THEWEATHERMOGIL:: Latitudes and altitudes, Colorado style
This article, which addresses the effects of altitude and latitude on temperature, could be for most anyplace(s) in the 50 states. But the western U.S. (including Alaska and Hawaii), with incredibly wild swings of altitude across relatively small distances, offers some of the best settings. Since I am stationed in Vail, CO this week, the “Centennial State” will be my focus.
According to netstate.com, Colorado’s elevation ranges from a low of 3,315 feet above sea level on the Arkansas River at the Kansas-Colorado border to a peak altitude of 14,440 feet atop Mt. Elbert. Pike’s Peak, the state’s most famous mountain, tops out at a scant 330 feet below Elbert’s. The state’s mean elevation of 6,800 feet makes it the highest state in the Nation.
Early morning temperatures today (Sun., Jun. 26, 2016), provide some insights into the effect of altitude (i.e. terrain) and latitude. For latitude, one only has to look across Kansas and Nebraska (Fig. 1). As is typically the case, from about 25 degrees latitude poleward, temperatures are lower the further one is from the Equator.
Across Colorado, latitude is partially masked by terrain effects on dew point and temperature. Dew points early on Jun. 26 were highest (mid-50’s) across the southeastern Plains (east of the Continental Divide – represented by the ochre colored line extending mostly north-south across the eastern part of the state). Dew points dropped into the 40’s across the northeast Plains. Across mountainous areas from the Continental Divide westward, dew points were mostly in the 30s.
When talking about low temperatures, dew point is extremely important. The dew point near the ground acts as a brake on nighttime cooling. It is hard for temperatures to fall below the air’s dew point temperature.
Since air temperatures normally drop off with increasing altitude, it is not a surprise that sunrise temperature readings were lower at higher mountain altitudes. The relationship isn’t one-to-one due to several reasons, including local terrain variations, geographic features (e.g., nearby river, nearby lake, nearby urban center) and the presence or absence of wind. Wind can mix the air near the ground and keep surface temperatures warmer.
Most notable is that the temperature at Craig (elevation 6,918 feet), in the northwest part of the state, dipped to 35 degrees. Eagle (elevation 6,547 feet), to the southeast of Craig only dipped to 46 degrees. But, Carol B., who works at a Vail timeshare resort, reported that at her home in Edwards, a community about 15 miles due east of Eagle, frost graced her windshield this morning.
While it may be summer, early on Jun. 26, there was a hint of cooler times across parts of Colorado.
© 2016 H. Michael Mogil
Originally posted 6/26/16