The Sullivan City 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.
33° on Nov. 14, 2018, the coldest reading for this week of the year since 1941. Next is 34° in 1970.
Sullivan City’s center stands about 190 ft above sea level. Within three miles the land runs from 110 ft to 270 ft, a difference of 160 ft: gently rolling country.
Under the town center the state geologic map shows Goliad Formation (clay, sandstone), from the Miocene, 5.3 to 23 million years old.
The section below crosses 3 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.
Clay, sandstone. Age: Miocene, 5.3 to 23 million years old. About 13 mi of the line.
Sand. Age: Pleistocene to Holocene, less than 2.6 million years old. About 2 mi of the line.
Fine-detrital, coarse-detrital. Age: Holocene, less than 12,000 years old. About 0.3 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 Sullivan City reaches the Gulf of America by way of the Rio Grande: about 210 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Sullivan City; river miles along the main stem, rounded.
Sullivan City has a hot semi-arid climate. Summer afternoons average 100° in August; winter nights fall to about 53° in January. About 22 inches of rain fall in a normal year.
On November 14 Sullivan City normally reaches 80° and falls to 60°. The record high is 93°, in 1989; the record low 33°, in 2018. The most rain on this date, 0.20 in, fell in 1959.
Normals 1991–2020 and records since 1941 from the McAllen Area threaded record (Mcallen Miller International Airport, 21 miles east-southeast). NOAA, through RCC-ACIS.