646
FXUS64 KBRO 190530
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1230 AM CDT Tue Aug 19 2025

...New AVIATION...

.DISCUSSION...
Issued at 1040 PM CDT Mon Aug 18 2025

The mid-level ridge continues to retreat into the Four Corners by
late week, as Hurricane Erin swings by the US East Coast. This
leaves weaker pressure at 500mb along the western Gulf. Moisture
builds through the weekend into early next week as a weak coastal
low and trough persist along the lower Texas coast. This helps set
up multiple rounds of beneficial rainfall each day through the
forecast period, especially Wednesday through Sunday.

Overall, there does not appear to be much flow at the surface,
leaving the sea breeze to be the main catalyst for initial
convection and meandering or colliding outflow boundaries helping
to spread the coverage. Slower moving storms with abundant
moisture also increases the flooding rain threat. At the moment,
WPC has kept a Marginal Risk (level 1 of 4) of excessive rainfall
mainly north of the CWA Thursday and Friday, barely reaching into
Zapata County.

Several CAMs were hinting at strong thunderstorms working
southwest across the ranchlands and into the brush country or
upper valley late Tuesday afternoon into Tuesday evening. The
guidance has diminished the threat some this evening, but would be
something to monitor. As the week progresses, abundant cloud
cover and better rain chances limit peak heating and stifle
instability.

Temperatures remain near normal and hot Tuesday, with highs
gradually dropping a degree or two each day through the forecast
period and lows remaining warm. Expect a Moderate (level 2 of 4)
Heat Risk each day. Patchy shallow fog or field fog may develop
each night and early morning, especially across the eastern
ranchlands and coastal counties.

&&

.AVIATION...
(06Z TAFS)
Issued at 1229 AM CDT Tue Aug 19 2025

Through 06z Wednesday....Flying conditions will mainly be VFR
through the 06z TAF period. There could be some MVFR low stratus
around, particularly during the overnight hours into the morning due
to the copious amounts of low level moisture left behind from recent
rains and lighter winds. Additionally, can`t rule out the low, yet
non-zero probability for some mist/fog developing as well overnight
into the morning hours for the same reasons described above.

Winds will be light and variable to calm through the overnight
hours. During the day on Tuesday, a light southeasterly component is
expected to develop with wind speeds ranging between 5-10 kts.


&&

.MARINE...
Issued at 1040 PM CDT Mon Aug 18 2025

With generally weak flow across coastal waters, expect generally
favorable marine conditions through the forecast period. The
chance of showers and thunderstorms persists offshore into next
week, working closer to the coast each night and early morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             95  78  95  78 /  20  20  40  10
HARLINGEN               97  74  95  73 /  20  20  50  10
MCALLEN                102  78  99  77 /  20  10  50  10
RIO GRANDE CITY        103  78  99  76 /  10  20  50  20
SOUTH PADRE ISLAND      88  80  88  80 /  10  20  30  10
BAYVIEW/PORT ISABEL     92  77  92  76 /  10  20  40  10

&&

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

$$

SHORT TERM...56-Hallman
LONG TERM....56-Hallman
AVIATION...23-Evbuoma