Area Forecast Discussion
Issued by NWS Brownsville, TX

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904
FXUS64 KBRO 171532 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
932 AM CST Wed Jan 17 2018

.DISCUSSION...Updated the Freeze warnings and wind chill
advisories/warning and cancelled the winter weather advisory.
Temperatures continues to hover between 29-32 this morning and
will be slow to rise and may take until 11am or noon for some
areas. Winds remain strongest in the Lower Valley with winds
chills still low but with the slow rise in temperatures wind chill
may only recover into the lower 30s today.

&&

.PREV DISCUSSION... /issued 553 AM CST Wed Jan 17 2018/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Obs from BRO/HRL/MFE not being transmitted long-line
at this time. That being said, radar indicates precip has pretty
much ended over the RGV with temps hovering near freezing. CIG`s
at HRL and MFE have risen to VFR levels, with BRO remaining at
MVFR currently. Some signal in the guidance that BRO will break
out to VFR for a hours around mid-day, but confidence in this
only medium. Later this afternoon and into the evening, a coastal
trough will develop, with increasing low-level moisture keeping
CIG`s MVFR for BRO. These may eventually move inland overnight.
Can`t rule out some light drizzle developing at BRO after 06Z,
but coverage/confidence not high enough to place in TAF at this
time.

PREV DISCUSSION... /issued 448 AM CST Wed Jan 17 2018/

SHORT TERM (Now through Thursday): The KBRO radar shows that most
of the pcpn has ended over the region with some light echoes still
being returned from south of the Rio Grande over NE Mexico and over
the Mexican Gulf waters. Since the the light pcpn is lingering near
the Cameron County with temps across the region still holding near
or just below the freezing mark will allow the Winter Weather
Advisory to continue until 10 am for Willacy and Cameron Counties in
case any additional icing occurs from the potential freezing
drizzle.

With the continued CAA prevailing over the region today from the
Arctic airmass, temps later today will not rebound much and will
hold them generally in the mid to upper 30s by this afternoon.

The CAA will then continue into the overnight hours tonight as the
center of the Arctic surface high remains centered over the Gulf
Coast region. This will push temps down close to or just below the
freezing mark across much of the region and anticipate a Freeze
watch/warning may be needed for much of the region later this
morning/afternoon.

Wind chill values will persist in the teens to lower 20s throughout
the early morning hours eventually rebounding to near the 30 degree
mark by this afternoon. Will maintain the Wind Chill
Warning/Advisory in place through the rest of this morning.

Although some drier air has moved into the region from the west and
northwest shutting down the pcpn for the moment, the combination of
a 500 mb closed low to our northwest and the lingering surface
troffing near the lower TX coastline will likely maintain the pcpn
chcs through Thurs.

LONG TERM (Thursday Night through Tuesday): A deep 500 mb
trough will dig southeastward over Texas Thursday night into Friday
night. The coastal trough will also linger along the lower Texas
coast Thursday night and Friday. This surface feature will support
showers across deep south Texas Thursday night and Friday. Rain
chances begin to decrease from west to east by Friday night as the
coastal trough weakens. Abundant cloud cover and increase in rain
chances should support temperatures near normal Thursday night
through Friday night. Surface high pressure moves east on Saturday
allowing southerly flow to return across the area. Above normal
temperatures are expected across deep south Texas Saturday through
Sunday. High temperatures Saturday will be in the 70s with a mix of
sun and clouds. Low temperatures Saturday night will be in the upper
50s to lower 60s. Sunday will be breezy, especially near the coast,
as the pressure gradient strengthens. High temperatures Sunday will
be in the 70s with some locations approaching 80 degrees. The next
cold front arrives Sunday night bringing cooler and much drier air
behind it. Some showers are possible, especially across the coastal
waters with the front Sunday night. Near normal temperatures are
expected early next week.

MARINE (Now through Thursday): The strong PGF will be gradually
weakening across the lower TX coastline through tonight and
Thursday. However SCA conditons will persist across the lower TX
Gulf waters throughout today and early this evening. More benign
marine conditions are expected for the Bay and Gulf waters on Thurs.

Thursday Night through Monday: Light to moderate winds and
moderate seas will continue Thursday night and Friday as the
coastal trough lingers along the coast. Southeast flow returns
Friday night through Saturday night and the long fetch will bring
wave heights up to Small Craft Advisory levels potentially. Marine
conditions will improve Sunday as the gradient relaxes ahead of
the next front. The next cold front arrives Sunday night bringing
strong winds and rough seas across the lower Texas coastal waters
on Monday.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Wind Chill Advisory until noon CST today for TXZ248>257.

     Freeze Warning until 11 AM CST this morning for TXZ252>257.

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

&&

$$

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