Alert archive / Colorado / Winter Weather Advisories in 2021
Winter Weather Advisory 10, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this winter weather advisory at Feb 11, 2021, 4:10 AM MST for 4 counties in Colorado. It took effect at Feb 11, 2021, 5:00 PM MST. It was in force for 36 hr.
The area
The counties it named.
The facts
- Issued
- Feb 11, 2021, 4:10 AM MST (11:10 UTC)
- In effect from
- Feb 11, 2021, 5:00 PM MST
- Expired
- Feb 13, 2021, 5:00 AM MST
- In force
- 36 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 11:10 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
Riverton, WY (KRIW), launched 00:00Z, 11.2 hours before the alert went out and 368 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
- 2300 m above ground
- 0-6 km bulk shear
- 71 kt
- 0-1 km storm-relative helicity
- 333 m²/s²
- 0-3 km storm-relative helicity
- 431 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 Feb 10, 9:09 PM MST, 7 hours 1 minute earlier.
Area forecast discussion, Feb 10, 9:09 PM MST, 7 hours 1 minute before
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</html>Hazardous weather outlook, Feb 10, 10:39 AM MST, 17 hours 31 minutes before
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 1039 AM MST Wed Feb 10 2021 COZ030>051-111745- Jackson County Below 9000 Feet- West Jackson and West Grand Counties Above 9000 Feet- Grand and Summit Counties Below 9000 Feet- South and East Jackson/Larimer/North and Northeast Grand/ Northwest Boulder Counties Above 9000 Feet- South and Southeast Grand/West Central and Southwest Boulder/ Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet- Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet- Central and Southeast Park County- Larimer County Below 6000 Feet/Northwest Weld County- Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County- North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County- Elbert/Central and East Douglas Counties Above 6000 Feet- Northeast Weld County-Central and South Weld County-Morgan County- Central and East Adams and Arapahoe Counties- North and Northeast Elbert County Below 6000 Feet/North Lincoln County- Southeast Elbert County Below 6000 Feet/South Lincoln County- Logan County-Washington County-Sedgwick County-Phillips County- 1039 AM MST Wed Feb 10 2021 This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Light snow showers and patchy fog will persist into the early afternoon across the urban corridor and plains. Temperatures will be cold today with highs in the low teens across much of the eastern plains. Light snow will continue across the mountains with an additional inch or two expected to accumulate throughout the day. More fog is possible late tonight over the eastern plains. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Cold air will remain over the plains Thursday with even colder air moving in Friday and this weekend. By the weekend temperatures will be approaching records, with lows below zero and highs in the single digits above zero expected across most of the plains. Periods of light snow are likely, but little travel impact is expected. The most likely time for accumulating snow looks like Friday night and again Sunday. For the mountains, light snow is likely over the ridges through this weekend. There will be some increase in the snowfall late Friday into early Saturday along with a bit more wind. The valleys and foothills will have periods of light snow with a cooling trend through the weekend. Model forecasts are uncertain for the beginning of next week. There will likely be some moderation in temperatures, but there is also a chance of snow and windy conditions, especially in the mountains. .SPOTTER INFORMATION STATEMENT... Spotter reports will not be needed today or tonight.
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 11, 1:17 PM MST | Wind Chill Advisory | BOU | Elbert, Lincoln, Logan, Morgan, Phillips, Sedgwick and 2 more | 28 min |
| Feb 11, 1:45 PM MST | Wind Chill Advisory | BOU | Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas and 10 more | 4 days |
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.