Alert archive / Colorado / Severe Thunderstorm Warnings in 2025

Severe Thunderstorm Warning 337, NWS Denver/Boulder, CO

August 23, 2025Boulder County, Gilpin County, Jefferson County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 23, 2025, 3:49 PM MDT for Boulder County, Gilpin County, Jefferson County, Colorado. It was in force for 26 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
Aug 23, 2025, 3:49 PM MDT (21:49 UTC)
Expired
Aug 23, 2025, 4:15 PM MDT
In force
26 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

Counties Boulder County, CO, Gilpin County, CO, Jefferson County, CO

The radar

The Denver radar (KFTG), 71 km from the middle of the area, began a volume at 21:52 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.

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 Aug 23, 2:59 PM MDT, 50 minutes earlier.

Area forecast discussion, Aug 23, 2:59 PM MDT, 50 minutes before
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Hazardous weather outlook, Aug 23, 10:31 AM MDT, 5 hours 18 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1031 AM MDT Sat Aug 23 2025

COZ030>051-241645-
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-
1031 AM MDT Sat Aug 23 2025

This hazardous weather outlook is for northeast and north central
Colorado.

.DAY ONE...Today and Tonight

Scattered showers and thunderstorms will redevelop this afternoon
and spread southeast across portions of the I-25 Corridor and
plains. While storms are expected to gradually weaken as they move
from the mountains and foothills into the lower elevations, there
is a small risk of one or two strong or severe storms. That is a
conditional threat, depending on exactly how much heating occurs
today. Temperatures would have to get at least into the lower 80s
to support that severe threat, and it looks like most locations
will stay slightly cooler than that.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

The weather pattern will remain active with daily chances of
showers and thunderstorms. A couple of the storms Sunday may also
become severe, and also produce locally heavy rain.

Monday will likely see more widespread showers and thunderstorms
and also a greater threat of heavy rainfall.

Scattered showers and storms, along with cooler temperatures,
will stay in the forecast picture for all of next week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today or tonight.

In the hours before

Special weather statement, Aug 23, 3:11 PM MDT, 38 minutes before
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Special weather statement, Aug 23, 3:29 PM MDT, 20 minutes before
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Special weather statement, Aug 23, 3:43 PM MDT, 6 minutes before
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The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 23, 3:11 PM MDTSpecial Weather StatementBOUBoulder34 min
Aug 23, 3:29 PM MDTSpecial Weather StatementBOUJefferson46 min
Aug 23, 3:43 PM MDTSpecial Weather StatementBOUGilpin47 min
Aug 23, 3:51 PM MDTSpecial Weather StatementBOUPark39 min
Aug 23, 4:13 PM MDTSevere Thunderstorm WarningBOUClear Creek, Gilpin, Jefferson47 min
Aug 23, 4:54 PM MDTSevere Thunderstorm WarningBOUDouglas, Jefferson, Park36 min
Aug 23, 5:27 PM MDTSpecial Weather StatementBOUDouglas48 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2025Every severe thunderstorm warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.