490
FXUS64 KBRO 071737
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1237 PM CDT Fri Jun 7 2024

...New AVIATION...

.SHORT TERM...
(Today through Saturday)
Issued at 235 AM CDT Fri Jun 7 2024

The mid-level ridge of high pressure continues to weaken slightly
into the weekend and settle into the north-central Gulf of Mexico,
as the surface high also pivots into the eastern Gulf. This breaks
the heat dome slightly across Deep South Texas, with slightly drier
air keeping peak Heat Indices between 105 to 109 degrees today and
Saturday. Highs still top off in the upper 90s for most, with some
triple digit heat across the upper valley and brush country. The
best chance of rain remains offshore late tonight into Saturday
morning as winds turn more southeasterly, with streamer showers or
storms briefly possible, mainly beyond 20 nautical miles. Patchy fog
and haze are possible each night and early morning, reducing
visibility to less than 5 miles. Overall a hot start to the weekend,
but not as hot as it has been, with beautiful conditions expected
along the beaches of the lower Texas coast.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 235 AM CDT Fri Jun 7 2024

Key Message:

* Despite changes in the 500 mb pattern, very warm to hot and humid
  conditions with little to no rain chances are expected to persist

Changes to the 500 mb pattern as indicated by the global weather
models and ensembles are expected during the long-term forecast
period. These changes include the weakening/flattening of a
persistent 500 mb ridge (associated with a southward advancing yet
weakening cold front) over the region taking place Saturday night
through Tuesday, followed by the re-amplification or re-emergence
of a strong 591 dam sub-tropical, Sonoran heat dome (on the order
of 1- 2 STDEVs above normal) taking place Wednesday and persisting
through the remainder of next week. Overall, not much in the way
of changes to our sensible weather here in the long- term with
very warm to hot and humid conditions, and little to no rain
chances continuing.

We open up the long-term period Saturday night where a trough over
the central U.S. will be shifting south-southeast. This will
effectively allow for the 500 mb ridge that`s plagued Deep South
Texas and the Rio Grande Valley to weaken/flatten Saturday night
through Tuesday. In conjunction with the trough will be a surface
cold front that will also be advancing southward from the central
Plains during this time period.

Forecast models has it that the trough and associated surface
cold front will weaken as it advances south and will not make it
as far south as Deep South Texas. In fact, the frontal boundary is
expected to slow/stall out over central Texas in the Monday or
Tuesday timeframe. So again not much change is expected as far as
our sensible weather here in Deep South Texas and the Rio Grande
Valley given the situation. We could see temperatures a couple of
degrees cooler (Monday or Tuesday), but still running warmer than
normal. Winds will maintain a southeasterly component during this
time or through Monday of next week. This will help in keeping the
atmosphere largely unchanged (very warm to hot and humid) with
highs staying in the upper 90s to lower 100s and dewpoints in the
70s through Tuesday. There could be a rogue shower or thunderstorm
on Monday, but much of the area should remain rain-free as the
better forcing and short wave energies/impulses traversing along
the aforementioned frontal boundary will be to our north.

Wednesday through Friday of next week, forecast models and ensembles
are depicting the re-emergence of the 591 dam sub-tropical, Sonoran
heat dome centered over northern Mexico, but possibly encompassing
the region. This will again re-enforce the very warm to hot and
humid conditions over the region during this time period. Dry
weather conditions will persist during this time period with strong
subsidence associated with the feature (the 500 mb heat ridge) in
place.

&&

.AVIATION...
(18Z TAFS)
Issued at 1237 PM CDT Fri Jun 7 2024

VFR and light southeasterly winds will prevail through the TAF
period, with the exception being near the early morning hours on
Saturday. As winds become light to calm overnight, patchy fog may
develop, mainly near HRL and north of the TAF sites. Some patchy
MVFR ceilings will also be possible, with the best potential for
MVFR ceilings at MFE.

&&

.MARINE...
Issued at 235 AM CDT Fri Jun 7 2024

Now through Saturday...High pressure maintains generally favorable
marine conditions into the weekend, with light easterly winds 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 may increase beyond 20 nautical miles Saturday
morning as winds turn more southerly.

Saturday night through Friday...Favorable marine conditions (light
to moderate southeasterly winds and mainly light seas) are
expected through this period.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             96  78  95  81 /  10   0  10   0
HARLINGEN               97  74  97  77 /   0   0   0   0
MCALLEN                100  77  99  80 /   0   0   0   0
RIO GRANDE CITY         99  75  98  78 /   0   0   0   0
SOUTH PADRE ISLAND      87  81  87  82 /   0   0  10   0
BAYVIEW/PORT ISABEL     92  77  92  80 /   0   0  10   0

&&

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

$$

SHORT TERM...56
LONG TERM....23
AVIATION...22-Garcia