Issue Date: Tuesday, September 10th, 2019
Issue Time: 9:25AM MDT

Summary:

Drier air began to move in from the west yesterday, and with rising pressure over the state promoting subsidence, rainfall was somewhat absent across the state after a long weekend of heavy rain. The morning started with quite a bit of fog over the Northeast Plains and Urban Corridor. It burned off with a little daytime heating, which helped mix out the lower level moisture. Other than some fair weather cumulus over the mountains and some sprinkles over the Northern Mountains (near the Continental Divide) it was a gorgeous day. There were some stronger storms over Prowers County that formed along a dryline. Dew points in the area were around 55°F, so high enough for some decent accumulations. An Areal Flood Advisory was issued around 3:30PM for this storm, but as of this morning, no flooding was reported. Trailing/nearly stationary movement allowed up to 1.75 inches to fall with max 1-hour rain rates just under 1 inch.

Another set of storms formed over the northern Urban Corridor around midnight. This set of thunderstorms was associated with a jet streak passing overhead. Surface moisture had returned by the time the storms kicked off, so dew points were in the mid to upper 50°Fs. This allowed for more efficient rain rates, and MetStorm estimates up to 1 inch fell. A CoCoRaHS station near Greeley (Galeton) recorded up to 0.88 inches. Higher amounts of accumulation were avoided due to the fairly quick storm movement and dry mid/upper layers of the atmosphere. Storms moved to the northeast and eventually exited into Nebraska early this morning. There was a report of 1 inch hail over Logan County, so a Severe Thunderstorm was issued last night.

To see estimated precipitation totals over your neighborhood on Monday, scroll down to the State Precipitation Map below.

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Issue Date: Monday, September 9th, 2019
Issue Time: 10:50AM MDT

Summary:

Moderate to heavy rainfall fell throughout the state yesterday as a shortwave trough moved over the state from the west. This feature brought in high levels of moisture to the northern and eastern portions of the state and provided upper level support for multiple rounds of severe thunderstorms. A few brief thunderstorms kicked things off over the Grand Valley, Southwest Slope and San Juan Mountains fairly early. Conditions were a little drier over these areas do to dry southwesterly surface flow which lead to lighter accumulations. CoCoRaHS stations reported widespread rain, but the highest report came in at only 0.13 inches for the Southwest Slope and San Juan Mountains.

Upper level moisture content and storm coverage increased to the north with multiple severe thunderstorm warnings issued throughout the northern Grand Valley, northern Central Mountains, Northwest Slope, and Northern Mountains. Most of these warnings were due to high thunderstorm wind gusts. Surface conditions were a little on the drier side, which lead to evaporative cooling and severe winds over the area. Notable reports to the NWS include:

–76 mph thunderstorm wind gust and 0.35 inch hail near Rifle in Garfield County
–69 mph thunderstorm wind gust near Massadona in Rio Blanco County
–61 mph thunderstorm wind gusts near Gypsum in Eagle County

Most of the rainfall for northern mountains fell over a 3 to 5 hour period as trailing storms continued to move over the area. Rainfall accumulations remained under 1 inch for the most part with a few isolated totals up to 1.03 inches over Routt and Eagle Counties. A RAWS station near Steamboat measured 0.72 inches over a 6 hour period.

Rainfall over the eastern mountains and eastern plains picked up significantly early yesterday afternoon as dew points in the 50°Fs and low 60°Fs pushed west towards the mountains. Heavy rainfall for the high country favored the Front Range with MetStorm estimating 1-hour rainfall rates up to 0.76 inches over Jefferson and Boulder Counties. CoCoRaHS stations measured 24-hour totals up to 0.71 inches over the Front Range and Urban Corridor. These are impressive amounts considering how quickly the storms were moving.

As storms moved off of the mountains, they quickly combined into a MCS that moved over the eastern plains throughout the afternoon and into the early morning. One system produced two tornadoes and wind gusts up to 68 mph over eastern Denver County and western Adams County respectively. 24-hour totals were on the high end throughout the Northeast Plains measuring from 1.78 inches to 2.59 inches from eastern Weld County to Phillips County. As outflow boundaries from the storms pushed to the south the spatial area of the storms extended well into the Southeast Plains. A Flash Flood Warning was issued early last night over Bent and Prowers County with heavy rainfall effecting highways 50 and 287, but no flooding was reported over the area as of this morning. CoCoRaHS stations in northern Prowers County measured up to 1.75 inches for the storm total. MetStorm estimated 1-hour rainfall rates up to 2.12 inches throughout the Northeast and Southeast Plains.

For a look at rainfall in your neighborhood, please visit the State Precipitation Map below.

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Issue Date: Sunday, September 8th, 2019
Issue Time: 10:20AM MDT

Summary:

The active pattern continued with the next shortwave trough helping spark more widespread coverage of thunderstorms and rainfall over southern Colorado yesterday. Drier air limited the rainfall potential over the Northeast Plains and northern western slope, so these areas mostly remained dry. Storms favored the southern Urban Corridor/Southeast Mountains and Raton Ridge area were better moisture was in place and cloud cover was able to break up and provide some instability for growth. With the cloud cover taking longer to break apart, the heavy rainfall was not widespread in nature yesterday. Additional storms formed along a boundary over the Southeast Plains. Finally, a second round of scattered storms formed around 10PM over the Palmer Ridge/southern Northeast Plains. An isolated total up to 2.5 inches was estimated by MetStorm over Cheyenne County associated with a nearly stationary storm.

With storm motion slow, totals up 1 inch were realized just north of Bailey, CO. There is a CoCoRaHS in the area that recorded 1.46 inches, but not thinking this is correct with the other observations around it. Over the adjacent plains, max 1-hour rain rates up to 1.5 inches were reached with the late night storms. A storm near Pueblo during the afternoon produced just under 1.5 inches with a CoCoRaHS station recording 1.23 inches just east of town. The NWS San Luis Valley gage recorded 0.25 inches, which was very much welcomed as the area is experiencing much below average rainfall this summer. An Areal Flood Advisory was issued east of Colorado Springs for those late night storms, but flooding was not reported as of this morning.

To see estimated precipitation totals over your neighborhood the last 48-hours, scroll down to the State Precipitation Map below.

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Issue Date: Saturday, September 7th, 2019
Issue Time: 10:25AM MDT

Summary:

It seemed like a cool, quiet weather day until storms really began to get going over the eastern mountains just after 2PM. A passing cloud front return a ton of low level moisture to the area, and slow steering winds helped allow for some very heavy accumulations. A strong thunderstorm formed over the southern foothills near Evergreen/Floyd Hill just after 1:30PM. Hail up to 1 inch in diameter was reported along with mud flows, debris slides and road flooding. Hail accumulated (inches in depth) on the roadways, which only exuberated the problem with the Cold Spring Gulch ALERT recording 1.14 inches. Storms also formed over the southern metro area and were nearly stationary. An incredible amount of rainfall ensued. An ALERT gauge in Centennial (Englewood Dam) had 2.72 inches of rain in an hour, which was truly a worst case scenario. That is the second highest gauge reading I’ve seen since I started watching those gages 3 years ago. To see 24-houir precipitation totals from the ALERT gages, click here: ALERT. Not surprisingly, there was a large area under a Flash Flood Warning during the afternoon commute with a car rescue at C-470 and Yosemite. Please don’t drive through high water. There was also a brief tornado reported near Centennial Airport and a tornado warning issued for Aurora briefly after for minor rotation in a storm. There was no tornado reported with this warning. Further south near the springs an ALERT gage recorded 1.93 inches near Perry Park. A USGS gage at Douglas Creek above Flying West Ranch Road had 1.61 inches with the USAF had 1.30 inches.

Flash Flood Warnings and Advisory was also issued for the Spring Creek and High Pass burn areas, respectively. Flooding was reported at Pass Creek Road (Spring Creek burn area), which is 3 miles north of Highway 160. There was CoCoRaHS station near Forbes Park that reported 0.8 inches for the 24-hour period. The Chalk Cliffs over Chaffee County also had a Flood Advisory issued for them at 2PM. MetStorm estimates up to 0.75 inches fell in the area with observations in the arear around 0.25 inches. As storms moved east, lack of instability and a capped environment kept the heavy rainfall threat away. Storms also picked up in intensity and coverage over the western high terrains. As much as 0.50 inches fell over the San Juan Mountains with two 0.4 inches observations near the Flat Tops.

To see estimated precipitation totals over your area on Friday, scroll down to the State Precipitation Map below.

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