Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 200606 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
106 AM CDT Sat May 20 2017

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

&&

.AVIATION...Low level moisture pooling under a surface inversion
will provide a MVFR ceiling between 15-25kft overnight and through
sunrise. Increasing southerly flow to mix out the moisture and
allow for the inversion to lift with VFR conditions developing
through the late morning and afternoon hours. MVFR redevelops a
few hours after sunset Saturday. Moderate southeast winds gusts
between 20-25 knots Saturday afternoon.

&&

.PREV DISCUSSION... /issued 555 PM CDT Fri May 19 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...VFR conditions right now will degrade to MVFR
conditions during the overnight hours courtesy of low stratus.
Breezy winds will become more moderate after sunset. Saturday,
VFR is anticipated during the daylight hours.

PREV DISCUSSION... /issued 241 PM CDT Fri May 19 2017/

Short Term (Now through Saturday Night):  Upper low over the
Rockies today will continue to lift northeast through Saturday
night. Associated cold front currently draped across the Panhandle
will slowly progress east southeast across the state tonight
through Saturday night, making it into South Texas, but likely not
making it into the Ranchlands. Tonight, generally rain free and
warm conditions expected, as southeasterly flow maintains low
dewpoints and overnight lows in the mid to upper 70s. Much of the
area expected to remain dry for much of the day Saturday, with
more moderate southeast winds and a mix of sun and clouds by the
afternoon. Above normal temperatures continue Saturday with highs
slightly cooler than today, especially out west, where cloud cover
will be greater. As the front continues its approach, moisture
will pool ahead of it and weak impulses will move through the flow
aloft, bringing slightly better chances of showers and tstms late
Saturday afternoon and overnight across the northern and western
zones.

LONG TERM (Sunday through Friday):  The large scale will boast of a
flat mid level ridge over the Gulf with broad high pressure at the
surface. A 500 hPa low will move northeast over the Plains into the
upper Midwest, with a weak front pushing into south central Texas
Sunday morning.

A weak cold front and high pressure air mass will filter into the
CWFA on Sunday, mainly a glancing blow as high pressure moves out
over the northwest Gulf. The main impact locally will be a slight
backing of wind from southeast to east, with minor moisture
pooling, allowing isolated showers or thunderstorms to develop.
Southeast flow will return fairly quickly as high pressure shifts
east, by Monday, with the boundary heading back north, and
setting up a slightly healthier chance of rain during the day.

A slightly stronger front followed by modified cP air will arrive
on Wednesday. A wind shift to north is due around daybreak, with
drier air filtering in later in the day. Until then, scattered
showers with isolated thunderstorms may develop, and high
temperatures will be slightly cooler, in the lower to mid 80s for
the day. Deep south Texas and the RGV will only see a brief and
mild decrease in RH however, since, as with the previous front,
return flow will be rather swift to reclaim its dominance,
thrusting a tongue of low level moisture north along the coast on
Thursday. At least low temperatures Wednesday night will respond
mildly downward, dipping into the 60s. After morning showers
Thursday, however, high pressure will dominate and rain chances
will fizzle, with a 500 hPa ridge building upstream.

MARINE:
Now through Saturday Night: Conditions at Buoy 42020 at 2 PM show
south southeast winds around 15 knots and seas around 6 feet.
Winds have increased to around 20 knots across the Laguna Madre
and expect winds to remain elevated across the Laguna through the
early evening hours; a Small Craft Advisory for winds remains in
place. Winds and seas will improve tonight into Saturday night as
a weak cold front moves into south Tex and the pressure gradient
weakens. Small craft exercise caution conditions likely across the
Laguna Madre and Gulf waters overnight and again Saturday for the
Gulf waters. The front is not expected to enter the lower Texas
coastal waters.

Sunday through Wednesday...Winds will remain light to moderate
from east to southeast Sunday through Tuesday night, under the
influence of the Gulf synoptic scale pressure pattern, with
moderate seas. A front will push through Wednesday morning with
moderate to fresh northeast winds through the day, and slightly
higher seas. Small craft should exercise caution conditions will
be the likely response. Light to moderate southeast winds and
moderate seas will return on Thursday as the center of high
pressure shifts east.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

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HTTP://WEATHER.GOV/RGV

59...aviation



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