SPM 09-01-2020: Fall Shortwave Brings Widespread Beneficial Rainfall & Some Wind

September 1, 2020 by ·

Issue Date: Tuesday, September 1st, 2020
Issue Time: 10:25AM MDT

Summary:

A strong shortwave system moved through Colorado yesterday afternoon and overnight, which was associated with a large-scale trough and southern dip in the polar jet stream. This system is just in time for the start of meteorological fall. The stronger surface winds with this system caused some gusty winds along the western slope, where wind gusts up to 58 mph were reported. Luckily these winds did not cause issues with the current wildfires (see updated wildfire info below). Rainfall was generally light showers over longer durations (stratiform), rather than convective in nature. The highest rainfall over the last 24-hours appears to have fallen over the northern San Juan Mountains and Southwest Slope, where numerous CoCoRaHS and USGS rain gauges are reporting between 0.4 and 0.5 inches in Ouray and eastern Montrose counties. A MesoWest station just east of the town of Montrose is reporting 0.56 inches of rainfall. Elsewhere across the mountains, rain totals were between a trace and a quarter of an inch. The plains of eastern Colorado did not miss out on this rain either. The highest rain totals over the plains were over the Palmer Ridge, where CoCoRaHS observers reported up to 0.34 inches of rain in Elbert County. Most locations saw at least measurable precipitation (0.01” or more). No flooding has been reported as of this morning. Although there wasn’t enough rain to make a dent in the drought, we’ll take it and the cooler temperatures after a dry and hot August. In fact, August was tied for the hottest on record.

If you were looking at webcams across Colorado this morning you might have been delighted (or upset) to see a dusting of SNOW at Pikes Peak! The webcam image below (looking northwest) shows this light dusting of snow at 14,115 feet above sea level this morning with the snowline falling to about 10K feet last night. Fall is on our doorsteps, but first another hot and dry week is ahead.

Colorado large wildfire updates (as of 9:30AM on InciWeb):
Pine Gulch – north of Grand Junction: 139,007 acres; 81% contained (0.14” of rain fell over fire, no flooding reported)
Grizzly Creek – Glenwood Canyon: 32,464 acres; 75% contained (0.2” of rain fell over fire, but no flooding)
Cameron Peak – Medicine Bow Mountains: 23,022 acres; 5% contained (increased containment)
Williams Fork – Arapaho National Forecast: 12,097 acres; 10% contained

To see how much rain your neighborhood received over the last 24 to 72 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.

Filed Under: State Precipitation Map ·

SPM 08-31-2020: Windy Conditions and Scattered Rainfall

August 31, 2020 by ·

Issue Date: Monday, August 31st, 2020
Issue Time: 9:50AM MDT

Summary:

Scattered storms formed over the mountains yesterday just after 1:30PM with some residual moisture. Generally, precipitation totals east and west over the mountains were under 0.25 inches with slightly higher totals over the Roan Plateau region and southern San Juan Mountains. A USGS gauge near Ouray picked up 0.36 inches, and most SNOTELS further south recorded between 0.30 and 0.40 inches. The main story over western Colorado were the gusty winds, which ranged from 45 mph to 56 mph with the inverted-V soundings.

As storms pushed eastward off the mountains, totals decreased for the most part as well as coverage. In Jefferson County, a weak microburst broke 3-4 inch limbs around 3:20 PM. A gust of 35 mph was found in the area from a MesoWest site. QPE indicates that storm totals over the adjacent plains were under 0.25 inches with CoCoRaHS reports mostly between 0.15 and 0.20 inches. The cold front that dropped through overnight produced gusts up to 55 mph with most stations recording gusts between 35 and 45 mph. Much cooler temperatures were reported behind the front over eastern Colorado, which can be seen into today’s FTB post.

Colorado large wildfire updates (as of 9:45AM on InciWeb):
Pine Gulch – north of Grand Junction: 139,007 acres; 79% contained
Grizzly Creek – Glenwood Canyon: 32,464 acres; 73% contained
Cameron Peak – Medicine Bow Mountains: 23,007 acres; 0% contained
Williams Fork – Arapaho National Forest: 12,097 acres; 10% contained

To see precipitation estimates over your neighborhood 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 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.

Note: The 24-hour, 48-hour and 72-hour total precipitation do not contain bias corrections today due to errors in the CoCoRaHS data. This means there may be underestimations in QPE over the southwest and southeast corners of the state.

Filed Under: State Precipitation Map ·

SPM 08-30-2020: Beneficial Rain and Some Isolated Flooding Issues

August 30, 2020 by ·

Issue Date: Sunday, August 30th, 2020
Issue Time: 10:00AM MDT

Summary:

Morning showers and some weak afternoon storms produced a healthy accumulation of rain over the mountain regions, with several locations picking up over 0.5 inches of rain from the northern San Juan Mountains north through the Central and Northern Mountains. The highest CoCoRaHS rain gauge report was 0.65 inches near I-70 just east of Vail in Eagle County. A couple of 2”+ reports were submitted in Eagle County, but they likely are erroneous measurements as a nearby report only shows 0.3 inches. Note that this has created erroneously high QPE values for Eagle County on the QPE map below. Some gusty winds were also reported with the afternoon storms that moved through the northwest part of the state, with gusts up to 64 mph. This wind was likely due to some drier air that moved into that area causing more evaporation.

As the shortwave moved off the mountains into the plains of eastern Colorado, it produced some heavy downpours with a north-south oriented band of storms that propagated to the eastern border. These storms produced up to 1.42 inches of rain just south of the town of Simla according to CoCoRaHS rain gauges. Up to 0.79 inches of rain also fell over the Colorado Springs area. This caused a rapid rise in flow in Fountain Creek, from 35 cfs to 455 cfs at the stream gauge in Colorado Springs. A bit further south in eastern Custer County, a debris slide closed highway 96 near the Junkins burn area (from 2016). A heavy rain report of 0.55 inches was sent in near the area, and some small hail was reported farther southeast in Pueblo County. In the town of Yuma (Northeast Plains), 0.83 inches of rain was reported in 20 minutes, which caused some minor flash flooding of paved roads.

Ongoing large fire update (as of 10:00 AM on InciWeb):
Pine Gulch – north of Grand Junction: 139,006 acres; 77% contained (Colorado’s LARGEST WILDFIRE)
Grizzly Creek – Glenwood Canyon: 32,464 acres; 73% contained (minimal growth, increased containment)
Cameron Peak – Medicine Bow Mountains: 23,007 acres; 0% contained
Williams Fork – Arapaho National Forest: 12,097 acres; 10% contained (minimal growth, increased containment)

To see how much rain fell near you over the last 24 to 72 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.
Filed Under: State Precipitation Map ·

SPM 08-29-2020: Widespread Beneficial Rainfall, Heavy Rain in Southeast Plains

August 29, 2020 by ·

Issue Date: Saturday, August 29th, 2020
Issue Time: 11:00AM MDT

Summary:

Beneficial rainfall covered much of Colorado yesterday, with most of it creating rainfall totals up to 0.5 inches. However, some locations were able to pick up some heavy rain totals, particularly in the Southeast Plains, where a convective system dropped up to 2.53 inches according to a USGS rain gauge in northeast Las Animas County. A CoCoRaHS gauge also reported 2.52 inches of rain just north in southeast Otero County, indicating this heavy rain was not an isolated event. In fact, today’s QPE map shows much of the northern Raton Ridge and southern Southeast Plains regions picked up over 0.5 inches. Fortunately, no flooding was reported with the heavy rain in this area, likely due to the prolonged period of rainfall and the dry soils. A Flash Flood Warning was issued by NWS Pueblo for the Spring Creek burn area last evening, but no reports of flooding have come in as of this morning. Rain gauges near the area indicate up to 0.3 inches of rain fell, with one gauge reporting up to 0.42 inches (CoCoRaHS). Rain totals up to 0.6 inches were reported by CoCoRaHS observers in Custer County, in the Southeast Mountains, with up to 0.44 inches reported in Boulder County along the Front Range.

Yesterday was also our first day of cooler air in quite awhile along the eastern plains as a cold front moved through. Denver only high a high temperature of 80F, 5 degrees below average. Some locations along the Urban Corridor didn’t even get out of the 70Fs. This is a welcome relief.

Ongoing large fire update (as of 11:00 AM on InciWeb):
Pine Gulch – north of Grand Junction: 139,006 acres; 77% contained (Colorado’s LARGEST WILDFIRE)
Grizzly Creek – Glenwood Canyon: 32,448 acres; 71% contained (little growth, increased containment)
Cameron Peak – Medicine Bow Mountains: 23,007 acres; 0% contained
Williams Fork – Arapaho National Forest: 12,079 acres; 5% contained

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.

Filed Under: State Precipitation Map ·
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