The Mercedes plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
Partly cloudy
Mostly sunny; warmer
Chance of showers; cooler
Mostly cloudy
Mostly cloudy; warmer
Partly cloudy
Partly cloudy
3.85 inches of rain fell in two days, the most for this week of the year since records began in 1914. The next wettest, 2.51 inches, fell in 2023.
Mercedes’s center stands about 70 ft above sea level. Within three miles the land runs from 50 ft to 80 ft, a difference of 30 ft: nearly flat ground.
Under the town center the state geologic map shows Alluvium in Rio Grande, subdivided into areas predominantly of clay (silt, clay), from the Holocene, less than 12,000 years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sand. Age: Holocene, less than 12,000 years old. About 12 mi of the line.
Silt, clay. Age: Holocene, less than 12,000 years old. About 9 mi of the line.
Clay, silt. Age: Pleistocene, less than 2.6 million years old. About 2 mi of the line.
Silt, sand. Age: Holocene, less than 12,000 years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Mercedes reaches the Gulf of America by way of the Arroyo Colorado: about 55 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mercedes; river miles along the main stem, rounded.
Mercedes has a humid subtropical climate. Summer afternoons average 97° in August; winter nights fall to about 50° in January. About 26 inches of rain fall in a normal year.
On November 14 Mercedes normally reaches 80° and falls to 59°. The record high is 94°, in 1921; the record low 30°, in 2018. The most rain on this date, 1.28 in, fell in 2008.
Normals 1991–2020 and records since 1914 at Weslaco, 4 miles west-northwest. NOAA, through RCC-ACIS.
