Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 301744 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
1144 AM CST Wed Nov 30 2016

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

&&

.AVIATION...After some low level bumpiness through mid afternoon,
 a quiet forecast to dominate the period through 18Z Thursday.
Gusty northerlies, near 30 knots toward the coast this morning,
will quickly settle down by 3 PM or so and lay down overnight as
low level flow quickly veers from north to east, not unusual in
this particular setup. Skies have cleared and this will continue
for most of the night, with perhaps a few MVFR cumulus developing
 at Brownsville and Harlingen just prior to daybreak. As surface
flow quickly veers to the east and southerly flow develops above
subsidence inversion, a solid deck of low VFR (3500 to 4000 feet)
stratocumulus will form up between 9 AM and Noon.
52/BSG

&&

.MARINE...Surge of very dry and somewhat cooler air over still
warmer than average (for late November) Gulf waters produced brief
Gale force gusts at Buoy 42020 with solid sustained winds in the
25+ knot range, as forecast. Seas responded more sharply due to
the contrast, and may have touched 10 feet at the same buoy, and
recently reached 10 feet at TABS buoy 45, about 40 nm east of
South Padre. For this reason, along with a little bit of a lag in
drop off later this afternoon and evening, raised seas to 8 to 9
feet in most of the waters east of 20 nm and dropped a bit later
into the evening as well. This will likely require an extension of
the Small Craft advisory for the sea component into the mid
evening...and perhaps through midnight...for the Gulf waters.

For Laguna Madre, winds continued to gust over 30 mph at KPIL and
35 mph at KSPL as of 11 AM, and to keep small craft operators in
safe mode elected to extend through 3 PM. Caution conditions 15
to 20 knots) will continue after that before winds rapidly
collapse by 5 PM or so.
52/BSG

&&

.PREV DISCUSSION... /issued 531 AM CST Wed Nov 30 2016/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION... A cold front has passed through all of Deep South
Texas and the Rio Grande Valley this morning. Brief IFR/MVFR
ceilings continue at BRO/HRL this morning as north winds remain
light. Breezy north winds will mix out the lower ceilings around
14z. Otherwise, VFR conditions will prevail for the next 24 hours
as surface high pressure builds then settles across the region.
Moderate and gusty north winds today will become light this
evening and overnight.

PREV DISCUSSION... /issued 432 AM CST Wed Nov 30 2016/

SHORT TERM (Now through Thursday): A cold front has nearly passed
through all of Deep South Texas and the Rio Grande Valley this
morning. Breezy northerly winds will prevail across the region today
in the wake of the front. Surface high pressure builds across the
area today resulting in much drier air filtering into the area. High
temperatures will be near normal, climbing into the mid to upper 70s
under mostly sunny skies. Surface high pressure settles across East-
Central Texas tonight before moving east across Louisiana on
Thursday. Clear skies and light winds will allow low temperatures
tonight to fall into the upper 40s across northern ranchlands to
around 60 near the coast. Return flow sets up on Thursday bringing
warmer temperatures and increasing surface moisture. High
temperatures Thursday will generally be the upper 70s to around
80.

LONG TERM (Thursday Night through Tuesday): The most significant
changes in the weather pattern for the long term portion of the
forecast is the slower progression of the closed 500 mb low pressure
system into northwest Mexico, and the delayed passage of a cold
front through the BRO CWFA, now anticipated to be closer to Sunday
instead of Saturday. Aside from isolated convection forecast for
Friday night, the time period of Friday through Monday will
feature scattered to numerous showers and thunderstorms, with the
best opportunity for rainfall occurring Saturday night through
Sunday morning as the previously-mentioned cold front works
northwest to southeast through Deep South Texas and the Rio Grande
Valley. Due to the frontal passage and the expected significant
cloud cover and rain chances, near normal daytime highs and
overnight lows continue to be anticipated.

MARINE (Now through Thursday): Buoy 42020 reported light
west-northwest winds with seas slightly over 4.9 feet with a period
of 8 seconds at 03 CST/09 UTC. Adverse marine conditions will
develop across the Lower Texas coastal waters this morning due to
the passage of a cold front. A Small Craft Advisory is in effect
until noon today on the Laguna Madre due to strong winds. A Small
Craft Advisory is in effect until 6 pm this evening for strong north
winds and hazardous seas. A brief period of gale-force wind gusts
are possible this morning with the passage of the cold front.
Marine conditions expected to gradually improve later this afternoon
into this evening as the pressure gradient weakens as high pressure
settles into the region. Seas may remain elevated across the Gulf
waters through late tonight. Light to moderate northeast winds
tonight will become easterly on Thursday as surface high pressure
shifts east.

Thursday Night through Tuesday: The most adverse marine conditions
will occur Friday though Sunday, with a Small Craft Advisory likely
for all or portions of the Lower Texas coastal waters, due to an
enhanced surface pressure gradient or passage of a cold front.
Outside of this time period, light to moderate winds and low to
moderate seas are forecast.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 3 PM CST this afternoon for
     GMZ130-132-135.

     Small Craft Advisory until 6 PM CST this evening for GMZ150-155-
     170-175.

&&

$$

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