646
FXUS64 KBRO 081143 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
643 AM CDT Wed Oct 8 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 631 AM CDT Wed Oct 8 2025

* Daily low to medium (20-60%) chances for isolated to scattered
  showers and thunderstorms are expected through Friday.

* Thursday will present a medium-high (30-70%) chance for showers
  and thunderstorms; highest chances along and east of IH-69C.

* Warmer than normal temperatures are expected to persist through
  early next week.

* Small Craft Exercise Caution (SCEC) conditions are possible late
  Wednesday night into Friday with wave heights between 4-6 ft.

&&

.DISCUSSION...
Issued at 1028 PM CDT Tue Oct 7 2025

The influx of moisture over the region coupled with a nearby weak
shortwave trough will continue to be the focus of day-to-day or near
day-to-day chances for isolated to scattered showers and thunderstorms
through Friday. The influx of moisture is evident over the region
this evening with precipitable water (PWAT) values of 1.90", per
this evening`s 00z BRO sounding. Through tonight, another round of
showers (isolated to widely scattered) are possible across Deep
South Texas and the Rio Grande valley as additional moisture is
seen streaming in from the Gulf via radar and satellite imagery
this evening. The best chance for any showers will be located
along the Rio Grande Valley and areas near the Lower Texas Coast.

Wednesday through Friday will be a rinse and repeat from
today/tonight as sfc convergence along the seabreeze, outflow
lift from nearby thunderstorms, and/or an adequate amount of sfc
based differential heating will serve as lifting mechanisms for
the initiation of showers and thunderstorms, particularly during
the daytime with isolated chances possible during the nighttime
hours. Any rain that develops could produce heavy downpours and
posing of roadways, but ultimately will prove to be beneficial
given the overall dry trends of late.

As far as probabilities, we continue to maintain a general low-
medium(20-60%) chance for showers and thunderstorms tonight through
Friday, with the best chance being anywhere from the late morning
to early evening hours and the greatest confidence/probabilities
being along and east of IH-69C. Wednesday and Thursday will be the
days where PoPs peak. That`s where we have a medium-high (30-70%)
chance for showers and thunderstorms with categorical PoPs being
located along the Rio Grande Valley, and along and east of IH-69C.

Temperature anomalies will continue to run warmer than normal for
this time of year, courtesy of a 588-591 dam heat ridge in place
overhead. This feature will generate daily daytime highs in the low
to mid 90s through early next week. Overnight lows will be in the
60s and 70s with 60s found across parts of the Northern Ranchlands
and occurring mainly late week into early next week (due to clearing
skies and increased radiational cooling).

&&

.AVIATION...
(12Z TAFS)
Issued at 631 AM CDT Wed Oct 8 2025

Light and variable winds prevail across Deep South Texas early
this morning. BRO radar currently indicates scattered activity
near HRL and over the Gulf waters. Mainly VFR conditions will
continue through the next 24 hours. However, scattered showers and
thunderstorms will continue to develop across the area this
morning into the afternoon. Will also mention a TEMPO for HRL and
BRO as the latest HRRR suggests some convection may impact the
aerodromes later this morning into early this afternoon. Brief
periods of MVFR/IFR conditions, heavy rainfall and gusty winds
will be possible in and around any convection.

&&

.MARINE...
Issued at 1028 PM CDT Tue Oct 7 2025

Light to moderate winds and low to moderate seas are expected
through the forecast period. An enhanced pressure gradient will
result in 3-6 ft seas developing Wednesday-Wednesday night and
persisting through Saturday, before potentially decreasing to 2-4
ft Sunday through early next week. Small Craft Exercise Caution
(SCEC) conditions are possible late Wednesday night into Friday,
with wave heights between 4-6 ft. Finally, daily low to medium
(20-60%) rain chances in general are expected to persist through
Friday. Thursday will see medium-high (60-80%) chances. Locally
enhanced winds and seas are likely within any showers or
thunderstorms.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             90  77  90  77 /  70  50  70  40
HARLINGEN               91  73  90  73 /  70  30  60  20
MCALLEN                 93  76  92  75 /  70  20  60  20
RIO GRANDE CITY         93  71  93  70 /  70  20  40  10
SOUTH PADRE ISLAND      86  81  86  81 /  70  50  60  40
BAYVIEW/PORT ISABEL     88  76  87  76 /  70  40  60  40

&&

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

$$

SHORT TERM...23-Evbuoma
LONG TERM....23-Evbuoma
AVIATION...63-KC