107
FXUS64 KBRO 310900
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
300 AM CST Fri Jan 31 2025

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

.SHORT TERM...
(Today through Saturday)
Issued at 258 AM CST Fri Jan 31 2025

Today through Saturday...

Tranquil and rain-free conditions are expected through the short
term period across Deep South Texas in wake of the passage of a weak
cold front. Drier air will filter in across the region, with dew
points falling into the upper 20s and low 40s this afternoon.
Temperatures will remain near or slightly above seasonal normals for
late January, ranging from the low 70s along the Lower Texas Coast
to around 80 degrees further inland this afternoon and Saturday
afternoon, but the lower humidity will make each afternoon feel
quite comfortable. Although afternoon relative humidity values will
range from 15-30% this afternoon, north winds around or less than 10
MPH will limit the rapid spread of any fire starts.

The combination of mostly clear skies (outside of passing high
clouds) and generally light winds will promote efficient radiational
cooling processes tonight, allowing low temperatures to fall into
the mid to upper 40s across the Northern Ranchlands to low 50s
across the Rio Grande Valley. Some patchy fog may develop across
portions of the Northern Ranchlands close to daybreak on Saturday.

Along the Lower Texas beaches, a moderate risk of rip currents will
prevail today. A low risk of rip currents will prevail tonight and
tomorrow.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 258 AM CST Fri Jan 31 2025

Key messages:

* Pick of the week weather for Sunday with sunny skies and
  comfortable humidity.
* Increasingly muggy and toasty conditions heading into mid week
  with low chance for minor heat risk in mid/upper valley.
* There is a 5 to 10 percent chance for thunderstorms on Tuesday and
  Wednesday.

There is high confidence (70 to 80 percent) for above normal
temperatures during the forecast period across Deep South Texas and
the Rio Grande Valley. We start the period sandwiched between a 588
Dm ridge centered over Baja California and another 588 Dm ridge
centered over Cuba. Sunday looks to be the pick of the weekend with
mostly sunny skies and comfortable dew points mainly in the 50s.
South winds could gust 15-20 mph at times as a surface low pressure
takes shape over the Texas Panhandle. With 925mb temperatures in the
+17 to +19C range and good boundary layer mixing, expect highs to
top out in the low to mid 80s except mid to upper 70s along the
coast. Heading into Sunday night, quiet conditions continue with
continued southerly breezes. There is a low chance for patchy fog
development in locales that manage to decouple and if dew points do
come up faster than expected overnight, but widespread fog is not
expected. Overnight lows fall into the 50s to low 60s. For
reference, average highs for early February across our region are in
the mid 70s while overnight lows are in the upper 40s to mid 50s.

Heading into early next week, generally benign conditions prevail
but there will be a noticeable uptick in humidity as dew points
climb into the 60s by later Monday into Tuesday. The culprit is an
upper level disturbance that gets cut off over Mexico and meanders
just south of the international border. It remains to be seen how
far north it progresses as we get into the mid week. There is a
general consensus, however, among both deterministic and ensemble
global model guidance that it could get rather toasty especially for
areas west and along the I-69C/US-281 corridor as 925mb temperatures
climb to +22 to +24C range for those locales, but +18 to +21C for
our eastern zones along and east of the I-69E corridor. This would
translate into mid 80s to near 90 for daytime highs on Tuesday
across the mid to upper Valley and low to mid 80s for the lower RGV,
except mid to upper 70s for SPI. Wednesday does look to be the
warmest day since January 5, with possibly more widespread upper 80s
to low 90s for the mid and upper valley and more widespread mid 80s
for the lower valley. How high the ambient temperatures get will
also hinge on the cloud cover and shower or thunderstorm
development. But this is undoubtedly a warm weather pattern. The
higher 925mb and surface temperature values will be near maximum of
the SPC sounding climatology for Brownsville, TX upper air site
while the lower values are around the 90th percentile. With an upper
low in the vicinity, the associated steep mid level lapse rates mean
that there could be a low chance (10 percent) for thunderstorms on
Tuesday and Wednesday afternoons. PWATs also do rise into the 1.3 to
1.6 inch range, which is 150 percent of normal. However, there are
no noticeable signal for significant rainfall outside of
thunderstorms, whose coverage and development remains highly
uncertain at this time. For now, have generally kept with 10 to 30
percent PoPs and stayed fairly close to the median of temperature
guidance. Maximum heat index values are currently forecast to be in
the low to mid 80s, but would not be surprised to see more
widespread upper 80s to near 90 values if the forecast trends drier.
No heat risk concerns, although WBGT could rise into the mid 70s
range Tuesday and Wednesday especially for the mid to upper Valley,
which could introduce some minor heat risk concerns. This also
serves as a reminder that warm season is not too far away with the
recent cold spell now an increasingly distant memory.

A cold front looks to cross the area late Wednesday into Thursday,
which should provide the momentum to push the pesky upper low
further out into the Gulf. But with the polar jet remaining well
north of our area, cool weather fans might be disappointed although
dew points should fall from the oppressive (AOA 65) to the more
comfortable or sticky range (55 to 65). Rip current risk increases
from the low to moderate range by Wednesday and potentially high
risk by Thursday as seas build to 4-6 ft and wave period increases.

&&

.AVIATION...
(06Z TAFS)
Issued at 1030 PM CST Thu Jan 30 2025

Dry air to spread south through Friday as weak high pressure
settles over Texas. VFR conditions and light nortwest to north
winds are expected for the next 24 hours. Any fog late tonight and
Friday morning would be brief with probability for IFR visibility
now at 10 percent.

&&

.MARINE...
Issued at 258 AM CST Fri Jan 31 2025

Today through Saturday...Favorable marine conditions will prevail
through the period with light to moderate winds and low to moderate
seas. Northerly winds today will gradually shift to the east on
Saturday.

Saturday night through Thursday...Favorable conditions will prevail
for Sunday into early next week with light to moderate winds and low
to moderate seas. Winds will generally be from the south-southeast
to south at 10-15 kt with gusts up to 20 kt. Wave heights are
generally 1-3 ft through Tuesday night and then increasing to 3-5 ft
by Wednesday into Thursday. Therefore, Small Craft Caution to Small
Craft Advisories could be needed Wednesday into Thursday. While
there is a low chance for thunder (5 to 10 percent) across the outer
waters Tuesday into Wednesday, generally quiet boating conditions
are expected to prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             78  52  75  56 /   0   0   0   0
HARLINGEN               79  50  76  53 /   0   0  10   0
MCALLEN                 82  53  78  56 /   0   0  10   0
RIO GRANDE CITY         80  48  78  52 /   0   0  10   0
SOUTH PADRE ISLAND      69  58  69  59 /   0   0   0   0
BAYVIEW/PORT ISABEL     74  52  72  54 /   0   0   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 6 AM CST early this morning for
     TXZ451-454-455.

GM...None.
&&

$$

SHORT TERM...22-Garcia
LONG TERM....88-Chai
AVIATION...22-Garcia