Alert archive / Colorado / Flash Flood Watches in 2021
Flash Flood Watch 2, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood watch at Jul 5, 2021, 3:13 AM MDT for 5 counties in Colorado. It took effect at Jul 5, 2021, 12:00 PM MDT. It was in force for 12 hr.
The area
The counties it named.
The facts
- Issued
- Jul 5, 2021, 3:13 AM MDT (09:13 UTC)
- In effect from
- Jul 5, 2021, 12:00 PM MDT
- Expired
- Jul 6, 2021, 12:00 AM MDT
- In force
- 12 hr
- Issued by
- NWS Denver/Boulder, CO
- Flood severity
- None
Counties Boulder County, CO, Grand County, CO, Jackson County, CO, Larimer County, CO, Summit County, CO
The radar
The Denver radar (KFTG), 124 km from the middle of the area, began a volume at 09:14 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, 9.2 hours before the alert went out and 229 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
- 2682 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- -65 m²/s²
- 0-3 km storm-relative helicity
- 75 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted.
490 WGUS65 KBOU 050913 FFABOU URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Denver CO 313 AM MDT Mon Jul 5 2021 .The flash flood threat will increase today due to slow moving thunderstorms, slightly greater moisture, and an increase in the number of thunderstorms. The main threat area will be across the East Troublesome, Williams Fork, Cameron Peak, and Calwood burn areas. COZ032-033-035-052100- /O.NEW.KBOU.FF.A.0002.210705T1800Z-210706T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Grand and Summit Counties Below 9000 Feet-South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet- Including the cities of Hot Sulphur Springs, Glendevey, Kremmling, Nederland, Red Feather Lakes, Dillon, Fraser, Laramie and Medicine Bow Mountains, Grand Lake, Cameron Pass, Granby, Estes Park, Rocky Mountain National Park, Willow Creek Pass, and Rabbit Ears Range 313 AM MDT Mon Jul 5 2021 ...FLASH FLOOD WATCH IN EFFECT FROM NOON MDT TODAY THROUGH THIS EVENING... The National Weather Service in Denver has issued a * Flash Flood Watch for Portions of central and north central Colorado, including the following areas, in central Colorado, Grand and Summit Counties Below 9000 Feet. In north central Colorado, Larimer and Boulder Counties Between 6000 and 9000 Feet and South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet. * From Noon MDT today through this evening. * Heavy rain will accompany slow moving thunderstorms this afternoon and evening. * Heavy rain may cause flashing flooding and debris flow in and near the East Troublesome, Williams Fork, Cameron Peak, and Calwood burn areas. Rapid increases in water in creeks and small drainages could make roads become quickly impassable. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ Meier
2 follow-up statements
483 WGUS65 KBOU 052058 FFABOU Flood Watch National Weather Service Denver/Boulder CO 258 PM MDT Mon Jul 5 2021 .Thunderstorms are ongoing this afternoon with the stronger storms producing heavy rainfall and flash flooding. Another round of showers and storms will be possible tonight which the flash flood risk continuing until midnight. The main threat area will be across the East Troublesome, Williams Fork, Cameron Peak, and Calwood burn areas. COZ032-033-035-060600- /O.CON.KBOU.FF.A.0002.000000T0000Z-210706T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Grand and Summit Counties Below 9000 Feet- South and East Jackson/Larimer/North and Northeast Grand/ Northwest Boulder Counties Above 9000 Feet- Larimer and Boulder Counties Between 6000 and 9000 Feet- Including the cities of Dillon, Fraser, Granby, Grand Lake, Hot Sulphur Springs, Kremmling, Cameron Pass, Laramie and Medicine Bow Mountains, Rabbit Ears Range, Rocky Mountain National Park, Willow Creek Pass, Estes Park, Glendevey, Nederland, and Red Feather Lakes 258 PM MDT Mon Jul 5 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT... The Flash Flood Watch continues for * Portions of central Colorado and north central Colorado, including the following areas, in central Colorado, Grand and Summit Counties Below 9000 Feet. In north central Colorado, Rocky Mountain National Park and the Medicine Bow Range and The Northern Front Range Foothills. * Until midnight MDT tonight * Heavy rain will accompany slow moving thunderstorms this afternoon and evening. * Heavy rain may cause flashing flooding and debris flow in and near the East Troublesome, Williams Fork, Cameron Peak, and Calwood burn areas. Rapid increases in water in creeks and small drainages could make roads become quickly impassable. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
825 WGUS65 KBOU 060536 FFABOU Flood Watch National Weather Service Denver CO 1136 PM MDT Mon Jul 5 2021 COZ032-033-035-060645- /O.EXP.KBOU.FF.A.0002.000000T0000Z-210706T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Grand and Summit Counties Below 9000 Feet-South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet- Including the cities of Hot Sulphur Springs, Glendevey, Kremmling, Nederland, Red Feather Lakes, Dillon, Fraser, Laramie and Medicine Bow Mountains, Grand Lake, Cameron Pass, Granby, Estes Park, Rocky Mountain National Park, Willow Creek Pass, and Rabbit Ears Range 1136 PM MDT Mon Jul 5 2021 ...FLASH FLOOD WATCH WILL EXPIRE AT MIDNIGHT MDT TONIGHT... The Flash Flood Watch for Portions of central and north central Colorado, including the following areas, in central Colorado, Grand and Summit Counties Below 9000 Feet. In north central Colorado, Larimer and Boulder Counties Between 6000 and 9000 Feet and South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet. will expire at Midnight MDT tonight. Flooding is no longer expected to pose a threat. Please continue to heed remaining road closures, including Colorado Highway 125 in Grand county. $$ Meier
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 5, 1:29 PM MDT | Areal Flood Advisory | BOU | Park | 91 min |
| Jul 5, 1:36 PM MDT | Areal Flood Advisory | BOU | Grand | 84 min |
| Jul 5, 1:39 PM MDT | Flash Flood Warning | BOU | Larimer | 96 min |
| Jul 5, 1:53 PM MDT | Areal Flood Advisory | BOU | Larimer | 82 min |
| Jul 5, 2:00 PM MDT | Flash Flood Warning | BOU | Grand | 90 min |
| Jul 5, 2:12 PM MDT | Flash Flood Warning | BOU | Larimer | 93 min |
| Jul 5, 2:22 PM MDT | Special Weather Statement | BOU | Teller | 23 min |
| Jul 5, 2:23 PM MDT | Areal Flood Advisory | BOU | Park | 97 min |
| Jul 5, 2:44 PM MDT | Special Weather Statement | BOU | Clear Creek | 31 min |
| Jul 5, 3:28 PM MDT | Flash Flood Warning | BOU | Grand | 92 min |
| Jul 5, 4:18 PM MDT | Areal Flood Advisory | BOU | Clear Creek, Park | 87 min |
| Jul 5, 5:14 PM MDT | Areal Flood Advisory | BOU | Arapahoe, Douglas | 91 min |
| Jul 5, 5:31 PM MDT | Flash Flood Warning | BOU | Grand | 89 min |
| Jul 5, 5:51 PM MDT | Special Weather Statement | BOU | Denver | 24 min |
| Jul 5, 5:53 PM MDT | Areal Flood Advisory | BOU | Arapahoe | 97 min |
Nearby
Flash Flood Watches in Colorado, 2021Every flash flood watch 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.