SPM 09-22-2017: Disturbance Moved Closer To Colorado, But Moisture Lacking

Issue Date: Friday, September 22, 2017
Issue Time: 11AM MDT

Summary:

A large upper-level trough approached Colorado on Thursday, but was hardly noticed at the surface. Gusty, dry southwesterly winds caused very low relative humidity levels once again, keeping the fire danger elevated. Additionally, plenty of sunshine and downsloping flow (east of the Continental Divide) resulted in temperatures much above normal. Temperatures reached as high as the mid-90s F in the lower elevations of the Arkansas River. The Denver metro reached the low-90s F, which was a daily record. Winds gusted to 45 mph statewide, with gusts up to 60 mph in the higher mountain passes.

Later in the day, some upper-level forcing generated isolated to scattered showers over the higher terrain of southwest Colorado. Due to the dry lower atmosphere, only a few tenths of an inch of rainfall were measured, limited to the higher elevations.

Flooding was not reported on Thursday. For rainfall estimates in your area, 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 accumulation ending time is 6AM of the date shown in the bottom right corner. Also shown optionally are fire burn areas since 2012. The home button in the top left corner resets the map to the original zoom.

Note: We have identified a possible underestimation in QPE over the southwest part of the state. We are working to on this issue, and will provide an update as soon as possible.

SPM 09-21-2017: Mostly Sunny with Continuing Wind

Issue Date: Thursday, September 21, 2017
Issue Time: 10:30AM MDT

Summary:

Another beautiful day for Colorado yesterday. Temperatures rebounded quite nicely after the cold front that came through Tuesday evening. High temperatures yesterday were in the mid to upper 70s over the lower elevations and reached 70F in some of the mountain valleys. The cold front helped increase relative humidity values and decrease temperatures enough for a temporary lift of the Red Flag Warning. There was also a bit of a break from the widespread, stronger winds though some of the mountain passes still saw had maximum winds around 45 mph and gusts up to 60 mph. Over the Palmer Divide, winds also decreased quite a bit from Tuesday with maximum wind speeds of 15 mph and gusts around 20 mph.

Downsloping winds limited cloud cover and rainfall over the Front Range and Southeast Mountains. A small shower did form over the Northern Mountains in the evening. A CoCoRaHS station in Routt County recorded 0.12 inches of rain, and the SNOTEL station at Rabbit Ear(s) Pass recorded 0.3 inches.

There was no flooding reported on Wednesday. To see how much rain fell in your neighborhood, take a peek at 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 6AM of the date shown in the bottom right corner. Also shown optionally are fire burn areas since 2012. The home button in the top left corner resets the map to the original zoom.

Note: We have identified a possible underestimation in QPE over the southwest part of the state. We are working to on this issue, and will provide an update as soon as possible.

SPM 09-20-2017: Gusty Winds and Snow for the Northern High Country

Issue Date: Wednesday, September 20, 2017
Issue Time: 10:45AM MDT

Summary:

The jet stream moved southeast yesterday with the front nose of the jet settling just north of Colorado. 100+ knot winds clipped the northwest corner of the state leading to a high wind advisory as the fast moving air aloft mixed down to the surface. Some mid-level energy also moved through northern Colorado, which helped trigger some rainfall and snow (at higher elevations) during the evening hours after the cold front passage. Elsewhere along the Front Range, downsloping winds lead to sunny skies and a windy afternoon and evening, especially along the Palmer Divide. Low relative humidity values were created by the descending air as it warmed adiabatically, and a Red Flag Warning was in place through last night. Early in the evening, a strong cold front pushed south and dropped temperatures 15-20F and produced windy conditions. Due to dew points in the 20s, negligible precipitation fell, but a lot of dust was kicked up. The cold front did moisten the lower atmosphere enough for the high terrain showers along the CO/WY border in the evening and overnight.

Over Routt County, two CoCoRaHS stations recorded 0.25 inches. A SNOTEL site in the Medicine Bow-Routt National Forest recorded 0.4 inches of precipitation from the late afternoon into early evening. Due to the cold front rapidly dropping temperatures, precipitation at higher elevations was in the form of snow. Webcams from Steamboat Ski Resort this morning show a light dusting of snow. Again, the real story yesterday were the wind gusts, which were quite impressive. Below is a handful of maximum gusts from around the state. There was no flooding reported on Tuesday.

Hayden – 48 mph
Steamboat – 40 mph
Gypsum – 48 mph
Berthoud Pass – 74 mph
Cottonwood Pass – 64 mph
Saguache Airport – 36 mph
Limon – 41 mph
Denver – 28 mph
Sterling – 46 mph

For an estimate of rainfall totals in your area, 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 6AM of the date shown in the bottom right corner. Also shown optionally are fire burn areas since 2012. The home button in the top left corner resets the map to the original zoom.

Note: We have identified a possible underestimation in QPE over the southwest part of the state. We are working to on this issue, and will provide an update as soon as possible.

SPM 09-19-2017: Sunshine with Increasing Winds

Issue Date: Tuesday, September 19, 2017
Issue Time: 10:30AM MDT

Summary:

Almost clear skies across the state yesterday. Below is a visible satellite image taken at 5PM yesterday, which shows just a few clouds over the state. Below it are the surface observations from the same time, which confirms very low dew point values. As expected, the wind speeds also started to increase with the approaching upper level trough and jet stream. The largest non-thunderstorm gust reported yesterday was 56 mph in San Juan County.

With dew point values in the 20s and 30s, very little rain made it to the surface. Any clouds that were able to form, quickly evaporated with the entrainment of drier air. Only one CoCoRaHS station recorded measurable precipitation, but it was under 0.05 inches. Radar estimates over the Northern and Central Mountains (where the clouds are in the visible image) were under 0.25 inches.

There was no flooding reported Monday as of this morning. For an estimate of rainfall totals in your area, 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 6AM of the date shown in the bottom right corner. Also shown optionally are fire burn areas since 2012. The home button in the top left corner resets the map to the original zoom.

Note: We have identified a possible underestimation in QPE over the southwest part of the state. We are working to on this issue, and will provide an update as soon as possible.