Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 171140 AAA

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
540 AM CST Tue Jan 17 2017

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

.AVIATION...MVFR is ruling right now with even some light fog at
MFE. VFR will set in after sunrise this morning with cloud decks
rising and surface winds becoming breezy. A return to MVFR is
anticipated after sunset tonight.

.PREV DISCUSSION... /issued 339 AM CST Tue Jan 17 2017/

SHORT TERM (Today through Wednesday): The most recent surface
analysis indicates a stationary front oriented roughly from north to
south over the central portion of Deep South Texas and the Rio
Grande Valley. However, surface observations from ASOS and AWOS
platforms within this region, and across the southern half of the
CRP CWFA, show generally southeasterly winds, with winds at LRD and
across the northern half of the CRP CWFA from the northeast,
suggesting the surface boundary bisects the CRP CWFA. This is
important, as the Day 1 Convective Outlook from the Storm Prediction
Center discusses the potential for severe thunderstorms on the north
side of this boundary today and tonight. Despite the fact that the
Storm Prediction Center places the BRO CWFA is a marginal risk for
severe weather today and tonight north of a line roughly from Rio
Grande City to Norias, have opted not to include a mention of severe
weather for any portion of Deep South Texas and the Rio Grande
Valley, as the aforementioned surface boundary is progged to remain
north of the BRO CWFA. Still, successive shifts will need to monitor
this developing weather situation and possibly include the mention
of severe weather if the position of the boundary shifts south or
developing thunderstorms appear poised to migrate into the BRO CWFA
from the neighboring CRP CWFA.

LONG TERM (Wednesday Night through Monday): 500mb low/trough
across New Mexico/northwest Texas into northern Mexico in
combination with low to mid level moisture across east TX
extending into deep south TX Wednesday will provide a good chance
of showers and thunderstorms across the CWA Wed night into
Thursday before the upper level low/trough moves eastward Thursday
bringing drier air from west to east across the area Thurs
morning. This will bring an end to rain chances across south TX
Thurs afternoon. West to northwest flow aloft will provide
subsidence across south TX Thurs night but a weak shortwave trough
is progged to move across the area Friday providing a slight
chance of showers across the coastal sections. Another weak
shortwave trough is expected to move across southwest TX Saturday
before a strong 500mb low develops across the southern plains Sat
night into Sunday. A cold front will move through south TX late
Sat night into Sun morning. Strong northwest winds will develop in
the wake of the front Sunday with very dry air. Wind advisories as
well as red flag warnings for wildfire potential are likely across
the CWA Sunday as a result.

Now through Wednesday...Buoy 42020 reported south-southeast winds
around 12 knots with seas slightly under 5 feet with a period of
8 seconds at 02 CST/08 UTC. Swells from roughly the southeast will
continue to approach the Lower Texas Coast today and tonight,
resulting in a Small Craft Exercise Caution for a portion of the
Gulf of Mexico waters east of Padre Island. The swells will
subside slightly for Wednesday, leading to improved sea
conditions. Moderate winds are also anticipated throughout the
forecast period.

Wednesday night through Saturday...Light south winds will prevail
across the coastal waters Wed night before briefly shifting to the
northwest Thursday as a weak frontal boundary moves offshore the
lower Texas coast. Winds will veer to the southeast on Friday as
the boundary retreats to the north Thurs night. Winds should be
light and variable across the western Gulf of Mexico Saturday
before a cold front moves through the coastal waters late Sat
night into early Sun morning.



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