972
FXUS64 KBRO 300523 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1223 AM CDT Sun Jun 30 2024

...New AVIATION...

.UPDATE...
Issued at 948 PM CDT Sat Jun 29 2024

Rain chances were bumped up to 20 percent over the coastal waters
along with the coastal counties as well as Hidalgo county for the
overnight period. Doppler Radar shows spotty showers moving over
Willacy and Kenedy county with another area of showers noted east
and southeast of South Padre Island/Port Isabel. All showers are
moving steadily west-northwest due to the deep easterly flow.
Showers may increase overnight as a tropical wave, currently over
the western Yucatan Peninsula, emerges over the Bay of Campeche.
Atmospheric moisture increases across the Western Gulf of Mexico
tonight and likely spreads inland. The 00Z evening balloon
sounding indicated pwats of 1.9 inches while the GOES derived
Total Precipitable Water shows pwats around 2.20 inches a few
hundred miles SE of the Lower Texas coast. An unstable atmosphere
(MU Cap 1500-2000 j/kg) and the increasing moisture should allow
for additional showers to develop over the warm Gulf and spread
inland.

&&

.SHORT TERM...
(Tonight through Sunday night)
Issued at 220 PM CDT Sat Jun 29 2024

An upper-level ridge will remain over Northern Texas through the
period, while a mid-level inverted trough moves across the Southern
Gulf and into Mexico. This will support a tropical disturbance
moving across the Bay of Campeche this weekend. The NHC has a 50%
chance of Tropical Cyclone development with this system over the
next 48 hours. Should further development occur, the system would
most likely make landfall in Mexico, with most of the impacts remain
to our south. Regardless of any further development, this system is
expected to increase moisture tonight and Sunday, supporting the
potential for showers and thunderstorms across Deep South Texas.
PWATs are expected to increase to 2  2.3 with moderate instability
and weak forcing.  Rain chances are expected to continue through the
day Sunday before decreasing Sunday night.

With the increased cloud cover, temperatures are expected to be
slightly lower Sunday and Sunday night. High temperatures Sunday
will likely remain in the low to mid 90s, with low temperatures
Sunday night in the mid 70s to low 80s.

&&

.LONG TERM...
(Monday through next Saturday)
Issued at 220 PM CDT Sat Jun 29 2024

The long term forecast begins on Monday with a 500 mb high
pressure centered over the general vicinity of northeastern Texas
and Oklahoma. Meanwhile, Deep South Texas will still be in a more
moist environment as the northern periphery of a tropical wave,
located in the Bay of Campeche, continues to advect remnant
influxes of deep tropical moisture as it moves inland into Mexico.
The National Hurricane Center (NHC) currently indicates a medium
chance (50%) of the system developing into a tropical disturbance
before making landfall somewhere between Veracruz and Tampico.
Despite the stabilizing effect of the nearby high pressure, a few
isolated to scattered showers and thunderstorms are possible on
Monday as precipitable water (PWAT) values may exceed 2.0 inches
during the day. However, the probability of rain is 20 to 30% and
limited to the RGV. By Monday evening, chances of rain drop off
considerably and winds will shift from easterly to southeasterly
as the 500 mb high pressure begins to push eastward.

The rest of the forecast looks to be quiet aside from daily isolated
showers and thunderstorms from sea breezes by midweek as the high
broadens across the southern U.S. and moisture wraps around its
southern fringe. In regards to temperatures, daily highs will range
from mid to upper 80s for the barrier islands and lower to upper 90s
inland. By midweek, maximum temperatures will approach, and slightly
surpass, 100 across the Rio Grande Plains and Special Weather
Statements may be issued for central and eastern Deep South Texas as
humid southeasterly onshore flow and temperatures result in heat
indices potentially reaching 110-113 for a few hours in the late
afternoon, but not long enough to meet Heat Advisory criteria.
Overnight low temperatures will range from lower 80s across the
barrier islands and lower RGV as well as mid to upper 70s elsewhere.
However, as the week progresses, lower 80s will expand into the rest
of the RGV and Rio Grande Plains while upper 70s are expected for
the rest of inland portions.

&&

.AVIATION...
(06Z TAFS)
Issued at 1213 AM CDT Sun Jun 30 2024

MVFR to VFR will prevail at the aerodromes through the next 24
hours. A TEMPO has been included for convection based on HRRR
model guidance for Sunday.

&&

.MARINE...
Issued at 220 PM CDT Sat Jun 29 2024

Tonight through Sunday night...A broad area of low pressure over
the Bay of Campeche is expected to move westward through the short
term period. Meanwhile a broad area of high pressure over the
Northern Gulf will support generally easterly winds across the
Northern Gulf. The combination of these systems will likely lead
to building seas through the period, with Small Craft Advisories
likely to be needed Sunday. While the NHC has a 50% chance for
Tropical Cyclone development in the Bay of Campeche over the next
48 hours, the system is expected to remain to the south before
making landfall in Mexico. Impacts from this system will likely be
limited to increased rain chances and slightly higher seas
Sunday.

Monday through Saturday...Small Craft Exercise Caution (SCEC) may
continue to result from elevated seas on Monday as swell,
generated by a tropical wave in the Bay of Campeche, continues to
push through the Gulf waters. However, seas will improve going
into Tuesday and beyond, leading to more ideal conditions for the
rest of the week though SCEC conditions are possible by midweek as
a weak pressure gradient results in moderate southeasterly winds
during the daytime.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             80  94  78  95 /  30  30   0  10
HARLINGEN               76  94  75  97 /  20  30   0   0
MCALLEN                 79  96  78  98 /  20  30   0   0
RIO GRANDE CITY         77  94  76  97 /  30  30   0   0
SOUTH PADRE ISLAND      84  88  81  89 /  20  20   0   0
BAYVIEW/PORT ISABEL     80  92  77  92 /  20  20   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...None.

&&

$$