Brownsville, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

734
FXUS64 KBRO 260457
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1157 PM CDT Mon May 25 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1157 PM CDT Mon May 25 2026

Key Messages:

 * SPC continues a Marginal Risk (level 1 of 5) of isolated severe
   thunderstorms, with a primary threat of damaging winds, across
   all of deep south Texas as well as a secondary threat of
   isolated large to very large hail across portions of the Upper
   RGV and Rio Grande Plains Tuesday/Tuesday night.

 * WPC maintains a Marginal Risk (level 1 of 4) of isolated flash
   flooding from excessive and heavy rainfall across the Northern
   Ranchlands and Rio Grande Plains on Tuesday/Tuesday night as
   well as the coastal counties and portions of the Northern
   Ranchlands and Middle RGV on Wednesday.

 * There are additional chances of strong to isolated severe
   thunderstorms on Wednesday and Thursday, though confidence is
   low at this time. Otherwise, drier weather returns Wednesday
   night and through the end of the work week/early weekend.
   Unsettled weather may return later weekend/early next week.

 * Daily minor to moderate (levels 1 and 2 of 4) heat risks and
   maximum afternoon heat indices of 95-105 F (locally hotter)
   continue, possibly peaking over the weekend.

 * A low risk of rip currents persists through Tuesday afternoon.

&&

.DISCUSSION...
Issued at 1026 PM CDT Mon May 25 2026

A strong mid/upper level trough digs from the PNW to the western US,
advancing another trough eastward over the Desert Southwest to
western Texas by midweek, thus resulting in a gradual increase in
forcing and ascension aloft. This, along with southeasterly flow re-
enhancing surface moisture beginning tonight, should build cloud
cover across deep south Texas through the next 24 hours. At this
time, we anticipate a low (15-30%) chance of showers and thunderstorms
developing over the Rio Grande Plains Tuesday morning and spreading
eastward across the entire region into the afternoon and evening
hours. Chances of rain could reach as high as a low to medium
(30-60%) chance Tuesday night, highest across the Northern Ranchlands.
This is more in alignment with this evening`s cam guidance, which
now generally suggest increased cloud cover and reduced surface-
based instability leading to more stratiform light to moderate
showers and a few sub-severe, though potentially locally strong,
thunderstorms capable of producing gusty winds and locally
heavier rain through the morning and afternoon hours on Tuesday
before another round Tuesday night, when strong to isolated
thunderstorms are possible across the Rio Grande Plains and
Northern Ranchlands.

Yet, should a further delay in the arrival of divergence aloft
result in more sparse cloud cover and lower rain chances during the
day on Tuesday, the probabilities of strong to isolated severe
thunderstorms during the afternoon and/or overnight hours could
increase considerably. Therefore, SPC continues a Marginal Risk of
isolated severe thunderstorms for Tuesday and Tuesday night, with
the primary risk of isolated damaging (58+ mph) winds across all
of deep south Texas as well as a secondary threat of isolated
large (1+ inch) hail across Zapata County and the far western
portion of Starr County if Sierra Madre convection makes it to the
border. Very large (2+ inch) hail is even possible near and along
the Rio Grande/US border in northern Zapata County. This
conditional and hypothetical scenario could also be supportive of
producing a squall line across all, or portions, of the CWA
Tuesday night. Additionally, as PWAT values rise to as much as 1.9
to 2.2 in. Tuesday into Wednesday, WPC keeps the majority of the
Northern Ranchlands and the Rio Grande Plains within a Marginal
Risk of isolated flash flooding from excessive and heavy rainfall
Tuesday and Tuesday night. More specifically, this includes most
of Zapata County (except the southern portions), all of Jim Hogg
county, most of Brooks County (except the southeastern areas) and
the northwestern part of Kenedy County.

A low to medium (30-60%) chance of showers and thunderstorms
continues through Wednesday morning and afternoon as the trough
passes over our region. Currently, SPC outlines a general outlooks
of sub-severe thunderstorms on Wednesday. However, a strong to
severe thunderstorm, or two, is not out of the question,
especially if a potential squall line is still working its way
through the region into the daytime, perhaps over the eastern
portions of the CWA. As such, SPC could add a Marginal Risk within
the next few updates. WPC maintains a Marginal Risk of isolated
flash flooding from excessive rainfall from the eastern half of
Jim Hogg and Hidalgo counties on eastward to the coast for
Wednesday. By Thursday morning, we expect rainfall amounts to
range from a trace to as much as 0.5 an inch across the RGV, while
the Rio Grande Plains and the Northern Ranchlands could receive
0.5 to 0.8 of an inch. However, due to very high moisture content
favoring efficient heavy rain production, localized rainfall
rates of up to 3 in./hr could produce 1 to 3+ inches within the
deepest convection, especially in slow-moving thunderstorms or
where thunderstorms train over an area one after the other.

Ridging behind the departing trough resumes and brings much drier
conditions Wednesday night. Minimal (<10%) chances of rain could
persist through the remainder of the work week, possibly into
Saturday. Yet, the 00Z RRFS and 18Z GFS portray an embedded mid-
level shortwave passing over on Thursday, bringing the possibility
of strong to isolated thunderstorms. However, confidence remains
low at this time. Otherwise, the next chance of unsettled weather
arrives possibly Saturday night into next Monday as the upper
level trough over the western US advances eastward. PoPs are low
to medium at this time. High temperatures continue to rise to the
upper 80s and 90s along with heat indices generally ranging from
95-105 F. Minor to moderate heat risks continue across the RGV and
coastal counties, where indices could briefly peak as high as 110
F. More abundant sunshine results in a more widespread moderate
heat risk on Friday and Saturday. Overnight lows continue in the
70s.

A low risk of rip currents continues through Tuesday afternoon.

&&

.AVIATION...
(06Z TAFS)
Issued at 1157 PM CDT Mon May 25 2026

Through 06z Wednesday....VFR conditions, by and large, will prevail
through the 06z TAF cycle. The exception could be during the
overnight hours into the early morning hours where MVFR-IFR
mist/low stratus could develop or be around.

If not light and variable, winds will be light out of the southeast
with speeds up to 5 kts through the overnight. During the day on
Tuesday, southeast winds are expected to pick up with speeds between
5-15 kts and gusts up to 25 kts.

&&

.MARINE...
Issued at 1026 PM CDT Mon May 25 2026

Gentle to moderate easterly to southeasterly winds and slight to
moderate (2-4 ft, occasionally higher) seas persist through the
next 7 days. Small Craft Exercise Caution headlines are possible for
the Laguna Madre and nearshore Gulf Waters (0-20 nm) Tuesday and
Wednesday afternoon/evening in response to a slight locally
enhanced pressure gradient, resulting in moderate to fresh winds.
Chances of showers and thunderstorms increase Tuesday night to as
much as a low to medium (3-60%) chance during the day on Wednesday.
Strong to isolated severe thunderstorms are possible as well.
Chances gradually diminish Wednesday night and much drier
conditions resume through this weekend before the next system
brings unsettled weather, possibly by early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             89  76  90  80 /   0   0  10  20
HARLINGEN               89  71  91  77 /   0   0  20  30
MCALLEN                 91  75  91  78 /   0   0  20  40
RIO GRANDE CITY         91  74  91  75 /   0   0  20  40
SOUTH PADRE ISLAND      83  79  85  81 /   0   0  10  30
BAYVIEW/PORT ISABEL     87  75  89  79 /   0   0  10  30

&&

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

$$

SHORT TERM...65
LONG TERM....65
AVIATION...23-Evbuoma