Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 68, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Aug 12, 2021, 11:41 PM MDT for Douglas County, Colorado. It was in force for 94 min. 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 12, 2021, 11:41 PM MDT (05:41 UTC)
- Expired
- Aug 13, 2021, 1:15 AM MDT
- In force
- 94 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Flood severity
- None
County Douglas County, CO
The radar
The Denver radar (KFTG), 47 km from the middle of the area, began a volume at 05:45 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 00:00Z, 5.7 hours before the alert went out and 155 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
- 616 J/kg
- Mixed-layer CIN
- -65 J/kg
- Mixed-layer LCL
- 2322 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 1 m²/s²
- 0-3 km storm-relative helicity
- 98 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
797
WGUS55 KBOU 130541
FFWBOU
COC035-130715-
/O.NEW.KBOU.FF.W.0068.210813T0541Z-210813T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
1141 PM MDT Thu Aug 12 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
North Central Douglas County in northeastern Colorado...
* Until 115 AM MDT.
* At 1141 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...
Southwestern Centennial, Highlands Ranch, eastern Littleton and
Louviers.
This includes the following streams and drainages...
Plum Creek, Indian Creek, South Platte River and Big Dry Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Move to higher ground now. Act quickly to protect your life.
Excessive runoff from this storm will cause flash flooding of small
creeks and streams, highways, streets, underpasses, drainage areas
and other low lying spots.
&&
LAT...LON 3957 10494 3949 10492 3947 10499 3948 10505
3954 10506 3956 10505 3956 10504 3957 10503
3957 10501 3957 10500 3957 10497 3957 10495
FLASH FLOOD...RADAR INDICATED
$$
RPK2 follow-up statements
831
WGUS75 KBOU 130620
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
1220 AM MDT Fri Aug 13 2021
COC035-130715-
/O.CON.KBOU.FF.W.0068.000000T0000Z-210813T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Douglas CO-
1220 AM MDT Fri Aug 13 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 115 AM MDT EARLY THIS
MORNING FOR NORTH CENTRAL DOUGLAS COUNTY...
At 1220 AM MDT, Doppler radar indicated thunderstorms had produced
heavy rain across the warned area earlier. Between 2 and 3 inches of
rain have fallen. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, gulches,
roads, and poor drainage and low-lying areas.
Some locations that will experience flash flooding include...
Southwestern Centennial, Highlands Ranch, eastern Littleton and
Louviers.
This includes the following streams and drainages...
Plum Creek, Indian Creek, South Platte River and Big Dry Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Move to higher ground now. Act quickly to protect your life.
Excessive runoff from this storm will cause flash flooding of small
creeks and streams, highways, streets, underpasses, drainage areas
and other low lying spots.
&&
LAT...LON 3957 10494 3949 10492 3947 10499 3948 10505
3954 10506 3956 10505 3956 10504 3957 10503
3957 10501 3957 10500 3957 10497 3957 10495
FLASH FLOOD...RADAR INDICATED
$$
RPK587
WGUS75 KBOU 130712
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
112 AM MDT Fri Aug 13 2021
COC035-130722-
/O.EXP.KBOU.FF.W.0068.000000T0000Z-210813T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Douglas CO-
112 AM MDT Fri Aug 13 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 115 AM MDT EARLY THIS MORNING
FOR NORTH CENTRAL DOUGLAS 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 3957 10494 3949 10492 3947 10499 3948 10505
3954 10506 3956 10505 3956 10504 3957 10503
3957 10501 3957 10500 3957 10497 3957 10495
$$
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 12, 6:10 PM MDT | Special Weather Statement | BOU | Elbert | 50 min |
| Aug 12, 7:01 PM MDT | Special Weather Statement | BOU | Elbert | 29 min |
| Aug 12, 7:49 PM MDT | Severe Thunderstorm Warning | BOU | Elbert | 26 min |
| Aug 12, 10:51 PM MDT | Areal Flood Advisory | BOU | Washington | 84 min |
| Aug 12, 11:09 PM MDT | Special Weather Statement | BOU | Douglas | 36 min |
| Aug 12, 11:21 PM MDT | Areal Flood Advisory | BOU | Douglas | 20 min |
| Aug 13, 12:38 AM MDT | Areal Flood Advisory | BOU | Douglas, Jefferson | 82 min |
| Aug 13, 1:20 PM MDT | Areal Flood Advisory | BOU | Grand | 85 min |
| Aug 13, 1:42 PM MDT | Areal Flood Advisory | BOU | Grand | 2 hr |
| Aug 13, 2:27 PM MDT | Flash Flood Warning | BOU | Grand | 2 hr |
| Aug 13, 3:36 PM MDT | Areal Flood Advisory | BOU | Grand | 69 min |
| Aug 13, 3:53 PM MDT | Areal Flood Advisory | BOU | Larimer | 2 hr |
| Aug 13, 5:39 PM MDT | Flash Flood Warning | BOU | Grand | 2 hr |
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.