SPM 07-08-2020: Weak T-Storms for Eastern and Southern Colorado with Hot Temperatures Statewide

Issue Date: Wednesday, July 8th, 2020
Issue Time: 9AM MDT

Summary:

It was toasty yesterday, and both Grand Junction and Denver hit 99F. It was 90F just after 10AM for both locations, so not too surprising that it got that hot. Highest temperature from NWS ASOS stations was in Greeley (102F), and there were a couple other stations over the Northeast Plains that reached 101F. Coverage of these stations isn’t great over the eastern plains, so there were likely local, hotter temperatures over the region. Not much moisture over western Colorado, the mountains, and Urban Corridor, so only elevated convection occurred back west. A passing shortwave helped carry the convection into the eastern plains. Slightly better low-level moisture allowed storms to intensify and drop some light to moderate rain. The highest rainfall totals were over Washington and Las Animas Counties. Of course there were no gages in these remote areas, so it’s hard to verify the QPE below. Based on the last week or so, I’d guess the rainfall was estimated a little high in the core of the storms. That’s due to the dry surface layer and high bases promoting evaporation as the drops fell. My best guess is totals were closer to 0.50 inches. The storm complex over the Northeast Plains also produced some 60 mph wind gusts in Yuma, Adams, and Phillips Counties. There was no damage reported as of this morning. I could only find one new fire report, which was just north of Meeker (Axial, CO). So far the fire has burned 25 acres, and is not occurring over steep terrain.

For precipitation estimates in your neighborhood 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 07-07-2020: Downtick in Moisture Causes a Downturn in Afternoon Storm Activity

Issue Date: Tuesday, July 7th, 2020
Issue Time: 9:30AM MDT

Summary:

The heat started to crank up yesterday, and Grand Junction hit the 100F mark. DIA hit 97F just before 5PM. Some nice afternoon and evening cloud cover helped cool it off at the lucky locations. Storms yesterday were mostly high-based with limited moisture available, so they didn’t produce a lot of rainfall or large rain cores. The best rainfall coverage was over Logan County where just under a half inch fell. Storms looked more menacing on radar than they actually were. A CoCoRaHS gage north of Sterling recorded 0.40 inches of rainfall, which was the highest observation of the day. Another stronger storm formed over the Palmer Ridge and 0.36 inches of rain were recorded at a gage near Ramah in Elbert County. QPE estimated rain totals just over a half inch northwest and north of Limon. Back west, storms produced some gusty outflow winds over the Northern Mountains/Northwest Slope. A 50 mph gust was recorded in Craig with rainfall totals estimated below 0.05 inches in the area. Flooding was not reported.

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 07-06-2020: Isolated Heavy Rainfall, But Lower Coverage on Sunday

Issue Date: Monday, July 6th, 2020
Issue Time: 9:15AM MDT

Summary:

With a gradual drying of the atmosphere, rainfall coverage and intensity took a step downward on Sunday. Nonetheless, scattered showers and thunderstorms were still abundant over certain regions like the Front Range, Central Mountains, San Juan Mountains and Southeast Mountains. Although storms were higher based, compared to Saturday, they were still able to deliver some short-term heavy rainfall. Amounts up to 0.40 inches, typically over a 10-15 minute period, were common mainly east of the Continental Divide. There were two areas that got more: first, a very isolated storms in Fremont County dropped just over 1.0 inch in less than 1 hour. A CoCoRaHS gage reported 1.07 inches this morning, which appears to be in the most intense part of the storm. Second, in Baca County, right along the Kansas border, a few slow moving cells dropped 1.0 to 1.5 inches of estimate rainfall. In both cases of the heavier rainfall, the areal coverage was too low to cause any flooding concerns.

In other news, the state enjoyed its last day of near normal temperatures on Sunday as a prolonged intense heat wave is expected to start today.

Flooding was not reported on Sunday. For precipitation estimates in your neighborhood 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 07-05-2020: Beneficial Rainfall to Southeast Plains Drought Region

Issue Date: Sunday, July 5th, 2020
Issue Time: 10:10AM MDT

Summary:

The moisture plume had settled in over the state yesterday, and paired with some mid-level energy and slow steering flow, this set the stage for another day where storms could produce heavy rainfall. Action kicked off a little earlier over the mountains, which limited the amount of instability that could form. Therefore, rain rates were on the lower end. There were still some impressive totals for the pulsing storms, and SNOTEL sites recorded between 0.30 and 0.40 inches. A RAWS station near Vail recorded 0.50 inches, and another gage near Ruedi Reservoir recorded 0.56 inches. A Flash Flood Warning was issued for the Spring Creek burn area at 3:45PM and again at 5:30PM. QPE from the storms was estimated between 0.50 and 0.75 inches over the north portion of the burn area. The La Veta Pass NWS gage was located just to the south of the rainfall, so it wasn’t helpful in determining how much rain actually fell. RAWS gages just north of the burn area measured between 0.43 and 0.49 inches of rain. Flooding was not reported.

As storms moved off the mountains, they encountered better moisture and instability, which let them grow in coverage and strength. CoCoRaHS stations in Rocky Ford recorded just under 2 inches for the 24-hour period. MetStorm estimated 1-hour rain rates at 2 inches between Rocky Ford and La Junta. The La Junta NWS gage recorded 1.08 inches for the 24-hour period, so that core of 3.5 inches in the MetStorm QPE is likely high. My best guess is around 2 to 2.25 inches for the 24-hour period. There was flooding reported in La Junta with 2.5 to 3 feet of water flooding Highway 50 closing the road at the railroad overpass. The totals along the Kiowa and Bent County border is also likely high as CoCoRaHS in the area reported between 1.15 and 1.29 inches. Nonetheless, this was beneficial rainfall for an area experiencing a severe and worsening drought. Over the Metro area, there were a few ALERT gages just east of town (Aurora) that recorded between 1.18 and 1.65 inches of rain. There was a report of 3.13 inches from a spotter at Buckley Air Force Base, which I believe is high. The ASOS gage at Buckley recorded 1.46 inches, which is in line with 1.65 inches at the ALERT Sand Creek and Colfax gage. Flooding was not reported in this area despite a Flash Flood Warning being issued.

For precipitation estimates in your neighborhood over the last 24 to 72-hours, scroll down to the State Precipitation Map below. Note that Yuma and Kit Carson County 48 and 72-hour totals are likely inflated as I’ve shown QPE was likely overestimated the last couple of days compared to observations in the area.

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.