Alert archive / Colorado / Flash Flood Warnings in 2024

Flash Flood Warning 15, NWS Denver/Boulder, CO

August 12, 2024Larimer County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Aug 12, 2024, 1:55 PM MDT for Larimer County, Colorado. It was in force for 3 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: Aug 12, 2024, 1:55 PM MDT (19:55 UTC)
Expired: Aug 12, 2024, 5:00 PM MDT
In force: 3 hr
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Larimer County, CO

The radar

The Cheyenne radar (KCYS), 77 km from the middle of the area, began a volume at 19:56 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

Grand Junction, CO (KGJT), launched 12:00Z, 7.9 hours before the alert went out and 310 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1559 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 91 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Aug 12, 11:56 AM MDT, 1 hour 59 minutes earlier.

Area forecast discussion, Aug 12, 11:56 AM MDT, 1 hour 59 minutes before

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Hazardous weather outlook, Aug 12, 5:26 AM MDT, 8 hours 29 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 6:06 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe, Denver	24 min
Aug 11, 8:23 PM MDT	Special Weather Statement	BOU	Denver	37 min
Aug 12, 1:20 AM MDT	Dense Fog Advisory	BOU	Logan, Morgan, Phillips, Sedgwick, Washington, Weld	8 hr
Aug 12, 9:50 AM MDT	Flood Watch	BOU	Adams, Arapahoe, Boulder, Broomfield, Clear Creek, Denver and 8 more	14 hr
Aug 12, 12:20 PM MDT	Areal Flood Advisory	BOU	Larimer	3 hr
Aug 12, 1:40 PM MDT	Areal Flood Advisory	BOU	Larimer	3 hr
Aug 12, 2:52 PM MDT	Flash Flood Warning Considerable damage threat	BOU	Larimer	2 hr
Aug 12, 3:51 PM MDT	Special Weather Statement	BOU	Arapahoe	39 min
Aug 12, 4:20 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Weld	40 min
Aug 12, 4:44 PM MDT	Tornado Warning	BOU	Weld	31 min
Aug 12, 5:08 PM MDT	Special Weather Statement	BOU	Elbert	52 min
Aug 12, 5:09 PM MDT	Flash Flood Warning	BOU	Arapahoe, Elbert	3 hr
Aug 12, 5:15 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Weld	45 min
Aug 12, 5:17 PM MDT	Areal Flood Advisory	BOU	Elbert	14 min
Aug 12, 5:21 PM MDT	Special Weather Statement	BOU	Weld	39 min
Aug 12, 5:26 PM MDT	Tornado Warning	BOU	Weld	34 min
Aug 12, 5:31 PM MDT	Flash Flood Warning	BOU	Elbert	3 hr
Aug 12, 5:31 PM MDT	Special Weather Statement	BOU	Elbert	44 min
Aug 12, 5:48 PM MDT	Tornado Warning	BOU	Weld	27 min
Aug 12, 5:54 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Morgan	51 min
Aug 12, 5:57 PM MDT	Areal Flood Advisory	BOU	Elbert	104 min

Nearby

Flash Flood Warnings in Colorado, 2024 Every flash flood warning in 2024

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.