SPM 08-24-2019: Heavy Rainfall for Eastern Colorado with Slow Moving Storms

Issue Date: Saturday, August 24th, 2019
Issue Time: 9:55AM MDT

Summary:

As anticipated yesterday, when storms moved east of the dryline they produced some very heavy rainfall. Upper air dynamics with the passing trough enhanced the area of lift for storms to form, so storms over the eastern plains were very widespread when compared to the previous days. A Severe Thunderstorm Watch was issued around 3:30PM over the eastern plains with storms following shortly after. Storm motion was to the east and decreased as storms moved in this direction, so the heaviest rainfall was over the far eastern plains. Storms were a little pulse-like and back building, so they were able to sit over an area for a longer period, which increased totals. Storms moved east of the state just after midnight.

With the placement of the surface low, high moisture was reinforced over the northern Colorado border, thus as storms moved off the northern Front Range and combined with storms coming off the Cheyenne Ridge, they produced some very heavy rain. Max 1-hour rain rates up to 1.5 inches were estimated by MetStorm and hail up to 2 inches was also reported. The heaviest rain was over Cheyenne and Kit Carson County where radar estimated just over 3.5 inches. There was a report of 2.5 inches of rain in about 2 hours over Aroya and another report of 1.25 inches of rain near Seibert that fell in a 30 minute span. With these severe thunderstorms there was also a brief tornado reported near Kit Carson and hail up to 1.75 inches. Two Flash Flood Warnings were issued after 6PM with a flooding report in Kit Carson as “water ran like a river through the yard and almost up to the porch.”

To see estimated precipitation totals over your neighborhood on Friday, scroll down 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.

Note: The 24-hour, 48-hour and 72-hour total precipitation do not contain bias corrections today due to errors in the CoCoRaHS data. This means there may be underestimations in QPE over the southwest and southeast corners of the state.