Brownsville, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

576
FXUS64 KBRO 060547 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1247 AM CDT Sat Sep 6 2025

...New AVIATION...

.KEY MESSAGES...
Issued at 1025 PM CDT Fri Sep 5 2025

 - Heat will continue to be a concern today with Moderate (level
   2 of 4) to Major (level 3 of 4) Heat Risk throughout Deep South
   Texas.

 - An unsettled, rainy weather pattern is expected to begin
   tomorrow and continue through the middle of next week.

 - It is uncertain exactly how much rain Deep South Texas and the
   Lower Rio Grande Valley will receive, but the Weather
   Prediction Center has Deep South Texas in a marginal (level 1
   of 4) risk for excessive rainfall tomorrow.

&&

.DISCUSSION...
Issued at 1025 PM CDT Fri Sep 5 2025

Hot, humid, and mostly precipitation-free weather is expected
today (though there is still a roughly 30% chance of sea breeze
activity east of I-69C), with heat index values remaining a
concern. Heat indices could get just over 110 degrees in some
areas throughout Deep South Texas, sparking Moderate (level 2 of
4) to Major (level 3 of 4) Heat Risk concerns, particularly in the
Lower Rio Grande Valley and the Western Ranchlands.

On Sunday, rain chances return to the region as an unsettled, moist
airmass makes its way into the area.  PWATs are expected to be high;
around 2 inches, which is favorable for the development of scattered
to widespread rainfall over the next several days.  However, the
extent and amount of rainfall remains highly uncertain and there is
currently model disagreement on a few important factors.  The
availability of upper-level tropical moisture (which would be
conducive to more widespread rain development and higher
precipitation amounts) is uncertain as differing model guidance is
not handling Lorena remnants with consistency.  Some models have the
remnant upper level moisture remaining in the mountains of
Mexico, whereas others are showing more of that moisture making
its way into our region. In addition, there is a cold front that
is expected to stall somewhere in Central Texas, but there isn`t
agreement as to exactly how far south it will get. The closer the
cold front makes it to Deep South Texas, the higher our
precipitation chances will be for the region.

As we come into the time range of some of the shorter-duration CAM
models, early guidance is showing agreement that our area will
see widespread scattered showers and thunderstorms Sunday,
particularly on Sunday afternoon. As more CAM guidance becomes
available, hopefully we will get a better idea and a more refined
forecast of the amount, timing, and location of precipitation for
the area for Sunday and beyond. However, models have overall
trended down on precipitation amounts over the past few days. DESI
guidance is currently showing a range of 20-50% probability that
areas within Deep South Texas will see over an inch of rain over
the next few days, which is down from guidance earlier this week
showing similar probabilities for two or more inches.

Despite all of the uncertainty with the precipitation forecast, the
Weather Prediction Center does still have Deep South Texas in a
marginal risk for excessive rainfall on Sunday.  This means that
heavy rainfall and possibly even nuisance flooding is possible,
but it is a conditional threat, depending on positioning of the
frontal boundary and moisture depth.

High temperatures are expected to get into the upper 90s/lower 100s
today, but are expected to decrease into the mid to upper 90s Sunday
through late next week. With slightly lower temperatures, Heat
Risk is expected to decrease as well, with only a minor (level 1
of 4) heat risk expected most days. Low temperatures will be in
the mid to low 70s. Winds should be overall light to moderate and
east-southeasterly throughout the week with mostly cloudy skies
on Sunday gradually clearing to partly cloudy to mostly sunny by
the end of the week.

&&

.AVIATION...
(06Z TAFS)
Issued at 1233 AM CDT Sat Sep 6 2025

VFR conditions primarily expected Saturday outside of the chance
of showers and thunderstorms along the seabreeze during the day.
Showers and thunderstorms already forming over the Gulf and will
continue translating NW into the morning. Confidence is low in
timing and location of said showers, hence no mention in TAF, but
a low (~30%) chance of precipitation is possible at all sites
late this morning through the afternoon.

Greatest chances for precip at all sites are from 18Z to 23Z,
however, showers at HRL as early as 14Z, or earlier at BRO, cannot
be ruled out as showers over the Gulf move inland.

&&

.MARINE...
Issued at 1025 PM CDT Fri Sep 5 2025

Overall favorable marine conditions are expected over the next week
with light to moderate east-southeasterly winds and low wave
heights.  Showers and thunderstorms are expected starting on Sunday
and conditions could temporarily deteriorate in and around any
showers and thunderstorms offshore.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             95  79  92  79 /  40  40  70  70
HARLINGEN               98  75  93  74 /  30  40  70  60
MCALLEN                101  80  96  77 /  30  50  80  60
RIO GRANDE CITY        103  77  96  76 /  10  40  70  60
SOUTH PADRE ISLAND      90  82  88  81 /  30  40  70  60
BAYVIEW/PORT ISABEL     93  77  91  78 /  30  40  70  50

&&

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

$$

SHORT TERM...55
LONG TERM....55
AVIATION...69-HK