Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 201940

Area Forecast Discussion
National Weather Service Brownsville TX
240 PM CDT Tue Mar 20 2018

.SHORT TERM (Tonight through Wednesday Night): Drier air continues
to filter into the Rio Grande valley this afternoon and surface high
pressure will continue to settle into south Texas and the western
Gulf of Mexico tonight. Clear skies and light winds tonight will
allow temperatures to fall into the 50s across most of the CWA with
temperatures in the lower 60s along the lower TX coast. The surface
pressure ridge will shift eastward Wednesday allowing winds to veer
more to the east and increase as the pressure gradient increases
across the area. Temperatures will be in the lower 80s across the
lower RGV to the middle 80s across the middle to upper RGV Wed
afternoon. Winds will veer to the southeast Wed night but moisture
appears limited for fog to develop Wed night. Temperatures will be
warmer Wed night with lows in the upper 50s north to lower to mid
60s south.

.LONG TERM (Thursday through Tuesday): As surface high pressure
continues to spread eastward across the northern Gulf states, a
warm/moist return flow will set up across the valley. Aloft,
upper level ridging will be setting up over northern Mexico and
southern TX. This will help keep the upper levels dry and should
help keep surface temps warm. Surface lee side trough is expected
just to our west through out the weekend. This troughing along
with the surface ridge will develop strong southerly winds. In a
well mixed boundary layer, expect winds to pick up by early
afternoon through sunset. Drier air aloft should be able to mix
downward, especially inland. There may be daily fire weather
threats as RH values drop to around 30% and winds gust upward of
20kts at times. There will also be a substantial temperatures
gradient across the region. Falcon Dam area may hit 100 through
the weekend, however, much cooler low to mid 80s expected near the
cooler waters.

The upper level ridge begins to spread eastward in time and a more
active southwest flow aloft develops as a strong upper level ridge
settles into the four corners region. Kept pops in as QPF signal
is present on most of the globals, however, given subtle
differences didn`t go quite as high as the blends.


.MARINE (Tonight through Wednesday Night): Seas were near 6 feet
with north winds near 21 knots at buoy020 early this afternoon.
Light to moderate northeast to east winds will prevail across the
coastal waters tonight as surface high pressure settles across the
western Gulf of Mexico. The pressure gradient will increase
Wednesday as low pressure develops across west Texas Wed afternoon.
Winds will veer to the east and increase Wednesday before veering to
the southeast Wed night. Moderate to strong southeast winds will
develop across the offshore waters Wed night as the pressure
gradient remains strong across the western Gulf. Small craft
advisories may be needed for the offshore waters Wed night.

(Thursday through Tuesday): The long term period starts tranquil,
however, marine conditions will decline going into next weekend as
southerly flow strengthens between high pressure to our east and
surface lee side trough to our west. This will bump winds and seas
up to Cautionary or perhaps SCA thresholds for some if not all
weekend. A pattern shift is then expected early next with with
continued breezy conditions as a cold front stalls fairly close to
the region. Additional SCA look possible early next week.


BAYVIEW/PORT ISABEL  62  79  65  81 /   0   0   0   0
BROWNSVILLE          59  81  64  83 /   0   0   0   0
HARLINGEN            58  82  62  84 /   0   0   0   0
MCALLEN              58  85  64  85 /   0   0   0   0
RIO GRANDE CITY      58  86  63  86 /   0   0   0   0
SOUTH PADRE ISLAND   64  76  68  79 /   0   0   0   0


GM...Small Craft Advisory until 4 PM CDT this afternoon for GMZ170-



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