SPM 07-04-2020: Heavy Rainfall Coverage Expands Across the Eastern Plains as Steering Flows Slow

Issue Date: Saturday, July 4th, 2020
Issue Time: 10:10AM MDT

Summary:

Higher dew points over the eastern plains yesterday help produce more widespread thunderstorm coverage. Storms had very slow steering winds, so they were able to produce extra rainfall over the areas they tracked across; especially east. Southwest Yuma County got hit again. The same WxUnderground gage from yesterday (south of Joes) showed 1.33 inches, whereas MetStorm had 1.50 inches. So, QPE estimations might be slightly overestimated again. If you’re keeping track, that’s a 48-hour total just over 2 inches for that station! Kit Carson County got hit again, and the coverage of wetting rain was greater than Thursday. There was a Flash Flood Warning issued for the thunderstorm complex just before 8PM as cars were hydroplaning off I-70. Gusts around 60 mph were also recorded with these storms, and hail up to 1.75 inches. There were a couple other Flash Flood Warnings over Yuma and Cheyenne County from NWS Goodland. No Flash Flood Warning was issued for Kiowa County despite storm totals being estimated at 3.50 inches. A WxUnderground station SE of Sheridan Lakes recorded 1.92 inches in the area of 3 to 3.50 inches in the QPE below, so totals were likely overestimated. Still, that’s quite a bit of rainfall!

Back west over the mountains, scattered totals were just under 0.50 inches with a lot of SNOTELS around 0.40 inches. There was a report of 0.54 inches of rain in Leadville for the 24-hour period. It was a bit too dry for much wetting rain in the western high county. More gusts than rainfall were reported with 45 mph gusts recorded over the Grand Valley. Outside of the hydroplaning, flooding was not reported as of this morning.

For precipitation estimates in your neighborhood over the last 24 to 72-hours, scroll down to the State Precipitation Map below. Note that the 72-hour QPE has some errors over the San Luis Valley. However, using the non-bias corrected QPE would really inflate totals from yesterday. Over Yuma and Kit Carson County, 48 and 72-hour totals are likely inflated as I’ve shown QPE was likely overestimated the last couple of days compared to observations in the area.

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.