Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 221150 AAA

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
550 AM CST Mon Jan 22 2018

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


.AVIATION...A weak cold front will move through the area later
this morning, but light winds and a shallow layer of moisture are
allowing areas of fog to develop early this morning. Visibilities
may drop to below 1 mile at times, especially from HRL to MFE. IFR
to LIFR conditions will continue through around 15Z before the
cold front moves through and the fog lifts. This afternoon, north
winds will increase with a few strong wind gusts possible. Skies
will clear, however, with VFR conditions expected this afternoon
through the overnight.


.PREV DISCUSSION... /issued 441 AM CST Mon Jan 22 2018/

SHORT TERM (Now through Tuesday): A weak cold front is slowly
moving southward into South Texas this morning and will move through
Deep South Texas by mid-morning. A line of convection is firing
along the boundary across Southeast Texas and the Mississippi
Valley, but not much luck for precipitation this far south. Much
drier air in the mid-levels and well-displaced upper level support
will limit any shower or thunderstorm activity to 10 to 20% today.
Ahead of it, however, shallow moisture and calming winds prior to
the passage is allowing for areas of fog to develop across the lower
Rio Grande Valley and coastal areas. Dense fog will be possible with
visibilities dropping to below 1 mile at times. Behind the front,
drier northwest flow will dissipate fog fairly quickly with clearing
by this afternoon from northwest to southeast. Not much cold air
will filter in behind the front this afternoon and temperatures are
actually expected to be above normal again today in the mid 70s.
However, much drier air and breezy conditions may lead to an
elevated threat of erratic fire behavior as RH values drop to below
20% in the afternoon for a few hours.

Tonight, drier air will allow temperatures to cool into the mid 40s
across much of the area. No rain is expected and winds will shift to
the northeast as surface high pressure moves into Central Texas.
Near normal temperatures are expected on Tuesday.

LONG TERM (Tuesday Night through Sunday): Isolated to scattered
showers continue to be expected through a majority of the period
due to persistent troughiness over the western United States and
the passage of a cold front on Sunday. Significant cloud cover
over the region coupled with the rain chances will maintain near
normal temperatures throughout the period.

MARINE (Now through Tuesday): Ahead of a weak cold front late
tonight, areas of dense fog will be possible over the Laguna Madre
and along the coastal Gulf waters as warm, moist air moves over
relatively cooler water. The front will allow fog to dissipate with
stronger north winds by mid morning. A Small Craft Advisory may be
needed for the offshore waters with winds nearing 20 knots and seas
rising to 5 to 7 feet this afternoon and evening. Conditions will
improve as winds shift to the northeast on Tuesday.

Tuesday Night through Sunday: Slightly adverse marine conditions
are expected Tuesday night through Saturday night as an enhanced
pressure gradient produces Small Craft Exercise Caution seas for a
portion of the Gulf of Mexico waters. Small Craft Advisory is more
likely on Sunday due to the passage of a cold front.


GM...Dense Fog Advisory until 9 AM CST this morning for GMZ150-155.



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