801
FXUS64 KBRO 081953
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
153 PM CST Wed Jan 8 2025

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(Now through Thursday night)
Issued at 151 PM CST Wed Jan 8 2025

The short term forecast for Deep South Texas will feature well below
normal temperatures, breezy north winds, periods of light rain
and/or drizzle, and adverse beach/marine conditions.

Although some light rain/drizzle has developed over the immediate
coast today, most of Deep South Texas has remained rain-free due to
the overall lack of moisture content present. Still, persistent low
level southerly flow (~850mb) has maintained overcast skies as warm,
Gulf moisture overruns the significantly cooler airmass at the
surface. Meanwhile, the latest surface observations and RAP guidance
reveal a tightening pressure gradient in response to a deepening
coastal trough along the Lower Texas and Northern Mexico coast,
which is expected to develop into a coastal low late tonight into
Thursday morning.

We should begin to see an increase in precipitable water after
midnight tonight as the coastal low develops, ranging from 1.2
inches across the Northern Ranchlands to upwards of 1.5 inches
closer to the immediate coast. This should result in an uptick in
precipitation coverage for portions of Deep South Texas tonight. The
latest suite of high res guidance indicates the highest rain chances
(~60-80%) will reside mainly across Cameron, Willacy, and southern
Hidalgo counties, as well as along the immediate coast, which
coincides with the placement of the highest moisture content and
proximity to the coastal low.

The combination of overcast skies, brisk north winds, and increasing
rain chances will result in another chilly night, with lows ranging
from the mid to upper 30s across most of Deep South Texas, and
closer to the low to mid 40s across the Lower RGV and the Lower
Texas beaches. In combination with breezy winds, "feels like"
temperatures tomorrow morning will be in the low to mid 30s
region wide.

The coastal low is expected to track northward along the Lower Texas
Coast on Thursday, which should maintain northerly winds, overcast
skies, and continued precipitation chances through the day. High
temperatures will be similar to today, ranging from the low to mid
40s across the Northern Ranchlands to upper 40s across the Rio
Grande Valley. The latest suite of high res guidance does indicate
we should see a decrease in precipitation chances across the Rio
Grande Valley Thursday afternoon as the coastal low tracks
northward. However, rain chances will return region wide once again
Thursday night as large scale forcing associated with an upper level
trough/low, currently centered over the Desert Southwest, translates
east and northeast and interacts with favorable moisture content.
With temperatures expected to remain above freezing Thursday night,
winter precipitation is not expected at this time.

Otherwise, a high risk of rip currents due to increased winds and
seas will continue across the Lower Texas beaches.

&&

.LONG TERM...
(Friday through next Wednesday)
Issued at 151 PM CST Wed Jan 8 2025

Key Messages:

-Below normal temperatures expected through the long term.

-Rain chances taper off for the weekend but return for the workweek.

The long term period will begin with an upper level trough digging
into northern Mexico and moving through Deep South Texas on Saturday
while a surface low continues to move eastward into the SE US. As
this low pushes eastward rain chances will decrease as we head into
Friday afternoon with dry conditions expected through much of the
weekend. Temperatures will remain quite chilly on Friday with highs
in the low 50s. Friday night, temperatures will fall into the 30s
across much of the region and temperatures could drop to right
around freezing across Kenedy, Brooks, Jim Hogg and northern Zapata
counties. Will keep an eye on the potential for a Freeze
Watch/Warning, but at this time temperatures remain just shy of
criteria (32 or below for 2+ hrs). A warm up starts on Saturday with
highs in the upper 50s to around 60 degrees as southeasterly flow
returns. The warm up continues through the weekend but afternoon
highs will still remain shy of seasonal norms. Clearer skies
overnight will allow for radiational cooling and low temperatures at
least 5 to 10 degrees below normal.

Another upper level trough moving across the Plains will bring
another cold front through Deep South Texas late Sunday with cooler
air moving back in for next week. While temperatures will not be
quite as cold as the current cold snap, will still remain well below
normal. As the aforementioned front passes, a coastal trough will
set up in its wake bringing back rain chances through the remainder
of the long term period.


&&

.AVIATION...
(18Z TAFS)
Issued at 1149 AM CST Wed Jan 8 2025

A dense blanket cloud cover across much of the state of Texas can
be seen on the latest GOES-16 satellite imagery, with observation
sites across all of Deep South Texas reporting MVFR ceilings at
the time of this writing. Widespread MVFR ceilings will prevail
through late tonight, before IFR ceilings overspread across the
TAF sites. Additionally, periods of light rain and/or drizzle will
continue through the TAF period, with the best potential for
precipitation at BRO and HRL. Reduced visibility of around 5-6SM
cannot be ruled out overnight as pockets of light to moderate
rain/drizzle develop, primarily over at BRO based on the latest
suite of high res guidance. Otherwise, brisk north winds around
10-15 knots with gusts upwards of 20-25 knots will persist through
late this evening before gusts begin to subside. However, north
winds around 10-15 knots will continue through 18Z Thursday.

&&

.MARINE...
Issued at 151 PM CST Wed Jan 8 2025

Now through Thursday night...A tightening pressure gradient in
response to a deepening coastal low/trough will result in increasing
winds and rough seas over the Gulf waters and the Laguna Madre
through the period. As a result, a Small Craft Advisory is in effect
through Thursday evening for the Gulf waters and the Laguna Madre.
Periods of light rain and/or drizzle may result in reduced
visibility as well.

Friday through Tuesday...Adverse marine conditions will
continue off the lower Texas coast into Saturday morning. As a low
pressure system moves into the SE US winds and seas will decrease
Saturday with more favorable conditions returning by Saturday
afternoon. Another cold front will push through the waters off the
lower Texas coast late Sunday with winds and seas increasing in its
wake which will lead to Small Craft Advisory conditions beginning
Sunday night and lingering into the workweek. Rain chances will
continue through the period, briefly drying out on Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             40  51  43  52 /  90  70  90  50
HARLINGEN               39  48  39  52 /  70  70  90  40
MCALLEN                 38  47  42  55 /  60  50  80  30
RIO GRANDE CITY         37  44  41  54 /  40  50  80  30
SOUTH PADRE ISLAND      48  57  48  55 /  90  80  90  60
BAYVIEW/PORT ISABEL     42  52  42  54 /  80  80  90  50

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Thursday afternoon for TXZ451-454-
     455.

GM...Small Craft Advisory until 6 PM CST Thursday for GMZ130-132-135-
     150-155-170-175.

&&

$$

SHORT TERM...22-Garcia
LONG TERM....68-McGinnis
AVIATION...22-Garcia