Alert archive / Colorado / Severe Thunderstorm Warnings in 2023
Severe Thunderstorm Warning 237, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 4, 2023, 1:00 PM MDT for Grand County, Colorado. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Jul 4, 2023, 1:00 PM MDT (19:00 UTC)
- Expired
- Jul 4, 2023, 1:30 PM MDT
- In force
- 30 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
County Grand County, CO
The radar
The Denver radar (KFTG), 139 km from the middle of the area, began a volume at 19:00 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, 7.0 hours before the alert went out and 231 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
- 7 J/kg
- Mixed-layer CIN
- -527 J/kg
- Mixed-layer LCL
- 2975 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 35 m²/s²
- 0-3 km storm-relative helicity
- 225 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jul 4, 10:22 AM MDT, 2 hours 38 minutes earlier.
Area forecast discussion, Jul 4, 10:22 AM MDT, 2 hours 38 minutes before
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</html>Hazardous weather outlook, Jul 4, 9:47 AM MDT, 3 hours 13 minutes before
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 947 AM MDT Tue Jul 4 2023 COZ030>051-051600- 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- 947 AM MDT Tue Jul 4 2023 ...Severe storms possible this afternoon and evening... This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Numerous showers and thunderstorms are expected this afternoon and tonight over the foothills and plains. Some of the storms could be severe with large hail, damaging winds and heavy rain. Heavy rainfall could also cause flash flooding problems, most notably over the burn areas. There could be severe rounds of storms today, with the second round coinciding with fire work displays and picnics this evening. Holiday enthusiasts are urged to have adequate ways to take cover during their outside festivities. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Showers and thunderstorms are likely over the mountains on Wednesday with mainly scattered showers over the plains. There will be a threat of flash flooding over the alpine burnt areas. Scattered late day showers and thunderstorms are forecast for Thursday through Saturday with hail and heavy rainfall possible. Chances for thunderstorms decrease Sunday and into early next week. .SPOTTER INFORMATION STATEMENT... Spotter activation will be needed after 1 pm this afternoon. Reports of hail, heavy rain and flooding will be appreciated.
In the hours before
Special weather statement, Jul 4, 12:44 PM MDT, 16 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 |
|---|---|---|---|---|
| Jul 3, 7:00 PM MDT | Special Weather Statement | BOU | Weld | 45 min |
| Jul 4, 12:44 PM MDT | Special Weather Statement | BOU | Larimer | 31 min |
| Jul 4, 12:47 PM MDT | Special Weather Statement | BOU | Douglas | 28 min |
| Jul 4, 1:11 PM MDT | Special Weather Statement | BOU | Larimer | 34 min |
| Jul 4, 1:17 PM MDT | Severe Thunderstorm Warning | BOU | Grand | 28 min |
| Jul 4, 1:36 PM MDT | Special Weather Statement | BOU | Larimer | 24 min |
| Jul 4, 1:43 PM MDT | Special Weather Statement | BOU | Boulder, Gilpin | 32 min |
| Jul 4, 2:00 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 30 min |
| Jul 4, 2:13 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 47 min |
| Jul 4, 2:21 PM MDT | Special Weather Statement | BOU | Boulder, Broomfield, Gilpin | 24 min |
| Jul 4, 2:38 PM MDT | Areal Flood Advisory | BOU | Larimer | 3 hr |
| Jul 4, 2:42 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 33 min |
| Jul 4, 3:40 PM MDT | Special Weather Statement | BOU | Logan | 35 min |
| Jul 4, 4:05 PM MDT | Special Weather Statement | BOU | Grand | 25 min |
| Jul 4, 4:31 PM MDT | Special Weather Statement | BOU | Jackson | 29 min |
| Jul 4, 4:52 PM MDT | Severe Thunderstorm Warning | BOU | Jackson | 23 min |
| Jul 4, 5:14 PM MDT | Severe Thunderstorm Warning | BOU | Jackson, Larimer | 31 min |
| Jul 4, 5:19 PM MDT | Special Weather Statement | BOU | Boulder | 26 min |
| Jul 4, 5:36 PM MDT | Severe Thunderstorm Warning | BOU | Larimer | 24 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 2023Every severe thunderstorm 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.