SPM 09-13-2017: Decrease in Shower Coverage over the High Terrains

Issue Date: Wednesday, September 13, 2017
Issue Time: 10:15AM MDT


Decreasing moisture and weak mid-level dynamics caused showers to be more scattered in nature over the high country yesterday. Mostly clear skies allowed for instability to build earlier in the day and showers began forming over the higher terrains just after noon. Initially, the most abundant showers were over the San Juan and Northern Mountains where dew points were in the low to 40s. This created high-based thunderstorms, which produced more wind than rainfall. Later in the afternoon and evening the shower activity shifted to the southern Front Range and Southeast Mountains.

Over the western mountains, up north, rain observations were as high as 0.38 inches. Radar estimates were around 0.5 inches. Further south, the totals decreased and most observations were in the 0.15 to 0.25 range although radar rainfall estimates in Conejos County were 0.5 inches. Along the Southeast Mountains, a SNOTEL station north of Fort Garland recorded 0.4 inches in the evening. This same storm prompted an Areal Flood Advisory over the Hayden Pass Burn Scar, but no flooding was reported. Radar estimates over this area were up to 0.5 inches. It should be noted that the Pueblo NWS radar is down for maintenance through the end of September, so radar rainfall estimates in this region will be affected.

There was no flooding reported on Tuesday. For rainfall estimates in your neighborhood, 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.