Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 211141 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
641 AM CDT Sun Apr 21 2019

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

&&

.AVIATION...Mostly clear skies with southeast winds around 10
knots prevail across deep south Texas early this morning. Latest
Brownsville VAD wind profile and Upper Air data both indicate
winds at 30 to 35 knots between 1-2k feet and VAD winds also
suggest winds near 50 knots between 2-3K feet. These strong winds
are expected to mix down to the surface after sunrise. Breezy to
windy south- southeast winds will quickly develop by mid- morning
as the pressure gradient strengthens. Winds will gradually
decrease to moderate levels by late this evening and overnight. VFR
conditions are expected for the next 24 hours with high pressure
in control.

&&

.PREV DISCUSSION... /issued 446 AM CDT Sun Apr 21 2019/

SHORT TERM (Today through Monday): Mid level ridge axis
overhead this morning will move east through the period. Surface
high pressure across the northern Gulf of Mexico will move further
east today and allow southeast winds to increase. The main issue
today will be the breezy to windy conditions across the eastern
portions of deep south Texas later this morning into the
afternoon. A Wind Advisory may be needed later today for some of
the coastal counties, but will hold off for now and issue an
Special Weather Statement instead. Surf conditions along the local
beaches of South Padre Island and at Boca Chica Beach could
potentially become hazardous as well, with large crowds, from
mostly inland locations, on hand. Will continue to monitor the
situation with help from SPI beach patrol. High temperatures today
and Monday will range from the lower 80s at the beaches to the
upper 80s to lower 90s far inland. Low temperatures tonight should
fall into the mid to upper 60s. Some passing high level clouds
are expected by late in the period.

LONG TERM (Monday Night through Saturday): As a strong upper
level trough continues to dig upstream across the desert
southwest states, expect southerly winds to increase across much
of the area. This will continue to bring in moisture and
eventually low level clouds. Winds are expected to be strongest
during the afternoon hours and lessen shortly after sunset on
Tuesday as we decouple.

Ahead of the aforementioned H5 trough, a very weak impulse is
showing up on the GFS and to a weaker extent the ECMWF Tuesday
evening. QPF signal is there for "something" to move into the
region from northern Mexico overnight Tuesday, however, there will
be a very impressive EML in place. Capping may be just too strong
for much, however, given the QPF signal, rain chances will
certainly be nonzero.

The main "event" in the long term will be what happens as the
stronger upper level trough/closed low move eastward across the
southern plains. Models continue to indicate cyclogenesis out
ahead of the trough, however, any surface low doesn`t really
deepen much before it vertically stacks with the upper low.
Across our area, model parameters indicate that both moderate
instability and appropriate 0-6km bulk shear (50kt+) will be in
place. The only limiting factor will be the EML. As upper level
height falls increase as the trough migrates eastward, think there
will be an opportunity for a line or broken line of convection.
In fact, the QPF signal from most of the globals indicate this as
well. The best POPs will reside up in the Ranchlands closer to the
better dynamics just slightly north, however, unlike prior
systems, this trough will dig just slightly more to the south,
which will allow for a bit higher chances for rain across the
lower valley than recent systems in the last couple of weeks.

The front will pass early Thursday. Winds do not appear to be that
strong behind the system. CAA will be limited to perhaps
nonexistent. Temperatures behind the front look about the same,
minus perhaps a few degrees overnight as a bit drier air moves
into the region. Going into next weekend, conditions look
gorgeous as dry northwesterly flow sets up as we`ll be on the
eastern periphery of a developing shortwave ridge across western
Texas and New Mexico. High pressure will remain in control so
more relaxed winds and temperatures at or slightly above average
for late April can be expected.

MARINE (Today through Monday): Moderate to strong southeast
winds are expected along the lower Texas coast today as high
pressure moves east and low pressure develops across the Plains. A
Small Craft Advisory is in effect for the Laguna Madre and near
shore Gulf waters from mid morning through early this evening.
Additional Small Craft Advisories may be needed tonight for the
Gulf waters as seas build. Moderate winds and seas are expected
for Monday as the gradient weakens slightly.

(Monday Night through Saturday): Ongoing adverse marine (SCA or
SCEC) conditions can be expected ahead of our next cold front due
into the region Late Wednesday or early Thursday. Prior to the
front moderate to strong southerly winds will take shape.
Eventually, SCA conditions will be met sometime Tuesday (cannot
rule out sooner as it will be borderline from the start). Showers
and perhaps a Thunderstorms can`t be ruled out late Tuesday,
however, the rain chances increase late Wednesday night and
Thursday as the front passes through. Behind the front winds and
seas don`t look overly impressive right now. SCEC low end SCA may
be possible, however, as high pressure quickly builds eastward
into the region, expect conditions to improve and remain rather
tranquil through the end of the marine long term period.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 8 PM CDT this evening for
     GMZ130-132-135.

     Small Craft Advisory until 8 PM CDT this evening for GMZ150-155.

&&

$$

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

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