Brownsville, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

855
FXUS64 KBRO 180441 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1041 PM CST Fri Jan 17 2025

...New AVIATION...

.SHORT TERM...
(Tonight through Saturday night)
Issued at 310 PM CST Fri Jan 17 2025

Key Messages:

- Patchy to widespread fog will develop tonight after midnight
across much of Deep South Texas.

- One final warm day is expected on Saturday, but the arrival of an
arctic airmass will bring well below normal temperatures Sunday
through next week.

- Low temperatures Saturday night will fall into the 30s and 40s.

Persistent low level southerly flow will maintain generally mild and
humid conditions, especially in comparison to earlier this week.
Tonight will be the warmest night for at least the next 5-6 days,
with lows ranging from the mid 50s across the Northern Ranchlands to
mid 60s. This is near or slightly above normal for low temperatures
mid January. High res and probabilistic guidance indicate there is a
medium chance (40-60%) of visibility falling below 3 SM  and a low
to medium chance (20-40%) of visibility falling below 1/2 SM after
midnight tonight into early Saturday morning across most of Deep
South Texas.

Any morning fog should quickly dissipate by mid Saturday morning,
and our attention will turn to the arrival of a cold front. We`ll
start to see southerly winds shift to the north late Saturday
morning into Saturday afternoon, but we`ll still warm up into the
low to mid 70s across the Northern Ranchlands to the upper 70s
across the Rio Grande Valley. Enjoy the warmth while it lasts, as
the arrival of the notably colder airmass is expected Saturday
night. Low temperatures will fall into the mid to upper 30s across
the Northern Ranchlands to mid and upper 40s across the Rio Grande
Valley. In combination with northerly winds around 10-15 MPH, the
"feels like" temperatures will be in the mid 20s across the Northern
Ranchlands to the upper 30s across the Rio Grande Valley. This is
just the start of another period of unseasonably cold weather.

&&

.LONG TERM...
(Sunday through next Friday)
Issued at 310 PM CST Fri Jan 17 2025

The primary concern for the long term forecast remains the
potential for freezing temperatures and winter precipitation early
next week. Much uncertainty still remains in the forecast, as
models vary with the evolution of the synoptic pattern, and its
impacts on Deep South Texas.

A deep upper-level trough centered over the Central US at the
start of the period will slowly shift east as an embedded
shortwave traverses the western periphery of the trough early next
week. This will enhance northerly low-level flow, driving an
additional surge of arctic air across the Plains. Here models
begin to differ, with recent GFS and GEFS runs moving the bulk of
the colder airmass towards the Mississippi River Valley, while
recent runs of the Canadian models drive the airmass further south
towards Texas. Recent ECMWF runs are This variation between the
models leads to a significant difference in the temperature and
precip type across Deep South Texas.

Starting with Monday morning, the warmer guidance is keeping
temperatures above freezing across the CWA, while the more extreme
of the colder guidance is driving freezing temperatures into the
Rio Grande Valley. Confidence is highest in reaching freezing
temperatures across portions of Jim Hogg and Zapata counties
Monday morning, with the remainder of the CWA more likely to stay
above freezing. However, given the uncertainty in the models, this
may change as the event approaches.

Tuesday morning looks to be the best chance of receiving any
winter precip. Models still vary wildly, however confidence is
higher for colder temperatures extending further south, with
freezing temperatures likely across the northern counties. There
is a low to medium chance for freezing drizzle across across
portions of the northern counties. Precipitation is more likely to
remain a cold rain or drizzle across the Rio Grande Valley,
though wintry precip cant be ruled out.

As another shortwave moves across the Southern Plains Tuesday,
rain chances and cloud cover will likely decrease as the low level
moisture moves out of the region. This will likely allow for
better cooling Tuesday night into Wednesday, which will result in
the best chances for a freeze across most of the CWA, and a deep
freeze for northern portions of the CWA.

Temperatures look to warm slightly through the remainder of the
period, with high temperatures returning to the mid 50s to low
60s, and low temperatures likely remaining above freezing.

&&

.AVIATION...
(06Z TAFS)
Issued at 1037 PM CST Fri Jan 17 2025

VFR conditions are expected to give way to MVFR and IFR conditions
late tonight as fog develops, with the best chance of any dense
fog at HRL. VFR ceilings return by mid morning Saturday. Southerly
winds continue to diminish into tonight with a cold front turning
winds northerly Saturday afternoon.

&&

.MARINE...
Issued at 310 PM CST Fri Jan 17 2025

Tonight through Saturday night...South to southwest winds prevail
through Saturday morning. Some patchy fog will be possible along the
Laguna Madre late tonight into early tomorrow morning. Winds will
shift to the north with the passage of a cold front. Northerly winds
will strengthen late Saturday night as the cold airmass spills
southward. Winds will likely approach Small Craft Advisory to Gale
Warning criteria after midnight Saturday night and into Sunday
morning.

Sunday through next Friday...Adverse marine conditions look to
persist through the first half of the week. A Small Craft Advisory
will likely carry over into the beginning of the long term period,
as strong northerly winds and high seas continue in the wake of
the cold front. Pressure gradients look to further tighten Tuesday
as a passing mid-level shortwave reinforces the northerly flow.
This will likely increase winds to around 30kts and gusts above
Gale Force Tuesday into Wednesday. Winds and seas look to decrease
Wednesday, with favorable marine conditions returning by Wednesday
night.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             64  77  47  54 /   0   0   0   0
HARLINGEN               59  77  41  53 /   0   0   0   0
MCALLEN                 60  79  43  55 /   0   0   0   0
RIO GRANDE CITY         54  78  41  54 /   0   0   0   0
SOUTH PADRE ISLAND      64  70  49  56 /   0   0   0   0
BAYVIEW/PORT ISABEL     61  73  44  54 /   0   0   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

SHORT TERM...22
LONG TERM....60
AVIATION...56-Hallman