Brownsville, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

335
FXUS64 KBRO 221118 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
518 AM CST Sun Dec 22 2024

...New AVIATION...

.SHORT TERM...
(Today through Monday)
Issued at 328 AM CST Sun Dec 22 2024

- Daytime highs to climb nearly 10 degrees above normal Monday.

Broad cyclonic flow aloft and anti-cyclonic flow at the surface to
maintain a partly to mostly cloudy sky and a mild to warmer
temperature profile. Overall, a benign weather pattern in the short-
term with limited moisture depth (< 800mb) and content (normal pwats
near 1.10 inches).

No rain is anticipated, although a few CAM models show isolated
showers developing this afternoon and even less coverage Monday,
with moisture remaining shallow and no substantial forcing or lift
from the weak disturbances aloft.  The deterministic and short range
ensemble model solutions been waffling back and forth on low end
pops over the last several model runs and with the forecast showing
some uncertainty can not totally rule out a few patches of morning
drizzle or a rouge afternoon shower more so today with even a lower
probability Monday. As for temperatures mid 70s today, low to mid
60s tonight and 79-83 degree Monday.

&&

.LONG TERM...
(Monday night through Saturday)
Issued at 328 AM CST Sun Dec 22 2024

Key Message
* Much above average temperatures will make the Christmas Week a spring-like
one.

The main story continues to be a balmy Christmas period...suitable
for the common outdoor activities both Christmas Eve and Christmas
Day. While it will be warm and rather humid, with temperatures
running about 10-12 degrees above the 30-year averages (averages
on each day range from the lower 50s at sunrise to the lower 70s
by mid afternoon), record highs (and "high minimums") should
remain intact (see Climate section below).

Aloft, a fast-moving but relatively weak 500 mb disturbance
cruises through north and east Texas on Tuesday, but the
associated surface front pulls up well north of the
region...stopping any southward progression in the same areas. A
flat ridge quickly follows into Christmas Day across the state
before it too zips eastward on Christmas night. A quick moving 500
mb trough moves across the Arklatex Thursday, with largely zonal
flow dominating thereafter into Saturday. Deterministic models
differ a touch with the next wave that follows this one, with the
ECMWF a bit more pronounced (and farther south) into central Texas
by Saturday, which pulls a weak front...a wind shift line...down
toward the Rio Grande by late afternoon while the GFS is flatter
and faster, with no appreciable wind shift. The latest model
blends lean into the slightly deeper solution with a surface wind
shift by Saturday afternoon.

Despite these quick-moving mid-latitude systems aloft, the lack of
any tap into the polar regions ensures that the sensible weather
for the RGV remains on the fair and warm side right through the
week and into next weekend. Forcing is minimal for any notable
precipitation...and there should be plenty of sunshine among
passing clouds each day. Model blends suggest some potential for
isolated streamer showers along the coast Christmas morning and
perhaps again Saturday along and just behind the potential weak
front...but nothing to cancel any outdoor plans.

Winds should remain from the southeast through at least early
Saturday, with later Saturday dependent on the strength of the
aforementioned trough. Could see some afternoon gusts to 20-25+
mph on Christmas Day and again Thursday afternoon ("Valley Wind
Machine") which would also help boost afternoon high temperatures
as well. Blends are a bit shy based on lighter surface flows with
the ECMWF...but climatology of the pattern suggest a lean toward
the GFS so folks should be prepared for warm gusts each day...for
activities with a southern exposure. Might also see a brief period
of early morning fog on Christmas...but this would favor the Brush
Country to the King Ranch area vs. the populated Valley where
speeds should be just high enough to preclude development.

&&

.AVIATION...
(12Z TAFS)
Issued at 507 AM CST Sun Dec 22 2024

Increasing mid-level moisture is producing VFR broken to overcast
conditions. These 6-8 kft cloud decks are to persist through the
day with a gradual lowering through tonight. There is a low 10-25%
probability of ceilings lowering to MVFR before 6 PM LST and a medium
40% probability after 6 PM. No anticipating and fog impacts and
wind should remain light with limited gustiness.

&&

.MARINE...
Issued at 328 AM CST Sun Dec 22 2024

Today through Monday...Pressure gradient remains weak across the
Western Gulf of Mexico as broad surface high pressure remains over
the northern Gulf of Mexico. A persistent light to moderate onshore
flow and a slight short period sea state is forecast to persist
through Monday. Mariners can expect fair conditions on the Laguna
madre as well as the offshore Gulf waters.

Monday Night through Thursday Night...moderate south to southeast
flow will prevail through the period, with some diurnal marine
layer situations expected. That means stronger afternoon winds
over Laguna Madre each day...shifting to the Gulf waters
especially beyond 20 nm out each night. Satellite and buoy data
indicate a modest nearshore marine layer (with sea surface
temperatures around 70) while readings remain in the upper 70s
offshore. Upwelling nearshore should keep a lid on the
temperatures this week, even though conditions warm up by Tuesday
and remain so through the week.

Seas will nudge up to 4, perhaps 5 feet in spots, beginning as
early as Christmas Day and peaking Thursday/Thursday night. Wind
waves will be the predominant factor so boaters and fishers
enjoying any new holiday gifts should be alert to some difficulty.
Expect to see some periodic Small Craft Exercise Caution on Laguna
Madre (afternoon) and 20-60 nm legs on the Gulf (overnight)
Christmas Day through Thursday night.

Other than isolated streamer-type showers, widespread and
potentially dangerous thunderstorm conditions are not anticipated.

&&

.CLIMATE...
Issued at 328 AM CST Sun Dec 22 2024

As mentioned above, the period from Monday night through Saturday
night will feature temperatures 10 to 15 degrees above average,
with the potential (a 10 to 20 percent chance) for up to 17 degrees above from
Christmas Day through Friday. As for Christmas Eve/Christmas Day records?
Despite the warmth, records on these days are quite toasty - upper
80s near the coast to lower 90s inland - and these markers should
remain well in hand.

Here are the records for Brownsville, Harlingen, and McAllen on
December 24 and 25:

Brownsville (since 1878):
Christmas Eve Maximum: 87 in 1964. Forecast: 80.
Christmas Eve High Minimum: 73 in 1987. Forecast:  66.
Christmas Day Maximum:  88 in 2012. Forecast:  80.
Christmas Day High Minimum: 70 in 2016.  Forecast: 64.

Harlingen (since 1912):
Christmas Eve Maximum: 87 in 1964. Forecast: 83.
Christmas Eve High Minimum: 73 in 1987. Forecast:  61.
Christmas Day Maximum:  89 in 2015. Forecast:  82.
Christmas Day High Minimum: 73 in 2015.  Forecast: 61.

McAllen (since 1942):
Christmas Eve Maximum: 92 in 1948. Forecast: 85.
Christmas Eve High Minimum: 72 in 1987. Forecast:  64.
Christmas Day Maximum:  92 in 1964. Forecast:  84.
Christmas Day High Minimum: 72 in 2015.  Forecast: 62.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             74  65  79  65 /   0   0   0   0
HARLINGEN               75  60  80  61 /   0   0   0   0
MCALLEN                 75  63  83  64 /   0   0   0   0
RIO GRANDE CITY         72  62  82  61 /   0   0   0   0
SOUTH PADRE ISLAND      72  69  75  69 /   0   0   0  10
BAYVIEW/PORT ISABEL     74  64  78  64 /   0   0   0   0

&&

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

$$

SHORT TERM...59-GB
LONG TERM....52-Goldsmith
AVIATION...59-GB