Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 211011
AFDBRO

Area Forecast Discussion
National Weather Service BROWNSVILLE TX
411 AM CST Sat Jan 21 2017

.SHORT TERM (Today through Sunday): The current dense fog
advisory might have to be cancelled ahead of scheduled expiration,
9am, with much of the fog lifting as boundary layer winds
increase. KBRO 88D VAD shows winds of 25knots at 1000 feet. Low
clouds and patchy, occasional dense, fog to continue this morning
but should mix out fairly quickly as very dry air in atmospheric
column begins to mix to the surface along with some of the wind.
Models suggest that the winds do diminish in the afternoon so any
stronger gusts could develop this morning but should not persist.
SW-W-NW downsloping winds develop as large scale mid level trough
advances out of the Southern Rockies and into Texas. We will see
temperatures soar as soon as the clouds break and dew points fall.
Will be issuing a RFD, Range Field Discussion, for elevated fire
weather risk over the Western Ranchlands due to a combination of
Low humidity and marginal winds. Not anticipating Red Flag
conditions with winds being the limiting factor. Temperatures to
climb well into the 80s and top 90 degrees today. ECMWF continues
to the warmest of the models topping out at Brownsville at 98
degrees. Little confidence to go this warm although Brownsville
did drop to 56 shortly after midnight and then jumped to 67 in
less than one hour. In any case, record temperatures are expected
today for much of the RGV and DSTX.

Tonight...winds do decouple as upper trough and cold front
approaches. clear skies lighter winds and cooling temperatures might
result in some patchy fog but most models suggest only modest RH
recovery before the cold front moves through after midnight so will
not mention fog at this time. The front pushes through the CWA
between midnight and 3 am with winds shifting NW and temperatures
cooling off a few more degrees. 925-850mb winds increase 40-55 knots
and dew points begin to crash. Winds mixing to the surface will be
delayed but can not rule out occasional stronger gusts developing
towards sunrise.

Sunday...A wind advisory will likely be issued the Fire Weather
Watch will be upgraded to a Red Flag Warning and the Gale watch has
already been upgraded to a Gale Warning. Strong vertically stacked
low pressure system moving into the Arklatex vicinity has a strong
jet on its back side with downward vertical motions and a highly
subsidence flow allowing for these winds to partially mix to the
surface.  Winds pick up mid to late morning with gusts exceeding 40
mph and possibly reaching 50 mph in some locations near the coast
early afternoon. Sustained winds of 30-40 mph will be common and may
exceed 40 mph at a few locals which might prompt a short fuse high
wind warning. Temperatures look to be somewhat cooler but still warm
and combine with dew points falling into the 20s and 30s humidity
levels to crash into the teens and 20s. Bone dry conditions and
strong winds will prompt very high fire danger with plenty of dry
fuels across the CWA.



.LONG TERM (Sunday Night through Friday): High pressure builds
quickly across Texas Sunday night into Monday, keeping skies clear
and winds light across the region. Milder conditions continue
Monday afternoon, with consistent forecast around 80 degrees from
all models. One Tuesday, southerly winds increase as inflow
develops into the next surface low in the Central Plains. With
winds from due south, and possibly a slight southwest component,
temperatures will again jump into the upper 80s. The next front
associated with the central plains low will sweep across Texas on
Wednesday. A prefrontal trough will moves across Deep South Texas
during the day, switching the winds to the north. Initial
intrusion of slightly cooler air arrives during the afternoon,
keeping highs around 80. The main surge of north winds arrives
Wednesday night, further abating temperatures for the remainder of
the week. No rain chances in the forecast through the entire long
term period.


&&

.MARINE:
Now through Sunday: Some patchy Sea Fog is expected this morning
and may linger offshore til noon and may reform briefly tonight
before a strong cold front moves offshore. Light offshore winds
and a slight seas to persist today and this evening in advance of
this strong front. Gale conditions develop after midnight and
should continue much of the day Sunday. Seas to quickly
deteriorate exceeding 10 feet shortly after sunrise and may exceed
14 feet by noon.

Monday through Wednesday: Much more tranquil marine conditions
expected Monday as high pressure moves into south Texas. Winds
will start the day around 10 knots from the north, but will switch
back to the south later in the afternoon. The lighter winds will
allow seas to further relax down to 2 to 3 feet by the afternoon.
Winds will increase again Tuesday morning as the ridge moves east
and the next surface low sweeps across Kansas. Gradient looks to
be tight enough to produce southerly winds around 20 knots, which
will kick seas back up to 5 to 7 feet. Small Craft Advisories may
be necessary at that time. A front associated with the central
plains low will sweep into South Texas later Wednesday, but winds
will no shift to the north until after sunset.

&&

CLIMATE:  Near-record high temperatures are expected on Saturday.
Record highs for Brownsville, Harlingen, and McAllen are 90/87/91F,
respectively.  Forecast highs are 90/92/94F.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  88  58  78  51 /   0   0   0   0
BROWNSVILLE          90  58  80  50 /   0   0   0   0
HARLINGEN            92  56  80  49 /   0   0   0   0
MCALLEN              94  56  83  49 /   0   0   0   0
RIO GRANDE CITY      94  55  83  47 /   0   0   0   0
SOUTH PADRE ISLAND   76  62  74  55 /   0   0   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Fire Weather Watch from Sunday morning through Sunday afternoon
     for TXZ248>257.

GM...Gale Warning from 3 AM to 6 PM CST Sunday for GMZ130-132-135-150-
     155-170-175.

&&

$$

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