Alert archive / Colorado / Winter Weather Advisories in 2021
Winter Weather Advisory 35, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this winter weather advisory at Dec 22, 2021, 2:33 PM MST for 8 counties in Colorado. It took effect at Dec 23, 2021, 2:00 PM MST. It was in force for 43 hr.
The area
The counties it named.
The facts
- Issued
- Dec 22, 2021, 2:33 PM MST (21:33 UTC)
- In effect from
- Dec 23, 2021, 2:00 PM MST
- Expired
- Dec 25, 2021, 8:40 AM MST
- In force
- 43 hr
- Issued by
- NWS Denver/Boulder, CO
Counties Boulder County, CO, Clear Creek County, CO, Gilpin County, CO, Grand County, CO, Jackson County, CO, Jefferson County, CO, Park County, CO, Summit County, CO
The radar
The Denver radar (KFTG), 104 km from the middle of the area, began a volume at 21:33 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Grand Junction, CO (KGJT), launched 12:00Z, 9.6 hours before the alert went out and 248 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1714 m above ground
- 0-6 km bulk shear
- 71 kt
- 0-1 km storm-relative helicity
- 98 m²/s²
- 0-3 km storm-relative helicity
- 253 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this winter weather advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Denver/Boulder, CO wrote its last area forecast discussion before this winter weather advisory went out at Dec 22, 9:50 AM MST, 4 hours 43 minutes earlier.
Area forecast discussion, Dec 22, 9:50 AM MST, 4 hours 43 minutes before
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</html>Hazardous weather outlook, Dec 22, 10:56 AM MST, 3 hours 37 minutes before
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</html>The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 22, 2:47 AM MST | Winter Storm Watch | BOU | Boulder, Grand, Jackson, Larimer | 12 hr |
| Dec 22, 3:11 AM MST | Red Flag Warning | BOU | Boulder, Clear Creek, Douglas, Gilpin, Jefferson, Larimer and 3 more | 14 hr |
| Dec 22, 2:33 PM MST | Winter Storm Warning | BOU | Boulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more | 68 hr |
Nearby
Winter Weather Advisories in Colorado, 2021Every winter weather advisory in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.