997
FXUS64 KBRO 010322
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1022 PM CDT Sun Aug 31 2025

...New DISCUSSION, MARINE...

.KEY MESSAGES...
Updated at 1016 PM CDT Sun Aug 31 2025

-Heat continues to be a concern on Monday with a Moderate (level 2
out of 4) to Major (level 3 out of 4 )Heat risk.

-Rain chances increase on Monday and Tuesday.

-The Weather Prediction Center continues to highlight portions of
 Starr, Zapata, Jim Hogg, Brooks, and Kenedy counties in a
 Marginal Risk (level 1 of 4) of excessive rainfall on Monday.

&&

.DISCUSSION...
Issued at 1016 PM CDT Sun Aug 31 2025

Heat continues to be the a concern for the start of the forecast
period. Mid-level ridging and moisture advection with south-
southeasterly winds will continue to bring hot temperatures rising
into the upper 90s to 100s and heat indices between 105 to 110
degrees across Deep South Texas and the Rio Grande Valley on
Monday. This will maintain a moderate (level 2 out of 4) to Major
(level 3 out of 4) Heat risk for the region. While heat indices
will remain below Heat Advisory criteria, Special Weather
Statements will be needed. With that said, a cold front begins to
push southward into the CWA on Monday. This will bring increasing
chances of showers and thunderstorms on Monday (40-50%). Rainfall
and cloud cover associated with the cold front could limit
afternoon high temperatures, heat indices, and heat risk.

WPC has portions of the Northern Ranchlands in a marginal risk
(level 1 of 4) of excessive rainfall for Monday into Monday night.
The NBM 90th percentile is at around 1 to 1.5 inches and mean
around 0.5 inch of rainfall for the marginal area, so confidence
on the excessive rainfall is somewhat low. With the said,
forecasted PWATs will be around 1.75 inches, which is above normal
so any showers or thunderstorms that do develop will be capable
of producing heavy rainfall that could lead to ponding of water,
especially on roadways and low lying areas.

The aforementioned cold front will move through the CWA Monday
night, but lift back north across Deep South Texas on Tuesday. This
will keep rain chances (50-70%) in the forecast for Tuesday.
Temperatures cool slightly, but will remain near to just above
seasonal norms through Thursday.

Rain chances taper off Tuesday night and the front finally pushes
south of the region. POPs will generally remain around 15% or less
for Wednesday through Friday. As we head into next weekend, we are
still watching for the potential of another front pushing through or
stalling across Deep South Texas that will increase rain chances and
lower temperatures slightly for the weekend.

&&

.AVIATION...
(00Z TAFS)
Issued at 552 PM CDT Sun Aug 31 2025

VFR conditions will prevail through the TAF period. South to
southeasterly winds will turn more easterly around midday Monday
as a front begins to push into Deep South Texas. As we head into
Monday afternoon, chances of showers and thunderstorms will
increase across the aerodromes with PROB30s in place. Any rain or
thunderstorm that moves over the airports could reduce
visibilities briefly to MVFR/IFR.

&&

.MARINE...
Issued at 1016 PM CDT Sun Aug 31 2025

Generally favorable conditions with mostly light to moderate
southerly to southeasterly winds and seas of 1 to 2 feet. A frontal
boundary will move through the waters off the lower Texas coast on
Monday increasing rain and thunderstorm chances Monday and
Tuesday (50-70%). This could lead to locally elevated winds and
seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             79  95  78  94 /  10  40  40  60
HARLINGEN               75  96  74  95 /   0  50  40  60
MCALLEN                 79 101  79  97 /   0  40  50  60
RIO GRANDE CITY         77 101  76  96 /   0  30  60  50
SOUTH PADRE ISLAND      82  88  80  88 /  10  40  40  50
BAYVIEW/PORT ISABEL     78  92  77  91 /  10  40  40  60

&&

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

$$

DISCUSSION/MARINE/AVIATION...68