 / 0 0 0 0 BAYVIEW/PORT ISABEL 78 94 77 94 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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