SPM 05-31-2021: Widespread Rain Along Front Range and Eastern Plains

Issue Date: Monday, May 31, 2021
Issue Time: 10:15 am MDT

Summary

Yesterday saw widespread, long-duration rain across the eastern half of Colorado – nearly all of it received at least 0.5 inches of rain, as seen in the 24-hour State Precipitation Map at the bottom of this post. Locally, even heavier totals were reported by CoCoRaHs observers which may not yet be reflected in the SPM. The top 5 reports for the state are seen in the table below, as well as estimated Average Recurrence Interval (ARI) from NOAA Atlas 14.

Even though it rained for most of the day yesterday, rainfall rates were relatively low despite available moisture, this was due to cooler temperatures and increased cloud cover preventing enhanced convection. This resulted in the low ARIs observed.

Despite the wet day, flooding was not reported on Sunday and all gauges in the state remain below flood stage. That is not to say that rivers are not running high. Gauges along the Arkansas River in Southeast Colorado, including its tributary the Purgatoire River, remain greater than 95% of normal streamflow for this time of year. In Northern Colorado the Cache la Poudre, Big Thompson, St. Vrain, Boulder Creek, and Cherry Creek are all also above 95% of normal streamflow too.

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.