FXUS64 KBRO 191837

AFDBRO



Area Forecast Discussion

National Weather Service Brownsville TX

137 PM CDT Tue Aug 19 2025



...New DISCUSSION...



.DISCUSSION...

Issued at 133 PM CDT Tue Aug 19 2025



Rest of Today...Hot temperatures and daily chances of showers 

continue into this weekend. A MCS to our north this afternoon is 

working its way south- southwestward and, if it is able to sustain

itself, can bring showers and thunderstorms to northern and 

western parts of the CWA. WPC has placed northern portions of 

Kenedy and Brooks counties in a Marginal Risk (level 1 of 4) of 

excessive rainfall, and rainfall rates up to 1-2" per hour are 

possible. Satellite- derived PWATs in coastal counties of 1.9-2" 

supports this (inland counties ranging from 1.6-1.8"). Hi-res 

guidance shows a large spread of how well this system will be able

to maintain itself through the afternoon, but the primary 

timeframe for anticipated showers is this afternoon into later 

this evening - 9 PM or so. Despite uncertainty of coverage, I've 

bumped up PoPs to 40% in northern and western portions of the CWA 

this afternoon/evening. 



Along with the MCS, showers and thunderstorms along the sea breeze 

boundary have started to develop south of the Rio Grande River, and 

may continue to force further isolated showers and thunderstorms 

through the afternoon along and east of US 281/I-69C. Mesoscale 

interactions between outflow of the MCS and sea breeze are possible 

into this evening as the two intersect. Any showers and storms that 

form are capable of bringing briefly heavy rainfall leading to 

localized flooding and ponding, gusty winds 40 mph (up to 50

possible), and lightning.



Wednesday onward...Diurnally driven rain chances with the sea 

breeze continue through midweek. As ridging over the Desert 

Southwest translates west, mid-level disturbances will provide 

instability and forcing to increase rain chances further. From 

Wednesday into the weekend, moderate rain chances across the CWA 

persist, however, details in precisely when and where scattered to

isolated showers and thunderstorms will form are too mesoscale to

pinpoint at this time. The greatest chances are late this week - 

Thursday to Friday - up to 60% in northern ranchlands, and 30-40%

in the RGV. Thursday, Northern Zapata county is in a Marginal 

Risk of excessive rainfall (level 1 of 4). 



With increased rain chances comes increased cloud cover, at least 

for the latter half of the week. While muggy conditions have no 

intention of slowing down, lack of solar heating during the day will 

keep "Feels Like" temperatures in the afternoons a few degrees 

cooler than we've seen for the last couple weeks. Despite being 

below Heat Advisory criteria, it is imperative to continue 

practicing heat safety. For more information on heat safety, visit: 

weather.gov/heatsafety



&&



.AVIATION...

(18Z TAFS)

Issued at 1236 PM CDT Tue Aug 19 2025



VFR conditions and southerly to easterly flow will prevail 

outside of a few notable mentions. Showers and thunderstorms 

continue to be possible along the sea breeze boundary this 

afternoon/early evening. Isolated convection is possible and may 

bring brief heavy downpours, gusty winds, and lightning to any 

sites that find themselves under a shower. Alongside sea breeze 

showers, an MCS over southern TX is making its way southwestward, 

bringing a further chance of convection to the region. Confidence 

is low with this system and not mentioned in TAFs as it is 

expected to stay further west than sites, but showers/storms at 

MFE cannot be ruled out.



Tomorrow morning, further isolated to scattered showers and 

storms are possible over the area, moving inland through the

day.



&&



.MARINE...

Issued at 1236 PM CDT Tue Aug 19 2025



A meek pressure gradient will allow for slight seas and gentlewinds out of the south-southeast, becoming moderate in the 

afternoons and evenings with land-sea breeze. There is a chance 

of isolated to scattered showers and thunderstorms every day 

through the weekend, primarily Wednesday through Sunday. 

Conditions will be degraded in any storms over the waters, with 

gusty winds, lightning, and heavy rainfall.



&&



.PRELIMINARY POINT TEMPS/POPS...

BROWNSVILLE             96  79  94  78 /  20  20  30  10 

HARLINGEN               97  74  96  73 /  20  20  30  10 

MCALLEN                101  78  99  77 /  30  20  40  10 

RIO GRANDE CITY        102  77  99  75 /  30  30  40  20 

SOUTH PADRE ISLAND      88  80  88  80 /  10  20  20  10 

BAYVIEW/PORT ISABEL     92  77  91  76 /  20  20  30  10 



&&



.BRO WATCHES/WARNINGS/ADVISORIES...

TX...None.

GM...None.

&&



$$



SHORT TERM...69-HK

LONG TERM....69-HK

AVIATION...69-HK