Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 270524
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1224 AM CDT Mon Mar 27 2017

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

.AVIATION...Satellite imagery shows skies have cleared over Deep
South Texas and the Rio Grande Valley, a trend that should persist
through the overnight hours with moderate winds in place. Monday,
VFR will continue as winds become breezy in the afternoon before
diminishing in the evening. MVFR cloudiness may develop beginning
around sunset.
&&

.PREV DISCUSSION... /issued 706 PM CDT Sun Mar 26 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Intermittent MVFR cigs will continue for another hour
before the CU field begins to dissipate with the loss of daytime
heating. Meanwhile, a strong capping inversion near 875mb will
allow low level moisture to remain in place and do expect some
cloud cover overnight, although cigs should remain mostly VFR.
Winds will continue to lessen as the surface decouples and the
pressure gradient weakens through the evening. Another gusty
day is expected on Monday, although speeds should be lower than
today.

PREV DISCUSSION... /issued 340 PM CDT Sun Mar 26 2017/

SHORT TERM (Tonight through Monday Night): The next midlevel trough is
currently crossing into northern OK, with a trailing cold front
across central Texas. Main effects for our area continue to be the
strengthening llvl jet along the coast, which is mixing well down to
the sfc. As the midlevel and sfc lows move east into the Ohio
Valley, the gradient between the sfc low and ridging across the Gulf
will decrease, allowing winds to relax as the llvl jet weakens.
Moisture flowing northward near the sfc will keep tempeartures above
normal tomorrow, edging a degree or two higher into the low 90s for
most areas.

LONG TERM (Tuesday through Sunday): The 500 mb pattern over
southern TX and the South Central Plains will be fairly typical of
a spring pattern for the region as a series of strong 500 mb
troughs/closed lows dive into the region from the northwest. The
passage of these troughs/closed lows will be marked by pretty
limited deep layer moisture advection through next Sunday.
Accordingly expect only some slgt chc pops through Day 7 with the
passage of both features. CAA will also be pretty limited as well
since the flow pattern is pretty progressive from west to east
which keeps the cooler air out of the southern Plains. Overnight
lows after the passage of the 500 mb systems will likely see the
biggest differences as somewhat drier air moving into the region
will allow for better radiational cooling at night. The surface
wind flow on Wed ahead of the first feature may set the stage for
a heat spike for the RGV as a drier W-SW low level flow may
enhance the downslope effects off of the higher terrain in NE
Mexico.

The ECMWF and GFS models are in pretty good agreement in showing
very limited pops through Day 7 and will go with a general blend
of the two. The ECMWF is maintaining a warmer bias versus the GFS.
Both of the models show pretty good agreement through Day 7 in the
overall 500 mb field and am not sure why the GFS is going so cool
especially towards the end of the forecast period. So will lean
closer to the ECMWF for temps for the RGV. Overall confidence in
the longer range forecast wording is above average today.

MARINE Now through Monday night: Gusty north winds continue this
afternoon due to inflow into the storm system across Oklahoma.
Small Craft Advisory remains in effect thorugh 7pm for the Laguna
Madre, while boaters on the open Gulf waters are advised caution
due to winds of 15 to 20 knots and seas 5 feet or greater.
Agitated marine conditions will continue through the next 36 hours
as southerly flow continues and fetch remains long from the
southeast.

Tuesday through Friday Night...The PGF ahead of both of these 500
mb troughs/closed lows will tighten up next week as the surface
low pressure systems strengthen. So expect some SCEC/SCA
conditions to develop for Tues and Wed for both the Bay and Gulf
waters. The PGF will then relax once again on Thurs and Fri as 500
mb ridging builds back in place over southern TX.
&&

.BRO WATCHES/WARNINGS/ADVISORIES...None.
&&

$$

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