926
FXUS64 KBRO 112347 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
647 PM CDT Tue Jun 11 2024

...New AVIATION...

.SHORT TERM...
(Tonight through Wednesday night)
Issued at 138 PM CDT Tue Jun 11 2024

The ongoing summer weather pattern will continue in the short term.
A broad, mid-level trough axis over East Texas will shift east over
the Northwest Gulf by Wednesday night. For the rest of today,
though, that trough will interact with a stalled frontal boundary to
our north, and some convection could push toward South TX tonight.
Short range models are not confident about pushing anything into or
through the CWA tonight, however. That said, look for partly cloudy
skies tonight with light onshore winds and low temperatures from the
mid 70s to near 80 degrees. The light winds may support patchy to
areas of light fog for the Northern Ranchlands and Mid-valley late
tonight.

The global weather forecast models advertise a rebuilding H5 ridge
over Northwest Mexico into the Desert Southwest. On the leeward side
of the ridge axis, deep South Texas and the Rio Grande Valley will
see slightly above normal temps. Max temps on Wednesday will range
from the mid 90s east to near the century mark far west. Afternoon
heat index values, then, will be in the 105 to 110 degree range,
below heat advisory criteria, though heat index values could briefly
touch 111 degrees in a limited number of spots.

Winds should remain light to moderate with mostly sunny skies on
Wednesday. A sea breeze will initiate just before noon on Wednesday.
PWAT will be similar to, or slightly higher than today. The CWA
remains in a general thunderstorm category outlook area, and a few
showers or tstorms could develop along the sea breeze on Wednesday.
The sea breeze line has not been able to build enhanced showers
today with the lower PWAT values. A healthy increase in PWAT will be
possible on Thursday based on forecasted soundings, so a few more
showers may develop then.

As for Wednesday night: warm and muggy under partly cloudy to mostly
clear skies with light winds. Low temps will range from the mid 70s
to near 80 degrees. We`re a few days past a new moon, with greater
illumination each night. Rip current risk should remain low due to
low wave heights.

&&

.LONG TERM...
(Thursday through next Tuesday)
Issued at 138 PM CDT Tue Jun 11 2024

A mid/upper level ridge axis centered across the Mexican state of
Chihuahua will prevail through Thu and Fri. The overall ridging
aloft does weaken its influence on our CWA over the weekend with
the approach of a southern stream closed low/shortwave moving
across the Great Basin into the Plains. At the same time, an
inverted trough axis will be developing across the eastern and
central Gulf. So through Sat, most of the CWA is expected to
maintain mostly dry conditions with continued slightly above
normal temperatures. Heat indices are expected to remain below
heat advisory thresholds at this time. There still will be the
potential for a slight chance to low chance of convection mainly
seabreeze-enhanced and diurnally-driven. Most of the convection
through Sat is expected to remain mainly east of I-69C.

An increasingly unsettled synoptic weather pattern is expected to
develop Sun through Tue of next week across our CWA. The inverted
trough axis with PWATs between 2.5 and 2.8 inches poised along
and east of this axis will slowly move westward through Tue. The
inverted trough axis will reach the CWA by Mon and begin to move
through the CWA on Tue. The net result will be a significant
moistening of the entire tropospheric column given this deep
moisture advection, especially on Mon and Tue. POPs will slowly
increase during the Sun-Tue time period and will be mostly in the
chance to likely POP range by Tue. Heavy rain at times will be a
given but with the worsening drought conditions of late, most of
this rainfall is expected to be welcome relief, especially for the
parched watershed.

There does appear to be some potential for limited tropical
cyclone development early next week. While the models are still a
bit chaotic, they are coming into somewhat better agreement in
potentially signaling a potential TD or even a weak TS
development in the Bay of Campeche early next week. Any potential
landfall would appear to stay in the favored region between
Tampico and Veracruz, well to our south. But of course, we will
need to monitor this potential scenario as northward reformation
has been known to occur with many weak W Gulf systems. Will lean
towards a Bay of Campeche potential development area as this is a
favored climatological region for TC development. Also, a broad
high pressure area entrenched across the central and eastern Gulf
further points to a more southerly development area.

Besides the rain, there will be an increased risk of rip currents
with the potential for minor tidal overflow early next week due to
incoming building swells originating from a developing moderate to
strong southeast gradient flow.

With the increase in cloud cover and rain chances, temperatures
are expected to slowly come down to more typical mid June levels
by early next week.

&&

.AVIATION...
(00Z TAFS)
Issued at 631 PM CDT Tue Jun 11 2024

Mostly clear skies and moderate east-southeast winds prevail
across Deep South Texas early this evening. Winds will decrease
and become light overnight into Wednesday morning. East to southeast
winds will increase and become moderate in the afternoon. VFR
conditions are expected for the next 24 hours, with the exception
of brief MVFR in any heavier showers or storms that develop.

&&

.MARINE...
Issued at 138 PM CDT Tue Jun 11 2024

Now through Wednesday night...A weak pressure gradient will produce
mainly light to moderate east to southeast winds and low to moderate
seas through the short term. Broad, mid-level troughing setting up
over the northwest Gulf will support an increase in marine showers
and thunderstorm activity.

Thursday through next Tuesday...Weak to moderate easterly flow
will prevail through Sat across the lower Texas coastal waters
with broad high pressure centered across the TN and MS valley
regions. Isolated to scattered convection will still be possible
as just enough moisture and forcing prevails. Rain chances will
increase beginning on Sun as an inverted trough axis with copious
amounts of deep tropical moisture associated with it advances
westward with time. Meanwhile, a long fetch of moderate to strong
southeast gradient flow of 20-25 kts with a few pockets of 30 kts
will develop early next week across the southern Gulf and
portions of the western Gulf as the overall gradient in the Gulf
tightens. The net result will be building seas/swells beginning on
Sun. Small craft advisories appear likely by Mon and Tue as the
larger swells arrive. As was stated above, there is also the
potential for TC development early next week across the Bay of
Campeche. Depending upon how this event unfolds, the winds and
seas could be higher than what is currently forecast.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             79  96  79  95 /   0  20  10  30
HARLINGEN               76  97  75  96 /   0  20   0  20
MCALLEN                 79 100  79  98 /   0  20   0  20
RIO GRANDE CITY         78 100  79  98 /   0  10   0  10
SOUTH PADRE ISLAND      82  87  82  87 /  10  20  10  30
BAYVIEW/PORT ISABEL     79  92  79  92 /   0  20  10  30

&&

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

$$

SHORT TERM...54-BHM
LONG TERM....80-MB
AVIATION...63-KC