Alert archive / Colorado / Flash Flood Watches in 2021

Flash Flood Watch 18, NWS Grand Junction, CO

July 22, 202117 counties in Colorado

NWS Grand Junction, CO issued this flash flood watch at Jul 22, 2021, 1:50 PM MDT for 17 counties in Colorado. It took effect at Jul 23, 2021, 12:00 PM MDT. It was in force for 14 hr.

The area

The counties it named.

The facts

Issued: Jul 22, 2021, 1:50 PM MDT (19:50 UTC)
In effect from: Jul 23, 2021, 12:00 PM MDT
Expired: Jul 24, 2021, 1:52 AM MDT
In force: 14 hr
Issued by: NWS Grand Junction, CO
Flood severity: None

Counties Archuleta County, CO, Delta County, CO, Dolores County, CO, Eagle County, CO, Garfield County, CO, Gunnison County, CO, Hinsdale County, CO, La Plata County, CO, Moffat County, CO, Montezuma County, CO, Montrose County, CO, Ouray County, CO, Pitkin County, CO, Rio Blanco County, CO, Routt County, CO, San Juan County, CO, San Miguel County, CO

The radar

The Grand Junction radar (KGJX), 64 km from the middle of the area, began a volume at 19:52 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, 7.8 hours before the alert went out and 87 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1949 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: -22 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

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 22, 11:38 AM MDT, 2 hours 12 minutes earlier.

Area forecast discussion, Jul 22, 11:38 AM MDT, 2 hours 12 minutes before

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Hazardous weather outlook, Jul 22, 2:17 AM MDT, 11 hours 33 minutes before

Hazardous Weather Outlook
National Weather Service Grand Junction CO
217 AM MDT Thu Jul 22 2021

COZ001>014-017>023-UTZ022>025-027>029-231400-
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-
217 AM MDT Thu Jul 22 2021

This hazardous weather outlook is for eastern Utah and western
Colorado.

.DAY ONE...Today and Tonight

Deep monsoonal moisture will result in another round of scattered
to numerous showers and thunderstorms across the region today.
Heavy rain and gusty outflow winds will accompany the strongest
storms. Localized flash flooding will be possible in response to
heavy rains and saturated soils. Showers will linger overnight.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

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. Localized flash
flooding will be possible in response to heavy rains and
saturated soils. Temperatures will trend near to slightly below
normal in response to increased clouds and showers. Unsettled
weather is expected into the new work week.

.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 21, 6:19 PM MDT	Special Weather Statement	GJT	Montrose	41 min
Jul 21, 6:37 PM MDT	Areal Flood Advisory	GJT	Delta, Mesa, Montrose	2 hr
Jul 22, 2:38 AM MDT	Areal Flood Advisory	GJT	Dolores	3 hr
Jul 22, 2:23 PM MDT	Special Weather Statement	GJT	Pitkin	52 min
Jul 22, 3:46 PM MDT	Areal Flood Advisory	GJT	Eagle	3 hr
Jul 22, 4:10 PM MDT	Areal Flood Advisory	GJT	Garfield	3 hr
Jul 22, 4:30 PM MDT	Flash Flood Warning Considerable damage threat	GJT	La Plata, Montezuma	6 min
Jul 22, 4:36 PM MDT	Flash Flood Warning Considerable damage threat	GJT	Eagle, Garfield	3 hr
Jul 22, 5:07 PM MDT	Flash Flood Warning	GJT	Eagle, Garfield	3 hr

Nearby

Flash Flood Watches in Colorado, 2021 Every 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.