Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 182333 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
533 PM CST Sat Nov 18 2017

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

&&

.AVIATION...A cold front is currently pushing through the CWA,
with winds shifting to moderate and gusty north in its wake. No
real weather is associated with the front, so VFR TAFs should
continue tonight and into Sunday, with moderate and gusty north
winds.

&&

.PREV DISCUSSION... /issued 324 PM CST Sat Nov 18 2017/

SHORT TERM (Tonight through Sunday Night): Another gorgeous/mostly
sunny day today across deep south Texas. There has been some
widely scattered CU right along the coast (sea breeze), however,
not much to write home about. Once again our temperatures are
soaring to near record territory. As of 2pm we haven`t quite made
it there yet, but we are close. Temperatures across the
middle/upper valley and northern Ranchlands have really jumped
over the last hour or so, especially as the surface flow veers
southwesterly ahead of the approaching cold front.

Speaking of cold front, it`s moving toward our area pretty swiftly
this afternoon. The front is very subtle on satellite imagery with
the only evidence being dust being picked up around the big bend
region. Decided to drop POPs even further given the lack of
meaningful clouds...much less precip currently associated with the
boundary. That said, if there were to be any precip it would likely
be along or off shore. Winds have begin to shift just ahead of the
front along the prefrontal trough. The main front should push
through between 6pm-12am with a strong push of dry/cool northerly
winds.

Behind the front a cooler and drier air mass will filter into the
region, so say good bye to near record warmth for a while.
Temperatures will top out in the 60s to near 70 and overnight lows
will range from the upper 40s across the northern ranchlands to the
middle and upper 50s closer to the coast.

LONG TERM (Monday through Saturday): A 500 mb trough axis will
move over much of TX on Mon. Some marginal moisture return occurs
over the RGV and Deep South TX as the trough crosses the region
and will maintain a mention of some low end pops early next week.
After this trough exits the region, another pretty fast moving
short wave will then dive southeast across the south central
Plains states on Tues. This next trough axis is expected to
eventually transition to a closed low over the mid Gulf coast
region late Wed of next week. This will bring through another cold
front through the RGV late Tues with a reinforcing shot of cooler
Canadian air moving into the region from the north. Model
moisture levels have been diminishing over the last several runs
so this midweek fropa looks drier than previously anticipated. The
cooler airmass will then start to moderate steadily through the
end of next week with temperatures warming some through next
weekend with dry conditions continuing. The Thanksgiving holiday
is shaping up pretty nicely for the RGV with near zero pops and
expected temps near climo for late November.

The ECMWF and GFS show reasonable agreement for temps through Day
7 for the RGV with the GFS MEX numbers showing a bit of a warmer
bias. Will go close to a model blend for maxes and mins through
the extended period. The ECMWF is wetter for Mon and Wed versus
the GFS with the most recent run. Will likely go closer to the
drier GFS numbers as the anticipated 500 mb pattern in the longer
range is not terribly conducive for decent pops due to the
general limited moisture advection.

Overall confidence in the longer range outlook is above average.

MARINE (Now through Sunday night): Marine conditions will begin to
deteriorate through the afternoon and evening as a strong cold front
moves through the region. Winds will quickly shift to the north and
northeast with time. Sustained winds offshore will likely top out at
around 30kts, however, there will be frequent gusts up to 40 knots
through the overnight period. Seas will be building with to as high
as 10 feet off shore.

The Laguna Madre will be gusty as well with sustained winds topping
out in the low to mid 20 knot range. Think that all headlines look
reasonable for both Gulf waters and Laguna at this time. Can`t rule
out a rogue gust or two in over the Laguna up to Gale force.

Hazardous marine conditions are expected to continue right through
Sunday with some gradual improvement toward the end of the period as
pressure gradient (wind) begins to relax.

Monday through Thanksgiving: A pretty weak pressure gradient will
prevail on Mon and Tues as the center of the surface ridge shifts
out to the east of the Gulf coast. In the wake of the fropa late
Tues expect the pressure gradient to strengthen once again
possibly pushing the marine conditions up close to SCEC/SCA range
into Wed and Wed Night. The pressure gradient then relaxes once
again on Thanksgiving allowing for more quiet marine conditions
later next week.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 9 AM CST Sunday for GMZ130-
     132-135.

     Gale Warning until 9 AM CST Sunday for GMZ150-155-170-175.

&&

$$

This product is also available on the web at:
HTTP://WEATHER.GOV/RGV

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