SPM 08-04-2020: Flash Flooding at Spring Creek burn area

Issue Date: Tuesday, August 4th, 2020
Issue Time: 10:55AM MDT

Summary:

Storms generated some flash flooding over the Spring Creek burn area yesterday. Three flash flood reports were generated southwest of the town of La Veta, over the southern portion of the Spring Creek burn area. Rushing water overtopped county route 421 and highway 12, and a debris flow closed a section of highway 12. USGS rain gauges in this area recorded up to 0.98 inches of rain, which is well over the expected 0.5 inch threshold for flash flooding. Nearby CoCoRaHS observers reported 0.54 and 0.7 inches of rain, which backs up the USGS rain gauge. The QPE map agrees with these totals and shows most of the southern half of the burn area likely picked up over 0.5 inches. This rainfall warranted the flash flood warnings issued by NWS Pueblo. Decent rain totals were also observed over the Raton Ridge as numerous storms moved over the area well into the evening hours, but limited rain gauges in the area indicate just under 0.5 inches fell.

Storms that fired over the southern Front Range produced isolated areas of moderate rainfall over 0.5 inches. The heaviest rain from a severe-warned storm that fired over northwestern Elbert County. Between 0.77 and 1.0 inches of rain was reported by CoCoRaHS observers from this storm, with the heaviest rain falling over the town of Elizabeth.

For rainfall estimates in your area over the last 24 hours, check out our 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 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.

SPM 08-03-2020: Strong Storms Produced Heavy Rain, Wind, and Hail over Plains

Issue Date: Monday, August 3rd, 2020
Issue Time: 09:25AM MDT

Summary:

Thunderstorms fired once again over the mountains yesterday, which were highest in coverage and strength over the eastern and southern mountains. An ASOS rain gauge picked up 0.33 inches of rain in Estes Park along the Front Range as more storms moved over Larimer County. Higher rain totals were observed in the southern mountains. Durango, just south of the San Juan Mountains, received up to 0.84 inches of rain from a severe thunderstorm that moved through the area. This storm also dropped up to marble-sized hail. Storms also produced rain over the eastern San Juan Mountains, where up to 0.35 inches of rain was reported in Rio Grande County. No flooding was reported across these mountain locations.

Heavier rain was produced from severe thunderstorms over the Palmer Ridge and Southeast Plains yesterday. Colorado Springs received up to 0.6 inches of rain according to rain gauges. Parts of western Pueblo also picked up similar totals. The strongest storms tracked over Lincoln County, where a 1.73 inch rain gauge report was submitted from a CoCoRaHS observer in southern Lincoln County. That same observer reported a wind gust of 71 mph, which broke tree limbs and even knocked over a whole tree. Radar indicates that this storm passed over the observer’s location within 1 hour, which makes the 1.73 inch a respectable 1-hour rain rate. A second round of storms moved over central Lincoln County (near Limon) later in the evening, which produced a wind gust of 67 mph and dropped up to golf ball sized hail. The highest CoCoRaHS rain report this morning was 1.19 inches from this storm. Radar indicates this storm moved over the report location over the course of 30-40 minutes. The QPE map shows these two storm swaths well with rain totals over 1 inch. Although no reports of flooding were sent in from these storms over Lincoln County, the Limon Police Department showed pictures of building and tree damage caused by the later storm.

Some storms also fired over far eastern portions of the Northeast Plains overnight, which produced some heavy rain. These storms appeared to fire due an outlow boundary from the severe storms that moved over Lincoln County. The QPE map indicates between 1.5 and 2 inches of rain fell over a NW to SE track in Phillips and Yuma counties. The highest CoCoRaHS rain report in the area was 0.78 inches on the northeast side of Wray. A CoAgMET rain gauge reported 0.84 inches over southeast Phillips County this morning. Unfortunately, these gauges were not located within the swath of heaviest rainfall indicated by radar, so the higher QPE rain totals cannot be verified. Flooding has not been reported over the area as of this morning, but it did occur over the early morning hours, so flood reports may be submitted later today.

For rainfall estimates in your neighborhood over the last 24 hours, check out our 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 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.

SPM 08-02-2020: Rinse and Repeat

Issue Date: Sunday, August 2nd, 2020
Issue Time: 10:15AM MDT

Summary:

Not much change in details from Friday into Saturday, so the QPE footprint looks pretty similar over eastern Colorado. Perhaps there was a bit more drying, so totals weren’t quite as high. A gauge in Fort Collins (from their mesonet) picked up 0.36 inches, and a USGS gage near Colorado Springs picked up the same. While the higher totals remained isolated, the stronger storm cores were likely producing around 0.5 inches. Over the Front Range, there was a severe thunderstorm in Larimer County that produced some severe hail. Reports of hail diameter were between 1 and 1.75 inches. Lastly, the Spring Creek burn area was warned for Flash Flooding. A Weather Underground station picked up about a quarter inch, and flooding was not reported as of this morning.

There were a couple differences between the QPE maps. One, additional storms fired overnight in the Northeast Plains associated with an upper level jet streak. Totals just under 0.75 inches were estimated with a 0.63 inch observation in eastern Kit Carson County. Secondly, more moisture was available over western Colorado, so storm coverage was bit better (south). High-bases still meant that storms produced more wind than rainfall, but the San Juan Mountains picked up isolated totals around 0.5 inches as well. A 62-mph gust was measured at the La Plata County Airport, but no damage was reported.

To see precipitation estimates over your community the last 24 to 72-hours, 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 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.

SPM 08-01-2020: Strong Storms Along Eastern Mountains Made Beautiful Sunset & Lightning Photos

Issue Date: Saturday, August 1st, 2020
Issue Time: 10:45AM MDT

Summary:

Clouds and thunderstorms fired over the mountains of Colorado yesterday, increasing in coverage and intensity from west to east. Some stronger severe-warned storms were able to develop over the Front Range and Southeast Mountains/Plains, which produced several hail reports of up to 1 inch diameter in Boulder County and a wind gust up to 61 mph at the Pueblo Airport. Some strong storms also moved over the Spring Creek burn area, which caused NWS Pueblo to issue a Flash Flood Warning based on radar. Drier air yesterday kept cloud bases high, which allowed more sub-cloud evaporation, limiting the amount of rainfall that actually made it to the surface. This made storms look more menacing on radar compared to the rain they were producing at the surface. The picture below was taken from Arvada, CO at 08:13 PM MDT looking northwest as a strong storm was moving into northern Boulder County, which shows the dry air and evaporation of rain below the clouds.

The heaviest rain fell from a train of storms that once again tracked over southern Larimer and northern Boulder County between 3PM and midnight local time. This seems to be a favorable location in these northwest flow setups. The heaviest rain report was 1.46 inches from a City of Fort Collins rain gauge located in the foothills between Fort Collins and Estes Park. A report of 1.06 inches was submitted by a CoCoRaHS observer southwest of the town of Berthoud, with nearby reports of 0.90 and 0.82 inches. Rain gauges picked up between 0.46 and 0.76 inches over the city of Longmont. The QPE map agrees well with these rain gauge reports and shows these higher rain totals stretch from east of Estes Park southeast to Firestone. No flooding was reported over this area, but social media is buzzing with plenty of lightning and sunset photos from these storms last night.

Further south, along the eastern portion of the Southeast Mountains and western Southeast Plains regions, storms dropped up to 0.43 inches of rain according to rain gauges. This highest report was from central Huerfano County, just east of the Spring Creek burn area. Radar indicates two rounds of storms tracked through this area between 4PM and 9PM local time, which caused the Flash Flood Warning. A second cluster of severe-warned storms tracked through Pueblo County between 6PM and 9PM, which caused the 61 mph wind gust reported at Pueblo Airport. Rain gauges reported up to 0.56 inches of rain from these storms, which agrees well with the QPE map. No flooding was reported with these storms.

For rainfall estimates in your area over the last 24 hours, check out our 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 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.