924
FXUS64 KBRO 160755
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
255 AM CDT Fri Aug 16 2024

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(Today through Saturday)
Issued at 248 AM CDT Fri Aug 16 2024

Key Messages:

- Elevated Heat Indices for Today and Tomorrow

- Mostly rain-free conditions

As the continuing trend as been for the last several days, the mid-
level ridge continues to be the dominate force for the weather over
Deep South Texas and the Rio Grande Valley. While normally, this
would mean there would be plenty of dry air aloft, model trends and
observations have shown otherwise. The mid and upper levels of the
atmosphere while not very moist, those levels are not entirely
dry either, so there is some potential for the showers and
thunderstorms. PWAT values are around 2 inches for most of the
period. Based on this information, there is an isolated chance of
showers and thunderstorms with the seabreeze during the afternoon
for today and tomorrow. Current trend of thought is to keep the
PoPs around 20 percent during the afternoons around the time that
the seabreeze would be active.

Since the surface flow for the short term forecast is expected to be
still out of the southeast, which will drawn in plenty of moisture
to the region and elevate the heat indices. While the heat indices
are expected to be around 110 for the next couple of days, thus
below the criteria for a Heat Advisory. A Special Weather Statement
will be out as conditions are so close.

As for the actual temperatures, highs are expected to be mostly in
the triple digits while the coastal regions are expected to be in
the upper 90s. Moving on to the low temperatures for tonight, those
are expected to be mostly in the 70s with a few places in the 80s.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 248 AM CDT Fri Aug 16 2024

Typical summer pattern (hot, dry, and humid conditions) expected
to continue through the extended period here in Deep South Texas.
The primary driver of our sensible weather will continue to be an
anomalously strong 594-600 dam sub-tropical heat dome centered
over the Southern Rockies into West Texas.

Each day through the extended, 850 mb temps are expected to range
between 20-23C as this synoptic feature stretches/expands into
our region. 850 mb temps of this value will translate to sfc
temperatures during the day reaching into the mid 90s to lower
100s (near normal levels), with the hottest of temperatures
located west of I-69C.

Factor in the humidity, and heat indices are expected to range
between SPS to Heat Advisory criteria each day with values between
105-115F. This is particularly true for areas over a Hidalgo to
Brooks County line or from I-69C east to Inland Kenedy, Willacy,
and Cameron Counties (I-69E). Slightly cooler heat indices
further west where humidity levels will be lower. Temperatures
will be coolest near/along the Texas Coast amid continued easterly
winds.

The other component that the aforementioned heat dome, which is +1
to +3 STDEVs above normal, will bring to the local forecast area,
will be the continuation of mainly dry weather conditions. Strong
subsidence amid the strong mid level ridge and nearby sfc high
pressure system will help to keep conditions mainly dry through
the long-term forecast period. Can`t rule out a stray/rogue shower
or storm given the tropical environment, but again things will by
and large be manly dry across the region through the extended.

&&

.AVIATION...
(06Z TAFS)
Issued at 1229 AM CDT Fri Aug 16 2024

VFR conditions are expected to persist through the cycle at all
TAF sites. Mostly light southeasterly winds are expected as well,
but some winds could be a bit more gustier during the afternoon
with gusts up to 20 knots. An isolated shower or thunderstorm is
possible with the seabreeze, but confidence is not high enough to
include in the TAFs.

&&

.MARINE...
Issued at 248 AM CDT Fri Aug 16 2024

Today through Saturday...Favorable conditions with low to moderate
southeasterly winds and low seas are expected through Saturday. A
streamer shower or thunderstorm is possible that could result in
locally elevated winds and seas.

Saturday night through Thursday....Weak pressure gradient amid a
surface high and mid-level ridging overhead will continue to result
in favorable marine conditions with light to moderate winds and low
seas through the extended.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             96  80  96  80 /  20   0  20   0
HARLINGEN               97  77  97  77 /  20   0  20   0
MCALLEN                102  80 102  80 /  20   0  20   0
RIO GRANDE CITY        101  78 101  78 /  10   0  10   0
SOUTH PADRE ISLAND      90  83  90  83 /  10   0  20   0
BAYVIEW/PORT ISABEL     94  79  93  78 /  20   0  20   0

&&

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

$$

SHORT TERM...64-Katz
LONG TERM....23-Evbuoma
AVIATION...64-Katz