San Isidro, Texas Weather Forecast Discussion

852
FXUS64 KBRO 010334
AFDBRO
Area Forecast Discussion
National Weather Service Brownsville TX
1034 PM CDT Tue Sep 30 2025
...New DISCUSSION, MARINE...
.KEY MESSAGES...
Updated at 1024 PM CDT Tue Sep 30 2025
- Daily chances of afternoon showers and thunderstorms along the
  seabreeze boundary return, beginning Friday, but temperatures
  remain near to slightly above average.
- A Moderate risk of rip currents is likely over the weekend,
  beginning Saturday.
&&
.DISCUSSION...
Issued at 1024 PM CDT Tue Sep 30 2025
Dry conditions continue across Deep South Texas today into tomorrow
as an expanding mid-level high pressure over northern Mexico
maintains riding aloft. Throughout tomorrow into Friday, an upper
level trough begins to deepen across the Midwest, leading to the
development of a mid-level low over the central Gulf Coast states,
which is forecast to linger and bring an increased chance of
unsettled weather. Beginning Friday morning, probabilities of
showers and thunderstorms increase along the coast to generally a
low to medium (20-50%) chance, persisting into next week, expanding
inland each day along the seabreeze boundary throughout the morning,
afternoon and early evening hours. Most days, PoP`s of 30% and
higher are likely to be near, and east of, US-281/I-69 C, with the
best chances along and east of I-69 E. The most widespread
coverage over the weekend appears to be Saturday, possibly
maximizing in coverage across the region at a low to medium
(20-60%) chance by the afternoon before decreasing to a 20-40%
chance into Sunday as ridging briefly re-enhances. There continues
to be disagreement between each run of the GFS and ECMWF
deterministic and ensemble forecasts with regards to PWAT values
during this timeframe, but there is some consensus that generally
a range of 1.3-1.6 or 1.7 inches is possible over the weekend,
highest along the immediate coast, potentially increasing into the
middle next week. Therefore, there exists the possibility of some
heavy rain in the strongest of convection over the weekend, but
the better chance for heavier rain may be towards the middle parts
of next week.
Near to slightly above average high temperatures continue each
afternoon, with mid 80`s near the coast, low to mid 90`s east of US-
281/I-69 C and mid to upper 90`s further west, falling to the 60`s
and 70`s inland overnight, becoming mostly 70`s over the weekend.
Lows around 80 degF continue at SPI. Mainly minor (level 1 of 4)
heat risks continue throughout the forecast, though moderate
(level 2 of 4) heat risks may be possible across portions of the
Rio Grande Valley beginning next Monday as moisture and relative
humidity increase.
A low risk of rip currents continues through Friday, becoming a
moderate risk by Saturday as wave heights and periods increase.
&&
.AVIATION...
(00Z TAFS)
Issued at 621 PM CDT Tue Sep 30 2025
Moderate (10-15 knots, gusting up to 20 knots) northeasterly winds
are expected to diminish to light and variable shortly after
sunset this evening and continuing overnight, before gradually
picking up throughout tomorrow to similar speeds by tomorrow
afternoon. Dry weather and VFR conditions continue.
&&
.MARINE...
Issued at 1024 PM CDT Tue Sep 30 2025
Light to gentle northeasterly to easterly winds and slight (1-2 ft)
seas become gentle to moderate and easterly to southeasterly with
slight to moderate (2-4 ft) seas over the weekend and into next
week. Low chances of rain return on Thursday, increasing to
generally a medium to likely (40-70%) chance, or higher, beginning
Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             72  92  73  92 /   0  10   0  20
HARLINGEN               67  94  68  93 /   0   0   0  10
MCALLEN                 71  97  72  97 /   0   0   0  10
RIO GRANDE CITY         68  97  68  98 /   0   0   0   0
SOUTH PADRE ISLAND      80  87  80  87 /   0   0  10  20
BAYVIEW/PORT ISABEL     72  90  72  89 /   0   0   0  10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM...65-Irish
LONG TERM....65-Irish
AVIATION...65-Irish

NWS BRO Office Area Forecast Discussion