Alert archive / Colorado / Flash Flood Watches in 2021
Flash Flood Watch 30, NWS Grand Junction, CO
NWS Grand Junction, CO issued this flash flood watch at Aug 17, 2021, 1:10 PM MDT for 13 counties in Colorado; 4 counties in Utah. It took effect at Aug 18, 2021, 12:00 PM MDT. It was in force for 36 hr.
The area
The counties it named.
The facts
- Issued
- Aug 17, 2021, 1:10 PM MDT (19:10 UTC)
- In effect from
- Aug 18, 2021, 12:00 PM MDT
- Expired
- Aug 20, 2021, 12:00 AM MDT
- In force
- 36 hr
- Issued by
- NWS Grand Junction, CO
- Flood severity
- None
Counties Delta County, CO, Dolores County, CO, Eagle County, CO, Garfield County, CO, Gunnison County, CO, Mesa County, CO, Moffat County, CO, Montrose County, CO, Ouray County, CO, Pitkin County, CO, Rio Blanco County, CO, Routt County, CO, San Miguel County, CO, Daggett County, UT, Grand County, UT, San Juan County, UT, Uintah County, UT
The radar
The Grand Junction radar (KGJX), 13 km from the middle of the area, began a volume at 19:08 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
Salt Lake City I, UT (KSLC), launched 12:00Z, 7.2 hours before the alert went out and 361 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
- 3488 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- 8 m²/s²
- 0-3 km storm-relative helicity
- 26 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Grand Junction, CO wrote its last area forecast discussion before this flash flood watch went out at Aug 17, 11:33 AM MDT, 1 hour 37 minutes earlier.
Area forecast discussion, Aug 17, 11:33 AM MDT, 1 hour 37 minutes before
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</html>Hazardous weather outlook, Aug 17, 4:44 AM MDT, 8 hours 26 minutes before
Hazardous Weather Outlook National Weather Service Grand Junction CO 444 AM MDT Tue Aug 17 2021 COZ001>014-017>023-UTZ022>025-027>029-181045- Lower Yampa River Basin-Central Yampa River Basin- Roan and Tavaputs Plateaus-Elkhead and Park Mountains- Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor- Central Colorado River Basin-Grand and Battlement Mesas- Gore and Elk Mountains/Central Mountain Valleys- Central Gunnison and Uncompahgre River Basin- West Elk and Sawatch Mountains-Flat Tops- Upper Gunnison River Valley-Uncompahgre Plateau and Dallas Divide- Northwest San Juan Mountains-Southwest San Juan Mountains- Paradox Valley/Lower Dolores River- Four Corners/Upper Dolores River-Animas River Basin- San Juan River Basin-Southeast Utah-Eastern Uinta Mountains- Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat- La Sal and Abajo Mountains-Canyonlands/Natural Bridges- 444 AM MDT Tue Aug 17 2021 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight Thunderstorm development will occur again this afternoon and evening mainly over higher terrain through sunset. Some storms will be capable of brief heavy rainfall rates and others capable of producing gusty outflow winds in excess of 45 mph. Storm formation will continue through the overnight hours in portions of eastern Utah and far western Colorado. Areas of smoke will continue to affect air quality conditons. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Thunderstorm coverage will increase significantly on Wednesday. Many storms will have the threat of heavy rainfall rates and gusty winds. Stronger storms in eastern Utah on Wednesday may also be capable of producing marginally large hail. Heavy rainfall rates or prolonged precipitation could impact burn scars and lead to other runoff issues during this time. The Grizzly Creek burn scar will be especially susceptible to flash flooding which will impact travel if this occurs. .SPOTTER INFORMATION STATEMENT... Spotter activation may be necessary Wednesday over portions of eastern Utah and far western Colorado for the possibility of severe thunderstorms and flash flooding.
Nearby
Flash Flood Watches in Colorado, 2021Flash Flood Watches in Utah, 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.