SPM 07-08-2021: Much Dryer Across Colorado

Issue Date: Thursday, July 8, 2021
Issue Time: 9:15 AM MDT

Summary:

Wednesday, July 7 saw a high-pressure ridge settle into the southwest, bringing subsidence and higher temperatures to the state. Along with the ridge, a dryer air mass prevented all but very isolated showers, which for many was welcome news after several days of wet weather and flooding. Conversely, the warm and dry weather contributed to an increase in heat and fire activity for the Sylvan Fire and Muddy Slide fires yesterday.

The only notable precipitation in Colorado was around Durango in the Southwest Slope, where between 0.38-0.57 inches was reported after an isolated afternoon storm according to CoCoRaHS and MesoWest gages. There was also an isolated cell overnight on the Eastern Plains. However, due to the rural location there are no gage reports to verify magnitude. For rainfall estimates in your area check out the State Precipitation Map at the bottom of today’s post.

It has been a few weeks since the Drought Monitor was shared here, largely because there hasn’t been much change in drought conditions. The drastic divide between the eastern and western halves of the state still persists, with much of the west experiencing exceptional drought and no drought conditions in the east.

The total precipitation anomaly for the first week of July from PRISM shows that while some portions of Western Colorado have received above average precipitation for the first week of July, conditions have largely been dryer than normal for this time of year, explaining the continued long-term drought. Comparatively, some portions of the eastern half of the state, especially the southeast mountains, have received over 400% of average for the first week of July.

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.
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.