SPM 09-13-2021: Severe Thunderstorms on Eastern Plains

Issue Date: Monday, September 13th, 2021
Issue Time: 10:05 AM MDT


Some northern portions of the Urban Corridor and Northeast Plains woke up to light showers Sunday morning along a weak trough axis, before moving eastward and lifting out of the state in the early afternoon. By that time, daytime heating allowed for convection to fire up in the Northern, Central, San Juan, and Front Range Mountains, while spilling onto the Urban Corridor and Palmer Ridge. As the afternoon progressed, thunderstorms became more organized on the Palmer Ridge, and Northeast and Southeast Plains. High winds were the main threat from these storms, though areas lucky enough to be under a thunderstorm did receive higher precipitation totals. A funnel cloud was reported by a pilot on the way to Colorado Springs, though it was not visible from ground. Additionally, up to 0.50 inches of rain was reported from CoCoRaHS observers in Colorado Springs, and 0.81 inches in Security. A bit northeast, thunderstorms produced 0.48 inches in Frankton, 0.67 inches of rain in Kiowa, and 0.83 inches in Agate.

By evening, severe thunderstorm warnings were issued for widespread storms on the Northeast and Southeast Plains. Up to 60 mph thunderstorm wind gusts were reported in Wild Horse in Cheyenne County. Nearby in Cheyenne Wells, up to 0.25 inch hail was reported and between 0.78-1.69 inches of rain from CoCoRaHS observers in town. Precipitation Frequency Estimates from NOAA Atlas 14 for Cheyenne Wells put 1.69 inches in a 6-hour period, just below a 2-year Average Recurrence Interval (or greater than 50% chance of occurring in any given year). A second round of thunderstorms formed further south by evening, dropping 0.46 inches of rain in Holly.

Even with the widespread showers, it was still a very hot day for September, especially for southern Colorado. Alamosa broke their daily record high temperature, reaching 86 degrees yesterday, topping the previous record of 84 set in 1956.

As things calmed down in eastern Colorado overnight, a weak cold front entered the state from the northwest during the very early morning hours. While most of the action has remained north of the Colorado border into Wyoming, there has been some light accumulations this morning.

No flooding was reported on Sunday. For rainfall estimates in your area, check out the State Precipitation Map below.

Click Here For Map Overview

The map below shows radar-estimated, rainfall gage-adjusted Quantitative Precipitation Estimates (QPE) across Colorado. The map is updated daily during the operational season (May 1 – Sep 30) by 11AM. The following six layers are currently available: 24-hour, 48-hour and 72-hour total precipitation, as well as maximum 1-hour, 2-hour and 6-hour precipitation over the past 24 hour period (to estimate where flash flooding may have occurred). The accumulation ending time is 7AM of the date shown in the bottom right corner. Also shown optionally are vulnerable fire burn areas (post 2012), which are updated throughout the season to include new, vulnerable burn areas. The home button in the top left corner resets the map to the original zoom.