067 FXUS64 KBRO 072338 AAA AFDBROArea Forecast Discussion...UPDATED National Weather Service Brownsville TX 638 PM CDT Sun Sep 7 2025
...New AVIATION...
.KEY MESSAGES... Updated at 637 PM CDT Sun Sep 7 2025
- There is a marginal (level 1 of 4) risk of excessive rainfall through tonight.
- Seasonal temperatures and rain chances continue into mid- September.
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.DISCUSSION... Issued at 1221 PM CDT Sun Sep 7 2025
Abundant moisture with a meandering frontal boundary near the CWA border and multiple remnant outflow boundaries continue increased rain chances through tonight. CAMs have still waffled a bit on timing, but overall the HRRR had the right idea, with convection across the ranchlands and Rio Grande this morning slowly winding down into the early afternoon. Most guidance limits convection this afternoon into this evening, bringing it back along the coastal counties from north to south tonight into Monday morning.
Have nudged high temperatures down today, with a good portion of peak heating now lost. A similar cut may be needed tomorrow if showers and storms persist through Monday morning.
The 12z BRO sounding showed an above normal PWAT of 2.03 inches and a deep column of moisture in place with most model guidance boosting PWATs up above 2.2 inches this afternoon through Monday morning, especially along the coast. Light winds and little storm motion will lead to locally heavy rainfall rates of 2 to 4 inches per hour with any persistent showers or thunderstorms.
For the remainder of the week, expect near normal temperatures with continued daily rain chances, especially along the coast each morning working inland with the sea breeze into each afternoon. The NBM still appeared to be a little overcooked on POPs into next weekend, so blended down with a little ADJMAV, CONSALL, and some pencil work.
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.AVIATION... (00Z TAFS) Issued at 637 PM CDT Sun Sep 7 2025
Light northeast to east winds with some low and high clouds prevail across Deep South Texas early this evening. Generally light northeast to east winds are expected to continue through the period. Another round or two of convection is possible late tonight/early morning and again Monday afternoon based on current CAMS. Brief MVFR or IFR conditions will be possible in and around any convection. Otherwise, VFR conditions will continue for the next 24 hours.
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.MARINE... Issued at 1221 PM CDT Sun Sep 7 2025
Generally favorable winds and seas continue, with increased chances for showers and thunderstorms each day. Winds and seas may be elevated near any showers or thunderstorms. Waterspouts may also be possible, especially near the edges of showers, with lighter winds and abundant low level moisture.
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.PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 77 89 76 91 / 60 50 50 50 HARLINGEN 73 91 73 92 / 60 60 40 50 MCALLEN 78 93 76 95 / 50 50 40 50 RIO GRANDE CITY 74 92 73 95 / 40 50 30 40 SOUTH PADRE ISLAND 79 87 81 87 / 70 70 50 50 BAYVIEW/PORT ISABEL 76 89 76 89 / 70 50 50 50
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.BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. &&
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SHORT TERM...56-Hallman LONG TERM....56-Hallman AVIATION...63-KC
NWS BRO Office Area Forecast Discussion