Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 241136 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
636 AM CDT SUN JUL 24 2016

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

&&

.AVIATION...VFR conditions still expected to prevail through the
TAF period. There remains a small chance that MVFR cigs could
develop briefly just after daybreak...however it would be for a
a very short period of time. Otherwise...a tightening pressure
gradient is expected for the afternoon...and some gusty SE winds
are anticipated. Over all chances for precip remain too low to
mention in the TAFS. Do expect a bit more cloud cover to build in
late in the period as an inverted trough approaches from the
east.



&&

.PREV DISCUSSION... /issued 429 AM CDT SUN JUL 24 2016/

SHORT TERM (Today through Monday): A area of high pressure remain
elongated across the CONUS...with its center over the Four-Corner
states. This system is generally keeping things quiet for Deep South
Texas. Meanwhile...broad surface high pressure over the eastern Gulf
will interact with a weak perturbation near the Bay of Campeche to
cause a slight tightening if the pressure gradient through the day
Sunday allowing for an uptick in the winds. As such do expect to see
slight more gusty conditions of light...with winds generally SSE to
SE. Given the more southerly component to the winds...do not expect
much in the of any seabreeze enhanced convection today and have
removed precip for the land areas.

By late Sunday night and into Monday...an inverted trough will take
hold across the far eastern Gulf waters. The trough will generally
track due west...remaining close to the northern Gulf coastline and
a weak surface low. Although this feature will bring some moisture
back to area...mid level flow around the trough will generally out
of the north and east...which may entrain drier air into the region
ahead of the system. Hence...the amount of moisture to work with may
be limited and have only kept slight POP chances in Monday`s
forecast.

As far as temperatures go...another warm Sunday is on tap with a
good portion of the inland upper valley and ranchlands expected to
see triple digit values. Heat indices will climb briefly into the
105 to 110 degree range today. Have opted to hold back temps a
degree or two on for Monday`s highs as the inverted trough will
bring a bit more cloud cover and possibly a shower.

Long Term (Monday Night through Saturday): The forecast challenge
this go around will be the impact or effect of an inverted mid
level trough that will be working its way across the Gulf early in
the long term period. The GFS and ECMWF agree that Tuesday will
bring the highest rain chances to the area, though those chances
will not be tremendous, but the ECMWF is somewhat more robust in
its numbers than the GFS. Went with a 60/40 GFS/ECMWF blend for
Monday night through Wednesday, which gave a nod to
climatologically drier times while bringing some measurable rain
across the area. The omega field shows lift over the water Tuesday
but less farther west, so not sure how much rain potential will
translate over the land areas. Thicker high clouds and the higher
rain potential will push the century mark high temperature line
west into the upper valley for a day or two, however, before
higher temps return later in the week.

After Wednesday, the weak inverted trough exits stage left into
western Mexico, allowing the Canicular ridge to slowly build back
east over into Texas beginning Thursday and continuing through the
weekend. A mid level trough rotating south around a northeast
Canadian low will dig across the upper midwest late in the week, but
the slow eastward transit of that feature will also assist ridge
strengthening over the southwest U.S., supporting rain-free, hot,
and somewhat breezy days. Breezes may slacken a bit by Saturday
while temperatures edge higher, returning to the 96 Brownsville, 99
Harlingen, 102 McAllen theme seen through the second week of July.

MARINE:
Now through Monday...As noted above, a slight tightening in the
pressure gradient is expected later today as high pressure over
the eastern Gulf interacts will a small tropical wave over the bay
of Campeche. The two features will generally bring slightly
gustier 15 to 20 knot SE winds during the afternoon for the bay
and nearshore coastal waters. However, winds should remain low
enough to avoid advisory criteria. The seas will remain low to
moderate, with wave heights of 2 to 3 feet.

Monday Night through Thursday...While high pressure continues more
or less unabated across the Gulf, a mid level trough will be making
its way from east to west, located above the central Gulf Monday
night. Light to moderate south southeast winds will be the norm
through the forecast period with low to moderate seas. Seas will
trend just a skosh higher Tuesday through Thursday, by maybe a foot,
though still moderate, as high pressure builds into the east Gulf
and supports slightly stronger winds. The mid level trough will
elevate convective chances over the marine areas through about
Wednesday when it exits stage left away from the lower Texas
Coast.

&&

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

$$

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HTTP://WEATHER.GOV/RGV

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