SPM 08-24-2017: Decrease in Surface Moisture Limits Heavy Rainfall

Issue Date: Thursday, August 24, 2017
Issue Time: 10:35AM MDT


A weak upper-level disturbance moved over the northern Colorado yesterday afternoon. This contributed to more widespread coverage of the daily diurnal storms over the northern portion of the mountains. With light westerly flow over the state, most of the low-level moisture was mixed out except over the far eastern plains. Over the Southeastern Plains, a surface low set up in the afternoon that brought in moisture rich air on its east side. Dew points were in the low 60s over the far eastern plains. The thunderstorms never quite made it to the moisture rich air yesterday and with a quicker, southerly storm motion, but there was still a few impressive 24-hour totals.

Over the higher terrain yesterday, a UDFCD mesonet station in Boulder County captured 0.63 inches of rainfall and a station over Teller County recorded 0.83 inches. Most other stations over the high terrains recorded around 0.5 inches with radar estimates about the same. In Rosita, CO (Southeast Mountains), there was a report of 0.69 inches falling in a 15 minute duration. With this same storm there was a report of 0.5 inch hail. 1-hour estimated rain rates were as high as 1.5 inches with the largest storm total over Huerfano County. 1.5 inches of rain were estimated to have fallen over Colorado City where a CoCoRaHS station recorded 1.21 inches. Over Trinidad, a CoCoRaHS station recorded 0.91 inches and rainfall radar estimates were 1.5 inches just southeast of town. There were no flooding reports as of this morning.

To see how much rain fell in your neighborhood, scroll down and check out 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.