Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 281549 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
949 AM CST Mon Nov 28 2016

.DISCUSSION...Winds are beginning to veer southwest and are
showing signs of lower in the Mid Valley but remain elevated and
just shy of wind advisory over the Lower Valley and along the
coast. A slow lower should is expected to commence shortly before
noon as the LLJ continues to track slowly east. Temperatures are
already 3 to 5 degrees above values from this time yesterday and
with the winds beginning to veer and the veil of cirrus expected
to move east...full sunshine and downslope conditions should
allow temperatures to soar the next 3 to 5 hours. As a result have
 bumped up temperatures 2 to 3 degrees over the Central and
Northern reaches of the CWA but not changes to the 3 climate
stations at this time. Record temperatures are already forecast
for MFE, HRL and BRO and another degree or two increase is not
out of the question. The only hold back is the lower sun angle and
 shorter days keeping the impact of insolation heating at a slight
 minimum.

&&

.DISCUSSION...Updated for latest marine discussion below.

&&

.MARINE...Strong southerly winds continue along and east of the
coast. Port Isabel and SPI Coast Guard Station still report SCA
conditions so will extend the SCA for winds over the Laguna Madre
until Noon. Occasional gale force gust are being observed at the
marine buoy 42020 and 42045 but will hold off on any issuance of a
gale warning for the offshore coastal waters with winds expected
to begin to slowly diminish which should lead to less frequent
higher gusts. In any case, strong winds and seas exceeding 10 feet
to prevail much of the early afternoon hours before a more
noticeable lower commences. May have to extend the offshore SCA
mainly for seas this evening.

&&

.PREV DISCUSSION... /issued 552 AM CST Mon Nov 28 2016/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Mostly clear skies and strong southerly winds prevail
across much of Deep South Texas this morning. BRO VAD wind
profile and sounding data suggests a low level jet of 45 to 50
knots between 1000 to 2000 feet above the surface. Have removed
the previous mention of LLWS from this TAF cycle as surface winds
have increased this morning. Breezy to windy conditions this
morning will gradually veer and diminish as a weak surface
boundary moves into region. The combination of light winds and
higher dewpoints will allow low ceilings and patchy fog to form
tonight. MVFR conditions expected to develop after 5z with IFR
conditions possible around sunrise Tuesday.


PREV DISCUSSION... /issued 421 AM CST Mon Nov 28 2016/

SHORT TERM (Now through Tuesday): Gulf high pressure interacting
with lower pressure across the Plains is providing moderate and
gusty south winds across Deep South Texas this morning. Brownsville
radar shows a few streamer showers moving north across the Gulf
waters.

South to southwest winds will increase through around noon,
supporting a very warm day with record high temperatures likely.
Inland temperatures this afternoon will range from the upper 80s to
lower 90s in most locations. A weakening front/dry line will
approach the northern ranchlands this afternoon and will push into
portions of the Rio Grande Valley evening. This boundary will shift
winds to northeast for some, briefly but winds turn back to the
southeast late tonight. Drier air will filter into portions of Deep
South Texas behind the front and no rain is forecast through the
period.

Surface high pressure across Texas will shift east tonight which
will allow weak return flow to develop. Higher dewpoints will push
inland tonight resulting in increasing clouds and some patchy fog.
Light winds late tonight may allow some fog to become locally dense.
Low temperatures tonight will range from the upper 50s across the
Ranchlands to the lower 70s along the coast. Tuesday will be warm
with above normal tempeatures as the weak front lingers across the
area. High temperatures Tuesday will be generally in the mid to
upper 80s with a mix of sun and clouds.

LONG TERM (Tuesday Night through Sunday): Although a cold front
will pass through Deep South Texas and the Rio Grande Valley
during the pre-dawn hours of Wednesday, producing isolated to
scattered showers and thunderstorms for most of the BRO CWFA, the
main event in the long term portion of the forecast will be a long
period of unsettled weather from Friday through Sunday. Generally
scattered showers and thunderstorms are forecast for this period
as closed 500 mb low pressure drops into northwest Mexico, and
another cold front passes through the BRO CWFA on Saturday. It is
increasingly likely that rain chances will need to be adjusted
upwards from the scattered to the numerous designation. With the
two cold front passages and expected significant cloud coverage
and precipitation, daytime high and overnight low temperatures are
expected to be around near normal levels for a majority of the
long term forecast period.

MARINE (Now through Tuesday): Buoy 42020 reported south winds
around 23 knots gusting to around 27 knots with seas slightly over
8.5 feet with a period of 7 seconds at 03 CST/09 UTC. Adverse marine
conditions will continue this morning courtesy of the tight pressure
gradient between surface high pressure across the Gulf and lower
pressure over the Plains. The small craft advisory remains in effect
through 9 am for the Laguna Madre and until 6 pm for the Lower Texas
Gulf waters. Winds will quickly weaken this afternoon and evening as
a weak cold front moves into Deep South Texas and stalls. As a
result, the front is not expected to move into the coastal waters
and southeast winds will continue to prevail through Tuesday.

Tuesday Night through Sunday: The passage of a cold front around
sunrise Wednesday, and the approach and passage of another cold
front Saturday night, are likely to create Small Craft Advisory
winds and/or seas for all or portions of the Lower Texas coastal
waters Wednesday through Wednesday night, and again Friday through
Sunday. A brief period of gale-force wind gusts are possible
Wednesday morning in association with the first cold front.
Outside of the time periods mentioned, generally moderate winds
and seas are likely.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  88  70  89  66 /  10   0   0  20
BROWNSVILLE          90  70  89  66 /  10   0   0  20
HARLINGEN            92  67  91  65 /  10   0   0  20
MCALLEN              94  66  93  62 /  10   0   0  20
RIO GRANDE CITY      93  62  91  58 /   0   0   0   0
SOUTH PADRE ISLAND   84  72  82  68 /  10   0   0  30

&&

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

     Small Craft Advisory until 6 PM CST this evening for GMZ150-155-
     170-175.

&&

$$

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