Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 270543 AAB

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1243 AM CDT Thu Apr 27 2017

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


.AVIATION...Weak cold front extending across the Coastal Bend and
into the Northern fringes of Deep South Texas is losing some
southward momentum and will have a difficult time making its way
into the vicinity of the 3 regional airports. Very weak surface high
pressure moves east with some bridging of the ridge into the Rio
Grande Valley overnight with winds briefly turning north to
northeast. As for flight categories VFR is currently observed at
all locations and should be the predominate condition overnight.
Very shallow moisture is indicated to pool ahead of the front with
scattered low level clouds forming around or shortly after
sunrise. Probabilities of MVFR ceilings are low but are the
highest in the KBRO and KHRL vicinity so will indicate a brief
window of MVFR between 13-16Z. Moisture is forecast to increase
through the day but should mix with the drier air aloft to produce
only SCT coverage. Strong surface inversion develops tonight with
low level jet strengthening which will allow for a stratus layer
to form a few hours after sunset and impacting all 3 terminal
sites. Light northeast to east winds this morning becomes
moderate east to southeast this afternoon before stronger winds
develop overnight with some gusts between 20-25 knots.


.PREV DISCUSSION... /issued 638 PM CDT Wed Apr 26 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...VFR is expected through the next 24 hours. Clear skies
tonight will become pockmarked with scattered cloudiness Thursday.
Surface winds will veer as high pressure centered north of the
aerodromes moves off towards the east.

PREV DISCUSSION... /issued 324 PM CDT Wed Apr 26 2017/

SHORT TERM (Tonight through Thursday Night): 500mb trough across
the south central United States this afternoon will move eastward
tonight and a broad 500mb trough will prevail across the southern
United States Thursday into Thurs night. At the surface...a weak
cold front will move through the CWA this evening providing some
relief tonight to the record high temperatures across the CWA this
afternoon. Surface high pressure across east Texas tonight will
move eastward Thursday and moisture will return at the surface
Thurs afternoon. Temperatures will not be as hot Thurs afternoon
as today but highs will be above normal after near normal lows

LONG TERM (Friday through Wednesday):Period starts out with
another round of extreme heat for the Rio Grande Valley and Deep
South Texas Friday and Saturday as mid and upper level flow from
the SW help temperatures rebound quickly. Highs expected to surge
past the century mark for areas of west of Highway 77, with upper
90s common across the coastal counties. Breezy to windy conditions
develop Friday as low pressure strengthens over the southern
plains, with windy conditions possible across the lower Valley
late Friday morning into Friday afternoon. Guidance continues to
show sustained winds of 25 to 27 knots across Cameron County
Friday afternoon and a wind advisory may be needed.

Cold front early Sunday will bring a much cooler day, with
temperatures at or just below seasonal norms. Highs will only top
in the mid 80s to around 90, a difference to 10 to 20 degrees from
Saturday afternoon. Expect frontal passage to be mostly dry, with
a few showers and thunderstorms possible over the coastal waters,
but little expected on land due to limited moisture to work with
(deep dry layer aloft and moisture confined to below 850 mb). Dry
air surging in behind the cold front will lead to elevated fire
weather concerns for Sunday with the greatest concern for the
westernmost three counties; RH values fall into the 15 to 25
percent range across much of the inland areas west of Highway 77
Temperatures rebound quickly going into the new work week as
southeasterly flow resumes with highs in the upper 80s and low 90
across much of the area Monday. The warming trend continues into
midweek with highs well into the 90s area-wide Tuesday and

MARINE (Tonight through Thursday Night): Seas were near 7 feet
with south winds near 10 knots at buoy020 this afternoon. Winds
will shift to the north and increase tonight as a weak cold front
moves through the coastal waters this evening. Strong northeast
winds will develop offshore the lower Texas coast late tonight so
will go ahead and issue a small craft advisory for the offshore
waters from midnight tonight through 7 am Thursday. The pressure
gradient will weaken across the western Gulf of Mexico Thursday
and winds will diminish and veer to the southeast as surface high
pressure across east TX tonight moves eastward. Moderate southeast
winds will prevail across the lower TX coast Thursday and
increase slightly Thurs night.

Friday through Sunday: Pressure gradient tightens Friday into
Saturday, with strong winds and building seas expected as the
next low pressure develops over the southwest and moves into the
Southern Plains. This will send a cold front south across Texas
and across the lower Texas coastal waters late Saturday night and
into Sunday morning. Behind the front northerly winds strong
northerly winds are expected. Small craft advisory conditions
likely Friday through end of the period with a brief lull early
Sunday morning before the frontal passage.


GM...Small Craft Advisory until 7 AM CDT this morning for GMZ150-155-



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