National Weather Service Raw Text Product

Displaying AFOS PIL: AFDBRO Received: 2018-10-12 00:17 UTC


512 
FXUS64 KBRO 120017 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
717 PM CDT Thu Oct 11 2018

.DISCUSSION...Updated for latest /00z/ aviation discussion below.

&&

.AVIATION...Looks to be a less tricky forecast tonight than this
time Wednesday night...as the Rio Grande Valley is under the
western core of the 500 mb ridge with no significant impulses to
kick off organized convection as we saw very early this morning
that continued through early afternoon, especially at Harlingen
but also in and near Brownsville. That said, it would not surprise
to see some pre-dawn showers stretch toward Brownsville (at least)
and have added a VCSH for this purpose, but with no PROB30/TEMPO
and no visibility restriction. 

Otherwise, the typical cumulus fractus with residual cirrus from
earlier convection. Despite the additional moisture in the ground
at Harlingen and 13+ hour night, the ground remains at summer-like
warmth and with just enough wind expect no visibility
restrictions.

For Friday, any showers should dissipate by mid morning.
Atmosphere looks to dry out as indicated by both GFS and ECMWF
models, though the NAM-12 seems to be suffering from it's deep
moisture issue. While isolated thunderstorms can't be ruled out,
the main story will be slowly increasing southeast flow which
should produce gusts near or just above 20 knots mainly at
Brownsville and Harlingen, and have added to cover.
52/BSG

&&

.PREV DISCUSSION... /issued 257 PM CDT Thu Oct 11 2018/ 

SHORT TERM (Tonight through Friday Night): A surface boundary 
associated with a cold is still analyzed to be sagging south over 
the lower CWA. Convection has been developing on and riding along 
this boundary all day, complicated by pulses of mid level energy 
moving in on southwest flow aloft and an abnormally deep, saturated 
moisture column. That said, the short term models shift the focus of 
precip farther south and west tonight as the relentless advance of 
incoming high pressure seems to finally win the battle and push the 
boundary farther inland and away from the CWA. Rain chances won't 
totally end tonight, but intrusions from the south should be 
restrained. On Friday into Friday night, more isolated coverage will 
occur, again moving over the lower to mid valley from the southeast. 
This due to the main high pressure over the plains shifting farther 
to the east on Friday, with local winds veering to southeast. Partly 
to mostly cloudy skies will prevail in the short term with a mix of 
low and high clouds. Low temperatures will be in the mid 70s with 
high temps in the 80s to near 90.

LONG TERM (Saturday through Thursday): Mostly zonal flow aloft to
start off the long term as a rather "flat" H5 high sits just south
of the forecast area. To the north, the remnants of Sergio will be
sliding northeast as a extratropical entity across the Red River
Valley and eventually into the Missouri River Valley. Although
there isn't a strong QPF signal during the early weekend, expect
some sea breeze activity to kick up a few isolated showers and
storms. 

A closed upper level begins to settled southward across coastal
California on Saturday. At the same time, a Canadian
impulse/surface front surges southward toward the central US late
in the weekend and eventually making it's way all the way to the
Rio Grande by Monday. With the approaching front and ample low
level moisture expect scattered to numerous showers and
thunderstorms along the cold frontal boundary. As the front
passes, expect winds to transition to a more northeasterly
direction. At the surface post FROPA models are still showing some
hints at some coastal troughing and isentropic upglide. Climo this
time of year isn't very supportive of prolonged coastal trough
that is being displayed by the ECM and CMC. Expect a rather speedy
rebound after a day or two of damp, cool, and gloomy conditions
on Tuesday...again based on climo and typical biases within the
globals to want to hang onto coastal trough a bit longer.  

MARINE (Tonight through Friday Night): Conditions will slowly
improve in the short term. Offshore wave heights tonight of 4 to 
6 feet will still be enough to necessitate small craft should 
exercise caution conditions, but wave heights should be down to 
moderate everywhere on Friday. East winds will become moderate 
southeast on Friday.

(Saturday through Thursday): Moderate winds and seas expected as
pressure gradient gradually tightens between high pressure across
the eastern US and leeside deepening of low pressure across N
Mexico. This should be enough to perhaps push conditions into
cautionary wording by the middle or end of the upcoming weekend. A
strong cold front then surges southward into the region on Monday.
Winds will sharply transition to an easterly or northeasterly
direction behind the front. Winds will increase to around 20-25kts
and seas will dramatically increase. Guidance still picks up on
coastal troughing through much of the long term marine period.
Kept winds and seas at low-end SCA criteria at the very least the
the end of the cycle. 

&&

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

$$

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