390
FXUS64 KBRO 200531 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1231 AM CDT Wed Aug 20 2025

...New AVIATION...

.DISCUSSION...
Issued at 1033 PM CDT Tue Aug 19 2025

The mid-level ridge continues to gradually 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 coastal trough persist along the lower
Texas coast. This sets up multiple rounds of beneficial rainfall
each day through the forecast period, with the highest POPs
topping 50-60 percent Thursday and Friday. High pressure returns
towards the western Gulf by mid next week cutting down rain
chances.

Overall, there does not appear to be much flow at the surface
either, with most convection developing along the sea breeze or
any meandering or colliding outflow boundaries. The convective
activity today featured strong outflow boundaries running away
from most storms fairly quickly at 40-50 mph, with a near severe
57 mph gust at MFE. Slower moving storms with abundant moisture
increases the flooding rain threat. At the moment, WPC has dipped
a Marginal Risk (level 1 of 4) of excessive rainfall across
portions of the ranchlands Thursday through Thursday night.

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

&&

.AVIATION...
(06Z TAFS)
Issued at 1228 AM CDT Wed Aug 20 2025

Tranquil conditions for the remainder of the overnight hours will
become unsettled on Wednesday. A TEMPO for convection has been
included for the aerodromes based on the HRRR model guidance.
Overall, VFR will prevail through the next 24 hours.

&&

.MARINE...
Issued at 1033 PM CDT Tue Aug 19 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             94  77  96  79 /  30  10  20  10
HARLINGEN               95  73  97  74 /  40  10  20  10
MCALLEN                 98  77 101  79 /  50  20  20  20
RIO GRANDE CITY         98  76 102  77 /  50  20  20  20
SOUTH PADRE ISLAND      88  79  89  80 /  20  10  10  10
BAYVIEW/PORT ISABEL     91  76  93  77 /  30  10  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...None.

&&

$$