478
FXUS64 KBRO 021731
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1231 PM CDT Sat Aug 2 2025

...New DISCUSSION, AVIATION, MARINE...

.KEY MESSAGES...
Issued at 1220 PM CDT Sat Aug 2 2025

* Relentless heat, some of the hottest temps of the year, and dry
  conditions will prevail through next weekend.

* HeatRisk will range between Moderate (Level 2 of 4) and Major
  (Level 3 of 4) through next weekend.

* Triple digit heat will be widespread and common along and west of
  IH-69E most days; heat indices will range between 105-115F degrees
  through next week.

* Low, non-zero probability (10-20%) of showers and thunderstorms
  along and east of IH-69C on Tuesday.

* Generally favorable marine conditions will continue with low to
  moderate winds and seas, and mainly low rip current risk. There
  will be a low (10-30%) chances of showers and thunderstorms
  over the Gulf Waters through next week.

&&

.DISCUSSION...
Issued at 1220 PM CDT Sat Aug 2 2025

Relentless heat, humid, rain-free, and at times breezy conditions
with elevated cooling demand/cooling degree days (CDDs) will
continue to be the storyline through the forecast period or through
next weekend. In fact, some of the hottest temperatures of the
season are expected to take place this weekend into next week,
coinciding with peak climatological temperature averages. While an
elongated 591 dam subtropical heat complex will envelope the
Southern U.S. through next weekend, forecast models and ensembles
continue to depict an anomalously strong and sprawling 594-600 dam
subtropical Sonoran heat dome (+2 to +4 STDEVs) over the Desert
Southwest, at times extending into Oklahoma and the west-
northwestern half of Texas.

As mentioned, some of the hottest temperatures of the year are
expected to take place this weekend into next week. That`s when the
Sonoran heat ridge "heat dome" will be the most expansive across the
Southwestern U.S. into the Plains. Over Deep South Texas and the Rio
Grande Valley 500 mb heights will range between 591-595 dam.
Meanwhile, 1000-500 mb thickness heights are expected to range
between 580-585 dam. 850 mb temperatures ranging between 21-23C will
translate to sfc high temperatures ranging between 95-106F degrees
each day through next weekend.

Triple digit heating will be widespread encompassing a vast
majority of real estate across Deep South Texas and the Rio Grande
Valley, basically extending from IH- 69E and points west, nearly
each day. Today and Sunday looks to be the hottest days or one of
the hottest days of the forecast period. We also have to watch for
temperature trends during the middle parts of next week (Wednesday
and/or Thursday) as potential hottest days of the period candidates
as the aforementioned heat ridge expands again, and potentially
reaches peak magnitude during this forecast period or through next
week. Daytime high temperatures along South Padre Island and
beaches along the Texas Coast are progged to be in the upper 80s
to near 90F degrees.

Given the very humid, tropical-like environment, heat indices will
generally range between 105-115F degrees each day through next
weekend. Special Weather Statements (SPSs) are in place today for
Kenedy, Willacy, Cameron and Hidalgo Counties. Our first Heat
Advisories of the season and to a greater extent (degree of
confidence) additional Special Weather Statements (SPSs) may be
needed at times to acknowledge these hot temperatures through next
weekend. Given these hot temperatures, Moderate (Level 2 of 4) and
Major (Level 3 of 4) HeatRisk will be common through the forecast
period.

To learn more about HeatRisk, visit wpc.ncep.noaa.gov/heatrisk/. To
learn more about heat in general, visit www.heat.gov. Finally, we
urge everyone to take the necessary measures to protect yourself
from the heat. Heat is the #1 cause of weather related deaths,
nationally and for that matter globally. Drink plenty of water, take
frequent breaks, stay in a cool, air- conditioned location/shelter,
and check on your family, friends, elderly, neighbors, and pets.

While rain-free conditions, by and large, will prevail through the
forecast period, courtesy of the anomalously strong 594-600 dam
Sonoran heat dome in place driving strong subsidence over the
region, day-to-day chances or near day-to-day chances for showers
and thunderstorms along the seabreeze is possible. Will continue to
monitor trends in the coming days. Any convection Monday-Wednesday
will largely be due to temporary weakness in the 500 mb pattern.
Right now, the best chances look to be on Tuesday. For now have
low grade (20%) chances for a shower or thunderstorm to develop on
Tuesday from IH-69C and points east to the Texas coast.
Additionally, there will be day-to-day or near day-to-day chances
(low grade 20-30%) for an isolated diuranlly-driven shower or
thunderstorm over the Offshore Gulf Waters each afternoon from
Monday through next Saturday.

Rip current risk will mainly be low through the period, but there
could be instances of moderate rip current risk and breezy
conditions.

&&

.AVIATION...
(18Z TAFS)
Issued at 1220 PM CDT Sat Aug 2 2025

Through 18z Sunday....By and large, VFR conditons will prevail
through the 18z TAF cycle. A few clouds, mainly diurnally driven,
will persist for the TAF sites (BRO/HRL) near the coast. Mainly SKC
skies will continue for MFE with strong mid-upper ridging overhead.

Winds will continue out of the south-southeast 5-15 kts through the
forecast period. This afternoon into this evening there could be
gusts as high as 20 kts or so, courtesy of increased mixing heights
and some brief thermal and sfc pressure gradients.

&&

.MARINE...
Issued at 1220 PM CDT Sat Aug 2 2025

Generally favorable marine conditions will prevail with low
to moderate seas and light to moderate south-southeasterly winds.
There remains a low chance of showers and thunderstorms over the
Gulf Waters, especially offshore next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             79  98  79  96 /   0  10   0  10
HARLINGEN               76 101  76  99 /   0  10   0  10
MCALLEN                 79 104  79 102 /  10  10   0   0
RIO GRANDE CITY         77 105  77 104 /  10  10   0   0
SOUTH PADRE ISLAND      80  90  81  89 /   0  10   0  10
BAYVIEW/PORT ISABEL     77  95  78  94 /   0  10   0  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

SHORT TERM...23-Evbuoma
LONG TERM....23-Evbuoma
AVIATION...23-Evbuoma