Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 291137 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
637 AM CDT Thu Sep 29 2016

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

&&

.AVIATION...Keeping trends mostly the same from previous set of
TAF`s. MVFR mist has developed at HRL over the past two hours but
should lift within an hour after sunrise. An area of showers is
apparent on radar over the Gulf coastal waters moving
southwestward. If they hold together, timing would be into the
BRO/HRL vicinity around 14Z with intermittent MVFR ceilings and
visibilities through around 18Z. Only VCSH expected, at most,
after that through 22Z with VFR thereafter continuing through the
overnight hours. VFR expected through the period away from the
coast at MFE.

&&

.PREV DISCUSSION... /issued 355 AM CDT Thu Sep 29 2016/

SHORT TERM (Today through Friday):
A coastal surface trough combined with a still rather moist
airmass (2.38" precipitable water on 00Z BRO sounding) will lead
to one more daytime period of isolated rain shower
coverage...primarily restricted to Cameron and perhaps Willacy
counties. Still significantly undercut PoP guidance for today.
Afternoon max temps will recover to just a tad above seasonal
norms.

A drier airmass, driven by surface ridging surging southward through
the Plains, arrives in the Lower RGV this evening, effectively
ending rain chances.  Per the 00Z GFS, this drier airmass will
progress southward through the CWA from mid-day today through early
this evening.  By 30/00Z, PW is progged to fall to about 1.4" across
the northern tier of the CWA to ~2.0" at BRO.  (Note that the NAM is
slower/less aggressive with the drying.  However, it has been
essentially discounted due to its recent wet bias.)

The drier air continues to filter in overnight on light northerly
winds.  Surface dewpoints will range from the upper 50`s F in the
northern ranchlands to the upper 60`s in SE Cameron County.  This
should allow morning low temps to fall to around 70 in the mid-lower
Valley...again very close to normal.  Friday looks to be quite
pleasant, with rain-free conditions and high temps in the upper 80`s
to perhaps near 90 in the mid-Valley.  Comfortable afternoon
dewpoint temperatures ranging from the lower 50`s NW to the mid-60`s
SE will also be place.

LONG TERM (Friday Night through Wednesday):
By Friday night, the surface ridge will be firmly into deep south
Texas, with drier air pouring into the region. Rain chances will
be finished through the weekend, with only some passing midlevel
clouds expected on Saturday. The ridge doesn`t depart the region
until later Monday, when southeast flow returns. Models continue
to agree on a front moving west to east across Texas during the
middle of next week. Moisture return ahead of the front may begin
to spark a few showers starting Wednesday, but the focus currently
looks to be more offshore.

MARINE:
Tonight through Friday: Light to moderate north to northeast
winds persist through today, with seas of 2-3 feet in most of the
Gulf waters. Of course, the showers, some with brief downpours,
will make boating/fishing less pleasurable through Thursday
morning, mainly south of Mansfield in the Gulf, but that will
change markedly by tonight. The building surface ridge from north
to south Texas will help kick up north/northeast winds a bit
across the Gulf, but now appears they will stay in the moderate
range of 10-13 knots. Latest wave guidance holds seas at about 3
feet from tonight on through Friday.

Saturday and Sunday: Marine conditions will remain tranquil as
northeast flow continues across the northwest Gulf. Winds will
remain around 10 knots, keeping seas in the 2 to 3 foot range.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

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