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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS64 KBRO 062329 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
529 PM CST Sat Mar 6 2021

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...VFR conditions are expected to generally prevail
through the TAF period. Dry northeasterly flow turns more easterly
into Sunday, with increasing cloud cover. At this time, do not
expect much of any fog across the RGV, but patchy fog may develop
along the coast and work inland toward BRO by early morning.

&&

.PREV DISCUSSION... /issued 222 PM CST Sat Mar 6 2021/

SHORT TERM (Now through Sunday Night): Weak 500mb ridging will make
its way over the region this evening, favoring continued subsidence
and clearing skies this evening. This will be quickly followed by
the approach of a weak 500mb shortwave as well as surface winds
shifting to onshore flow. This will favor some fairly persistent
cloud cover through the remainder of the short term. Temperatures on
Sunday arent expected to rebound quite as quickly as today owing to
lower level cloud cover hanging around for most of Sunday. The same
500mb shortwave may also help ignite some shower activity later
Sunday afternoon and evening, but the lack of deep layer moisture
suggests isolated activity at best so will leave any mentionable
chances for precipitation out of the forecast. Onshore flow then
looks to persist through Sunday night, with the associated moisture
return and eventual calming winds possibly contributing to some
patchy fog developing overnight Sunday into Monday.

LONG TERM (Monday through Saturday):12Z model suite in good
agreement and consistency through much of next work week with some
discrepancy showing up for next weekend. In the meantime...the
battle of the season`s will be the theme next week as a large cold
upper trough and low pressure center settle over the Western third
of the U.S. while the subtropical ridge builds over Northern Mexico
and the Western Gulf of Mexico.

The outlook for Deep S Texas and the RGV for next week sums up to
be a very warm, dry and breezy to windy period. The building of
the subtropical ridge steadily increases heights and thicknesses
which will support temperatures climbing well into the 80s and
some 90s for the mid and upper Valleys the latter half of the
week. The building ridge caps the atmosphere with a very shallow
airmass in place not enough to warrant any significant rain
chances at this time. A series of surface low pressure areas are
expected to develop and eject out into the Plains States, courtesy
of the Upper trough/low, which will combine with broad surface
ridge over the Gulf South to the Mid-Atlantic producing a steadily
strengthening pressure gradient. The South Texas wind machine
will be in full swing Tuesday through Friday with the strongest
gradient anticipated along the coastal counties spreading inland
through the Mid-Valley locations. As the previous forecast
mentioned Wind Advisories are likely to be issued with best days
next Wed-Friday. As the period moves into next weekend GFS is
aggressive with a frontal passage as it shows the Western U.S.
trough moving east. The ECMWF is somewhat delayed in ejecting the
upper trough eastward keeping the RGV warm, breezy and dry.
Consensus takes the ECMWF route keeping any fronts well north of
Deep South Texas.

With an anticipated extended period of a large fetch of east to
southeasterly winds developing across the northern Gulf of Mexico,
the lower Texas coast may be impacted by slightly elevated swells,
likely increasing the risk of rip currents and possibly some minor
overwash of tidal action. Even though the weather should be pleasant
at the beach next week, beach-goers should pay attention to the
flags and signs at the beach and be very cautious if entering the
surf.

MARINE:(Now through Sunday Night): Gusty northerly winds continue
across much of the coastal waters this afternoon with the Small
Craft Advisory running through 3 PM for the Laguna Madre and 6 PM
for the Gulf Waters. Some Small Craft Exercise Caution conditions
will persist through the evening hours as winds gradually relax and
seas subsequently fall. Seas will then remain elevated through the
end of the short term as winds shift and create an easterly fetch,
favoring persistent easterly swell.

(Monday through Thursday)...Mariners can expect to see a
strengthening of the pressure gradient over the Western Gulf and
along the lower Texas coast next week with a steady increase in
winds and build up in total seas.  Large expansive surface high
pressure spreads over the Gulf South and Mid-Atlantic States
extending well into the Northern Gulf of Mexico. The ridge is
expected to combine with a series of low pressure areas that will be
developing over the leeside of the Rockies and track into the Plains
States. At this time the strongest gradient is expected Wednesday
through next Friday with Small Craft Advisories likely for portions
or all of the lower Texas coastal waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  56  70  58  72 /   0  10   0   0
BROWNSVILLE          55  73  59  74 /   0  10  10   0
HARLINGEN            52  73  56  75 /   0  10   0   0
MCALLEN              51  74  56  76 /   0  10   0   0
RIO GRANDE CITY      49  75  56  79 /   0  10   0   0
SOUTH PADRE ISLAND   59  66  61  67 /   0  10   0   0

&&

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

$$

This product is also available on the web at:
HTTP://WEATHER.GOV/RGV

56-Hallman...Aviation