768
FXUS64 KBRO 220323
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1023 PM CDT Mon Jul 21 2025

...New DISCUSSION, MARINE...

.KEY MESSAGES...
Updated at 1014 PM CDT Mon Jul 21 2025

* Hot, humid, mainly rain-free, and at times breezy conditions are
  expected to prevail through early next week with Moderate (Level 2
  of 4) Heat Risk in place.

* Temperatures will run near normal to slightly hotter than normal
  levels through the forecast period.

* Low, but non-zero probability of increased diurnal clouds and
  perhaps an isolated shower/thunderstorm Friday through Sunday;
  greatest confidence near the coast and over the Gulf Waters.

* Generally favorable marine conditions will prevail with low to
  moderate winds and seas. Rip current risk will range between low
  to moderate through the forecast period or through next Tuesday.

&&

.DISCUSSION...
Issued at 1014 PM CDT Mon Jul 21 2025

Hot, humid, rain-free, and at times breezy conditions will continue
through the forecast period or from tonight through next Tuesday.
Tonight through Wednesday, forecast models and ensembles depict a
591-594 dam Southeastern U.S. heat ridge strengthening and expanding
with the southwestern edge of this feature extending over Deep South
Texas and the Rio Grande Valley. Closer to the sfc, the local
forecast area will be on the western edge of a westward building
1015-1020 mb sfc high pressure system. Subsidence from these key
weather features will result in continued hot, humid, and rain-free
weather through Wednesday.

Overnight low temperatures tonight and Tuesday night will range
between the mid 70s over the Northern Ranchlands to near 80F degrees
along the Rio Grande Valley. Daytime highs Tuesday and Wednesday
will range between the mid 90s to lower 100s with triple digit
heating located along and west of IH-69C. Humid conditions with
dewpoints in the 70s will result in Moderate (Level 2 of 4) Heat
Risk each day (Tuesday and Wednesday) with max heat indices between
105-112F degrees Winds will continue moderate to breezy at times out
of the southeast through Wednesday, courtesy of an enhanced thermal
and pressure gradient nearby.

The aforementioned Southeast U.S. heat ridge weakens slightly
Wednesday night through Friday before shifting westward,
strengthening, and establishing itself over the Plains Saturday into
the early parts of next week (Monday-Tuesday time period). Saturday
through Monday/Tuesday of next week, forecast models/ensembles are
depicting a mid summer 500 mb pattern with an anomalously strong
heat ridge emerging over the central/southern Plains and
strengthening between 595-600 dam, some 2-3 STDEVs above normal,
which will effectively result in a major heat wave across the
interior sections of the country.

Closer to home across Deep South Texas and the Rio Grande Valley,
the area will reside underneath this anomalously strong feature
resulting in an east-southeast flow aloft regime. While the synoptic
setup will support slightly hotter than normal temperatures in the
Saturday through next Tuesday time period, forecast models are
signaling a shortwave (weak) trough nearby, particularly in the
Friday and Saturday timeframe. This nebulous feature coupled with an
easterly flow aloft regime could trigger some diurnal clouds and
perhaps some isolated convection across our CWA Friday through
Sunday. If realized, this ultimately could result in slightly
cooler temperatures than would be otherwise, and closer to normal
levels.

Afterwards (Sunday through Tuesday of next week), temperatures could
trend towards slightly hotter than normal levels. Overall, the
weather pattern will remain status quo Wednesday night through next
Tuesday. That is hot, humid, mainly rain-free, and at times breezy
with Moderate (Level 2 of 4) Heat Risk continuing.

&&

.AVIATION...
(00Z TAFS)
Issued at 532 PM CDT Mon Jul 21 2025

Through 00z Wednesday....VFR conditions will by and large prevail
through the entire 00z TAF cycle as a sfc high pressure system
remains anchored over the region. There could be some MVFR clouds
around from time to time.

Southeast winds will continue through the forecast period with
sustained speeds between 10-15 kts and gusts between 20-25 kts,
particularly during the late morning to early evening hours.

&&

.MARINE...
Issued at 1014 PM CDT Mon Jul 21 2025

Generally favorable marine conditions will prevail with low to
moderate seas and light to moderate winds. A locally enhanced
pressure gradient may result in brief Small Craft Exercise Caution
conditions along the Laguna Madre and nearshore Gulf waters each
afternoon. There will also be a low to moderate rip current risk for
area beaches through the forecast period or through early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             80  95  79  95 /   0   0   0   0
HARLINGEN               77  98  76  98 /   0   0   0   0
MCALLEN                 80 100  79 101 /   0   0   0   0
RIO GRANDE CITY         77 102  76 102 /   0   0   0   0
SOUTH PADRE ISLAND      80  87  80  88 /   0   0   0   0
BAYVIEW/PORT ISABEL     78  93  77  93 /   0   0   0   0

&&

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

$$

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