Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 211737 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
1237 PM CDT WED SEP 21 2016

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

&&

.AVIATION...Atmospheric moisture limited to the lowest 10000
feet, so cu field is having trouble gaining altitude. a couple
showers are still forming, but the dry air aloft is holding them
in check. Winds currently are light and variable, but will slowly
shift southeast this afternoon as the weak seabreeze moves inland.
Winds will become l/v again overnight, and cloud cover will end
with the loss of daytime heating. Winds will again be light and
variable through most of the morning, with no shower activity
expected at local airports.

&&

.PREV DISCUSSION... /issued 626 AM CDT WED SEP 21 2016/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...A very dry atmosphere will aid in ensuring VFR
conditions through the next 24 hours, with no rain and only a few
clouds anticipated. Light winds right now will veer throughout the
day before becoming light and variable tonight.

PREV DISCUSSION... /issued 350 AM CDT WED SEP 21 2016/

SHORT TERM (Today through Thursday): The most recent KBRO upper air
sounding recorded only 1.19 inches of precipitable water throughout
the atmospheric column. This dry atmosphere will persist today even
as a weak inverted 500 mb trough passes to the south of the BRO
CWFA, and rainfall is not expected within Deep South Texas and the
Rio Grande Valley. The recent trend of above normal temperatures
will continue. Tonight, the atmosphere will moisten considerably as
a weak surface area of low pressure transitions from the western
Gulf of Mexico to the Middle Texas Coast. This increased moisture
will result in isolated showers for the Lower Texas coastal waters,
a trend that will persist on Thursday as the low moves inland.
Another round of above normal temperatures is likely on this day as
well.

LONG TERM (Thursday Night through Tuesday): 500mb ridge across
Texas Thurs night will begin to shift eastward Friday as a 500mb
trough across the western United States moves eastward Friday
into Saturday. Southeast flow aloft veers to the south Friday into
Saturday and to the southwest Saturday into Sunday. Low to mid
level moisture will pool along and ahead of a weak cold front
moving across northwest TX Sunday. Chance of showers and
thunderstorms will increase Sunday into early next week as the
frontal boundary makes its way into south TX Monday. Rain chances
will diminish through the rest of the forecast period even though
the 12Z GFS progs elevated convection across portions of the CWA
through Tuesday even as high pressure builds into the area in the
wake of the front.

MARINE: Now through Thursday...Buoy 42020 reported East winds
around 10 knots with seas slightly under 1.5 feet with a period of
4 seconds at 03 CDT/08 UTC. High pressure over the western Gulf of
Mexico will be briefly interrupted by weak surface low pressure
that will move inland into the Middle Texas Coast tonight through
Thursday morning. Overall, light winds and low seas will affect
the Lower Texas coastal waters with Small Craft Exercise Caution
and Small Craft Advisory not likely.

Thursday night through Sunday...Light to moderate southeast winds
will prevail across the coastal waters Thurs night before the
pressure gradient weakens across the western Gulf of Mexico
Friday as weak high pressure prevails across the northern Gulf of
Mexico. Light southeast winds will prevail across the western
Gulf of Mexico Friday. The pressure gradient is expected to
increase slightly across the lower Texas coast through the weekend as
low pressure develops on the lee side of the Rockies Saturday and
a weak cold front moves through northwest TX Sunday. Light to
moderate southeast winds will prevail across the coastal waters
Saturday before increasing Sat night. Moderate southeast to south
winds will prevail across the western Gulf of Mexico Sat night
into Sunday.

&&

.BRO Watches/Warnings/Advisories...
TX...None.
GM...None.
&&

$$

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