The Thomson 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.
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Mostly sunny; warmer
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Chance of showers
74° on Nov. 11, 1964, the hottest reading for this week of the year since 1938. Next is 74° in 2022.
Thomson’s center stands about 600 ft above sea level. Within three miles the land runs from 570 ft to 830 ft, a difference of 260 ft: rolling country.
Under the town center the state geologic map shows Galena Group (Trenton Limestone) (dolostone, limestone), from the Late Ordovician, 447 to 459 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 63×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone, limestone. Age: Silurian, 422 to 445 million years old. About 9 mi of the line.
Dolostone. Age: Late Ordovician to Silurian, 434 to 447 million years old. About 7 mi of the line.
Dolostone, limestone. Age: Late Ordovician, 447 to 459 million years old. About 4 mi of the line.
Shale, limestone. Age: Late Ordovician, 445 to 454 million years old. About 2 mi of the line.
Shale, dolostone. Age: Late Ordovician, 447 to 454 million years old. About 1 mi of the line.
Dolostone, limestone. Age: Late Ordovician, 447 to 459 million years old. About 0.4 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 Thomson reaches the Gulf of America by way of Johnson Creek and the Mississippi: about 1,500 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Thomson; river miles along the main stem, rounded.
Thomson has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 14° in January. About 34 inches of rain fall in a normal year.
On November 14 Thomson normally reaches 48° and falls to 32°. The record high is 73°, in 1989; the record low 7°, in 2019. The most rain on this date, 2.20 in, fell in 1951.
Normals 1991–2020 and records since 1938 at Fulton L&D # 13, 5 miles southwest. NOAA, through RCC-ACIS.
