SPM 09-30-2020: Smoky Skies with No Precipitation

Issue Date: Wednesday, September 30th, 2020
Issue Time: 10:30AM MDT

Summary:

Below is the visible satellite imagery from 4PM yesterday. All large ongoing fires have visible smoke plumes, including the Williams Fork fire. This likely is helping to contribute to the smoke being reported in the Denver Metro this morning. In fact, smoke is visible across the entire I-25 corridor (gray hue): CLICK ME. Ash and soot has been observed further north within the Urban Corridor. Low air quality is forecast again today along the I-25 Corridor.

The image below also shows cloud free conditions, which meant that no precipitation fell. The stronger surface winds yesterday, associated with the upper jet, were located over the northern Northeast Plains, which caused elevated fire danger. Northwest winds were in the 10 to 20 mph range with gusts up to 28 mph observed. It also got windy over the higher elevations along and near the northern Continental Divide, and northwest wind gusts up to 25 to 30 mph were observed. This likely helped flare up the Williams Fork fire, which is why we saw an increase in smoke yesterday afternoon.

Large ongoing Colorado wildfires update (as of 9:30AM from InciWeb):
Cameron Peak in the Medicine Bow Mountains: 125,006 acres; 22% contained
Middle Fork Fire in Routt County: 7,897 acres; 0% containment
Williams Fork in the Arapaho National Forest: 12,898 acres; 14% 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 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 09-29-2020: Cool Temperatures, Clear Skies & Gusting Winds

Issue Date: Tuesday, September 29th, 2020
Issue Time: 9:50AM MDT

Summary:

Another night with some very cold temperatures as the clear skies increased radiational cooling. Below are NWS ASOS stations overnight lows (deg F). Freeze Warnings were in effect for portions of the Northwest and Southwest Slopes as well as over the higher elevations in the Northern Mountains. With the jet over the state yesterday, it remained breezy during the afternoon. Thankfully, it doesn’t look like there was much (if any) change in ongoing wildfire behavior. Generally, winds were in the 8 to 15 mph range (from the northwest) over the northern and central mountains. Slightly higher winds were recorded over the highest elevations. Gusts reached between 15 and 25 mph with a couple 30+ mph gusts recorded over the mountains. Near surface smoke was highest north, near the Cameron Peak/Mullen fires, but most of this smoke was aloft along the Front Range and Urban Corridor. Much cooler temperatures were recorded yesterday behind the front, and the dry air mass/subsidence kept rainfall out of the forecast. Light showers over the Southeast Mountains during the morning hours cleared out as dry air filled in from the north. Other than some cirrus over the Northwest Slope, it was a clear, fall day.

Large ongoing Colorado wildfires update (as of 9:40AM from InciWeb):
Cameron Peak in the Medicine Bow Mountains: 124,026 acres; 21% contained
Middle Fork Fire in Routt County: 7,897 acres; 0% containment
Williams Fork in the Arapaho National Forest: 12,889 acres; 14% contained

To see precipitation estimates over your neighborhood the last 24 to 48-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 09-28-2020: Major Cool-off with Rain/Snow Mix

Issue Date: Monday, September 28th, 2020
Issue Time: 9:40AM MDT

Summary:

A second, stronger cold front dropped through Colorado pretty early yesterday, which caused the high temperatures to be recorded in the morning hours for most locations north. Light showers over the Northeast Plains during the morning were observed, and precipitation increased in coverage after the front dropped through and brought a little moisture/upper air support. For the most part, accumulations were over the lower elevations in eastern Colorado. Even some light snow was observed over the Front Range. The band-like precipitation dropped between 0.05 and 0.20 inches, but isolated totals up to 0.25 inches were possible as MetStorm indicates. This is especially true where the front stalled out along the Palmer Ridge area/east. The highest observation was from a CoCoRaHS station in western Washington County, which recorded 0.13 inches. Flooding was not reported.

High surface winds continued yesterday, although the fire danger dropped off a little from Friday/Saturday due to cooler temperatures. In Gunnison, CO wind gusts up to 53 mph were reported and further south over La Plata County, gusts up to 48 mph were reported. Fire growth was minimal, but containment on the Cameron Peak fire decreased slightly.

It also got very cold overnight, and a Freeze Warning was issued for the Yampa river valley. Temperatures fell to 19F over Craig and 14F near Walden. Other mountain valley locations also reached freezing temperatures, which is typical. Below is a nice picture from the top of Pike’s Peak this morning where rime ice formed. This is when very cold water droplets freeze onto surfaces.

Large ongoing Colorado wildfires update (as of 9:30AM from InciWeb):
Cameron Peak in the Medicine Bow Mountains: 124,026 acres; 21% contained
Middle Fork Fire in Routt County: 7,897 acres; 0% containment
Williams Fork in the Arapaho National Forest: 12,850 acres; 14% contained

To see precipitation estimates over your neighborhood the last 24-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 09-27-2020: Windy Conditions and High Fire Danger

Issue Date: Sunday, September 27th, 2020
Issue Time: 9:40AM MDT

Summary:

The main concern on Saturday was increasing fire danger, both in intensity and coverage with winds really picking up as the jet stream moved overhead. Gusts near the Cameron Peak fire reached around 45 mph during the late afternoon. Paired with dry, warm conditions, the fire unfortunately grew about 13K acres yesterday, which caused a lot of additional smoke. This is now the 3rd largest fire in Colorado history. The Middle Fork fire was also dealing with 30+ mph gusts, so it grew about 700 acres, and a gust of 49 mph was reported near Steamboat in Routt County at 5:30PM. Even the Williams Fork fire grew slightly. Thankfully, it doesn’t look like containment went down at all for any of the fires. Over the Central Mountains, gusts reached into the mid-40s (mph). As of this morning, no new fires were reported.

During the evening hours, a cold front moved through and shifted the wind from the north. This caused heavy smoke to roll into the Urban Corridor and Front Range foothills. However, the northerly winds helped clear out the near surface smoke over western Colorado (north) and the eastern plains. It was too dry for any rainfall yesterday, but some very light showers were generated this morning over the northeast corner of the state. Total rainfall estimated from radar look to be under 0.10 inches.

Large ongoing Colorado wildfires update (as of 9:20AM from InciWeb):
Cameron Peak in the Medicine Bow Mountains: 124,021 acres (~13K acre growth); 25% contained
Middle Fork Fire in Routt County: 7,499 acres (~700 acre growth); 0% containment
Williams Fork in the Arapaho National Forest: 12,850 acres (~400 acre growth); 14% contained

To see precipitation estimates over your neighborhood the last 24-hours, scroll down to the State Precipitation Map below. Note that the map below is nearly blank due to the lack of rainfall over the last 72-hours, and the QPE over the eastern border is an error.

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.