640
FXUS64 KBRO 251117 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
617 AM CDT Fri Jul 25 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 614 AM CDT Fri Jul 25 2025

* Hot, humid, and at times breezy conditions will continue through
  Friday of next week.

* Heat Risk will range between Minor (Level 1 of 4) and Moderate
  (Level 2 of 4) with max heat indices ranging between 100-112F
  degrees each day.

* Day-to-day chances for showers and thunderstorms Friday through
  Sunday remain on the table; storms will be capable of producing
  heavy rainfall.

* Outside of thunderstorm chances, generally favorable marine
  conditions can be expected with low to moderate winds and seas.

&&

.DISCUSSION...
Issued at 1018 PM CDT Thu Jul 24 2025

After days of mostly rain-free weather, the weather pattern is
expected to turn a bit more active/wet. Forecast models and
ensembles continue to indicate day-to-day risk for tropical sourced
showers and thunderstorms developing Friday through Sunday. This
activity is largely connected to moisture associated with a broad,
westward propagating disturbed low pressure area, currently located
over the north-central Gulf, as seen on satellite and radar. This
disturbed area of showers and thunderstorms and its moisture is
being steered by a 594 dam southeastern U.S. sub-tropical heat
ridge.

In response to the approach of this unorganized tropical wave area,
clouds will begin to increase tonight and on especially Friday as
will precipitation chances (PoPs). There continues to be a low to
medium (20-50%) chance for showers and thunderstorms to develop
Friday-Friday night with the best chances being located east of IH-
69C and over the Gulf Waters. Saturday will feature more uniformed
chances for diurnally driven showers and thunderstorms areawide with
probabilities ranging between 30-40%. Finally, on Sunday, there will
yet again be low to medium (20-50%) chances for showers and
thunderstorms with the best chances located along and east of IH-69C
and over the Gulf Waters.

The atmosphere will support efficient rain producing showers and
thunderstorms due to the very high atmospheric moisture content.
Precipitable water (PWAT) values between Friday and Sunday will
range between 1.80" to 2.30", some 1-2 STDEVs above normal and in
some cases within the 90th percentile of climatology. While we
currently aren`t outlooked under the risk for excessive rainfall,
heavy downpours are possible in this environment. This could result
in some areas of localized ponding of roadways. Despite the risk for
heavy downpours, the rainfall over the next few days will be
welcomed and beneficial for the area after weeks of dryness.

Outside of the threat for showers and thunderstorms Friday through
Sunday, the forecast period running from tonight to next Friday
night will continue to be hot and humid with Minor (Level 1 of 4) to
Moderate (Level 2 of 4) Heat Risk prevailing. Winds will also be
breezy at times out of the south-southeast due to the occasional
enhancements of the thermal and sfc pressure gradients.

Friday through Sunday, high temperatures will be close to normal
levels and maybe even slightly cooler than normal levels, courtesy
of additional cloud coverage, rain chances, and the brief weakening
of the aforementioned southeastern sub-tropical heat ridge. Daytime
high temperatures Friday through Sunday are expected to run in the
lower 90s near the Texas Coast to the upper 90s west of IH-69C.
Insulation from cloud coverage will help to keep overnight low
temperatures elevated tonight through Sunday night with values
ranging between the mid 70s over the Northern Ranchlands to the
lower 80s along the Rio Grande Valley.

A slight warming trend will take place during the next workweek
(Monday-Friday) as the aforementioned heat ridge over the southeast
strengthens and shifts over the Mid-South and Plains Region. Daytime
highs are progged to range between the mid 90s near the coast to the
upper 90s/lower 100s along and west of IH-69C. Heat indices are
expected to range between 100-112F degrees through the forecast
period with dewpoint temperatures being maintained in the 70s. Again
due to either the very warm and humid nights or the hot daytime
temperatures, heat risk will range between Minor to Moderate through
next Friday night. Continue to take necessary heat safety
precautions over the next week.

&&

.AVIATION...
(12Z TAFS)
Issued at 614 AM CDT Fri Jul 25 2025

VFR conditions will likely persist through much of the TAF period.
There is a low chance for some isolated showers or thunderstorms
this afternoon, however confidence in any of these storms moving
over the airfields is too low to include in the TAFs at this
time. Cloud cover will likely increase this afternoon, with some
VFR ceilings possibly developing later today. Light to moderate
southeasterly winds are expected to continue through the TAF
period.

&&

.MARINE...
Issued at 1018 PM CDT Thu Jul 24 2025

Outside of the day-to-day chances for showers and thunderstorms
developing over the Gulf waters and Laguna Madre Friday through
Sunday, generally favorable marine conditions will continue through
the forecast period with low to moderate seas and light to moderate
winds.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             93  79  94  80 /  20  20  20  10
HARLINGEN               95  76  96  77 /  20  20  20  10
MCALLEN                 98  79  98  80 /  20  20  20  10
RIO GRANDE CITY        100  78  97  77 /  10  10  20  10
SOUTH PADRE ISLAND      87  79  88  80 /  30  20  20  10
BAYVIEW/PORT ISABEL     92  78  93  79 /  30  20  20  10

&&

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

$$

SHORT TERM...23-Evbuoma
LONG TERM....23-Evbuoma
AVIATION...60-BE