Issue Date: Wednesday, July 18th, 2018
Issue Time: 9:30 AM MDT

Summary:

As an upper-level low shifted over the Northern Rockies, a few disturbances were sent Colorado’s way, leading to a day full of scattered showers/thunderstorms. Plenty of low-level moisture was available to storm development, resulting in efficient rainfall production, as well as increased instability that led to more intense thunderstorms (relatively speaking) than recent days. A couple storms were able to reach severe thresholds, with the following observations being reported to the National Weather Service:

70 mph wind gust: Grand Junction Regional Airport (Mesa County)
60 mph wind gust: 3 miles ENE of Redlands (Mesa County)
59 mph Wind Gust: Eagle County Regional Airport (Eagle County)
Sub-severe hail (0.25 inch diameter) was also reported in Montezuma County

Heavy rainfall was a concern with the amount of moisture available, and thunderstorms were able to produce plenty of it. A trained NWS spotter reported 0.7 inches/20 minutes 4 miles N of Florissant (Teller County). Flash flooding was reported 3 miles SW of Dolores (Montezuma County), where flooding occurred along Highway 184. A few debris flow observations were also reported:

1 mile ENE of Trimble (La Plata County): US 550 was closed at mile marker 30-31 due to mud flow
8 miles W of Chimney Rock (Archuleta County): Mudflow closed Highway 160 at mile marker 121-124. Cars were stuck in deep mud. Additionally, rocks were reported on the road near mile marker 123.
9 miles WSW of Chimney Rock (Archuleta County): Mud and debris on Highway 151 at mile marker 28

For a look at precipitation estimates in your area, please see our State Precipitation Map below.

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Issue Date: Tuesday, July 17th, 2018
Issue Time: 10:00 AM MDT

Summary:

Drier air moved into northern Colorado, which limited thunderstorm development over the Front Range, Northern Mountains and Central Mountains yesterday. Subtropical moisture was better able to hold on over the Southeast Mountains, Raton Ridge and San Juan Mountains. Thus, afternoon upslope flow driven thunderstorms were more abundant further south. These storms moved into the eastern plains and brought some much needed rainfall to Las Animas and Baca County in the evening hours. Overnight, an MCS that moved through the NE panhandle and clipped the northeast corner of the state, which brought some heavy rainfall to Sedgwick and Phillips Counties.

As far as totals, the northeast corner of the state was the winner yesterday. A couple CoCoRaHS recorded over an inch of rainfall with radar estimates up to 2 inches. No flooding was reported as of this morning. Several flood advisories were issued yesterday including two for the 416 and Weston Pass burn scars. Thankfully, no mud flows or debris slides were reported. There was a heavy rain report over Cortez of 1.55 inches. This caused street flooding and some minor flooding of apartments. There were two CoCoRaHS reports greater than 1 inch in this area. SNOTEL stations in this area recorded rainfall between 0.9 and 1.5 inches. Over the Southeast Mountains, the Apishapa SNOTEL station near La Veta recorded 1.7 inches over the 24 hour period.

To see how much precipitation fell in your area, scroll down to the State Precipitation Map below.

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Issue Date: Monday, July 16, 2018
Issue Time: 10:00 AM MDT

Summary:

A lot of widespread and heavy rainfall on Sunday after the passage of a cold front help moisten the low-levels for afternoon upslope flow. Upper disturbances also increased coverage and intensity of showers and thunderstorms yesterday through this morning. The start to Sunday morning was quite cloudy with temperatures quite a few degrees cooler after the passage of the front. So rain kicked off around noon over the higher terrains and along a pre-frontal convergence boundary over the Urban Corridor/Palmer Ridge. With nearly no upper flow, the storms continued to pulse over the same area for a couple hours at a time. Throughout the day, the storm coverage increased and a few showers slowly moved off the mountains into the Urban Corridor.

Along the pre-frontal convergence area, rain fall estimates by radar were just over 2 inches with max 1-hour rain rates between 0.5-1.5 inches/hour. At E-470 and Highway 83, an ALERT gage recorded 2.05 inches. Most CoCoRaHS captured between 1.5 and 2.3 inches over this area and further south over El Paso County. The highest reported values yesterday was in Pueblo West where 2.62 inches fell over a 5 hour span. Flash flooding occurred near the Junkins burn scar between county roads 386 and 389. The highway remains closed through noon today. Other places along the Front Range saw a jump in river height between 1-3 feet, but no flooding occurred. Over the San Juan Mountains, there were mud flows in San Miguel County along Highway 145. Rainfall radar estimates were just over 0.5 inches. A couple SNOTEL stations in the area recorded 0.9 inches.

To see how much precipitation fell in your area, scroll down to the State Precipitation Map below.

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Issue Date: Sunday, July 15th, 2018
Issue Time: 9:30 AM MDT

Summary:

Mid-level high pressure began the day centered over southwestern Colorado, and finished the day more-or-less centered over central Colorado. This slight shift to the east allowed for monsoonal moisture to set up over the western third of the state, producing scattered showers/thunderstorms over the Southwest Slope, Grand Valley, Northwest Slope, and western portions of the Northern Mountains, Central Mountains, and San Juan Mountains. Stronger storms produced periods of heavy rainfall, and thankfully the heaviest rain fell west of the 416 Fire and Burro Fire burn scars. A few showers continue this morning across the higher terrain of the Grand Valley and Southwest Slope regions.

To the east, drier air and more subsidence aloft was in charge, suppressing all but a few isolated thunderstorms over the Front Range, Southeast Mountains, Palmer Ridge, Raton Ridge, and western portions of the Southeast Plains. This activity diminished quickly after sunset, with the final showers ending around 9:30 PM. The strongest storm of the day for these regions occurred over the southern Urban Corridor, where 0.96 inches/30 minutes was reported 6 miles W of Falcon (El Paso County).

No flash flooding was reported yesterday. For a look at precipitation estimates in your area, please see our State Precipitation Map below.

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