SPM 09-06-2017: Cooler Temperatures East with Heat Continuing West

Issue Date: Wednesday, September 6, 2017
Issue Time: 10:00AM MDT


Much cooler temperatures yesterday for the eastern portion of the state with the passage of a cold front Monday night. High temperatures yesterday were 15-20F cooler than Monday with the eastern plains reaching the mid-70s. Overnight lows were around 40F (east) and 30F (west). Over the western portion of the state, temperatures remained warm. The shallow cold front was not able to move over the Continental Divide, and highs in the Grand Valley were in the mid-90s. There was a reduction in haze at the low-levels yesterday for the eastern portion of the state with the cold front passage. However, smoke continued to be advected into the state with the high pressure to the west. The northwest corner of the state had visibility limited to a 6 mile range during the afternoon with haze also reported in the mountains.

Dry air and cooler, stable east limited convection to light showers over the mountains yesterday. A couple SNOTEL stations recorded 0.2 inches over the higher terrains. Radar rainfall estimates over the San Juan Mountains were only 0.25 inches. There was no flooding reported Tuesday.

Below is a look at the percent of normal precipitation for the month of August across Colorado. The eastern plains, northern Front Range and Central Mountains all received above normal precipitation. Aligned with climatology, the Wet Mountains also received above average precipitation. The majority of the western portion of the state was abnormally dry for August including the climatologically favored region of the San Juan Mountains.

To see if rain fell in your area, scroll down to 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 6AM of the date shown in the bottom right corner. Also shown optionally are fire burn areas since 2012. The home button in the top left corner resets the map to the original zoom.

Note: We have identified a possible underestimation in QPE over the southwest part of the state. We are working to on this issue, and will provide an update as soon as possible.