Alert archive / Colorado / Flash Flood Watches in 2021
Flash Flood Watch 15, NWS Grand Junction, CO
NWS Grand Junction, CO issued this flash flood watch at Jul 20, 2021, 12:37 PM MDT for 6 counties in Colorado. It was in force for 8 hr.
The area
The counties it named.
The facts
- Issued
- Jul 20, 2021, 12:37 PM MDT (18:37 UTC)
- Expired
- Jul 20, 2021, 8:36 PM MDT
- In force
- 8 hr
- Issued by
- NWS Grand Junction, CO
- Flood severity
- None
Counties Eagle County, CO, Garfield County, CO, Moffat County, CO, Pitkin County, CO, Rio Blanco County, CO, Routt County, CO
The radar
The Grand Junction radar (KGJX), 114 km from the middle of the area, began a volume at 18:36 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
Grand Junction, CO (KGJT), launched 12:00Z, 6.6 hours before the alert went out and 124 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
- 1 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2685 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- -7 m²/s²
- 0-3 km storm-relative helicity
- 31 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 Jul 20, 12:00 PM MDT, 37 minutes earlier.
Area forecast discussion, Jul 20, 12:00 PM MDT, 37 minutes before
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</html>Hazardous weather outlook, Jul 20, 2:29 AM MDT, 10 hours 8 minutes before
Hazardous Weather Outlook National Weather Service Grand Junction CO 229 AM MDT Tue Jul 20 2021 COZ001>014-017>023-UTZ022>025-027>029-211300- 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- 229 AM MDT Tue Jul 20 2021 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight Monsoonal moisture will fuel scattered to numerous showers and thunderstorms across the region today. Storms will be efficient rain producers with heavy rain possible in addition to gusty outflow winds. Isolated showers may linger overnight. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Daily scattered to numerous showers and thunderstorms can be expected through the weekend. Moderate to heavy rain and gusty winds will be the primary threats with storms. Temperatures will trend cooler than normal in response to increased clouds and showers. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected today or tonight, however spotters are encouraged to relay rainfall amounts or any observed flooding to the National Weather Service in Grand Junction.
The office that day
Everything else NWS Grand Junction, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 20, 2:36 PM MDT | Special Weather Statement | GJT | Ouray | 39 min |
| Jul 20, 2:50 PM MDT | Flash Flood Warning | GJT | Ouray, San Juan, San Miguel | 5 hr |
| Jul 20, 3:19 PM MDT | Areal Flood Warning | GJT | Dolores, San Juan, San Miguel | 2 min |
| Jul 20, 3:21 PM MDT | Flash Flood Warning | GJT | Dolores, San Juan, San Miguel | 3 hr |
| Jul 20, 3:53 PM MDT | Flash Flood Warning | GJT | San Miguel | 76 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.