726
FXUS64 KBRO 171935
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
235 PM CDT Sat Aug 17 2024

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

.SHORT TERM...
(Tonight through Sunday night)
Issued at 230 PM CDT Sat Aug 17 2024

Upper-level ridging along the Rocky Mountains will continue to
build through the period, generally supporting broad subsidence
and relatively dry mid-level flow across the region. This will
work to keep rain chances low through most of the period, however
a brief increase in mid-level moisture Sunday afternoon will
provide an opportunity for increased rain chances.

At the surface, high pressure is expected to remain in control
across the Gulf of Mexico, with a weak pressure gradient across
Deep South Texas. This will support light to calm winds overnight
tonight, with southeasterly winds picking up Sunday morning as the
sea breeze develops. Weak forcing along the sea breeze, combined
with an uptick in PWATs (values exceeding 2) and CAPE (>1500
J/kg), will allow rain chances to increase to around 20% Sunday
afternoon. The majority of the convection looks to remain
generally along and west of I-69C.

Heat will continue to remain a concern through the period, with
high temperatures Sunday ranging from the upper 90s to low 100s.
Heat indices will likely reach 110 across the eastern half of the
CWA, with a few locations briefly reaching 112. A special Weather
Statement will likely be needed for eastern portions of the CWA,
though a Heat Advisory cant be ruled out. Overnight temperatures
tonight and Sunday night are expected to be in the mid 70s to low
80s.

&&

.LONG TERM...
(Monday through next Saturday)
Issued at 230 PM CDT Sat Aug 17 2024

Key Messages:

* There is a moderate risk of hazardous heat through the week. Heat
  advisory conditions will be possible from at least Monday through
  Thursday afternoons, with the risk easing some at the end of the
  week.

* We do not expect tropical cyclone formation for the Gulf.

As suggested above, sizzlingly hot weather will be at the fore in
the long term. A 594 dam (plus) mid-level ridge will be anchored
over the southern High Plains through Thursday, with broad high
pressure covering the Gulf and South Texas. This pattern will send
high temperature readings to the century mark and higher for most
inland areas. Dew points in the mid 70s over eastern sections
will support heat index values slightly above 110 degrees (heat
advisory criteria) each afternoon for inland areas covering the
eastern half of the CWA.

Beyond Thursday, the ridge will shift west and be replaced by a
broad, inverted mid-level trough. This pattern shift will "break"
the heat somewhat, and though temps will still remain near to
above normal, the risk of hazardous heat/heat advisory conditions
will lower. Coastal rain chances will likewise increase slightly
Friday and Saturday as mid level heights over the region decrease
and West to Southwest Gulf instability reemerges.

Rip current risk will be suppressed through the long term due to
lower wave heights.

&&

.AVIATION...
(18Z TAFS)
Issued at 1236 PM CDT Sat Aug 17 2024

VFR conditions are expected to continue through the period. Weak
isolated convection is beginning to form along the sea breeze to
the north of the TAF sites this afternoon. Additional development
is possible this afternoon, however showers are expected to remain
brief and isolated. The likelihood of any TAF site seeing impacts
from showers this afternoon is too low to include in the TAFs at
this time. Winds will become light and variable overnight, then
pick up out of the southeast after sunrise Sunday.

&&

.MARINE...
Issued at 230 PM CDT Sat Aug 17 2024

Tonight through Sunday night...Favorable marine conditions are
expected to continue through the period as surface high pressure
remains in place across the Gulf of Mexico. This will support a
weak pressure gradient along the Lower Texas Coast, which in turn
will foster generally light to moderate winds and slight seas.
Some isolated showers and thunderstorms could be possible Sunday,
and locally higher winds and seas could be produced by any storms
that do develop.

Monday through Thursday night...High pressure will result in mostly
light to moderate winds and low to moderate seas. East to southeast
winds on Monday will turn more southerly Tuesday onward.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             80  95  80  96 /   0  20   0  10
HARLINGEN               77  96  76  97 /   0  20   0   0
MCALLEN                 80 100  79 102 /   0  20   0   0
RIO GRANDE CITY         78 100  78 101 /   0  10   0   0
SOUTH PADRE ISLAND      82  90  83  90 /   0  10   0   0
BAYVIEW/PORT ISABEL     79  92  79  93 /   0  10   0   0

&&

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

$$

SHORT TERM...60-BE
LONG TERM....54-BHM
AVIATION...60-BE