Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 211150 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
550 AM CST Sun Jan 21 2018

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

&&

.AVIATION...Light southeast to south winds and patchy light fog
prevail across deep south Texas this morning. BRO VAD Wind Profile
and current BRO Sounding data indicates low level winds around
2K FT near 40 knots. Will continue to mention LLWS at BRO and HRL
through around 15z then winds are expected to mix down to the
surface. Strong/gusty winds (a bit less at MFE) for most of today
before a late afternoon decrease and a more rapid diminish by
sunset, as a cold front approaches. Latest surface observations
suggest a mix of ceilings and visibilities across the area. Will
show prevailing MVFR conditions with some TEMPOs through 15z. Low
ceilings will lift to VFR through the day as winds increase. The
cold front arrives late tonight into Monday morning but with light
winds ahead of the front, fog is expected at all Valley airports
by 06z. Some fog may become locally dense, mainly after 09z.

&&

.PREV DISCUSSION... /issued 406 AM CST Sun Jan 21 2018/

SHORT TERM (Now through Monday): A Closed 500 mb low pressure over
the Four Corners Region early this morning will move from west to
east across Texas Today. The associated cold front is located across
west Texas this morning and will approach deep south Texas by late
this evening. Some light fog and patchy drizzle will be possible
through mid morning, especially across the northern ranchlands where
winds will be lighter, no dense fog is expected. The Low Level Jet
will strengthen today as the front approaches the region. As winds
mix down to the surface by mid morning, winds of 25 to 30 mph will
be possible across the Rio Grande Valley and along the coast late
this morning into the afternoon. A Wind Advisory is not expected
today as winds should remain slightly below Wind Advisory criteria.
Breezy and warm today with high temperatures in the 80s, except for
the 70s near the coast.

The weak cold front is expected to move into the northern Ranchlands
around midnight and off the lower Texas coast after dawn bringing
slightly cooler and drier air behind it. Low temperatures tonight
will range from the lower 50s across the western portions of the CWA
to the lower 60s near the coast. Upper level support and frontal
forcing should allow a few showers to develop along the front,
mainly near the coast. Some lingering showers are possible Monday
morning across the Gulf waters. Otherwise, moderate northwest winds
and clearing skies are expected on Monday. High temperatures Monday
should reach the lower 70s.

LONG TERM (Monday Night through Saturday): A fairly active long
term forecast period is anticipated weather-wise. Persistent 500
mb troughiness over the western United States, coupled with the
passage of a cold front on Saturday, will produce isolated to
scattered showers through a vast majority of the period. Cloudy
skies in addition to the precipitation will help hold temperatures
at near normal levels throughout the period.

MARINE (Now through Monday): Buoy 42019 reported southeast winds
around 19 knots gusting to around 23 knots with seas slightly
under 5.6 feet with a period of 6 seconds at 02 CST/08 UTC. Buoy
42044 (TABS J) reported south-southwest winds around 5.8 knots
along the nearshore waters at 01 CST/07 UTC. Cooler nearshore Gulf
waters are keeping the winds lower near coast with stronger winds
offshore this morning. Stronger winds are forecast for the Laguna
Madre today. A Small Craft Advisory is in effect for the Laguna
Madre due to strong winds from 10 am to 6 pm today. Small craft
will need to Exercise Caution today on the Gulf waters 20 to 60 NM
out due to winds between 15 to 20 knots and seas of 4 to 6 feet.
A weak cold front arrives late tonight with moderate north winds
developing in the wake of the front. Small Craft Should Exercise
Caution likely, with Small Craft Advisory conditions possible, on
the Gulf waters Monday with winds near 20 knots and seas
approaching 7 ft.

Monday Night through Saturday: The persistent interaction between
high pressure over the northern Gulf of Mexico and low pressure
over the southern Gulf of Mexico will produce an enhanced pressure
gradient throughout the period. Although generally moderate winds
will prevail along the Lower Texas Coast, sea heights will be high
enough that Small Craft Exercise Caution or Small Craft Advisory
is likely for the Gulf of Mexico waters.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds from 10 AM this morning to 6 PM
     CST this evening for GMZ130-132-135.

&&

$$

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