Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 240906

Area Forecast Discussion
National Weather Service BROWNSVILLE TX
406 AM CDT Mon Oct 24 2016

.SHORT TERM (Today through Tuesday): Back to the Autumn weather
doldrums. The relatively cool and drier air has retreated and the
typical muggy Deep South Texas weather regime has returned. The
advertised shortwave trough is crossing Texas as we write without
much fanfare in our CWA outside of some multi-layered clouds.
Moisture values and depth remain depleted especially in that mid
layer between 850-600mb keeping the chance of rain near or below
10 percent. Model guidance continues to show very low pops so
confidence remains rather high that no accumulated precipitation
will develop today. The mid level shortwave trough weakens as it
lifts northeast tonight and gets absorbed into the general
westerly anticyclonic flow Tuesday leaving all of Texas under a
broad mid level ridge. The dry mid layer deepens but moisture in
the near surface layer increases as the influx of Gulf moisture in
response to a broad easterly flow continues. No substantial lift
provide by a weak seabreeze and with subsidence provided by the
building mid level ridge keeping us under a partly to occasionally
mostly cloudy sky with no rain anticipated. As for temperatures
the broad mid levels ridge and increasing dew points will maintain
near to slightly above normal highs, upper 80s to lower 90s and
lows mid 60s to lower 70s.

LONG TERM (Tuesday night through Monday):

At the beginning of the long term, broad H5 ridging will run from
west to east in a zonal pattern. A short wave trough signature will
be over the High Plains, moving east. Surface high pressure will
extend over the North Gulf from the north.

A weak east to east southeast wind will prevail on Wednesday, and
sea breezes will be possible then and each afternoon through Friday.
A weak surface trough axis will be marked by showers moving up the
West Gulf shoreline along Northeast Mexico. Through the end of the
week, mid level ridging over North Mexico and the Southwest border
states will also influence the local area, providing stability
aloft, leaving open only the Gulf for the introduction of any rain
chances, which will remain slight.

Late in the week, the GFS seems to develop a Western Caribbean low,
which will help tighten the gradient over the East Gulf. Other than
that, and the potential for more swell moving toward the CWA, the
effects of the feature for the CWA appear to remain minimal during
the forecast period. The ECMWF is less solid with the development of
any low, but does carry a weak surface circulation nonetheless.

In summary, upstream ridging will block any serious weather threat
from the west, while activity over the Gulf will be more inclined to
show up on the doorstep as Gulf based shower or diurnal sea breeze
activity. Without a strong focusing mechanism or lift rainfall, if
any, will remain fairly light. Temperatures will be around five to
ten degrees warmer than normal.


Today through Tuesday...Broad surface high pressure extends
across the entire Gulf Waters with weak low pressure over West
Texas. This will maintain a light to moderate southeast wind and a
low sea. Latest buoy data suggest the long period swell has
temporarily relaxed with mainly a local wind wave to impact the
coastal waters through Tuesday.

Tuesday night through Friday...Broad ridging will extend across
the Gulf, but at the surface high pressure will weaken slightly,
yielding to lower pressure both upstream and over the Southwest
Gulf. Light to moderate east winds will prevail across much of the
Gulf, with low to moderate seas which will include a significant
swell component. Swell may add another foot to wave heights by
Thursday and Friday as the persistent east winds continue across
the Gulf, with exercise caution conditions for seas possible going
into the weekend. Despite stabilizing ridging aloft, low level
instability over the Southern Gulf will be enough to support
shower and thunderstorm generation, and isolated nearshore and
coastal convection will be possible at times.


BAYVIEW/PORT ISABEL  87  73  86  71 /   0  10  10  10
BROWNSVILLE          88  71  89  70 /   0  10  10  10
HARLINGEN            89  71  90  68 /   0  10  10  10
MCALLEN              91  70  93  68 /  10  10  10  10
RIO GRANDE CITY      88  67  89  67 /   0  10  10   0
SOUTH PADRE ISLAND   82  76  84  74 /   0  10  10  20




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