Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 132001

Area Forecast Discussion
National Weather Service Brownsville TX
301 PM CDT Sun Oct 13 2019

.SHORT TERM (Tonight through Monday Night)...

The relatively "cool" weather has been a nice break from what had
been "endless summer" across Deep South Texas and the Rio Grande
Valley (with average temperatures through the 10th running up to 6
degrees above normal, ranking in the top five in several
locations). That cool-ish weather continued today for many inland
locations, were temperatures have only reached the mid 70s as of
230 PM. Toward the coast, partial clearing allowed a bump into the
lower 80s. Each of these trends have been accounted for in a mid
afternoon update, which both lowered forecasts inland and raised
them near the coast in southeast Cameron County.

Hereafter through Monday night, the summer sultriness
returns...gradually overnight and more robustly Monday through
Monday night. For tonight, deeper moisture along a pseudo warm front
remains/shifts north of the region, with perhaps a tail of moisture
continuing through Jim Hogg/Brooks southeast to the Lower Texas Gulf
waters. Left the slight chances for the overnight...matching
guidance consensus. Confidence not very high...and overall
precipitation would be passing light showers with minimal impact.
Otherwise, the only other concern is potential for patchy to areas
of fog.  With light to calm winds and recovery of warm/humid air
expected to raise dewpoints over neutral temperature ground...and
considering length of day...ingredients are in place for some fog
across rural areas. Based on a look at HRRR deterministic and
HREF probabilistic forecasts for low visibility, introduced patchy
wording across the brush country. Signal less clear across the
Valley so left out for now.

Any fog will burn of by 9 AM or so Monday, and any notable forcing
for precipitation shifts north.  What`s left is the potential for
isolated streamer showers/few storms mainly in the Gulf.  Current
forecast of 90 to 95 from east to west was left alone...a lean
toward the ECMWF which has done best through this summer and early
fall when the heat is on.

The soup arrives in full Monday night as light gentle southeast
breezes return.  Those breezes should end any fog threat though
sometimes the northern ranchlands can see development.  Lows will be
similar to those last work week (lower to upper 70s)...10 degrees
above average for mid October. Overall deep dry air sufficient for
no mentionable rainfall.


.LONG TERM (Tuesday through Sunday)...

A strong ridge of high pressure aloft anchored across the CWA on
Tuesday will boost temps well above normal.  Limited moisture and
subsidence will keep things dry as well.  A cold front is expected
to move slowly southward overnight Tuesday, reaching the northern
ranchlands by Wednesday morning.  A gradual push south across the
CWA is expected on Wednesday.  Sufficient moisture aided by an
accompanying shortwave will boost PWATs up to 2.2 inches on
Wednesday. Dynamical forcing from this shortwave and the RRQ of
an upper jet streak along with kinematic forcing are expected on
Wednesday. As a result, will go with at least chance to likely
POPs for much of the CWA for Wednesday and Wednesday night. With
the front expected to stall near or just south of the CWA on
Thursday, decent rain chances will persist, especially across the
southeast areas and the adjacent waters given the strong coastal
troughing in this region. A bit of a drying trend is expected for
the end of the week as another shortwave moves through the CWA and
advects the deeper moisture east and northeast of the CWA. Not
totally convinced that we will completely dry out and so will tend
to keep slight chance to chance POPs for mainly eastern areas.
Will indicate a warming trend during this timeframe as the airmass
really begins to modify quickly. An influx of deeper moisture on
Sunday ahead of the next strong cold front will maintain chance

NHC and some NWP output has been indicating the small potential
of a weak low pressure area developing across the southwest Gulf/Bay
of Campeche towards the end of the week. Even if this scenario does
pan out, the westerly shear will keep any such system weak and
likely remain east and northeast of the CWA. Indirectly, it will
only likely contribute to the continuing elevated water levels and
resulting minor coastal flooding.



Much has quieted down since Friday afternoon-Saturday with
moderate seas and light to moderate winds. As gradients collapse
completely overnight (coastal trough dissipation) winds should
drop to 10 knots or less on the Gulf and nearly calm over the bay.
Southeast winds generally 10 knots or less Monday with the usual
afternoon increase over Laguna Madre...then gradient picks up
overnight over the Gulf but still 15 knots or less...with seas
remaining at 3 feet or less though wind waves will increase a

Otherwise...scattered showers/few thunderstorms tonight fading to
isolated streamers (mainly Gulf) Monday and no mentionable
precipitation Monday night with deeper dry air in place.

Brief SCA conditions will be possible on Wednesday across the
offshore waters as the next cold front moves south across the CWA.
Coastal trough development Wednesday night through Friday morning
will contribute to numerous to widespread showers and
thunderstorms over the waters. A weakening of the coastal trough
by the end of the week will diminish winds and seas and also rain
chances. Rain chances will increase once again by Sunday as
another surge of moisture occurs ahead of the next strong cold
front early next week.


BAYVIEW/PORT ISABEL  72  89  77  91 /  20  20  10   0
BROWNSVILLE          71  91  78  93 /  20  10  10  10
HARLINGEN            70  92  75  94 /  20  10  10   0
MCALLEN              71  94  77  97 /  10  10  10   0
RIO GRANDE CITY      70  96  74  99 /  10  10  10   0
SOUTH PADRE ISLAND   77  86  82  86 /  20  20  10  10




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