Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 62, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Aug 2, 2021, 3:47 PM MDT for Jackson County, 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 outline as issued.
The facts
- Issued
- Aug 2, 2021, 3:47 PM MDT (21:47 UTC)
- Expired
- Aug 2, 2021, 6:45 PM MDT
- In force
- 3 hr
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Flood severity
- None
Counties Jackson County, CO, Larimer County, CO
The radar
The Cheyenne radar (KCYS), 111 km from the middle of the area, began a volume at 21:50 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
Denver, CO (KDNR), launched 12:00Z, 9.8 hours before the alert went out and 238 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
- 1582 m above ground
- 0-6 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- -13 m²/s²
- 0-3 km storm-relative helicity
- 34 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
536
WGUS55 KBOU 022147
FFWBOU
COC057-069-030045-
/O.NEW.KBOU.FF.W.0062.210802T2147Z-210803T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
347 PM MDT Mon Aug 2 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
East Central Jackson County in north central Colorado...
Southwestern Larimer County in north central Colorado...
* Until 645 PM MDT.
* At 347 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 0.5 and 1 inch of rain
has fallen. Additional rainfall amounts up to 0.5 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, gulches,
roads, and poor drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Chambers Lake.
This includes the following additional locations...
Long Draw Road.
This includes the following streams and drainages...
Joe Wright Creek, North Fork Joe Wright Creek, Cache La Poudre
River, Laramie River, North Fork West Branch Laramie River, Poudre
Pass Creek, La, Canadian River and Michigan River.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Move to higher ground now. Act quickly to protect your life.
Heavy Rainfall will cause flash flooding of small creeks, streams,
and ditches in the affected part of the Cameron Peak burn area. Rock
slides or debris flows can also be expected across rural roads.
&&
LAT...LON 4061 10593 4063 10584 4058 10577 4052 10581
4052 10594 4053 10596
FLASH FLOOD...RADAR INDICATED
$$
RPK2 follow-up statements
098
WGUS75 KBOU 022249
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
449 PM MDT Mon Aug 2 2021
COC057-069-030045-
/O.CON.KBOU.FF.W.0062.000000T0000Z-210803T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson CO-Larimer CO-
449 PM MDT Mon Aug 2 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM MDT THIS
EVENING FOR EAST CENTRAL JACKSON AND SOUTHWESTERN LARIMER COUNTIES...
At 449 PM MDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Up to 1 inch of rain has fallen.
Additional rainfall amounts up to 0.5 inches are possible in the
warned area. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, gulches,
roads, and poor drainage and low-lying areas.
Some locations that will experience flash flooding include...
Chambers Lake.
This includes the following additional locations...
Long Draw Road.
This includes the following streams and drainages...
Joe Wright Creek, North Fork Joe Wright Creek, Cache La Poudre
River, Laramie River, North Fork West Branch Laramie River, Poudre
Pass Creek, La, Canadian River and Michigan River.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Move to higher ground now. Act quickly to protect your life.
Heavy Rainfall will cause flash flooding of small creeks, streams,
and ditches in the affected part of the Cameron Peak burn area. Rock
slides or debris flows can also be expected across rural roads.
&&
LAT...LON 4061 10593 4063 10584 4058 10577 4052 10581
4052 10594 4053 10596
FLASH FLOOD...RADAR INDICATED
$$
RPK664
WGUS75 KBOU 030038
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
638 PM MDT Mon Aug 2 2021
COC057-069-030048-
/O.EXP.KBOU.FF.W.0062.000000T0000Z-210803T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson CO-Larimer CO-
638 PM MDT Mon Aug 2 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 645 PM MDT THIS EVENING FOR
EAST CENTRAL JACKSON AND SOUTHWESTERN LARIMER COUNTIES...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
A Flash Flood Watch remains in effect until 1000 PM MDT for Portions
of central and north central Colorado.
LAT...LON 4061 10593 4063 10584 4058 10577 4052 10581
4052 10594 4053 10596
$$
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 2, 2:40 PM MDT | Areal Flood Advisory | BOU | Grand | 95 min |
| Aug 2, 3:38 PM MDT | Areal Flood Advisory | BOU | Grand | 82 min |
| Aug 2, 4:11 PM MDT | Flash Flood Warning | BOU | Larimer | 3 hr |
| Aug 2, 4:16 PM MDT | Areal Flood Advisory | BOU | Grand | 89 min |
| Aug 2, 5:08 PM MDT | Areal Flood Advisory | BOU | Boulder, Grand | 82 min |
| Aug 2, 5:14 PM MDT | Areal Flood Advisory | BOU | Larimer | 91 min |
| Aug 2, 5:18 PM MDT | Areal Flood Advisory | BOU | Park | 87 min |
| Aug 2, 5:40 PM MDT | Areal Flood Advisory | BOU | Boulder, Grand, Larimer | 95 min |
| Aug 2, 5:57 PM MDT | Areal Flood Advisory | BOU | Larimer | 93 min |
Nearby
Flash Flood Warnings in Colorado, 2021Every flash flood warning 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.