264
FXUS64 KBRO 292324 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
624 PM CDT Fri Aug 29 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 622 PM CDT Fri Aug 29 2025

 - Moderate to major heat risks (levels 2 and 3 of 4) continue
   across all of deep south Texas through Sunday as daily
   afternoon heat indices reach 105-110 degrees F, with some
   locations experiencing indices of up to 112 degrees F for brief
   periods of time. Visit weather.gov/heatsafety for more
   resources.

 - The Weather Prediction Center (WPC) has included the
   northernmost portions of Brooks and Kenedy counties within a
   Marginal Risk (level 1 of 4) of excessive rainfall on Sunday as
   well as the northern half of Zapata, Jim Hogg, Brooks and
   Kenedy counties on Monday.

&&

.DISCUSSION...
Issued at 1206 PM CDT Fri Aug 29 2025

Dangerous heat continues to be the main focus for all of deep south
Texas through Sunday, thanks to a mid-level high pressure persisting
over the region, extending from the Desert Southwest to the Gulf,
which is providing subsidence and maintaining mostly sunny skies
with very low (less than 10%) chances of rain through Saturday.
Although air temperatures are expected to remain near to above
average, moderate southeasterly winds continue to advect moist Gulf
air inland, resulting in moderate to major (levels 2 and 3 of 4)
heat risks as afternoon heat indices reach 105-110 degrees F for a
few hours, with a few locations potentially experiencing indices up
to 112 degrees for brief periods of time. Like today, Special
Weather Statements (SPS`s) are possible again for all, or portions,
of deep south Texas, except for the barrier islands, on Saturday and
Sunday. The hottest indices are likely to be felt across portions of
the coastal counties and the Rio Grande Valley.

Meanwhile, amplification of the jet stream over the Rockies and
Plains throughout the weekend is expected to gradually push a
stationary boundary southward into southern Texas, gradually
enhancing surface convergence and upper level forcing from north to
south into the beginning of next week; probabilities of rain
increase from a low (15-20%) chance along the seabreeze on Sunday to
a medium (40-60%) chance by Monday afternoon, persisting overnight
into Tuesday and further elevating to a medium to likely (60-70%)
chance Tuesday afternoon and evening, before pushing through all of
the CWA by Wednesday morning. As the boundary approaches,
moisture pooling will aid in elevating PWAT`s to at least 2.0
inches by Monday evening, increasing into Tuesday. As these
ingredients interact with the high levels of instability already
in place, slow-moving convection producing heavy rainfall (in
addition to lightning and gusty winds) is expected and WPC has
included the northernmost portions of Brooks and Kenedy counties
within a Marginal Risk (level 1 of 4) of excessive rainfall on
Sunday as well as the northern half of Zapata, Jim Hogg, Brooks
and Kenedy counties on Monday due to the possibility of isolated
instances of minor flooding.

Following, PWAT`s decrease substantially throughout Tuesday night
and Wednesday, diminishing probabilities of rain to a low (15-30%)
chance along the seabreeze each afternoon from Wednesday through
Friday, expanding in coverage from southern portions of the Rio
Grande Valley on Wednesday to the northern ranchlands by Friday as
southeasterly return flow arrives and lifts the boundary
northward. Temperatures gradually cool to average by next Tuesday
along with mostly minor (level 1 of 4) heat risks into Friday.

&&

.AVIATION...
(00Z TAFS)
Issued at 622 PM CDT Fri Aug 29 2025

VFR conditions will prevail over the period. Moderate south-
southeasterly winds will lessen overnight at all sites becoming
light to gentle. Late morning, moderate flow returns (gusts to
around 20 kts) at all sites through Saturday afternoon.

&&

.MARINE...
Issued at 1206 PM CDT Fri Aug 29 2025

Favorable marine conditions continue as mainly light to gentle
(moderate in the afternoons) southeasterly winds and slight (1-2
feet) seas prevail. Chances of showers and thunderstorms increase
to a medium to likely (30-60%) chance Monday into Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             97  79  96  79 /   0   0   0   0
HARLINGEN               99  76  98  76 /   0   0   0   0
MCALLEN                103  79 102  79 /   0   0   0   0
RIO GRANDE CITY        104  77 103  77 /   0   0   0   0
SOUTH PADRE ISLAND      90  83  90  82 /   0   0   0   0
BAYVIEW/PORT ISABEL     95  79  93  79 /   0   0   0   0

&&

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

$$

SHORT TERM...65-Irish
LONG TERM....65-Irish
AVIATION...69-HK