127
FXUS64 KBRO 280336
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1036 PM CDT Fri Jun 27 2025

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

.KEY MESSAGES...
Updated at 1027 PM CDT Fri Jun 27 2025

 - The National Hurricane Center (NHC) is monitoring a broad area
   of low pressure over the Yucatan Peninsula, giving it a low
   (30%) chance of tropical development over the next 48 hours and
   a low (30%) chance within the next 7 days.

 - Little to no impacts from this system are expected for deep
   south Texas and the Rio Grande Valley.

 - Tropical moisture is likely to generate a medium to high
   (30-75%) chance of showers and thunderstorms on Sunday and
   30-60% chance on Monday, with the highest chances closer to the
   coast.

 - There is the potential for brief heavy rain on Sunday and
   Monday, but we do not anticipate impacts worse than minor
   nuisance flooding at this time.

&&

.SHORT TERM...
(Tonight through Sunday night)
Issued at 1027 PM CDT Fri Jun 27 2025

Diurnally-driven convection continues through Sunday night, but an
overall drier forecast is expected to start; mid-level ridging over
the eastern U.S. continues breaking down, resulting in continued
hot, humid and mostly dry conditions over deep south Texas through
the daytime on Saturday, generating a low (15% or less) chance of
brief isolated to scattered showers and thunderstorms Saturday
afternoon, mostly across the lower and middle RGV. Overnight
temperatures tonight through Sunday night are expected to fall into
the 70s inland to near 80 degrees closer to the coast. Saturday`s
high temperatures are likely to range mostly into the mid low to mid
90s, though portions of the mid/upper RGV and the Rio Grande Plains
could hit upper 90s. Mid 80s are expected along the coastline.

Meanwhile, southeasterly winds circulating around a high pressure
over the northeastern Gulf will aid in advecting moisture
northwestward from a broad area of low pressure currently over the
Yucatan, which the NHC expects to move over the Bay of Campeche
later tonight, indicating a low (30%) chance of development over
the next 48 hours, given that the low`s center remains over water.
As such, short term high resolution models and global models
feature PWAT values rising above 2.0 inches late Saturday night as
PoP`s increase from east to west, bringing a medium to high
(30-75%) chance across the CWA during the day on Sunday, with the
highest probabilities closer to the coast and falling to a low to
medium (20-30%) chance Sunday night, mainly east of I-69 E. Due to
the tropical air mass in place, there is the potential for heavy
rain within showers and thunderstorms, though, at this time, we do
not anticipate anything more than minor nuisance flooding as
convection continues moving further inland. Increased cloud
coverage is expected to limit Sunday`s high temperatures to the
low 90s inland and mid 80s at the beaches.

&&

.LONG TERM...
(Monday through next Saturday)
Issued at 1027 PM CDT Fri Jun 27 2025

Tropical moisture, PWAT`s above 2.0 inches and a medium to high (30-
60%) chance of showers and thunderstorms, bringing the potential for
heavy rain at times, return next Monday across the CWA, with the
higher chances generally near and east of I-69 E and highest near
the coast. NHC poses a 30% chance of development within the next 7
days for the area mentioned in the short term, but expects chances
of additional development to end as the system moves inland over
eastern Mexico by Monday. Therefore, we expect for PoP`s to
gradually diminish throughout Monday night and into Tuesday, though
lingering instability and elevated moisture could still generate a
medium (30-40%) chance of showers and thunderstorms on Tuesday.
Following, chances of unsettled weather decrease as moisture to our
south dissipates and daily afternoon PoP`s return to low (20-30% or
less).

Across inland deep south Texas and the RGV, increased cloud coverage
is expected to result in slightly below average high temperatures
for Monday through Wednesday, with upper 80s and low 90s. Highs
in the low 90s on Thursday warm back to slightly above average
next weekend with highs in the mid to upper 90s, possibly nearing
100 degrees in the Rio Grande Plains. Highs in the mid 80s at the
beaches persist. Overnight low temperatures continue to range in
the 70s to near 80 degrees along the coastline.

&&

.AVIATION...
(00Z TAFS)
Issued at 603 PM CDT Fri Jun 27 2025

VFR conditions are expected to prevail throughout the 00Z TAF
cycle with east-southeasterly winds (gusting to 20-25 knots) this
evening gradually lightening throughout the remainder of this
evening and into tonight. East-southeasterly winds pick back up to
similar speeds as today, by Saturday afternoon, along with
building clouds, though still anticipate VFR conditions to
persist.

&&

.MARINE...
Issued at 1027 PM CDT Fri Jun 27 2025

Gentle to moderate southeasterly winds and slight to moderate (2-4
feet) seas are expected to continue throughout the period. There
is a medium to likely chance (40-80%) on Sunday and Monday as
moisture spreads northwestward from a broad area of low pressure
over the Yucatan Peninsula, expected to emerge over the Bay of
Campeche later tonight. NHC indicates a low (30%) chance of
tropical development if the center of low pressure remains over
waters. At this time, we are not expecting impacts aside from the
potential of heavy rain, but mariners should continue to monitor
as forecasts update.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             78  93  78  91 /  10  10  30  70
HARLINGEN               74  94  75  92 /   0  10  10  60
MCALLEN                 77  97  78  94 /   0  10  10  50
RIO GRANDE CITY         76  95  76  92 /   0  10   0  30
SOUTH PADRE ISLAND      80  88  79  87 /  10  10  30  70
BAYVIEW/PORT ISABEL     77  90  77  89 /  10  10  20  70

&&

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

$$

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