Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 12, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Jul 1, 2021, 12:24 PM MDT for Weld County, Colorado. It was in force for 2 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
- Jul 1, 2021, 12:24 PM MDT (18:24 UTC)
- Expired
- Jul 1, 2021, 2:30 PM MDT
- In force
- 2 hr
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Flood severity
- None
County Weld County, CO
The radar
The Denver radar (KFTG), 54 km from the middle of the area, began a volume at 18:26 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, 6.4 hours before the alert went out and 94 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
- 240 J/kg
- Mixed-layer CIN
- -180 J/kg
- Mixed-layer LCL
- 1308 m above ground
- 0-6 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 17 m²/s²
- 0-3 km storm-relative helicity
- 9 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
971
WGUS55 KBOU 011824
FFWBOU
COC123-012030-
/O.NEW.KBOU.FF.W.0012.210701T1824Z-210701T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
1224 PM MDT Thu Jul 1 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
South Central Weld County in northeastern Colorado...
* Until 230 PM MDT.
* At 1224 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 2 and 3 inches of rain
have fallen. 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...
Roggen and Masters.
This includes the following streams and drainages...
Lost Creek, South Platte River, East Lost Creek, Kiowa Creek, Mule
Creek, Sand Creek, Rock Creek and Jack Rabbit Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 4029 10441 4029 10415 4025 10415 4024 10415
4023 10415 4020 10415 4006 10417 4006 10441
FLASH FLOOD...RADAR INDICATED
$$
RPK2 follow-up statements
647
WGUS75 KBOU 011850
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
1250 PM MDT Thu Jul 1 2021
COC123-012030-
/O.CON.KBOU.FF.W.0012.000000T0000Z-210701T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Weld CO-
1250 PM MDT Thu Jul 1 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 PM MDT THIS
AFTERNOON FOR SOUTH CENTRAL WELD COUNTY...
At 1250 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 2 and 3 inches of rain
have fallen. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, gulches,
roads, and poor drainage and low-lying areas.
Some locations that will experience flash flooding include...
Roggen and Masters.
This includes the following streams and drainages...
Lost Creek, South Platte River, East Lost Creek, Kiowa Creek, Mule
Creek, Sand Creek, Rock Creek and Jack Rabbit Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 4029 10441 4029 10415 4025 10415 4024 10415
4023 10415 4020 10415 4006 10417 4006 10441
FLASH FLOOD...RADAR INDICATED
$$
RPK907
WGUS75 KBOU 012024
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
224 PM MDT Thu Jul 1 2021
COC123-012034-
/O.EXP.KBOU.FF.W.0012.000000T0000Z-210701T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Weld CO-
224 PM MDT Thu Jul 1 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 230 PM MDT THIS AFTERNOON FOR
SOUTH CENTRAL WELD COUNTY...
Flood waters have receded. The heavy rain has ended. Flooding is no
longer expected to pose a threat. Please continue to heed remaining
road closures.
LAT...LON 4029 10441 4029 10415 4025 10415 4024 10415
4023 10415 4020 10415 4006 10417 4006 10441
$$
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 30, 8:20 PM MDT | Areal Flood Advisory | BOU | Weld | 115 min |
| Jun 30, 8:50 PM MDT | Flash Flood Warning | BOU | Weld | 3 hr |
| Jun 30, 10:32 PM MDT | Flash Flood Warning | BOU | Weld | 3 hr |
| Jul 1, 12:56 AM MDT | Flash Flood Warning | BOU | Weld | 3 hr |
| Jul 1, 8:46 AM MDT | Flash Flood Watch | BOU | Adams, Arapahoe, Boulder, Broomfield, Clear Creek, Denver and 7 more | 12 hr |
| Jul 1, 11:27 AM MDT | Areal Flood Advisory | BOU | Elbert | 93 min |
| Jul 1, 11:49 AM MDT | Flash Flood Warning | BOU | Larimer | 116 min |
| Jul 1, 11:51 AM MDT | Areal Flood Advisory | BOU | Weld | 84 min |
| Jul 1, 12:13 PM MDT | Flash Flood Warning | BOU | Clear Creek, Gilpin | 86 min |
| Jul 1, 12:21 PM MDT | Areal Flood Advisory | BOU | Elbert | 114 min |
| Jul 1, 12:28 PM MDT | Areal Flood Advisory | BOU | Weld | 92 min |
| Jul 1, 12:30 PM MDT | Special Weather Statement | BOU | Adams | 30 min |
| Jul 1, 12:56 PM MDT | Special Weather Statement | BOU | Adams | 34 min |
| Jul 1, 12:58 PM MDT | Areal Flood Advisory | BOU | Grand | 92 min |
| Jul 1, 1:05 PM MDT | Areal Flood Advisory | BOU | Adams, Weld | 85 min |
| Jul 1, 1:12 PM MDT | Areal Flood Advisory | BOU | Weld | 93 min |
| Jul 1, 1:25 PM MDT | Areal Flood Advisory | BOU | Douglas | 95 min |
| Jul 1, 1:28 PM MDT | Flash Flood Warning | BOU | Weld | 2 hr |
| Jul 1, 1:33 PM MDT | Areal Flood Advisory | BOU | Grand | 87 min |
| Jul 1, 1:55 PM MDT | Areal Flood Advisory | BOU | Elbert | 95 min |
| Jul 1, 2:20 PM MDT | Areal Flood Advisory | BOU | Adams, Arapahoe | 3 hr |
| Jul 1, 2:24 PM MDT | Special Weather Statement | BOU | Arapahoe | 21 min |
| Jul 1, 2:26 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe | 34 min |
| Jul 1, 2:52 PM MDT | Areal Flood Advisory | BOU | Boulder, Larimer | 83 min |
| Jul 1, 3:04 PM MDT | Areal Flood Advisory | BOU | Arapahoe | 86 min |
| Jul 1, 3:09 PM MDT | Flash Flood Warning | BOU | Larimer | 114 min |
| Jul 1, 3:17 PM MDT | Areal Flood Advisory | BOU | Boulder | 88 min |
| Jul 1, 3:21 PM MDT | Flash Flood Warning | BOU | Arapahoe | 114 min |
| Jul 1, 3:36 PM MDT | Special Weather Statement | BOU | Boulder | 24 min |
| Jul 1, 3:51 PM MDT | Areal Flood Advisory | BOU | Larimer | 84 min |
| Jul 1, 3:55 PM MDT | Areal Flood Advisory | BOU | Arapahoe, Denver | 95 min |
| Jul 1, 4:03 PM MDT | Areal Flood Advisory | BOU | Boulder | 87 min |
| Jul 1, 4:27 PM MDT | Areal Flood Advisory | BOU | Jefferson | 93 min |
| Jul 1, 4:36 PM MDT | Flash Flood Warning | BOU | Jefferson | 84 min |
| Jul 1, 4:42 PM MDT | Areal Flood Advisory | BOU | Larimer | 93 min |
| Jul 1, 5:19 PM MDT | Areal Flood Advisory | BOU | Park | 86 min |
| Jul 1, 5:57 PM MDT | Areal Flood Advisory | BOU | Jefferson, Park | 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.