Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 270004 AAA

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
704 PM CDT Wed Jul 26 2017

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


.AVIATION...VFR conditions tonight. Afternoon convection has
waned, and expecting a quiet night. Will have some lingering
upper clouds as per current satellite imagery. High pressure
remains over the Gulf, supporting light to moderate southeast
winds. Forecast soundings show a weak cap for Thursday morning,
so may see a few low clouds, but guidance was not strong on MVFR
conditions and left mention out for now. PWat will remain near to
slightly above normal on Thursday, with at least the coastal
areas currently in a general thunderstorm outlook. Thus, may see
isolated sea breeze convection with a few thunderstorms Thursday
afternoon, along with broken decks above 3 kft. Conditions should
remain substantially VFR.


.PREV DISCUSSION... /issued 239 PM CDT Wed Jul 26 2017/

SHORT TERM (Now through Thursday Night): Scattered convection
has broken out over the central and eastern portions of Deep South
Texas and the Rio Grande Valley and the adjacent coastal waters
due to the combination of daytime heating of a moist atmosphere
(2.22 inches of precipitable water), the westerly movement of the
sea breeze boundary, and the northerly movement of an outflow
boundary from earlier convection over the nearshore coastal waters
of the State of Tamaulipas. The convection will continue until
around sunset this evening, after which time, streamer activity
will affect the Lower Texas coastal waters and the extreme inland
coastal area. Tomorrow, a slightly drier atmosphere will lead to
dry weather conditions, but another round of coastal streamer
convection is anticipated tomorrow night. Temperature-wise, above
normal daytime highs and overnight lows are likely.

LONG TERM (Friday through Wednesday): 500mb subtropical ridge
across the southwest and south-central United States Friday will
amplify across the state Saturday as a 500mb trough deepens across
the eastern United States. Subsidence will be strong across south
Texas Friday through the weekend as a result. Not much in the way
of rain chances will develop across the CWA through Sunday and hot
temperatures will prevail across the area as a result. Moisture is
expected to increase across south TX early next week as a weak
frontal boundary moves into the northern Gulf coast Sunday and
northern Gulf of Mexico Monday before stalling. This will provide
a slight chance of showers and thunderstorms across portions of
the Rio Grande valley and northern ranchlands through the rest of
the forecast period. A more easterly flow is also expected to
develop and with the increase in cloud cover and rain
chances...temperatures should not be as hot Monday through

MARINE (Now through Thursday Night): Buoy 42020 reported south-
southeast winds around 14 knots gusting to around 16 knots with seas
slightly over 3.5 feet with a period of 7 seconds at 14 CDT/19 UTC.
Surface high pressure will continue to be the dominant influence
over the western Gulf of Mexico through the period, providing the
Lower Texas coastal waters with light to moderate winds and low to
moderate seas. Small Craft Exercise Caution and Small Craft
Advisory continue to be unlikely.

Friday through Monday...Light to moderate south to southeast winds
will prevail across the coastal waters Friday with surface high
pressure across the Gulf of Mexico. With the pressure gradient
will remain weak across the lower Texas coast through the weekend.
Light to moderate south to southeast winds will prevail across the
coastal waters Saturday and Sunday. Winds are expected to back to
the east but remain light Monday as a weak frontal boundary moves
across the upper TX coast and stalls.




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