Area Forecast Discussion
Issued by NWS Brownsville, TX

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938
FXUS64 KBRO 201121 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
621 AM CDT Sat Jul 20 2024

...New AVIATION...

.SHORT TERM...
(Today through Sunday)
Issued at 317 AM CDT Sat Jul 20 2024

The mid-level ridge over the Four Corners will slowly drift towards
the west, as a mid-level trough moves over the Central U.S. and
Southern Plains. A weak frontal boundary will remain north of Deep
South Texas and the Rio Grande Valley.

Light southeasterly winds are expected to continue through the
period. PWAT values are around 2 inches for most of the region
during the forecast period. However models keep the development of
showers and thunderstorms on the low end. Even so, a sea breeze
today or tomorrow could be enough to generate some isolated showers
and thunderstorms. Greater chances of rain are expected to occur on
Sunday based on the latest model analysis. Meanwhile along the
coast, low risk of rip currents is expected to persist through the
period.

As for temperatures, expect them to be above slightly normal with
low temperatures for tonight in the mid to upper 70s. While the high
temperatures for today and tomorrow are in the mid to upper 90s.
Heat indices are expected to be in the range of 104 to 108, thus
they will be below the Heat Advisory criteria.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 317 AM CDT Sat Jul 20 2024

A mid to upper level ridge will remain centered over the Great Basin
through much of the period as a large scale 500mb trough over the
central CONUS deepens and sinks south through Texas into mid to late
week. A series of mid-level shortwaves will result in isolated to
scattered showers and thunderstorms across the area through the
period. The Storm Prediction Center (SPC) 3 Day Outlook outlines a
general outlook for thunderstorms for Deep South Texas on Monday.
The best rain chances will be Tuesday through Friday as deeper
moisture (PWATs 2.2 to 2.5 inches) arrives and lingers across the
area. As elevated precipitable water (PWAT) values increase over the
region, heavier rainfall will be possible and the Weather Prediction
Center (WPC) 5 Day Excessive Rainfall Outlook includes our area
within a Marginal risk (>5 percent) for flash flooding on Tuesday
and Wednesday.

Temperatures are expected to be near to slightly above normal, in
the 90s to near the triple digits for highs on Monday. High
temperatures will decrease a few degrees on Tuesday and continue
through the rest of the week due to the increase in rain chances and
cloud cover, but will remain in the 90s. Heat indices will range
from 103 to 108 degrees Monday and Tuesday afternoon, but will drop
a bit mid to late week as rain chances increase. Overnight lows are
expected to fall into the mid to upper 70s inland, around 80 at the
beaches.

&&

.AVIATION...
(12Z TAFS)
Issued at 615 AM CDT Sat Jul 20 2024

VFR conditions are expected to persist through the TAF cycle.
Southeasterly winds are expected to persist through the period as
well. HRL and MFE could see some gustier winds during the
afternoon hours. While there is an isolated chance for showers and
thunderstorms, but confidence was not high enough to include in
the TAF package.

&&

.MARINE...
Issued at 317 AM CDT Sat Jul 20 2024

Today through Sunday...Light to moderate southeasterly winds and low
to moderate seas are expected to persist through Sunday due to high
pressure over the Northern Gulf of Mexico. Isolated showers and
thunderstorms are possible, which could generate locally enhanced
winds and seas.

Sunday night through Thursday...Light to moderate southeast to south
winds and low to moderate seas will prevail. Periodic isolated to
scattered showers and thunderstorms will be possible through the
period. The best rain chances are expected Tuesday through
Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             94  80  93  80 /  20  10  40  10
HARLINGEN               95  76  93  77 /  20  10  40  10
MCALLEN                 99  79  97  80 /  20   0  30   0
RIO GRANDE CITY         99  77  97  78 /  10  10  20   0
SOUTH PADRE ISLAND      89  82  89  82 /  10  20  40  10
BAYVIEW/PORT ISABEL     92  78  92  79 /  20  10  40  10

&&

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

$$

SHORT TERM...64-Katz
LONG TERM....63-KC
AVIATION...64-Katz