453
FXUS64 KBRO 161052 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
552 AM CDT Mon Jun 16 2025

...New AVIATION...

.SHORT TERM...
(Now through Tuesday) Issued at 1101 PM CDT Sun Jun 15 2025

In the big picture...no change to the sensible weather through the
period. Other than isolated afternoon sea-breeze enhanced
showers/thunderstorms Monday across the Brooks/Kenedy area,
conditions should remain rain-free with a continuation of
seasonably hot (for June 16-17) afternoons and steamy overnights.
Despite the presence of a very weak shear axis between 500 mb
subtropical ridges over Florida/Bahamas and northwest Mexico/New
Mexico (out to Baja California), dry air off the surface should
mix down by afternoon each day to preclude heat index values
exceeding 110...in fact, if today is an indicator of trends, dew
points will drop to near 70 over the mid Valley and lower 70s
along IH-69E/US 77, sufficient to keep values between 103 and 108
which is about average for this time of year in this pattern.

As for precipitation...have left the slight chances of streamer
showers pinned to the coast early Monday, with isolated
showers/perhaps a thunderstorm favoring the northern ranchlands
Monday afternoon. A mid-Sunday evening cluster of storms rolling
across the Coastal Bend may leave some boundaries behind that
could aid late morning redevelopment in Brooks/Kenedy...which will
need to be watched.

Beach conditions overall should be ideal, with comfortable surf a
relief from the inland heat. That said, rip/longshore current
intensity will be on the edge of moderate, so swimmers should
remain aware of their situation over the next two days.

&&

.LONG TERM...
(Tuesday Night through next Monday) Issued at 1101 PM CDT Sun Jun
15 2025

Tuesday night and most of Wednesday continue more of the same,
with a continued expected arrival of deeper layer moisture along
the coast and across the Gulf waters by late Wednesday afternoon.
This will allow an increasing chance (though still low) for
onshore showers, perhaps a thunderstorm, before sunset. Still
plenty hot inland but dewpoints in the low 70s by mid to late
afternoon should keep heat index values in check.

The one difference this evening compared with the last two is the
organization of timing of the tropical-upper tropospheric trough
(TUTT). Both GFS and ECMWF deterministic are rather bearish on the
intensity of the "inverted" trough, which makes forecasting the
total amount of rainfall (and location thereof) even more
difficult than what appeared a couple days ago. That said, the
trend remains the same - enough cloud cover, deep layer moisture,
and favorable situation on the east side of whatever comes of the
TUTT to favor at least likely chances (60-70 percent) with highest
rain totals favoring Cameron and Willacy for Thursday through
Saturday.

In a way, this would be good news, since most of these areas have
missed the recent rains the past two weeks but have been plenty
hot and breezy and on the edge of abnormal dryness. Total QPF
through Saturday has dropped a bit, now closer to 1-1.5"
along/east of IH-69C and 1.5-2" east of IH-69E, but uncertainty
remains with some model blends chances continuing at 30-40+% for
3"+ in Cameron/Willacy between Thursday and Sunday morning.

Bottom line for drainage clearing remains the same: take advantage
through early Wednesday in case conditions go downhill thereafter.

&&

.AVIATION...
(12Z TAFS)
Issued at 547 AM CDT Mon Jun 16 2025

Only minor adjustments made to the previous issuance of TAFs. VFR
will generally prevail at the aerodromes through the next 24 hours.
Light winds and mainly a few clouds around sunrise will become
breezy with partly cloudy skies for the remainder of the day. Winds
will then diminish and clouds will thin beginning around sunset.

&&

.MARINE...
Issued at 1101 PM CDT Sun Jun 15 2025

Now through Tuesday: Little change from today, right through
Tuesday: Modest winds, generally 10-15 knots across the Gulf and
Bay but periodically 15 knots and gusty across Laguna Madre each
afternoon and the Gulf for a short window overnight. Seas should
remain at 3-4 feet with a moderate chop overall on the bay, as
pressure gradients are unchanged, diurnally. Other than isolated
to scattered mainly offshore showers and perhaps a thunderstorm,
conditions should be rather quiet.

Tuesday Night through Friday Night: The main issue will remain
increasing rain chances and coverage as the aforementioned upper
level TUTT makes its move across the Mexican coast and west of the
area. For now, better coverage still looks to be Thursday through
Friday night with periodic lulls. Background winds may veer a
touch to the east-southeast but speeds don`t pick up
any...however, in and around stronger cells that would change,
along with increasing wind chop.

Seas begin at 3-4 feet through Wednesday night and may climb to
4-5 feet, especially in agitated conditions in coverage
showers/storms, but latest forecast has backed off Caution (6
foot) levels at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             94  78  94  80 /  20  10  10   0
HARLINGEN               96  76  96  78 /  20   0  10   0
MCALLEN                100  78 100  79 /  10   0   0   0
RIO GRANDE CITY         98  76 100  77 /  10  10   0   0
SOUTH PADRE ISLAND      87  80  88  81 /  20  10  10  10
BAYVIEW/PORT ISABEL     92  78  93  79 /  10  10  10   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...None.

&&

$$