Area Forecast Discussion
Issued by NWS Brownsville, TX

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658
FXUS64 KBRO 201003
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
403 AM CST Mon Jan 20 2020

.SHORT TERM (Now Through Tuesday): Mid-level 500 mb ridging will
gradually build across the region through the short term period
while surface high pressure over the state shifts to the east on
Tuesday. As the surface high advances eastward, anticipate for
returned onshore flow. The flow will advect higher dew points into
the region, resulting in increasing cloud cover during Tuesday.

Slightly below average but comfortable temperatures will remain
through Tuesday. Do anticipate for a slightly cooler night for
tonight into Tuesday morning as less cloud coverage is expected
compared to the current early morning hours this morning as a
mixture of mid-to-high level clouds have kept the temperatures
slightly elevated compared to previously forecasted. The high
temperatures will trend in the mid 60s today while the highs
increase to around 70 degrees on Tuesday. Expect little to no
rainfall with near zero pops on Monday and near 10 percent for
Tuesday.

.LONG TERM (Tuesday Night through Sunday): A shortwave mid/upper-level
trough will replace a west-to-east-exiting shortwave ridge over
Southern Texas Tuesday night into Wednesday morning. Vorticity
advection associated with this shortwave trough will enhance lift
upstream of its axis, producing showers and possibly isolated
thunderstorms Wednesday and Wednesday night for Deep South Texas.
Precipitation will end west-to-east on Thursday morning as drier
and more stable air advects in from the west. At the surface,
global models are in better agreement that low pressure develops
and deepens Wednesday morning across the Panhandle of
Texas/Northwest Texas. This will increase the pressure
gradient/southeast winds, especially along the coast, during the
day on Wednesday. A cold front will push through the CWA Thursday
afternoon into the early evening as the surface low progresses
southeastward across northern Texas and towards the northern Gulf
of Mexico by Thursday evening.

The latest runs of the GFS and ECM models begin to diverge
Thursday night and into Friday morning. The ECM has dry and stable
conditions persisting for South Texas through Saturday, before an
upper-level low/shortwave trough approaches from the west and
increases showers and thunderstorms Sunday evening and into
Monday. Meanwhile, the GFS suggests a series of high amplitude
shortwave troughs/ridges flowing over Texas Saturday through the
end of the long-term period. Went with a blend of these two
solutions Saturday-Tuesday for now.

Warmer than average high temperatures will persist Wednesday and
Thursday afternoons, with Thursday being the warmest day of the
week (highs in the upper 70s/lower 80s). High temperatures will
fall back to near seasonal average Friday-Sunday; highs in the
upper 60s to near 70 degrees each day. Low temperatures will
remain above average through Friday morning before dropping down
to near average Saturday and Sunday mornings, behind Thursday`s
cold front.

&&

.MARINE (Now through Tuesday): Marine conditions remain adverse
across the Lower Texas coastal gulf waters as buoy observations
indicate continued moderate to breezy northeasterly winds and
elevated seas of 7 to 9 feet. Adverse marine conditions will
continue throughout today as the pressure gradient remains
concentrated over the region. A Small Craft Advisory continues
across the lower Texas coastal gulf waters through 9 pm Monday.
Marine conditions will gradually improve into and throughout
Tuesday.

(Tuesday night through Saturday): Marine conditions will
deteriorate once again starting late Tuesday night and into
Wednesday as southeast winds and seas increase ahead of the next
cold frontal boundary on Thursday afternoon/evening. Small Craft
Advisory conditions are expected on Wednesday and will continue
into Thursday morning. A lull in winds and seas will occur ahead
of and along the front on Thursday. Northerly winds and seas are
expected to increase again Friday and Saturday behind Thursday`s
cold front. At this time, SCA are not anticipated behind the
front, but cannot rule out SCEC conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  65  51  68  59 /   0   0  10  20
BROWNSVILLE          67  51  69  60 /   0  10  10  20
HARLINGEN            66  48  70  58 /   0   0  10  20
MCALLEN              66  49  69  60 /   0   0  10  20
RIO GRANDE CITY      66  47  70  58 /   0   0  10  30
SOUTH PADRE ISLAND   65  53  66  61 /   0  10  10  20

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory until 9 PM CST this evening for GMZ150-155-
     170-175.

&&

$$

This product is also available on the web at:
HTTP://WEATHER.GOV/RGV

Short Term/Aviation...Brady-62
Long Term...Mejia-67
Upper Air...Castillo-61



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