360
FXUS64 KBRO 251728 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1228 PM CDT Wed Sep 25 2024

...New AVIATION...

.SHORT TERM...
(Today through Thursday)
Issued at 349 AM CDT Wed Sep 25 2024

An upper level trough over the eastern US looks to develop a closed
low over the Central Mississippi River Valley by tonight. Forcing
associated with this system will support a cold front dropping south
from Central Texas and moving through the CWA late tonight into
early Thursday morning. PWAT values above 1.5 inches and CAPE values
around 1000 J/kg ahead of the front could support showers and
thunderstorms developing ahead of and along the front. HiRes models
are showing some isolated seabreeze convection this afternoon, then
a line of scattered thunderstorms developing along the cold front
tonight. Ample shear and instability may be present to support some
of these thunderstorms becoming strong to severe. The SPC day one
outlook has a marginal risk for northern Kenedy County through 7 am
Thursday.

High temperatures this afternoon are expected to reach the low to
mid 90s, with heat indices topping out around 105 to 108. The
spatial coverage of the higher heat indices looks to remain low
enough not to warrant a Special Weather Statement this afternoon.
Low temperatures tonight are expected to fall to the low to mid 70s.
High temperatures Thursday are expected to top out in the upper 80s
to low 90s. Drier air behind the front is expected to keep heat
index values below 100.

Lastly, swell from Tropical Storm Helene is expected to arrive
Thursday along the Lower Texas Coast. This will likely lead to a
higher risk of rip currents and some minor coastal flooding at area
beaches.

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 349 AM CDT Wed Sep 25 2024

The forecast period starts with a 500mb low centered over the Middle
Mississippi River Valley and a mid-level ridge located over New
Mexico. The aforementioned deep layer trough will begin to absorb
the remnants of Helene as the 500mb trough/low lingers over the
Middle Tennessee Valley and the Appalachians through the weekend as
the mid-level ridge remains centered near the Four Corners.

At the surface, much drier air will continue filter into the region
in the wake of the front. Hurricane Helene is forecast to make
landfall around the Florida Big Bend region by late Thursday
evening. Please refer to the latest forecast by the National
Hurricane Center for the latest information on Hurricane Helene. The
combination of the Thursday`s frontal passage and the arrival of
long period swell from Helene will result in increased wave heights
and adverse ongoing beach conditions Thursday night into Friday. An
enhanced rip current risk and minor coastal flooding will be
possible at beaches along the Lower Texas Coast Thursday night into
Saturday.

Near to above normal high temperatures will prevail through the
period with highs in the low to mid 90s, except for the 80s at the
beaches. Drier air will keep heat indices below 100 degrees and will
support a minor heat risk through the period. Overnight lows will
feel rather comfortable with below normal temperatures and slightly
drier air expected through the weekend.

&&

.AVIATION...
(18Z TAFS)
Issued at 1224 PM CDT Wed Sep 25 2024

VFR conditions are expected to persist through the TAF cycle at
all TAF locations. While skies are expected to be in the range of
mostly sunny to partly cloudy, the ceilings themselves are not
expected to be affected. There is the possibility that some IFR
conditions could occur again for MFE, but confidence is not high
enough to include in the TAF package. Winds are expected to remain
out of the southeast and could become more gusty by the end of the
period.

&&

.MARINE...
Issued at 349 AM CDT Wed Sep 25 2024

Today through Thursday...Generally favorable marine conditions are
expected through tonight, as winds remain light to moderates with
slight seas. Winds look to pick up out of the north early Thursday
morning with the passage of a cold front. Additionally, seas will
increase thanks to the combination of stronger winds associated with
the cold front, and the arrival of swell from Tropical Storm Helene
Thursday afternoon. As such, Small Craft Should Exercise Caution
headlines will likely be needed Thursday for the Gulf waters.

Thursday night through Tuesday...Swells from Hurricane Helene and
the passage of a cold front will likely lead to lingering adverse
conditons at the start the period. Ongoing Small Craft Should
Exercise Caution conditions or Small Craft Advisories may continue
for the Gulf waters Thursday night into Friday with wave heights
between 6-7 feet. Seas are expected to subside over the weekend,
with favorable conditions prevailing through the remainder of the
period.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             76  88  70  90 /  20  30   0   0
HARLINGEN               73  89  65  92 /  20  20   0   0
MCALLEN                 76  94  70  95 /  30  10   0   0
RIO GRANDE CITY         74  91  67  94 /  30  10   0   0
SOUTH PADRE ISLAND      79  86  76  86 /  30  30  10   0
BAYVIEW/PORT ISABEL     75  86  70  88 /  20  20   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

SHORT TERM...60-BE
LONG TERM....63-KC
AVIATION...64-Katz