Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 241146 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
646 AM CDT Fri Mar 24 2017

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

&&

.AVIATION...Low cloud decks with moderate and gusty south-
southeast winds prevail across Deep South Texas this morning.
MVFR ceilings should persist at all TAF sites through mid
morning. The interaction between high pressure and an approaching
frontal boundary from the west will support breezy south-
southeast winds this morning into the afternoon. Winds will
lessen some as the weak front moves into the area later this
afternoon. MVFR ceilings may return late tonight towards sunrise
Saturday but will maintain VFR conditions overnight for now.

&&

.PREV DISCUSSION... /issued 444 AM CDT Fri Mar 24 2017/

SHORT TERM (Now through Saturday): Above normal temperatures will
continue through the short-term. Current water vapor imagery shows a
500mb low over the High Plains and much drier airmass across
northern Mexico and west Texas. The latest surface analysis shows a
cold front across northwest Texas extending south to the Big Bend
region. The latest BRO VAD winds indicate south winds between 35 to
40 knots below 2000 feet. Moderate and gusty south-southeast winds
persist across the area early this morning due to the 850mb jet.

The mid level low/trough will move over Oklahoma today, pushing a
weak cold front into Deep South Texas this afternoon. A few showers
or thunderstorms will be possible across the northern ranchlands,
but the main energy will remain well to the north of the region.
Breezy to windy conditions will develop/continue across the area
this morning courtesy of the interaction of the front/surface trough
and high pressure across the Gulf of Mexico. The latest short term
guidance suggests winds should not reach or marginally reach wind
advisory criteria this morning. Will hold off on the mention of a
wind advisory at this time due to below average confidence and the
brief opportunity to reach wind advisory criteria. Winds will
decrease from west to east later today as the surface
trough/boundary moves eastward. Drier air will filter into the
western half of the CWA this afternoon. High temperatures today will
range from the 80s near the coast to the low to mid 90s across the
west.

The 500mb low will lift northeast tonight and Saturday as mid level
ridge axis moves over Texas. Low temperatures tonight will be in the
60s, except for the lower 70s along the coast. Partly cloudy skies
and light winds are expected across the area tonight. High
temperatures Saturday will range from the 80s along the coast to the
low to mid 90s inland under partly cloudy skies.

LONG TERM (Saturday Night through Thursday): The majority of the
long term forecast period will be dominated by surface high
pressure and a nearly zonal 500 mb flow over Deep South Texas and
the Rio Grande Valley. This pattern will allow a trio of weak cold
fronts that will intrude into the BRO CWFA but not fully move
through, resulting in dry weather for the aforementioned time
period. For the final 48 hours of the long term forecast period,
however, 500 mb low pressure moving through the Central Plains
will allow of pair of cold fronts to sweep through the BRO CWFA,
but with available moisture at paltry levels, no precipitation is
forecast with either of these fronts. Daytime high and overnight
low temperatures are expected to remain at well above normal
levels despite the frontal intrusions and passages.

MARINE (Now through Saturday): Buoy 42020 reported south-southeast
winds around 21 knots with gusts near 25 knots and seas of 5.9 feet
with a period of 7 seconds at 03 CDT/08 UTC. Breezy south-southeast
winds will prevail along the Lower Texas coast this morning due to a
tight gradient. A surface trough will move across Deep South Texas
later today and will weaken the gradient. Light to moderate winds
are expected across the coastal waters tonight and Saturday as weak
high pressure builds across the area. Gulf seas will remain elevated
through the period. A Small Craft Advisory is in effect until 4 pm
today for the Laguna Madre due to the strong southeast winds. A
Small Craft Advisory is in effect for the Lower Texas Gulf waters
through 7 pm, which may need to be extended for elevated seas.

Saturday Night through Thursday: The most favorable wind and sea
conditions will occur Monday night through Tuesday as a weak cold
front intrudes into Deep South Texas and the Rio Grande Valley and
weakens the surface pressure gradient. Outside of the mentioned
time period, Small Craft Advisory winds and/or seas will prevail
for all or portions of the Lower Texas coastal waters due to the
interaction between high and low pressure.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 4 PM CDT this afternoon for
     GMZ130-132-135.

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

&&

$$

This product is also available on the web at:
HTTP://WEATHER.GOV/RGV

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