Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 311803 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
103 PM CDT TUE MAY 31 2016

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

&&

.AVIATION...Fairly quiet for the moment at the terminals, apart
from some breezy S-SE winds...gusting to 22KT at MFE. Otherwise
VFR conditions in place. Main forecast challenge regarding
aviation concerns over the next 24 hours is timing of periods of
thunderstorms. Will retain previous TAF`s idea of convection
developing this afternoon, as upper-level ridge has begun to
flatten and move eastward. Will have to watch this for amendments
though, as not much development noted just yet. May be a break in
the convection after sunset until an upper-level disturbance
approaches...possibly affecting MFE after 06Z, but lower
confidence for HRL and BRO. Thunderstorms could develop again by
late morning on Thursday, but confidence on timing not especially
high since much will depend on what happens between now and then.
Will cover with PROB30`s for now.

&&

.PREV DISCUSSION... /issued 458 AM CDT TUE MAY 31 2016/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...A couple streamer showers already popping up around
the valley, but they should stay away from the local airports
before sunrise. Later this morning, shower activity will become
more widespread, with passing mvfr bases. stronger thunderstorm
activity is expected starting around noon, with heavy downpours
and locally gusty winds. Storms will move slowly, so any storms
in the vicinity of airports may delay operations for a significant
amount of time. Winds today will remain modest from the southeast,
reaching 10 to 15 knots with a few higher gusts in the afternoon.

PREV DISCUSSION... /issued 359 AM CDT TUE MAY 31 2016/

SHORT TERM (Today through Wednesday): The next 36 hours will be marked by
the continued active southwesterly flow aloft ahead of the H5 low
diving into north Mexico. Models continue to indicate a very moist
atmospheric profile into Wednesday, with minimal to no capping and
PW values in excess of 1.8 inches. Showers and thunderstorms will
start to develop later this morning, initially popping up on any
remaining outflow boundaries from yesterday, with enhancement
likely later in the day when the next midlevel impulse moves into
south Texas. Storm motion forecast to be 5 knots or less areawide,
so any thunderstorms that develop will be slow moving and outflow
dominated. Evening sounding showed CAPE above 2500 with minimal
capping. Enough instability is available, especially with passing
impulses, that some storms could get strong, with some hail
possible. Once daytime heating ends, and remaining storms
stabilize the atmosphere, a period of calm will arrive overnight
tonight, before the next round of showers develops sometime
tomorrow. Expect things to spark along the seabreeze and any
remnants outflows.

LONG TERM (Wednesday Night through Monday): A heavy rainfall
event is expected to develop across portions of the CWA Wednesday
night into Thursday and possibly continue into Friday...as the
500mb low across northern Mexico and west Texas Wednesday moves
into portions of west-central TX Thursday and meanders across
portions of central TX Friday. With the abundant low to mid level
moisture across south TX...showers and thunderstorms...some
producing heavy rainfall...will develop across portions of south
TX Wed. night through Friday as steep lapse rates prevail across
the area and a weak cold front across north TX Thursday moves into
south TX Friday and stalls providing a focus for low level
convergence. A flash flood watch will likely be needed for the CWA
Wed. night and Thursday and possibly through Friday. With the
upper level low drifting across south TX Saturday...rain chances
will continue to remain high through the rest of the week into the
weekend before some drier air filters into the area by the end of
the weekend into early next week. &&

MARINE:
Now through Wednesday...Modest southeast flow will continue
through the next 36 hours as low pressure moves through the
central plains and high pressure remains across the gulf. this
will keep seas 3 to 4 feet through the period. Some shower and
thunderstorms activity is possible, mainly right along the coast.

Wednesday night through Saturday...Moderate to strong southeast
winds will prevail across the coastal waters Wed. night before the
pressure gradient begins to weaken Thursday as a weak cold front
moves into north Texas. Moderate southeast winds should prevail
Thursday and Friday before veering to the south and diminishing
Saturday as a broad area of low pressure develops across the lower
TX coast.

&&

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

$$

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