Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 162101

Area Forecast Discussion
National Weather Service Brownsville TX
301 PM CST Fri Nov 16 2018

.SHORT TERM (Tonight through Saturday Night):A mostly
zonal/progressive flow will reside aloft over Deep South Texas
through the short term period. At the surface, high pressure that
brought us below average temperatures will continue to gradually
slide eastward over the Gulf of Mexico. Surface winds have
transitioned to more of a southerly or southeasterly flow. This
should help increase moisture just a bit across the CWFA through the
weekend. Temperatures will gradually increase too with some places
reaching near 80 degree in the mid and lower valley on Saturday.

Eventually, a cold frontal boundary will drop southward into TX
later this weekend just beyond the scope of the short term period.
As low level moisture increases and as a coastal trough sharpens
offshore, there is some developing QPF signal by later Saturday or
early Sunday. At this time the best signal resides right along the
coastline through 12z Sunday. The short term ends with cool, gloomy,
and damp conditions (what we tend to expect with a coastal trough).

.LONG TERM (Sunday through Friday):A lot of uncertainty is
creeping into the models mainly in the day to day pops and
temperatures details. Latest model suite remains rather wet
Sunday-Monday with pops beginning to taper off Tuesday. Current
thinking and trends for the travel day before Thanksgiving (Wed)
and Thanksgiving Day is for rain chances to be limited and
possibly ending by Thursday.

Shortwave energy within the subtropical southern stream looks to
produce a surface trough over South Texas and NE Mexico Sunday.
A influx of Gulf moisture will be well underway with PWATS
nearing 1.7 inches along the immediate coast. Rain chances
increase and Sunday looks wet with best chance along the coast
where some moderate rainfall is possible. A mid level trough
moves through the Rockies Sunday with a cold front moving into
South Texas Sunday night into Monday. Surface high pressure is
relative weak and mid level flow remains more zonal then northwest
to southeast so expect the surge of cooler air and the frontal
passage to be weak. Sunday night and Monday surface trough moves
east and sets up along or just off the coast as the cold front
pulls up stationary south of the Rio Grande. Surface convergence
and southeast 850mb flow over the relative cooler air is likely to
produce another good chance of rain Monday once again with the
best chances along the coast. All three models show widespread
coverage of rain with differences in amounts and placement. Looks
likely the EC is plagued by convective feedback east of Kenedy
county with better overall QPF depicted by the GFS. As for
temperatures GFS remains the warmest while the NAM is much colder
and EC is in between the two for Monday.

For the latter half of the period as well as the holiday a strong
shortwave trough in the southern stream moves over Texas
Wednesday. Coastal trough remains in place keeping the best rain
chances for the Eastern coastal counties for Tuesday and early
Wednesday. Expecting light rain showers at times maybe some
drizzle at night. As the shortwave trough tracks over the state
Wednesday the the coastal trough begins to lift northeast and
shortwave ridge moves in from the west Thursday. The travel day
before thanksgiving may start off wet but may end up drier with
Thanksgiving day may looking like a very nice day with mild
temperatures and decreasing cloudiness.


.MARINE:(Tonight through Saturday Night): Favorable marine
conditions expected through much of the short term marine period.
High pressure will initially be in control with light winds and seas
across adjacent waters and the Laguna. Eventually, the southerly
flow will begin to strengthen in time, especially toward the end of
the cycle as our next cold front begins to approach the region from
the north. Additionally, coastal troughing will begin developing
toward the end of the short term period. This will likely cause at
least cautionary headlines (SCEC).

Sunday through Wednesday...Weak cold front arrives early Monday
morning and looks to become stationary south of the coastal waters
later Monday and Tuesday. A coastal trough or low pressure area
may form along the front and begin to lift northeast later
Wednesday into Thanksgiving day. Northeast flow in wake of the
front looks weak with only small craft exercise caution possible.
Stronger northerly flow and seas may develop later Wednesday and
Thursday with the departing low pressure area/trough. Low end
Small Craft advisories may be necessary at that time.


BAYVIEW/PORT ISABEL  59  77  67  76 /   0  10  40  60
BROWNSVILLE          58  77  66  76 /  10  10  40  50
HARLINGEN            52  78  66  76 /   0  10  40  60
MCALLEN              56  80  65  75 /   0  10  30  50
RIO GRANDE CITY      52  79  62  73 /   0  10  20  50
SOUTH PADRE ISLAND   64  77  70  74 /   0  10  40  60




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