Alert archive / Colorado / Flash Flood Watches in 2021

Flash Flood Watch 12, NWS Grand Junction, CO

July 13, 20216 counties in Colorado

NWS Grand Junction, CO issued this flash flood watch at Jul 13, 2021, 11:51 AM MDT for 6 counties in Colorado. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jul 13, 2021, 11:51 AM MDT (17:51 UTC)
Expired
Jul 13, 2021, 3:06 PM MDT
In force
3 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 17:52 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, 5.9 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.

Skew-T log-pSkew-T log-p diagram, Grand Junction, CO at 12:00Z on 2021-07-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 27 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Grand Junction, CO at 12:00Z on 2021-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 111 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
27 J/kg
Mixed-layer CIN
-350 J/kg
Mixed-layer LCL
3436 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
111 m²/s²
0-3 km storm-relative helicity
184 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 13, 11:46 AM MDT, 5 minutes earlier.

Area forecast discussion, Jul 13, 11:46 AM MDT, 5 minutes before
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Hazardous weather outlook, Jul 13, 2:52 AM MDT, 8 hours 59 minutes before
Hazardous Weather Outlook
National Weather Service Grand Junction CO
252 AM MDT Tue Jul 13 2021

COZ001>014-017>023-UTZ022>025-027>029-141300-
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-
252 AM MDT Tue Jul 13 2021

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

.DAY ONE...Today and Tonight

Smoky skies will continue across the region through at least this
morning. Scattered to numerous showers and thunderstorms will
develop this afternoon with storms producing gusty outflow winds
as well as brief moderate to heavy rain. Isolated activity will
linger overnight, particularly down south.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Another round of widespread showers and thunderstorms is expected
for Wednesday with slow moving storms capable of producing heavy
rain. Drier conditions look to return for the end of the week as
high pressure returns, though diurnal storms will persist over the
higher terrain through the weekend.

.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.

IssuedProductOfficeCountiesLasted
Jul 13, 12:28 PM MDTSpecial Weather StatementGJTRio Blanco47 min
Jul 13, 12:50 PM MDTSpecial Weather StatementGJTSan Juan25 min
Jul 13, 12:52 PM MDTSpecial Weather StatementGJT38 min
Jul 13, 1:28 PM MDTSpecial Weather StatementGJTSan Juan47 min
Jul 13, 1:37 PM MDTSpecial Weather StatementGJTRio Blanco38 min
Jul 13, 1:43 PM MDTSpecial Weather StatementGJTPitkin47 min
Jul 13, 2:29 PM MDTFlash Flood WarningGJTHinsdale, Ouray3 hr
Jul 13, 2:48 PM MDTSpecial Weather StatementGJT42 min
Jul 13, 2:56 PM MDTSpecial Weather StatementGJTDelta49 min
Jul 13, 3:06 PM MDTFlash Flood Warning Considerable damage threatGJTEagle, Garfield114 min
Jul 13, 3:11 PM MDTSevere Thunderstorm WarningGJTDelta, Mesa34 min
Jul 13, 3:27 PM MDTAreal Flood AdvisoryGJTOuray, San Miguel3 hr
Jul 13, 3:33 PM MDTSpecial Weather StatementGJTMesa42 min
Jul 13, 3:52 PM MDTSevere Thunderstorm WarningGJTDelta, Mesa23 min
Jul 13, 4:24 PM MDTSpecial Weather StatementGJTDelta, Mesa51 min
Jul 13, 4:59 PM MDTFlash Flood WatchGJTEagle, Garfield, Moffat, Pitkin, Rio Blanco, Routt3 hr
Jul 13, 5:10 PM MDTSpecial Weather StatementGJTMontrose50 min
Jul 13, 5:21 PM MDTSpecial Weather StatementGJT39 min
Jul 13, 5:33 PM MDTSpecial Weather StatementGJTMontrose42 min
Jul 13, 5:42 PM MDTSpecial Weather StatementGJTOuray48 min
Jul 13, 2:35 PM MDTFlash Flood WarningGJTGrand, Uintah3 hr
Jul 13, 4:47 PM MDTSpecial Weather StatementGJTGrand28 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.