-- Discussion containing changed information from previous version are highlighted. --
837
FXUS64 KBRO 081110 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
610 AM CDT Sat Jun 8 2024

...New AVIATION...

.SHORT TERM...
(Today through Sunday)
Issued at 233 AM CDT Sat Jun 8 2024

The mid-level ridge of high pressure continues to weaken slightly
through the weekend and settle into the north-central Gulf of
Mexico, as the surface high pivots into the eastern Gulf. Slightly
drier air keeps peak Heat Indices generally between 105 to 109
degrees today, with more borderline Heat Indices returning on Sunday
as humidity nudges back. Highs still top off in the upper 90s to
near 100 for most, with triple digit heat across the upper valley
and brush country. The best chance of rain remains offshore, with
streamer showers or storms briefly possible mainly beyond 20
nautical miles. Patchy fog and haze are possible again early this
morning. Overall a hot weekend with beautiful conditions expected
along the beaches of the lower Texas coast.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 233 AM CDT Sat Jun 8 2024

Key Messages:

* Very warm to hot and humid conditions to persist

* Low, yet non-zero probability of a stray shower or thunderstorm
  Monday-Monday night

* Special Weather Statements to Heat Advisories likely needed each
  day for at least parts of the region

* Widespread major to at least pockets of extreme HeatRisk
  anticipated through the extended

The long-term weather forecast period will feature slight weakening
of the 500 mb ridge to start the period (Sunday night through
Tuesday) before the 500 mb ridge/sub-tropical Sonoran heat dome re-
emerges/re-establishes itself during the middle and through the end
of the long-term period or from Wednesday through next Saturday.
Despite the slight changes early in the mid-upper levels of the
atmosphere, weather conditions at the surface will remain intact,
that is continued very warm to hot and humid.

We open up the extended Sunday night through Tuesday where forecast
models and ensembles continue to depict the weakening/flattening of
the H500 pattern. This slight change in the mid-upper levels will be
associated with a surface frontal boundary that will advance
southward from the north-central U.S. before slowing/stalling over
the central or north-central Texas by Monday/Tuesday. That said, no
airmass change is expected as winds will continue to advect warm and
moist air from the south-southeast. During the weakening process of
the aforementioned ridge, there remains an isolated, yet non-zero
probability of a rogue shower or thunderstorm developing over the
region Monday-Monday night as precipitable water (PWAT) values
approach 2 inches. Otherwise, expect for the weather pattern to
remain status quo, that is very warm to hot and humid, and rain-free
(daytime highs upper 90s to lower 100s, and nighttime lows in the
mid 70s to lower 80s).

Starting on Wednesday, forecast models and ensembles suggest the
strengthening/re-emergence of the 500 mb ridge as a 591-594 dam sub-
tropical, Sonoran heat ridge (1.5 to 2 STDEVs above normal) develops
over the region with the core of the heat centered over north-
central to northwest Mexico. This feature in place over the region
will yield strong subsidence and therefore a continuation of very
warm to hot and humid conditions with little to no rain chances.
Highs are projected to be in the upper 90s to lower 100s, however,
with strong subsidence expected given the magnitude of this 500 mb
heat dome, the likelihood of sunny/clear skies could result in
slightly hotter temperatures in the Wednesday through Saturday time
period.

All told, Special Weather Statements (SPS`s) to Heat Advisories will
likely be needed across at least parts of Deep South Texas and the
Rio Grande Valley each day through the extended. Widespread major
with at least pockets of extreme HeatRisk can be expected during
this timeframe.

&&

.AVIATION...
-- Changed Discussion --
(12Z TAFS)
Issued at 607 AM CDT Sat Jun 8 2024

VFR conditions are generally expected to prevail through the TAF
period, with brief MVFR ceilings possible over the next hour or
two. Southeast winds stay light today with a breeze possible by
the afternoon.
-- End Changed Discussion --

&&

.MARINE...
Issued at 233 AM CDT Sat Jun 8 2024

Now through Sunday...High pressure maintains generally favorable
marine conditions through the weekend, with light southeasterly
winds today, a little bit of a southeast breeze on Sunday, and low
seas. Some haze or smoke may limit visibility at times, especially
late at night or early in the morning. Offshore streamer showers and
storms are possible, mainly beyond 20 nautical miles each night or
early morning.

Sunday night through Saturday....Favorable marine conditions are
expected to persist through the long-term weather forecast period
with light to moderate southeasterly winds and low seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             98  81  96  82 /  10   0   0  10
HARLINGEN               99  77 100  78 /   0   0   0   0
MCALLEN                100  80 101  81 /   0   0   0   0
RIO GRANDE CITY        100  79 100  80 /   0   0   0   0
SOUTH PADRE ISLAND      87  82  88  82 /  10   0   0  10
BAYVIEW/PORT ISABEL     91  80  94  80 /  10   0   0   0

&&

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

$$

SHORT TERM...56-Hallman
LONG TERM....23-Evbuoma
AVIATION...56-Hallman