585
FXUS64 KBRO 181110
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
610 AM CDT Mon Aug 18 2025

...New AVIATION...

.DISCUSSION...
Issued at 1051 PM CDT Sun Aug 17 2025

Despite some subtle differences, the forecast over the next 7 days
continues to feature a weak mid-level high pressure over the Central
Plains shifting westward and expanding across the Four Corners
region by Tuesday. As a result, dry conditions continue across the
CWA through Monday, with PoP`s remaining below 10%. Meanwhile, mid-
level troughing expands over the Gulf, bringing an upward trend in
moisture, with probabilities increasing from a low (20-30%) chance
of showers and thunderstorms on Tuesday to a low to medium (30-50%)
chance on Wednesday, followed by a 20-40% chance on Thursday. Later
in the week, a trough over the mid-Atlantic extends southwestward,
further elevating PWAT values to near and above 2.0 inches,
resulting in a 30-50% chance on Friday and over the weekend.
Throughout the week, convection is expected to be diurnally driven
and brief in nature, occurring along the seabreeze boundary in the
late morning and afternoon hours with the highest probabilities
along and east of US-281/I-69 C, becoming more widespread in
coverage into the weekend. As PWAT`s increase, any convection that
develops brings the possibility of brief heavy downpours, lightning
and gusty winds. This wet pattern may continue into the beginning of
next week, though potentially beginning to shut off as recent runs
of the deterministic GFS and ECMWF hint at an eastward expansion of
the mid-level high residing over the Desert Southwest.

High temperatures continue to range from near to slightly above
average with mid 80`s at the beaches, mid to upper 90`s along and
east of I-69 E as well as nearly widespread lower 100`s further west
at least into Tuesday. Following, cloud coverage and probabilities
of rain increase, resulting in 90`s across all of inland deep south
Texas and the Rio Grande Valley by the weekend, while mid 80`s
continue along the immediate coast. Mostly a moderate (level 2/4)
heat risk is expected Monday and Tuesday, followed by a minor (level
1/4) to moderate heat risk Wednesday, through the weekend and into
next Monday as afternoon heat indices generally remain between 100
and 109 degF, though a few locations may experience higher apparent
temperatures for a brief period of time. At this team, heat indices
are borderline Special Weather Statement criteria for Monday across
portions of the coastal counties and Rio Grande Valley, though not
as high of a likelihood as today.

There is a low risk of rip currents through Monday.

&&

.AVIATION...
(12Z TAFS)
Issued at 610 AM CDT Mon Aug 18 2025

Through 12z Tuesday.....Copious amounts of low level moisture from
recent rains coupled with light winds and mainly clear skies
overnight have once again resulted in the development of some low
stratus and/or mist/fog over parts of the region. Latest GOES-19
Nighttime fog and Microphysics channels confirms this. As of this
update, KHRL was reporting LIFR conditions due to 1/2 statute mile
visibilities from fog and cigs between 500-1,000 feet AGL. Have
applied a TEMPO group from 10z-13z for KHRL to account for the
mist/fog and/or low stratus.

Any mist/fog/low stratus from this early this morning will gradually
scour or burn off by mid morning giving way to a return to mostly
VFR conditions at all of the local terminals through the rest of the
day. It`s possible that there could be a few MVFR clouds around,
especially this morning.

Later tonight, most TAF sites will remain VFR, however, there may
once again be a low, non-zero probability for some patchy mist/fog
or even low stratus developing due to narrowing dewpoint depressions
from the combination of still large amounts of low level moisture in
place, some radiational cooling from clearing skies, and light winds.

Light and variable to calm winds this morning will become
southeasterly with speeds between 5-15 kts through the 12z TAF
period. Winds could gust as high as 20 kts during the afternoon
hours before waning later in the evening.

&&

.MARINE...
Issued at 1051 PM CDT Sun Aug 17 2025

Mainly light to gentle, moderate at times, southeasterly winds and
slight (1-2 feet) seas are expected to prevail throughout the
period, leaving for favorable marine conditions. Daily probabilities
of brief showers and thunderstorms increase to a low (20-30%) chance
Tuesday, increasing to a low to medium (30-50%) chance over the
weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             96  77  96  78 /  10   0  20  10
HARLINGEN               97  74  98  73 /  10   0  20  10
MCALLEN                101  78 101  78 /  10   0  20  10
RIO GRANDE CITY        103  76 103  77 /   0   0  10  20
SOUTH PADRE ISLAND      88  80  88  80 /  10   0  20  20
BAYVIEW/PORT ISABEL     92  76  92  77 /  10   0  20  10

&&

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

$$

SHORT TERM...65-Irish
LONG TERM....65-Irish
AVIATION...23-Evbuoma