Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 291131 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
631 AM CDT Wed Mar 29 2017

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

.AVIATION...Satellite images and surface observations indicate low
clouds across the CWA this morning. Ceilings were near 1300ft at
KHBV to near 2100ft at KBKS. Visibilities were near 4SM with fog
at KHBV to near 5SM with fog at KAPY. Expect MVFR conditions
through 15Z before a pre-frontal trough moves through the Rio
Grande valley and northern ranchlands later this morning. VFR
conditions will prevail across the CWA this afternoon and evening
as drier air filters into the area. Low level wind shear will
continue this morning across the coastal sections of the CWA as
a 55kt low level jet continues across the lower Texas coast.
&&

.PREV DISCUSSION... /issued 401 AM CDT Wed Mar 29 2017/
SHORT TERM (Today through Thursday): Satellite and radar images
continue to indicate the quasi-linear convective system across
north- central and central Texas early this morning continues to
move eastward. Some convection is trying to develop on the
southwest flank of the line of showers and thunderstorms but the
warm and dry air aloft across the Rio Grande plains appears to be
inhibiting development further south. With that said...cannot rule
out isolated showers and thunderstorms developing across the CWA
this morning...mainly across the northern ranchlands...before the
prefrontal trough moves through later this morning. Dry air will
filter into the area this afternoon and west to northwest flow
will provide compressional heating which will result in
temperatures into the 90s to near 100 in some locations this
afternoon. The record high for McAllen in 99 degrees set in 2000
and temperatures will be near record highs for the McAllen area
today. A weak cold front will move into deep south TX late tonight
and this will provide a slight chance of showers and
thunderstorms...mainly across the eastern portions of the
CWA...late tonight through early Thurs morning before the front
moves offshore the lower TX coast. Some slightly cooler air will
filter into the area Thursday providing near normal temperatures
for the area for a change.

LONG TERM (Thursday Night through Tuesday): By Thursday night,
the larger H5 trough has swept through the region, and drier air
is fully returning to the region at all levels. Ridging aloft
continues for the area into the beginning of the weekend, keeping
temperatures well into the 90s. Starting Sunday, the next large h5
trough sweeps out of the four corners region into Texas. And as
with the previous few midlevel disturbances, the main dynamics
remain well to the north, and dry air punches into the region
early during passage. This will limit local chances again for
showers, with better chances the further north you go. The
progressive pattern continues to advance early next week, with H5
ridge moving in on the heels of the weekend trough, keeping
temperatures in the 90s through the middle of next week.

MARINE:
Today through Thursday: Seas were near 8 feet with south winds
near 18 knots at buoy020 early this morning. Strong south winds
across the coastal waters this morning will diminish this
afternoon as a surface trough moves across the lower Texas coast.
Will continue SCA for the offshore waters through this afternoon
and let SCA for the Laguna Madre expire this morning. Light to
moderate south winds offshore the lower TX coast this afternoon
will back to the southeast tonight before a weak cold front moves
through the coastal waters late tonight. Winds will shift to the
southwest late tonight and northwest Thurs morning and increase.
Small craft advisories will be needed for the Laguna Madre and
offshore Thurs morning for strong northwest winds in the wake of
the front. Winds will diminish and veer to the northeast Thurs
afternoon as high pressure moves over the northwest Gulf of
Mexico.

Friday through Sunday: Moderate southeast flow continues to sweep
northward across the northwest Gulf, keeping seas agitated over
the weekend. Winds will generally remain 15 to 20 knots, with
higher gusts during the overnight hours. Seas will build again to
5 to 6 feet over the weekend, as a long fetch develops across the
gulf. A weak cold front will move across the Gulf waters Sunday
afternoon, briefly shifting winds to the north, but remaining
around 10 knots.
&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 8 AM CDT this morning for
     GMZ130-132-135.

     Small Craft Advisory until 7 PM CDT this evening for GMZ150-155-
     170-175.
&&

$$

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