Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 13, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Jul 1, 2021, 1:28 PM MDT for Weld County, Colorado. It was in force for 2 hr. 5 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Jul 1, 2021, 1:28 PM MDT (19:28 UTC)
- Expired
- Jul 1, 2021, 3:30 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), 76 km from the middle of the area, began a volume at 19:30 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 was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 1, 2:30 PM MDT | HEAVY RAIN 4.4 | 1 Wnw Greeley, CO | |
| Jul 1, 2:34 PM MDT | FLASH FLOOD | 2 N Garden City, CO | GREELEY FIRE DEPARTMENT HAS CLOSED STREETS AND IS DOING RESCUES (FROM FLOODED CARS) IN NORTHEAST GREELEY. |
| Jul 1, 2:48 PM MDT | FLASH FLOOD | 2 Nnw Garden City, CO | THERE IS SIGNIFICANT FLASH FLOODING BETWEEN 11TH STREET AND 8TH STREET AND FROM 14TH AVENUE, EAST, ALL THE WAY INTO DOWNTOWN. PLEASE AVOID THESE AREAS AND TAKE ALTERNATE ROUTES SO YOU DONâT PLACE YOURSELF OR OTHERS IN DANGER!. |
| Jul 1, 2:48 PM MDT | FLASH FLOOD | 2 Nnw Garden City, CO | THERE IS SIGNIFICANT FLASH FLOODING BETWEEN 11TH STREET AND 8TH STREET AND FROM 14TH AVENUE, EAST, ALL THE WAY INTO DOWNTOWN. PLEASE AVOID THESE AREAS AND TAKE ALTERNATE ROUTES SO YOU DONâT PLACE YOURSELF OR OTHERS IN DANGER!. |
| Jul 1, 2:51 PM MDT | FLASH FLOOD | 2 Se Greeley, CO | REPORT FROM MPING: STREET/ROAD FLOODING; STREET/ROAD CLOSED; VEHICLES STRANDED. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Denver, CO (KDNR), launched 12:00Z, 7.5 hours before the alert went out and 142 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.
019
WGUS55 KBOU 011928
FFWBOU
COC123-012130-
/O.NEW.KBOU.FF.W.0013.210701T1928Z-210701T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
128 PM MDT Thu Jul 1 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
Southwestern Weld County in northeastern Colorado...
* Until 330 PM MDT.
* At 128 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...
Greeley and Lucerne.
This includes the following streams and drainages...
Cache La Poudre River, South Platte River, Lone Tree Creek, Willow
Creek and Sand Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Excessive runoff from this storm will cause flash flooding of small
creeks and streams, highways and underpasses. Additionally, country
roads, farmlands along the banks of creeks, and other low lying
areas are subject to flooding.
&&
LAT...LON 4049 10478 4051 10460 4041 10459 4039 10479
FLASH FLOOD...RADAR INDICATED
$$
RPK2 follow-up statements
197
WGUS75 KBOU 012000
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
200 PM MDT Thu Jul 1 2021
COC123-012130-
/O.CON.KBOU.FF.W.0013.000000T0000Z-210701T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Weld CO-
200 PM MDT Thu Jul 1 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 PM MDT THIS
AFTERNOON FOR SOUTHWESTERN WELD COUNTY...
At 200 PM MDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Between 2.5 and 4 inches of rain have
fallen. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Life threatening flash flooding. Thunderstorms producing
flash flooding.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of creeks and streams,
roads, and low lying areas.
Some locations that will experience flash flooding include...
Greeley and Lucerne.
This includes the following streams and drainages...
Cache La Poudre River, South Platte River, Lone Tree Creek, Willow
Creek and Sand Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Excessive runoff from this storm will cause flash flooding of small
creeks and streams, highways and underpasses. Additionally, country
roads, farmlands along the banks of creeks, and other low lying
areas are subject to flooding.
&&
LAT...LON 4049 10478 4051 10460 4041 10459 4039 10479
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
RPK264 WGUS75 KBOU 012122 FFSBOU Flash Flood Statement National Weather Service Denver CO 322 PM MDT Thu Jul 1 2021 COC123-012132- /O.EXP.KBOU.FF.W.0013.000000T0000Z-210701T2130Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Weld CO- 322 PM MDT Thu Jul 1 2021 ...FLASH FLOOD WARNING WILL EXPIRE AT 330 PM MDT THIS AFTERNOON FOR SOUTHWESTERN 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 4049 10478 4051 10460 4041 10459 4039 10479 $$ RPK
The 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, 12:24 PM MDT | Flash Flood Warning | BOU | Weld | 2 hr |
| 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, 1:33 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.