Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 211706 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1206 PM CDT Wed Jun 21 2017

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

&&

.AVIATION...VFR conditions to prevail through the next 24 hours.
Scattered cumulus should dissipate after 21Z with nearly clear
skies overnight. Northwest gusts around 20 knots decrease by
sunset becoming light and variable overnight. Tropical Storm
Cindy continues to slowly move northwest away from Deep South
Texas with no impacts expected.

&&

.PREV DISCUSSION... /issued 644 AM CDT Wed Jun 21 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Some low level clouds are beginning to move in from
the north this morning as a little moisture warps around the
periphery of TS Cindy. However, VFR conditions should prevail
through the period. Winds will shift from the NW to NE through the
day with some gusts expected as TS Cindy move across the
Northwest Gulf. Winds will lessen tonight as the tropical system
moves farther away with variable winds and clear skies expected.

PREV DISCUSSION... /issued 407 AM CDT Wed Jun 21 2017/

SHORT TERM (Today through Thursday): There have not been any
significant changes made to the forecast over the next 36 hours.
The main concerns continue to be the coastal and marine impacts from
Tropical Storm Cindy and the oppressive heat across the region.

TS Cindy is slowly moving northwest-ward across the North Central
Gulf early this morning, with the latest forecast from NHC having
the track continue towards the NE Texas/SW Louisiana coastline.
Again the main impacts for us here will be the dangerous rip
currents and high surf that will continue across the beaches at SPI
and Boca Chica beach. Wave heights at Buoy 42020 are already between
7 to 9 feet with higher swells expected to push in through the day.
With summertime crowds at the beach, this will be dangerous for poor
and even experienced swimmers a like. Meanwhile, high tide is
occurring now(3:38am), with levels running about a foot above
predicted levels. As such, there will likely be some minor coastal
flooding through the morning hours as the swell enhanced tidal run-
up brings water to or near the duneline. As TS Cindy moves farther
away this evening and low tide occurs, coastal conditions should
improve although lingering northerly swell could cause some
surf run-up where the beaches are narrow.

As far as rainfall chances from this system, probabilities remain
small, and even then, generally over some isolated coastal areas and
the offshore waters. The strong subtropical ridge sitting across the
southwestern CONUS will keep dry northwest flow and subsident
conditions over Deep South Texas through the period. This is what is
limiting our rain chances and keeping temperatures extreme. High
temperatures today and Thursday will range from the lower 90s at the
Island to near 108 across the Western Ranchlands and Upper RGV.
Although humidity values are low given the dry air, the heat index
will still make it seem like 105 to near 110 degrees.

LONG TERM (Thursday Night through Tuesday): Dry northerly
flow aloft and subsidence will prevail over Deep South Texas
Thursday night and Friday. Low to mid level moisture will increase
across the area this weekend as an 500mb inverted trough moves over
the Bay of Campeche. The mid level weakness combined with daytime
heating should support a chance of showers and thunderstorms across
the area this weekend into early next week. Above normal high
temperatures are expected for Friday with near normal temperatures
for the weekend into early next week due to the increase in cloud
cover and rain chances.

MARINE (Now through Thursday): Buoy 42020 is reporting NNE winds at
around 15 knots and seas at 8 feet as of 3 AM CDT. Dangerous swells
generated by Tropical Storm Cindy will continue through today with
seas upwards of 10 or more feet expected. Winds will also increase
to around 20 to 25 knots from the north to northwest as TS Cindy
continues to move into the Northwest Gulf. Small Craft Advisories
remain in effect for the Gulf waters east of Padre Island and have
been extended through at least midnight for lingering high seas.
Marine conditions will improve briefly on Thursday although
southerly winds will increase by the afternoon as the pressure
gradient increases. Additional small craft advisories may be
needed.

Thursday Night through Sunday Night...Moderate to strong south winds
will prevail Thursday night into Friday as the pressure gradient
tightens across the western Gulf of Mexico. Winds are expected to
shift to the east and southeast on Saturday as the pressure gradient
weakens courtesy of a weak frontal boundary moving into central
Texas. Light to moderate east to southeast winds should prevail
across the lower Texas coastal waters through the weekend and into
early next week. Rain chances begin to increase Friday night with
better rain chances expected through the weekend.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 7 PM CDT this evening for TXZ251-256-
     257.

     High Surf Advisory until 7 PM CDT this evening for TXZ251-256-
     257.

GM...Small Craft Advisory until 1 AM CDT Thursday for GMZ150-155-170-
     175.

&&

$$

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