651
FXUS64 KBRO 291747
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1147 AM CST Sat Nov 29 2025

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

.KEY MESSAGES...
Updated at 1138 AM CST Sat Nov 29 2025


* A strong cold front is expected overnight, which will bring the
  coldest air we have experienced since last winter, and an
  increased chance of rain tonight through Monday, with the best
  chances being tomorrow and tomorrow night.

* Adverse to dangerous surf and boating conditions are expected to
  persist through at least Sunday in response to an enhanced
  pressure gradient and a strong cold front.

* Temperatures should gradually begin warming to seasonal levels
  again starting midweek, but another shortwave could bring more
  rain chances Thursday.

&&

.DISCUSSION...
Issued at 1138 AM CST Sat Nov 29 2025

An approaching Arctic shortwave is expected to usher in a pattern
change and bring a strong cold front to our area overnight.  This is
expected to be the strongest cold front of the season thus far,
bringing some of the coldest air to the region since last winter.
Model guidance is inconsistent as to how cold the temperatures will
get.  The NAM (which tends to handle stronger cold fronts more
accurately for Deep South Texas) is more robust than the longer
ranged Euro and GFS, proposing a temperature drop of around 10
degrees colder than what the Euro/GFS is proposing.  Shorter range
CAMs (such as the HRRR) are also trending cooler, closer to the NAM.
For this reason, more weight was given to the NAM in blending it
with NBM guidance for forecasting the temperatures tomorrow through
Tuesday.

Tomorrow`s high temperatures are likely to occur earlier in the day,
possibly even before sunrise, and be in the upper 60s for the
Northern Ranchlands and the mid-70s for the Rio Grande Valley. Post-
frontal northerly winds will continue to funnel cooler air into the
region throughout the day and gradually drop temperatures into the
upper 40s/lower 50s by tomorrow night.  This low temperature range
is expected to continue to persist through Tuesday night, before a
warming trend begins to take hold.

High temperatures will be coolest on Monday, getting into the upper
50s for most of Deep South Texas as cloud cover is expected to limit
daytime heating. Gradual clearing should allow Tuesday`s highs to
warm into the 60s, and Wednesday`s highs will continue warming into
the 70s, with temperatures holding steady at seasonal levels in the
70s through the end of the week.

The frontal passage will also bring an increased chance of rain to
the area.  There could a non-severe thunderstorm or two just ahead
of the front, but precip is expected to transition to stratiform
rain and drizzle following the frontal passage.  Rain chances should
start increasing tonight, with a low (20-30%) chance of showers
mainly for the coastal counties this evening overnight. This will
become more widespread tomorrow with a low to medium (20-50%) chance
expanding west of I-69C, with higher chances (50-80%) further east.
The best chance for rain in the Western counties will be Sunday
night into Monday, when a moderate chance of rain (60-70%) will be
in place for all of Deep South Texas.

Rainfall totals are not expected to be excessive for our
region, with DESI guidance suggesting only a 30-40% probability that
any areas within the CWA will see more than an inch.  Therefore, any
rain that falls is expected to be beneficial. Conditions will begin
to dry out Monday, with low to moderate (20-40%) precip chances
continuing for areas east of I-69C. The driest days next week will
be Tuesday and Wednesday.  Another shortwave disturbance is possible
on Thursday and Thursday night, bringing a low to moderate (20-50%)
chance of rain to Deep South Texas.

A moderate risk of life-threatening rip currents is in effect for
area beaches tonight and tomorrow.  Most drowning deaths for our
region occur in times when the risk is moderate (since surf looks
more inviting on higher risk days), so any swimmers will want to
exercise caution.

&&

.AVIATION...
(18Z TAFS)
Issued at 1138 AM CST Sat Nov 29 2025

VFR conditions are expected through the remainder of today with
gusty southeasterly winds. Cloud cover is expected to become more
widespread throughout the afternoon and ceilings are expected to
lower, but still remain VFR. Showers are possible beginning
around 14-15z tomorrow, which could decrease visibility to MVFR
conditions. This is most likely to occur at BRO and HRL. Winds
are expected to shift to a northerly direction around this time as
well, as a strong cold front passes through the region.

&&

.MARINE...
Issued at 1138 AM CST Sat Nov 29 2025

Marine conditions are expected to be hazardous to smaller vessels
over the next few days as a strong cold front passes through the
area.  A Small Craft Advisory is currently in effect for the Bay and
Gulf waters through this evening, and buoy readings are being
monitored to see if any possible extension is warranted. Once winds
drop below Small Craft Advisory conditions, Small Craft Exercise
Caution conditions are expected.

Conditions should start improving on Tuesday night and remain more
favorable with light to moderate winds and seas through Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             68  77  51  61 /  20  80  70  30
HARLINGEN               63  74  47  58 /  20  70  70  20
MCALLEN                 64  74  50  58 /  10  50  60  10
RIO GRANDE CITY         61  72  47  60 /   0  30  60  10
SOUTH PADRE ISLAND      72  76  57  64 /  30  80  80  40
BAYVIEW/PORT ISABEL     66  76  50  62 /  20  80  80  30

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 6 PM CST this evening for TXZ451-454-
     455.

GM...Small Craft Advisory until 6 PM CST this evening for GMZ130-132-
     135-150-155-170-175.

&&

$$

SHORT TERM...55-MM
LONG TERM....55-MM
AVIATION...55-MM