Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 271128 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
628 AM CDT WED JUL 27 2016

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

&&

.AVIATION...Lingering moisture associated with weak upper level
disturbances will keep high clouds in place for much of the
period...along with the typical diurnal CU field. VFR conditions
are expected...with very little chances for precipiation. A stray
shower or Tstorm may be possible with any seabreeze
convection...but chances remain too low to mention in TAFs at this
time. S-SE winds will become more SERLY with higher gust of 20 to
25 knots during the late morning and afternoon hours.

&&

.PREV DISCUSSION... /issued 444 AM CDT WED JUL 27 2016/

SHORT TERM (Today through Thursday): General weak upper level
troughing remains across the western half of the Gulf of Mexico as
the over all flow pattern continues to move westward. A weak upper
level low pressure center is situated over the Louisiana
coastline...with a secondary disturbance located over portions of
southern and Deep South Texas.

The weak upper level low centered over the region is allowing for
some ascent over mainly the western Upper Valley and Ranchland
locations of the CWA. This feature has kept a few showers and even a
thunderstorm in the area during the early morning hours. Do expect
that any lingering precip will likely dissipate as the low continues
to move west to the higher terrain of Mexico. That being said...do
expect some chances for precip today...mainly over the coastal
waters and near shore....otherwise much of the area will remain day.
There will be at least one more shot of precip for Thursday as a
another weak wave quickly passes by and brings a surge of higher
moisture levels. High pressure will then fill back in over the
region with dry and hot weather retuning.

Have trended temperatures up for today and Thursday as not even
precipitation coverage is expected to really make a dent in the
persistent heat. Heat indices will approach the 105 to 110 degree
range again today...but should remain below advisory levels. Will
instead over with an SPS.

LONG TERM (Thursday Night through Tuesday): A weakness in the 500
mb ridge axis over the south central Plains state will persist
through Thursday night and Friday. The 500 mb ridging will then
restrengthen over the Texas coastline this weekend. Another 500 mb
inverted trough axis will then push towards the Texas coastline by
next Tuesday. Enough decent moisture levels will linger over Deep
South TX through next Tuesday which may interact with the daytime
heating and the general weaknesses in the 500 mb pattern to allow
some potential for isold conv to linger on through the longer
range period.

The GFS and ECMWF 500 mb fields are in pretty good agreement
through next Tuesday in the overall placement and amplitude of the
ridge axes. However the ECMWF maintains a slight warm bias in
overall temp trends versus the GFS temps. Both model sets maintain
slgt chc pops all through the way through midweek of next week.
Will go closer to the ECMWf numbers for temps and will go close to
a model blend for pops.

MARINE: (Now through Thursday): More moderate of around 2 to 4
feet...with some 5 feet height will continue into Thursday surface
high pressure strengthens over the eastern Gulf. This will cause the
pressure gradient to tighten locally with steady SSE winds in the 15
to 20 knot range for the coastal water during the overnight
hours...with SCECs likely. Possible SCEC conditions maybe needed for
the Laguna Madre as well. Isolated convection will also possible
over the next 36 hours as a couple of upper level lows pass from
east to west across the region.

Thursday night through Sunday night...The persistent surface
ridging over the Gulf of Mexico and the western Atlantic will
maintain a fairly steady but moderate S-SE wind flow over the
lower TX bay and Gulf waters. Some potential for SCEC conditions
will be possible through Sunday night but no SCA conditions
expected at this time.

&&

.BRO Watches/Warnings/Advisories...
TX...None.
GM...None.
&&

$$

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

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