Alert archive / Colorado / Winter Weather Advisories in 2021
Winter Weather Advisory 29, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this winter weather advisory at Oct 11, 2021, 2:55 PM MDT for 4 counties in Colorado. It took effect at Oct 12, 2021, 6:00 AM MDT. It was in force for 24 hr.
The area
The counties it named.
The facts
- Issued
- Oct 11, 2021, 2:55 PM MDT (20:55 UTC)
- In effect from
- Oct 12, 2021, 6:00 AM MDT
- Expired
- Oct 13, 2021, 6:00 AM MDT
- In force
- 24 hr
- Issued by
- NWS Denver/Boulder, CO
Counties Boulder County, CO, Grand County, CO, Jackson County, CO, Larimer County, CO
The radar
The Cheyenne radar (KCYS), 121 km from the middle of the area, began a volume at 20:56 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
Denver, CO (KDNR), launched 12:00Z, 8.9 hours before the alert went out and 227 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
- 2297 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- -40 m²/s²
- 0-3 km storm-relative helicity
- 24 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 Oct 11, 10:15 AM MDT, 4 hours 40 minutes earlier.
Area forecast discussion, Oct 11, 10:15 AM MDT, 4 hours 40 minutes before
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</html>Hazardous weather outlook, Oct 11, 11:09 AM MDT, 3 hours 46 minutes before
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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.