Alert archive / Colorado / Winter Storm Warnings in 2023
Winter Storm Warning 12, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this winter storm warning at May 11, 2023, 2:09 AM MDT for 9 counties in Colorado. It took effect at May 11, 2023, 2:18 AM MDT. It was in force for 32 hr. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- May 11, 2023, 2:09 AM MDT (08:09 UTC)
- In effect from
- May 11, 2023, 2:18 AM MDT
- Expired
- May 12, 2023, 10:14 AM MDT
- In force
- 32 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, Larimer County, CO, Park County, CO, Summit County, CO
The radar
The Denver radar (KFTG), 102 km from the middle of the area, began a volume at 08:08 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
N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 8.2 hours before the alert went out and 453 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
- 1736 J/kg
- Mixed-layer CIN
- -13 J/kg
- Mixed-layer LCL
- 900 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 92 m²/s²
- 0-3 km storm-relative helicity
- 141 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 3.8
What forecasters said that day
The local office's own words before this winter storm warning 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 storm warning went out at May 10, 11:51 PM MDT, 2 hours 18 minutes earlier.
Area forecast discussion, May 10, 11:51 PM MDT, 2 hours 18 minutes before
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</html>Hazardous weather outlook, May 10, 1:30 PM MDT, 12 hours 39 minutes before
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 130 PM MDT Wed May 10 2023 COZ030>051-111930- 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- 130 PM MDT Wed May 10 2023 This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...This Afternoon and Tonight More widespread severe convection expected, mainly after 20Z, with all severe hazards possible. Large hail and a few tornadoes looks to be the initial threat before developing into a wind threat late this evening. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Flood potential creeps upwards Thursday morning through Friday morning across the northern I-25 corridor and the burn scars. Heavy snowfall is expected for higher elevations above 9k ft mainly Thursday into Friday morning. A cool and wet pattern continues this weekend. .SPOTTER INFORMATION STATEMENT... Spotter reports of hail, strong wind gusts and rainfall would be appreciated. Stay weather aware.
In the hours before
Local storm report, May 10, 9:26 PM MDT, 4 hours 43 minutes before
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</html>Local storm report, May 10, 9:27 PM MDT, 4 hours 42 minutes before
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</html>Local storm report, May 10, 9:28 PM MDT, 4 hours 41 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 |
|---|---|---|---|---|
| May 10, 6:05 PM MDT | Severe Thunderstorm Warning | BOU | Washington | 40 min |
| May 10, 6:11 PM MDT | Tornado Warning | BOU | Morgan, Washington | 34 min |
| May 10, 6:12 PM MDT | Areal Flood Advisory | BOU | Adams, Morgan, Washington | 3 hr |
| May 10, 6:14 PM MDT | Tornado Warning | BOU | Morgan | 31 min |
| May 10, 6:33 PM MDT | Tornado Warning | BOU | Logan, Morgan | 27 min |
| May 10, 6:39 PM MDT | Tornado Warning | BOU | Washington | 36 min |
| May 10, 6:42 PM MDT | Severe Thunderstorm Warning | BOU | Logan, Weld | 48 min |
| May 10, 6:55 PM MDT | Tornado Warning | BOU | Logan, Weld | 35 min |
| May 10, 7:48 PM MDT | Areal Flood Advisory | BOU | Logan, Morgan, Weld | 117 min |
| May 10, 8:35 PM MDT | Winter Weather Advisory | BOU | Boulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more | 6 hr |
| May 10, 9:02 PM MDT | Winter Storm Watch | BOU | Boulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more | 5 hr |
| May 11, 10:12 AM MDT | Areal Flood Advisory | BOU | Douglas, Jefferson | 6 hr |
| May 11, 10:16 AM MDT | Winter Weather Advisory | BOU | Park | 4 hr |
| May 11, 11:28 AM MDT | Areal Flood Advisory | BOU | Arapahoe, Elbert | 6 hr |
| May 11, 12:14 PM MDT | Areal Flood Advisory | BOU | Adams, Denver | 2 hr |
| May 11, 12:34 PM MDT | Areal Flood Advisory | BOU | Arapahoe, Denver | 26 hr |
| May 11, 2:09 PM MDT | Tornado Warning | BOU | Phillips, Sedgwick | 21 min |
| May 11, 2:35 PM MDT | Areal Flood Advisory | BOU | Arapahoe | 25 hr |
| May 11, 2:42 PM MDT | Areal Flood Warning | BOU | Adams, Denver | 27 hr |
| May 11, 2:47 PM MDT | Special Weather Statement | BOU | Sedgwick | 28 min |
| May 11, 4:45 PM MDT | Areal Flood Advisory | BOU | Douglas | 24 hr |
Nearby
Winter Storm Warnings in Colorado, 2023Every winter storm warning in 2023
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.