SPM 08-01-2020: Strong Storms Along Eastern Mountains Made Beautiful Sunset & Lightning Photos

Issue Date: Saturday, August 1st, 2020
Issue Time: 10:45AM MDT


Clouds and thunderstorms fired over the mountains of Colorado yesterday, increasing in coverage and intensity from west to east. Some stronger severe-warned storms were able to develop over the Front Range and Southeast Mountains/Plains, which produced several hail reports of up to 1 inch diameter in Boulder County and a wind gust up to 61 mph at the Pueblo Airport. Some strong storms also moved over the Spring Creek burn area, which caused NWS Pueblo to issue a Flash Flood Warning based on radar. Drier air yesterday kept cloud bases high, which allowed more sub-cloud evaporation, limiting the amount of rainfall that actually made it to the surface. This made storms look more menacing on radar compared to the rain they were producing at the surface. The picture below was taken from Arvada, CO at 08:13 PM MDT looking northwest as a strong storm was moving into northern Boulder County, which shows the dry air and evaporation of rain below the clouds.

The heaviest rain fell from a train of storms that once again tracked over southern Larimer and northern Boulder County between 3PM and midnight local time. This seems to be a favorable location in these northwest flow setups. The heaviest rain report was 1.46 inches from a City of Fort Collins rain gauge located in the foothills between Fort Collins and Estes Park. A report of 1.06 inches was submitted by a CoCoRaHS observer southwest of the town of Berthoud, with nearby reports of 0.90 and 0.82 inches. Rain gauges picked up between 0.46 and 0.76 inches over the city of Longmont. The QPE map agrees well with these rain gauge reports and shows these higher rain totals stretch from east of Estes Park southeast to Firestone. No flooding was reported over this area, but social media is buzzing with plenty of lightning and sunset photos from these storms last night.

Further south, along the eastern portion of the Southeast Mountains and western Southeast Plains regions, storms dropped up to 0.43 inches of rain according to rain gauges. This highest report was from central Huerfano County, just east of the Spring Creek burn area. Radar indicates two rounds of storms tracked through this area between 4PM and 9PM local time, which caused the Flash Flood Warning. A second cluster of severe-warned storms tracked through Pueblo County between 6PM and 9PM, which caused the 61 mph wind gust reported at Pueblo Airport. Rain gauges reported up to 0.56 inches of rain from these storms, which agrees well with the QPE map. No flooding was reported with these storms.

For rainfall estimates in your area over the last 24 hours, check out our 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 24-hour, 48-hour and 72-hour total precipitation contain bias corrections that are not disaggregated into the hourly estimates, so there will likely be some differences. 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.