Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 182347 AAA

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
647 PM CDT Mon Mar 18 2019

.DISCUSSION...Will let Coastal Flood Statement expire as scheduled
at 7 PM. Webcams at South Padre Island indicated that water was
not washing up to the dunes, even at normally narrower spots on
the beach, around high tide at 4:03 PM. Tidal gauges also show
slightly lower readings vs. 24 hours ago. While these readings
are still running nearly 1 foot above predicted levels, tomorrow
afternoon`s high tide is predicted to be lower than those of the
past several days. Another complicating factor is the easterly
swell that is expected to reach the coast late tonight or early
tomorrow morning. So, while tidal overwash to near the dune line
may return tomorrow afternoon, the current episode appears to be
winding down.


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


.AVIATION...Area of light rain apparent on KBRO radar should move
east of all the aerodromes by 01-02Z. Thereafter, stubborn coastal
trough will continue to dominate the weather over the next 24
hours. Light northerly winds and VFR ceilings should continue
overnight. By mid-day Tuesday, the trough axis is progged to move
inland, shifting winds to NE and lowering CIG`s to MVFR, as well
as increasing precip coverage due to convergence associated with
the trough.


.PREV DISCUSSION... /issued 242 PM CDT Mon Mar 18 2019/

SHORT TERM (Tonight through Tuesday Night): Skies are overcast
with light, low level north winds under more southwesterly flow
aloft. There was an elevated inversion base at BRO this morning
around 4 kft, and a few light showers continue to drift across the
CWA from west to east this afternoon, mainly in the saturated
lower portion of the inversion. A trough of low pressure lies
offshore, and moisture continues to funnel north along the trough

Light rain chances will continue through the short term as the
coastal trough remains largely in place and the upper pattern
remains rather zonal. Subtle dips in the 500 mb pattern may provide
weak enhancement of rain chances, though timing remains tricky.
Showers may increase a little in coverage for the lower valley
tonight as one of these weak pulses moves overhead. Temperatures
will be below normal for this time of year.  Look for 50s and some
60s overnight, and mid to upper 60s Tuesday during the day.
Otherwise, the cloud, cool weather with spotty light showers will
continue through the next 36 hours.

LONG TERM (Wednesday through Monday): Highly amplified pattern
sets up for the latter half of the week, with large trough diving
along the east coast, and another trough ejecting into the Four
Corners region. This leaves Texas in ridging between, so active
weather will be minimized. There is a little isentropic lift
trying to set up Wednesday and Thursday, so the latter half of the
week will still see cloudy skies and light precipitation.

Friday and Saturday the western trough moves eastward into the
Central Plains. This will bring better diffluence aloft, along
with more scattered vorts embedded in the southern edge of the
trough. This will lead to a better chance for showers and
thunderstorms, vs. the gray and drizzly pattern before it. While
the midlevel energy will be present, the lack of a surface forcing
mechanism will limit the chances for organized convection, so
shower activity Friday and Saturday will be scattered, with better
chances to the north closer to the main part of the trough.

Sunday the leading edge of the trough will be moving north, lack
of midlevel support will lower rain chances. Models have continued
to back away from the next frontal passage, and are now waiting
for the trailing lobe of the larger-scale trough to swing around
into Texas Sunday night, driving the dryline southeastward on
Monday. Still low confidence on it getting to south Texas, but if
this pattern holds out, it would bring light south to southwest
flow to the valley, which would push temperatures well into the
90s a week from now.

Now through Tuesday night: Coastal troughing will remain in place
through Tuesday night, supporting moderate northeast to east
winds. A long Gulf fetch will provide a swell contribution,
resulting in elevated Gulf wave heights. Small craft should
exercise caution to low end small craft advisory conditions will
be possible on the Gulf tonight through Tuesday night.

Wednesday through Saturday: For the remainder of the week, winds
will remain nearly easterly with high pressure across the lower
Mississippi valley. Winds would remain around 10 knots, but the
long fetch would continue to press long period swells up against
the coast. Southeast flow would finally reestablish Friday night
into Saturday as the high moves east and low pressure tries to
form in the Panhandle. Winds would likely remain at or below 15
knots, as the Panhandle low has trouble organizing to start.




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