563
FXUS64 KBRO 290508
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1108 PM CST Fri Nov 28 2025

...New KEY MESSAGES, DISCUSSION, AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1103 PM CST Fri Nov 28 2025

* Breezy southeasterly winds 15-25 mph with higher gusts to continue
  through Saturday.

* A brief warm spike takes place on Saturday with highs in the 80s.

* Big changes to the weather pattern as a strong cold front Saturday
  night into Sunday will bring a notably cooler airmass (potentially
  the coldest since last February) to the region Sunday through
  early next week.

* 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.

* Rain chances increase inland Saturday night through Monday and
  again Wednesday night through Thursday night. Greatest chances
  Sunday through Sunday night. Rain chances nearly everyday
  through next week for the Gulf Waters.

&&

.DISCUSSION...
Issued at 1103 PM CST Fri Nov 28 2025

A strong early season cold front that promises to bring the
coldest airmass yet of the season (coldest since last February)
and an unsettled weather pattern will be the main highlights
through the forecast period.

The latest satellite and radar data depicts scattered to overcast
sky coverage with some light streamer showers driven by breezy
southerly gradient winds and a weak shortwave over the Sierra Madre.
Through tonight, expect for light streamer showers to continue
across parts of the area with the best chance of showers occurring
closer to the coast.

Warm air advection (WAA) regime will continue on Saturday and
will result in warm spike, albeit brief. Breezy southerly winds
15-25 mph with higher gusts will aide in daytime high temperatures
climbing into the mid to upper 80s on Saturday. However, during
the day on Saturday, a strong south-southeastward advancing cold
front will be sweeping its way through the state of Texas. This
cold front will be associated with a highly amplified and active
large- scale pattern featuring a mild West U.S. vs a Cold and
wintry Central and East U.S. in which forecast models have been
advertising for the past several days. While this will bring
plenty of wintry weather across the northern tier states, this
cold front will bring markedly cooler temperatures to Deep South
Texas and the Rio Grande Valley late this weekend into the early
parts of next week. There still remains some discrepancies amongst
forecast guidances on the precise timing and strength of the cold
fropa, which would impact high temps on Sunday and potentially
beyond. Typically, these cold shallow airmasses tend to be
stronger and have a faster timing than than what most global
forecast models suggest. The hi-res, CAM North America Model (NAM)
captures these trends better.

That said, it still appears that sometime Saturday night into
Sunday, this strong cold front with Arctic origins will sweep
through all of Deep South Texas and the Rio Grande Valley. In it`s
wake will be the coldest airmass of the season seen so far (since
last February). High temperatures on Sunday will likely be reached
early in the day as temperatures are expected to fall through the
day. High temperatures from Saturday to Sunday will be 10-15 F
degrees cooler, however closer to seasonable norms with values on
Sunday in the low to mid 70s and 60s over Brush Country.

Clearing skies amid additional cold and dry air advection will
result in a noticeably chilly Sunday night as overnight low
temperatures are expected to plunge into the 40s most places, some
15F degrees or so cooler than Saturday night, and some 10F degrees
cooler than normal. A full cold and dry air advection regime will be
in place by Monday. This combined with a modified 1020-1025 mb sfc
Arctic high pressure system over the region will result in continued
cooler than normal temperatures with high temperatures failing to
make it out of the 50s on Monday and 60s on Tuesday. Clear skies and
additional radiational cooling will result in overnight low
temperatures Monday and Tuesday nights holding in the 40s most
places (50s along the RGV and immediate coast), which again will be
well below normal levels.

In addition to the cooler changes, the pattern will become unsettled.
Rain showers (some perhaps stratiform type) are possible Saturday
night through Monday in response and connection to the cold
frontal boundary. Currently, we still have low to medium (20-60%)
PoPs over Deep South Texas during this time period with the best
chances being near the coast. Sunday-Sunday night is where we
expect the most widespread coverage. We`ve maintained categorical
PoPs along and east of IH-69C Sunday-Sunday night. Even greater
chances will take place over the open Gulf Waters during this same
time period. Rain showers are also possible over the Gulf Waters
Friday night and Saturday in connection to the aforementioned warm
front and again Monday night of next week.

Another bout of unsettled weather is expected to develop over the
forecast area as a nearby shortwave trough/developing low pressure
system will increase the threat for showers and thunderstorms
Wednesday night through Thursday night. Currently, we have low to
medium (20-50%) chances across Deep South Texas with the higher
chances located near the coast.

Temperatures will gradually moderate through the week, however,
the combination of rain chances and increased cloud coverage will
limit warming potential. That said, high temperatures by Wednesday
are progged to reach the 70s across much of Deep South Texas.
Highs mainly in the 70s are then expected to persist through next
Saturday. Overnight lows Wednesday through Saturday night will
mainly be in the 50s. Given the explanation above about model
biases and after collaboration with neighboring offices, have
decided to use a blend of the NBM 25th percentile and NAM12 Sunday
through Wednesday.

&&

.AVIATION...
(06Z TAFS)
Issued at 1103 PM CST Fri Nov 28 2025

Through 06z Sunday....VFR conditions are expected to prevail
through the 06z TAF cycle. VCSH will be around tonight (decreasing
in coverage with most confined close to the coast). Cloud
coverage is expected to improve towards the end of the forecast
period.

Winds will remain breezy out of the southeast with speeds between 10-
20 kts and gusts as high as 30 kts or so through much of the
forecast period. Saturday evening, winds are expected to wane.

&&

.MARINE...
Issued at 1103 PM CST Fri Nov 28 2025

A Small Craft Advisory remains in effect for the Laguna Madre and
the Gulf Waters through Saturday evening due to continued breezy
southeasterly winds. A second, stronger cold front will sweep
through the region Saturday night into Sunday. This will result in
continued adverse to hazardous marine conditions to persist and a
Small Craft Exercise Caution or Small Craft Advisory may be
needed through at least Sunday. Marine conditions could improve by
Tuesday night with low to moderate winds and seas prevailing
through next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             78  71  83  67 /  30  10  10  20
HARLINGEN               78  66  85  61 /  20   0  10  20
MCALLEN                 78  69  87  63 /  30   0   0  10
RIO GRANDE CITY         77  66  87  58 /  30   0   0  10
SOUTH PADRE ISLAND      77  73  80  71 /  20  10  10  30
BAYVIEW/PORT ISABEL     78  68  83  64 /  20  10  10  30

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Saturday afternoon for TXZ451-454-
     455.

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

&&

$$

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