Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 201146 AAA

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
646 AM CDT Thu Oct 20 2016

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


.AVIATION...l/v to calm winds currently at local airports will
shift to the northeast after sunrise. Some fog formation has been
noted at sites to the north of the valley, but should remain
minimal and brief at the main TAF sites. Showers noted on radar
are a bit farther offshore than expected, so showers at local TAF
sites may be delayed until late morning. Shower activity will
increase from the north late in the afternoon as the front
arrives. Brisk north winds will not arrive until after sunset,
with winds increasing to 15 to 20kts.


.PREV DISCUSSION... /issued 417 AM CDT Thu Oct 20 2016/

SHORT TERM (Now through Friday): The cold front has begun
progressing through Texas this morning, currently about half way
through the state. The front will not reach Deep South Texas
before sunset, so there will be one more day of full daytime
heating for the region. Winds today will already shift to the
northeast as weak prefrontal troughing sets up along the coast.
This will also provide a focus for showers and thunderstorms,
enhanced by moisture pooling ahead of the front. Shower activity
will hold temperatures down some from the past several days, but
will still reach the lower 90s. The cold front will finally pass
through the region later this evening, with a final round of
showers during passage. Most significant cold air advection will
not really get going until after sunrise, so lows tonight will
only fall into the mid 60s. The front will slow down late tonight,
hanging up near KBRO for most of the day Friday. This will keep
the threat for showers continuing for the lower valley through
much of the day Friday. Most of the rest of the region will see
gradual clearing as the drier air moves in with the core of the
surface high.

LONG TERM (Friday Night through Wednesday): Models are in fair
agreement with the mid level flow but uncertainty enters the
picture in regards to the moisture parameters as the forecast
moves into the end of the weekend and the beginning of next week.

A cool start to Saturday morning followed up by mild dry day
as high pressure will reside overhead and at the surface. The low
humidity and drier conditions don`t last too long as Surface high
pressure quickly moves east and a mid level shortwave moves into
Texas later Sunday exiting to the northeast Tuesday. GFS is
trending more aggressive with pops showing deeper moisture while
the ECMWF is trending much lower with pops as the moisture depth
and content not as aggressive. Forecast takes the middle road but
with a lot of uncertainty confidence is low. Forecast remains dry
on Sunday but clouds will likely increase with southwest winds
aloft increasing as the shortwave approaches. Will play up a slight
chance pops for the entire CWA Monday as the disturbances passes
across the state and will tapper off the chances on Tuesday as the
impulse weakens and tracks eastward. The rest of the week with
remain dry as a ridge builds over Western Texas and NW Mexico.
After the cool start Saturday temperature guidance trends upward
fairly quickly with a dominate ridge over the region. ECMWF is
warmer during the day with GFS showing warmer overnight
temperatures. The daytime warming might be slowed Sunday through
Monday with the disturbance move nearby and the increase in clouds
and low rain chances. Again confidence remains below average due
to the indifference of the spread of the model solutions.

MARINE:(Now through Friday): Light and variable winds will shift to
the northeast later this morning as a trough develops along the
coast ahead of the approaching front. Winds will remain light
through sunset, allowing seas to hover around 2 feet. The cold front
races across the coastal waters later this evening, with an expected
surge of northerly winds reaching 20 knots. Small Craft Advisories
will be posted with the next update starting later this evening and
continuing through at least sunset Friday. Gusty north winds will
agitate seas up to 8 to 9 feet offshore through the short term
period. The front is also expected to be accompanied by a broken
line of showers and thunderstorms, which may further agitate marine
conditions temporarily on passage.

Friday night through Monday...Winds and seas continue their
gradual lowering Friday night into Saturday as surface high
pressure builds into the nortwest gulf. Small craft advisories to
linger into Friday night with seas slower to lower. High pressure
builds over the Gulf Sunday then moves east next week with a
moderate east to southeast flow returning. Some showers or even a
few thunderstorms may enter the picture next Sunday night trough
Tuesday as Gulf moisture returns along with the southeast flow.


GM...Small Craft Advisory from 10 PM this evening to 7 PM CDT Friday
     for GMZ130-132-135-150-155-170-175.



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