000
FXUS64 KBRO 271119 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
619 AM CDT Sat Apr 27 2024

...New AVIATION...

.SHORT TERM...
(Today through Sunday)
Issued at 250 AM CDT Sat Apr 27 2024

The next bout of low pressure swings into the Plains today into
Sunday, maintaining the tightened pressure gradient across Deep
South Texas into this evening. The LLJ strengthens toward 40-45 kts
this afternoon, with frequent 40 mph wind gusts likely mixing down
into Cameron and Willacy counties. DESI probabilities spiked above
50 percent for wind gusts over 40 mph across central to western
Cameron County mid-afternoon, keeping the strongest winds south of
Kenedy County and west of the coast. Have issued a Wind Advisory for
inland portions of Cameron and Willacy counties, leaving out the
coastal portions and Kenedy County at this time.

A weak pre-frontal trough of low pressure or dryline may work into
the brush country into Sunday afternoon, finally breaking the
persistent elevated southeasterly winds. A frontal boundary across
Central Texas may kick up a couple of showers or thunderstorms
Sunday afternoon. Chances of thunderstorms or outflow boundaries
making a run into our CWA generally remain less than 30 percent,
with a short window of convective activity across the ranchlands
Sunday afternoon.

Elevated surf, with increasing wave periods, will maintain a high
risk of rip currents through the weekend. Have extended the High
Risk of Rip Current Statement through Sunday afternoon. Expect
clouds to break by mid-afternoon for most locations, with slightly
above normal high temperatures and well above normal lows.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 250 AM CDT Sat Apr 27 2024

An upper-level trough will be exiting the region allowing for zonal
flow aloft to set up for the next couple of days. A weak mid-level
ridge will move over the region mid-week, that that will then be
replaced by another upper-level trough by the end of the period. To
further aid the development of convection, on the surface southerly
to southeasterly flow will continue to persist that will bring in
more moist, warm air to Deep South Texas and the Rio Grande Valley.
However, rain chances remain 20 to 30 percent through the long term
forecast period. While there are a few different opportunities for
showers and thunderstorms to develop over the long term forecast
period.

The first possibility for rain will be at the start of the long term
forecast period with a stalled out cold front towards the northwest.
The showers and thunderstorms could develop along the frontal
boundary and then move into the region. However, there does not
appear to be a lot of instability for showers and thunderstorms to
work with, thus limiting chances that said showers and thunderstorms
will be able to make it south.

The second possibility will occur Monday night into Tuesday, as a mid-
level shortwave will bring a source of forcing that will help
develop showers and thunderstorms along the Sierra Madre Mountains.
It is possible that some of these showers and thunderstorms make it
into Deep South Texas and the Rio Grande Valley, the environment
will not be as favorable. These means that any showers and
thunderstorms that try to move into the region are likely to
dissipate before they make it very far. This cycle is likely to
repeat on Tuesday night and Wednesday as more shortwaves move into
the region.

Towards the end of the period, a cold front start to approach Deep
South Texas and the Rio Grande Valley, which will be another chance
for showers and thunderstorms to develop, but doesn`t look to push
through the region based the current model guidance. This is
scenario is different than the previous model run output. Since this
event is nearly a week out and the changing models runs, confidence
with how the models are resolving this cold front is not high.

As for temperatures, the previously mentioned southerly to
southeasterly flow will keep the temperatures rather warm. High
temperatures are expected to be in the 90s for most of the area,
while areas along the coast and the island will be in the upper 80s.
On the other hand, the low temperatures will be in the 70s through
the period.

&&

.AVIATION...
(12Z TAFS)
Issued at 610 AM CDT Sat Apr 27 2024

Conditions are MVFR at the TAF sites due to ceilings. Strong
southeast breezes will develop today, potentially scattering out
lower clouds for a few hours this afternoon, but the window will
be short lived and is not guaranteed. Could see some wind gusts
above 40 mph this afternoon. Ceilings will drop to MVFR this
evening and overnight while winds diminish to a moderate breeze.

&&

.MARINE...
Issued at 250 AM CDT Sat Apr 27 2024

Today through Sunday...Low pressure across the Plains and high
pressure east will maintain increased southeasterly winds through
the  weekend, with winds diminishing gradually from west to east.
Small Craft Advisories are in effect through tonight for all coastal
waters, shifting to just offshore Gulf waters through Sunday night.
There is a slight chance of thunderstorms across northern coastal
waters Saturday afternoon.

Sunday Night through Friday...Hazardous conditions are expected for
Sunday night into Monday, due to elevated seas that will require
Small Craft Advisory. During the day on Monday, conditions will
start to improve as the winds weaken and the seas decrease. Small
Craft Exercise Caution might be needed for short periods of time for
the rest of the period as the pressure gradient becomes enhanced due
to several passing upper level shortwaves.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             90  76  91  76 /  10   0  10   0
HARLINGEN               92  73  93  74 /  10   0  10   0
MCALLEN                 93  76  94  76 /  10   0  10   0
RIO GRANDE CITY         96  74  93  72 /   0   0  10   0
SOUTH PADRE ISLAND      82  76  83  76 /  10   0  10   0
BAYVIEW/PORT ISABEL     88  74  90  74 /  10   0  10   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Wind Advisory from 11 AM this morning to 7 PM CDT this evening
     for TXZ254-255.

     High Rip Current Risk through Sunday evening for TXZ451-454-455.

GM...Small Craft Advisory until 7 AM CDT Sunday for GMZ130-132-135.

     Small Craft Advisory until 7 AM CDT Monday for GMZ150-155-170-
     175.

&&

$$

SHORT TERM...54-BHM
LONG TERM....64-Katz
AVIATION...54-BHM