SPM 06-03-2020: Severe Thunderstorms and Flooding for Northeast Border Counties

Issue Date: Wednesday, June 3rd, 2020
Issue Time: 10:15AM MDT

Summary:

The drying trend began yesterday with the high located to our south and westerly/northwesterly flow aloft. This caused a downtick in afternoon storms activity over the mountains with little to no activity west of the Continental Divide. Totals over the eastern mountains were typically under 0.10 inches with the southern Southeast Mountains receiving around 0.25 inches. As storms moved east, moisture increased a little, so totals increased to about 0.50-0.75 inches. A Severe Thunderstorm Warning was issued for Weld County during the evening.

Higher moisture was located over the eastern plains where a convergence boundary was located (weak “cold” front). Nearly stationary storms in the late afternoon/evening produced some very high totals, landspouts, and flash flooding over Kit Carson and Cheyenne Counties. A strong outflow gust south of Burlington caused a mini dust storm with zero visibility. Over 2 inches of rain fell in 30 minutes between Goodland and Burlington along the border! Not surprising that a Flash Flood Warning was issued for these storms.

For precipitation estimates in your area over 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 06-02-2020: Early Summer Heat Continues, Along With Scattered Storms

Issue Date: Tuesday, June 2, 2020
Issue Time: 10:40AM MDT

Summary:

Very hot temperatures continued across Colorado on Monday, fittingly the first day of meteorological summer. Noteworthy high temperatures included:

99F at La Junta (4,200 ft)
97F at Fort Morgan (4,500 ft)
92F at Denver International Airport (5,400 ft)
81F at Steamboat Springs (6,900 ft)
86F at Alamosa (7,600 ft)
72F at Leadville (9,900 ft)

Along with the heat came above average moisture, by early June standards, leading to scattered afternoon showers and thunderstorms mainly across southern areas. The highest observed rainfall came in at 1.05 inches from near Fort Garland in the San Luis Valley. This is extremely unusual for this time of year, as that area typically does not see heavier rainfall until the monsoon season. More common were amounts in the 0.25-0.50 inch range. These amounts are usually not enough to warrant flooding, unless of course they fall over fire burns. Indeed, there were two such NWS products issued. First, a Flash Flood Warning was issued for the Hayden Pass burn scar around 2:40PM. Second, a Small Stream Flood Advisory was issued for the High Park burn scar in Larimer County around 4:55PM. Fortunately, neither location reported any flooding, but we are reminded how sensitive these areas can be due to a lack of vegetation and a hygroscopic top layer that can efficiently repel water.

For precipitation estimates in your neighborhood over the last 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 06-01-2020: Scattered Storms Fire with Residual Moisture Under the Ridge

Issue Date: Monday, June 1st, 2020
Issue Time: 9:55AM MDT

Summary:

A bit of drying under the ridge with more westerly flow aloft helped decrease the rainfall threat yesterday. With a similar pattern over the last few days, storms were diurnally driven beginning in the early afternoon. Yesterday, storms favored the eastern foothills with lighter rainfall over western Colorado. A strong gust was recorded over Logan County associated with a storm becoming downdraft dominate around 8PM (58 mph). Westerly flow helped push a few of the storms into the adjacent plains, but they mostly only survived over the Palmer and western Raton Ridge (convergence on the higher elevations). Fort Collins got a nice storm with totals on their mesonet up to 0.47 inches. They’ve had about 2 inches of rainfall over the last 30 days. Some stronger storms were also present near the Air Force Academy/Fort Carson areas where USGS gauges recorded just over a half inch of rainfall in 20 minutes.

Back west, the eastern San Juan Mountains got some nice accumulations with the Del Norte area receiving about a half inch of rain. Even the edges of the San Luis Valley received some measurable rainfall, but Alamosa (interior) only received about 0.05 inches. Storms started to come to an end around 11PM, which is a couple hours after instability began to drop off. Flooding was not reported as of this morning.

For precipitation estimates in your neighborhood over 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 05-31-2020: Heavy Rainfall and Flash Flooding for Pueblo and Fremont Counties

Issue Date: Sunday, May 31st, 2020
Issue Time: 10:05AM MDT

Summary:

It was setting up to be heavy rainfall day with dew points in the 50Fs and slow steering winds, but the rain rates over Pueblo County were more than impressive. It looks like radar estimated up to 3 inches of rain in both Pueblo and El Paso! The Young Hallow station at Fort Carson was the day’s big winner. It recorded 1.80 inches for the day with 0.72 inches falling in 10 min, which is between at 10-year and 25-year event. A CoCoRaHS station in downtown Pueblo recorded 1.88 inches. Not surprisingly, this caused some flooding issues:

  • Roads washed out in Midway Ranches neighborhood
  • Water overtopping I-25 at mile marker 104
  • Water breaching banks along Four Mile Creek
  • 3 to 4 inch deep water flowing over Pueblo Blvd and Highway 50
  • Damage to the shoulder of I-25
  • Multiple manhole covers dislodged
  • Cars stalled in flood waters

Over the Front Range, storms remained somewhat capped during the afternoon hours, which kept the flood threat lower. None the less, MRMS and Stage IV QPE had between 1 and 1.5 inches of rain along the Divide in Larimer, Boulder, Gilpin and Clear Creek Counties. These estimates were both a little higher than MetStorm Live (below). Hail was also reported in Fort Collins around 6:30PM that was just under an inch in diameter with a stronger storm that formed and dropped around a half an inch of rain. The San Juan Mountains got between 0.25 to 1 inch of rainfall, as well as small hail and wind gusts (downdraft outflow) around 50 mph.

For precipitation estimates in your neighborhood over the last 24-hours, scroll down to the State Precipitation Map below. Reminder, you can also report any flooding to our website: http://www.coloradofloodthreat.com/?page_id=11165

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.