Area Forecast Discussion
Issued by NWS Brownsville, TX
FXUS64 KBRO 271931
Area Forecast Discussion
National Weather Service BROWNSVILLE TX
231 PM CDT Tue Sep 27 2016
.SHORT TERM (Now through Wednesday night): A weak coastal trough
lies offshore, still triggering isolated convection, but coverage is
on the decrease over land as north winds and lower dew points take
hold. Have trimmed back pops for tonight through Wednesday night,
and gone with scattered or less showers through the short term,
which is a lot less than a model consensus was advertising, probably
trying to bring the coastal trough onshore. Cooler, drier air is
filtering in and essentially turning a convective situation into an
overrunning one, however, and a weak one at that. As a result, may
still see light precip through tomorrow, with forecast PWAT values
still remaining well above two inches in a saturated lwr atmosphere,
but cloud cover will tend to erode through the day, relegating most
residual shower activity to the Gulf (see marine discussion below).
Temperatures will be slightly cooler, in the lower to middle 70s at
night, with some upper 60s possible in the upper valley. High temps
on Wednesday will be mainly in the 80s, possibly touching 90 inland.
.LONG TERM (Thursday through Tuesday): Not many changes to the
long term forecast today. Lingering moisture due to the coastal
trough will still be in place early on Thursday and have left low-
end rainfall chances generally over portions of the lower RGV.
However...a large area of surface high pressure will slide south
across the Central and Southern Plains. Meanwhile...a ridge of
high pressure build across Texas in response to a deepening storm
system that will be centered around the Great Lakes region.
The high pressure systems and northerly flow will help drive any
remnant rainfall south of the the RGV and generally bring a much
drier air mass to the Deep South Texas. Temperatures will begin to
warm up to near or even above normal values once again.
However... with the dry air in place...the heat indices will not
be nearly as oppressive as noted the last few weeks.
Now through Wednesday night...North winds have picked up through
the day, and are almost at SCEC criteria offshore. Will leave it
to the oncoming shift to make that call with respect to the
afternoon CWF issuance. In the mean time, disorganized showers and
thunderstorms over the Southwest Gulf lie along a surface trough
extending north into the lower Texas coastal waters, meaning some
convection may continue offshore in the short term. Otherwise,
looking for mainly light north to northeast winds and low to mdt
seas after tonight.
Thursday through Sunday...Light to moderate N to NE winds will
generally be on place through the period as surface high pressure
dominates the weather through the weekend. Seas will be be in the
2 to 3 feet range.
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 76 87 77 92 / 30 30 30 20
BROWNSVILLE 75 88 76 93 / 30 30 30 20
HARLINGEN 74 89 74 94 / 30 30 20 20
MCALLEN 73 90 74 96 / 30 30 20 20
RIO GRANDE CITY 71 89 73 95 / 20 20 20 10
SOUTH PADRE ISLAND 78 85 79 91 / 40 30 30 20
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