323
FXUS64 KBRO 171939
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
239 PM CDT Tue Sep 17 2024

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

.SHORT TERM...
(Tonight through Wednesday night)
Issued at 236 PM CDT Tue Sep 17 2024

Midlevel high pressure over Texas will continue to slowly dry out
the midlevels and minimize rain chances today and tomorrow. Any
showers and thunderstorms that do develop will be isolated in nature
and most likely develop along the sea breeze. With that said, PWATs
on this mornings KBRO sounding were still abnormally high at 2.33
inches with forecasted PWATs only falling to around 2 inches by
Wednesday afternoon. Any showers or thunderstorms that do develop
over the next few days will be capable of producing heavy rainfall
that could lead to minor flooding along low lying and poor drainage
areas, especially with the ground being saturated in many areas.

Temperatures will continue to warm over the next few days. Overnight
lows will be in the mid to upper 70s. Tomorrow will be slightly
warmer than today and heat indices will rise to 105-110 degrees. A
few locations could reach 111+ degrees briefly, mainly in southern
Hidalgo county. A Special Weather Statement may suffice but
will continue to monitor for potential for a Heat Advisory.

&&

.LONG TERM...
(Thursday through next Tuesday)
Issued at 236 PM CDT Tue Sep 17 2024

The long-term period will feature warmer-to-hotter than normal
temperatures and mainly dry/rain-free conditions through the end of
the week before a slight cool down ensues over the weekend into
next week.

Global deterministic forecast models and ensembles continue to
depict a 591 dam heat dome/ridge over northeastern Mexico into Deep
South Texas Thursday through Friday.

Atmospheric moisture content will be lower compared to previous
days/weeks with precipitable water (PWAT) values between 1.5-2.0
inches. However, it should be adequate enough to support a rogue or
isolated chance for a shower or thunderstorm nearly each day.
Subsidence, however, with the aforementioned mid-level ridging in
place, will help to keep things mostly suppressed through the
period. That said, expect for mainly dry or rain-free conditions to
prevail through the long-term period with an isolated chance for a
shower or storm nearly each day.

Temperature anomalies will run slightly warmer/hotter than mid-late
September standards Thursday and Friday. High temperatures are
expected to be in the mid to upper 90s for much of the region.
Moderate HeatRisk can be expected for the most part through the
extended. There could be areas of major HeatRisk developing,
especially in the Thursday-Friday timeframe. Heat indices are
expected to range between 105-115F Thursday and Friday. That said,
Special Weather Statements (SPS) to Heat Advisories may be needed
during this time period.

The heat ridge is progged to break down over the weekend as a trough
out west shifts southeastward, which will allow for temperatures
(the warmth) to relax some over the weekend into next week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1212 PM CDT Tue Sep 17 2024

VFR conditions will prevail through the forecast period. Some
showers and thunderstorms have already developed around KBRO and
isolated activity is possible through the rest of the afternoon
across all terminals that could briefly lower visibility to MVFR.
If a heavy shower or thunderstorms passes directly over a
terminal brief IFR conditions can not be ruled out but confidence
is low at this time on direct impact.

&&

.MARINE...
Issued at 236 PM CDT Tue Sep 17 2024

Now through Wednesday Night...Generally favorable marine conditions
will prevail with light winds and seas around 1 to 2 feet. Chances
of showers and thunderstorms will continue at times through the
forecast period that could lead to locally enhanced winds and
seas.

Thursday through Tuesday....Outside of any convection,
favorable marine conditions (light to moderate winds and light seas)
are expected to prevail Thursday through next Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             79  92  79  93 /  10  10  10  30
HARLINGEN               75  93  76  95 /   0  20   0  30
MCALLEN                 79  97  80  99 /  10  10   0  10
RIO GRANDE CITY         77  95  77  97 /  10  10   0  10
SOUTH PADRE ISLAND      82  88  82  89 /  10  20  10  20
BAYVIEW/PORT ISABEL     78  90  78  92 /  10  20  10  20

&&

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

$$

SHORT TERM...68-McGinnis
LONG TERM....23-Evbuoma
AVIATION...68-McGinnis