Area Forecast Discussion
Issued by NWS Brownsville, TX

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992
FXUS64 KBRO 221714 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
1114 AM CST Sun Jan 22 2017

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

&&

.AVIATION...Strong, gusty north northwest winds will be ongoing
through the afternoon now that the boundary layer has mixed out.
Winds will diminish this evening. VFR conditions next 24 hours.

&&

.PREV DISCUSSION... /issued 544 AM CST Sun Jan 22 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Currently experiencing a lull in post-frontal winds as
mixing of lower levels has stopped. Surface winds have fallen to
around 10 knots, while morning balloon sounding shows winds at
2000 feet of 55 knots. Once the sun rises, winds will begin to mix
to the sfc quickly, with sustained winds of 25 to 30 knots with
gusts to 40 through the day. Skies will be completely CLR all day.
Winds will gradually decrease through the evening as high
pressure moves into south Texas. Later tomorrow night, winds will
be light and variable.

PREV DISCUSSION... /issued 355 AM CST Sun Jan 22 2017/

SHORT TERM:(Now through Monday): The latest cold front came
sweeping through the lower valley right around midnight, bringing
a slight cool down but a significant decrease in humidity. Winds
also remain 10 to 15 knots with some higher gusts, while winds
offshore have already jumped above 20 knots. This sets the stage
for the very windy day areawide, with forecast winds of 30 to 40
mph with higher gusts, critically dry conditions, along with
freshly cured fine fuels from recent freezes. Current advisories
include a Red Flag Warning and a Wind Advisory. No burning should
be done anywhere in Deep South Texas today due to the extremeness
of the northwest flow today. Otherwise skies will remain crystal
clear, with high temperatures in the upper 70s. Surface high
pressure behind the front will center on Texas overnight tonight,
quickly dropping winds to 5mph or less. Clear skies will allow
temps to drop into the upper 40s by sunrise. The high will move
offshore during the day Monday, gradually shifting winds back to
the south, but will remain below 10mph areawide. With dry air
remaining for most of the day, skies will again be pretty much
clear for the entire day, with temperatures moderating a bit into
the lower 80s.

LONG TERM (Monday Night through Saturday): A mid/upper longwave
trough settles over the Conus during the long term period with a
slow but eventual cool down after a period of well above normal
temperatures. Models are in relative good agreement with the
overall pattern and remain consistent in the sensible weather
until next weekend when moisture/pop differences show up.

The establishment of the longwave trough begins Monday
night/Tuesday as a potent shortwave moves in from the Pacific
northwest and into the Rockies. Southerly winds return to Deep
South Texas Tuesday becoming strong enough to warrant another wind
advisory for at least the Lower Valley and possibly the Mid
Valley. Temperatures will respond climbing back into 80s to lower
90s. ECMWF is once again the warmest of the models with mid 90s
across interior Hidalgo and the Western Ranchlands. As the
shortwave/mid-level low moves east into the Central Plains it
drags a cold front through the CWA by Wednesday morning. This
front is initially weak but high pressure builds over the Rockies
as the longwave expands and strengthens. Heights and 1000-500
thickness and overall temperatures begin to lower Wed-Saturday.
Our area is not expected to get cold but temperatures should
approach normal or may dip slightly below normal (mid-upper 60s)
by Saturday and Sunday. Dry conditions are expected Tuesday-
Thursday. As the longwave trough becomes established from a deep
low near Hudson Bay Canada to an upper low over Northwest Mexico a
steady increase of northeast to east winds to slowly increase
across the Gulf. Moisture should steadily deepen over South Texas
as an overrunning pattern develops. This sets up an increase in
rain chances as early as Friday with best chances being advertised
for next weekend. GFS at this time is shows near 100 percent with
ECMWF showing near zero percent. As these two models battle will
go the conservative route and take a blend which pushes rain
chances into the chance category.

MARINE:(Now through Monday): Gale Warning now in effect for all
marine zones as the front as pushed well to the south. The initial
surge brought gusts to 40 knots, which should continue through the
day today. Seas have already jumped to 6 feet offshore, and once the
strongest winds develop later this morning, seas of 10 to 12 feet
are expected. High pressure quickly moves into the region this
evening, with winds dropping below 20 knots around midnight. Seas
will gradually improve tonight, falling below 7 feet nearshore
around midnight, and offshore around sunrise Monday. Monday will be a
much more tranquil marine day, with seas down to 2 to 3 feet and
variable winds around 5 knots through the day.

Monday night through Friday...High pressure tracks east and the
next upper stream low pressure trough drops into the Rockies
Monday night and Tuesday. South winds return and increase to
strong levels Tuesday with Small Craft Advisories likely for all
marine waters for either winds or seas. Weak cold front moves
through Wednesday with a persistent but fluctuating moderate to
strong north to northeast wind the rest of the week. Seas and or
swell is anticipated to build with the persistent flow which might
result in an extended period of marginally adverse marine
conditions.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Red Flag Warning until 6 PM CST this evening for TXZ248>257.

     Wind Advisory until 6 PM CST this evening for TXZ248>257.

GM...Gale Warning until 6 PM CST this evening for GMZ130-132-135-150-
     155-170-175.

&&

$$

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