156
FXUS64 KBRO 141805 CCC
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1243 PM CDT Sat Sep 14 2024

...New AVIATION...

.UPDATE...
Issued at 822 AM CDT Sat Sep 14 2024

Added Brooks, Inland Cameron, Inland Kenedy, Inland Willacy and
Starr Counties to the Heat Advisory initially effective for just
Northern and Southern Hidalgo counties as these additional
counties also forecast for heat indices to surpass 111 F,
potentially as high as 114 F, for at least 2 hours. The Heat
Advisory is effective from 1 PM CDT to 5 PM CDT this afternoon.

&&

.SHORT TERM...
(Today through Sunday)
Issued at 308 AM CDT Sat Sep 14 2024

Modest ridging will lie over the area in the short term. As well,
the surface pressure field will be rather flat. Max temps today will
be mainly in the 90s but could touch the century mark this afternoon
in a few spots, mainly inland. Afternoon heat index values of 111 to
113 degrees will possible in a few areas due to the interaction of
heat with enhanced relative humidity values. The elevated heat index
values will be more widespread and prolonged over Hidalgo County
today. Thus, a (low end) heat advisory has been issued for a few
hours this afternoon. Heat index values may also reach 105 to 110
degrees for a few hours for a few additional spots this afternoon.
With better rain chances on Sunday, however, high temps will be
slightly lower and there will be a lesser threat for heat advisories.

The models have been backing off on the rain threat in the short
term. The best chances today will be isolated to scattered and
mainly for the mid and upper valley along the Rio Grande. Rain
chances will become scattered across the CWA on Sunday as a slug of
moisture spreads north over the CWA. SPC places the CWA in the
general thunderstorm category through the short term. Overnight low
temperatures will be mainly in the mid 70s to near 80 degrees. Rip
current risk should remain low.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 308 AM CDT Sat Sep 14 2024

The long term forecast is a little bit drier than the previous one
as the mid-level ridge is expected to have a greater impact on Deep
South Texas and the Rio Grande Valley. So while there will be plenty
of low-level moisture transport with the southeasterly surface
winds, there will be a lack of instability to help generate showers
and thunderstorms. This does not rule out some isolated showers and
thunderstorms along the coast however as the afternoon seabreeze
could still produce enough instability for showers and thunderstorms
along the coast.

With the mid-level ridge taking the center stage of the long term
forecast, that will mean that elevated heat indices are going to
become the primary concern. While the currently forecasted heat
indices are not expected to reach Heat Advisory criteria, further
forecast shifts will need to continue to monitor them to see if they
continue to increase. As of this forecast, a series of Special
Weather Statements for elevated heat indices of 108 to 110 will be
needed.

As for the actual temperatures, the highs are expected to be in
mostly the upper 90s each day for the entire region. Meanwhile, the
low temperatures for the period are expected to be mostly in the
70s, with a few places climbing into the low 80s.

&&

.AVIATION...
(18Z TAFS)
Issued at 1224 PM CDT Sat Sep 14 2024

Currently, all TAF sites are experiencing broken VFR skies with a
gentle to moderate southeasterly breeze. As the afternoon
progresses, skies are anticipated to dissipate to scattered VFR as
well as lift, but a scattered MVFR cloud deck is still likely with
winds diminishing to a light-to-gentle southeasterly breeze beyond
sunset. Have included a PROB30 group for tomorrow morning as skies
may build to broken MVFR accompanying possible light rain showers,
persisting into the early afternoon hours.



&&

.MARINE...
Issued at 308 AM CDT Sat Sep 14 2024

Today through Sunday...We expect light to moderate southeast to
south winds and low to moderate seas. Isolated showers and tstorms
will be possible across the waters late Saturday night through
Sunday.

Sunday Night through Friday...Generally favorable conditions are
expected Sunday night through Friday, with light to moderate
southeasterly winds and seas between 1 to 3 feet. Isolated showers
and thunderstorms are possible and could result in elevated winds
and seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             79  91  78  90 /  20  50  30  50
HARLINGEN               76  92  75  92 /  10  40  20  50
MCALLEN                 81  96  79  96 /  10  50  20  40
RIO GRANDE CITY         79  93  76  94 /  30  60  30  40
SOUTH PADRE ISLAND      82  88  81  87 /  20  40  30  40
BAYVIEW/PORT ISABEL     78  90  76  89 /  10  40  30  40

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory until 5 PM CDT this afternoon for TXZ250>255-353.

GM...None.
&&

$$

SHORT TERM...54-BHM
LONG TERM....64-Katz
AVIATION...65-Irish