Area Forecast Discussion
Issued by NWS Brownsville, TX
FXUS64 KBRO 201158 AAA
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
658 AM CDT SAT AUG 20 2016
.DISCUSSION...Updated for latest aviation discussion below.
.AVIATION...IR Satl imagery shows mid and high level cld cover
from the convection over south central TX moving over the RGV
from north to south. Surface obs indicate some patchy low level SC
decks near the Weslaco area reducing ceilings down to MVFR levels.
The 00z BRO sounding shows drier air in place over the region at
most levels which will likely limit any significant ceilings from
forming over the region. So expect aviation conditions over the
next 24 hours to be mainly VFR with some potential for brief MVFR
conditions due to the lower ceilings.
.PREV DISCUSSION... /issued 401 AM CDT SAT AUG 20 2016/
SHORT TERM (Now through Sunday): The 500 mb ridging that edged
into the Texas coastline over the last couple of days will start
to erode some as 500 mb troffing builds into the central U.S.
This strengthening 500 mb trough axis will in turn push cold front
into central Texas which will then likely stall as a stationary
front later this weekend. Deep layer tropical moisture will remain
concentrated along and south of the cold front/stationary front
through Saturday and Sunday which will maintain pretty significant
pops in the middle sections of the Lone Star state. The deeper
layer moisture values will drop off pretty quickly closer to the
Texas coastline where the 500 mb ridge axis has more of an
influence. The short term guidance reflects this trend pretty
dramatically maintaining likely pops for the LRD area throughout
the weekend with the lower RGV seeing mainly slight chc/low end
chance pops. So will maintain the best pops over the western
counties closer to the deeper moisture levels.
As the conv chcs increase steadily over the region the cld cover
will also be on the increase which will tend to hold down the max
temps and heat indices a bit. The short term temp/pop guidance for
the RGV is in decent agreement through Sunday. So will opt for a
general blend of the short range guidance.
LONG TERM (Sunday Night through Friday): Lingering moisture
from the subtropical jet will interact with a weak upper level
impulse and keep chances for scattered showers and a few
thunderstorms in the forecast to round out the weekend and into
early next week. Precip activity will be largely hit and miss as
overall deep layer moisture will be lacking as high pressure
builds in across the Gulf and Deep South Texas. The 500mb ridge
will set up and strengthen over the mid Gulf region through the
week...keeping subsidence and drier conditions on place. A weakly
inverted trough will bring a quick boost of moisture Thursday into
Friday...but have gone with a dry forecast as moisture levels
remain rather shallow. Temps will start out near normal...with
readings expected to increase a bit through the week due to the
decreased rainfall chances.
Now through Sunday: Buoy020 data from the lower TX Gulf waters
indicates that SCEC conditions are occurring right now with light
surface winds prevailing across the Laguna Madre. A pretty good
surface PGF will prevail along the lower TX coastline throughout
the weekend due to the surface low pressure system moving across
the central U.S. These moderate surface winds will maintain the
marine conditions close to SCEC criteria through Sunday. The PGF
will not be strong enough to likely produce SCA conditions for
either Saturday or Sunday.
Sunday Night through Wednesday Night: Lingering moderate ESE to SE
winds will continue over the coastal waters Sunday night as high
pressure gradually builds westward over the northeastern Gulf.
Seas will continue to be moderate before gradually relaxing later
on Tuesday and through the day Wednesday. Winds will also slacken
as the high pressure becomes centered over the Gulf...reducing the
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