Alert archive / Colorado / Flash Flood Warnings in 2024

Flash Flood Warning 39, NWS Grand Junction, CO

August 11, 2024Mesa County, Montrose County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Aug 11, 2024, 7:41 PM MDT for Mesa County, Montrose County, Colorado. It was in force for 77 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 11, 2024, 7:41 PM MDT (01:41 UTC)
Expired: Aug 11, 2024, 8:58 PM MDT
In force: 77 min
Issued by: NWS Grand Junction, CO
Area: Storm-based polygon
Flood severity: None

Counties Mesa County, CO, Montrose County, CO

The radar

The Grand Junction radar (KGJX), 41 km from the middle of the area, began a volume at 01:44 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 00:00Z, 1.7 hours before the alert went out and 380 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: 523 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 2828 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 56 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning 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 warning went out at Aug 11, 5:05 PM MDT, 2 hours 36 minutes earlier.

Area forecast discussion, Aug 11, 5:05 PM MDT, 2 hours 36 minutes before

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Hazardous weather outlook, Aug 11, 3:24 AM MDT, 16 hours 17 minutes before

Hazardous Weather Outlook
National Weather Service Grand Junction CO
324 AM MDT Sun Aug 11 2024

COZ001>014-017>023-UTZ022>025-027>029-120930-
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-
324 AM MDT Sun Aug 11 2024

This Hazardous Weather Outlook is for northwest Colorado, southwest
Colorado, west central Colorado, east central Utah, northeast Utah
and southeast Utah.

.DAY ONE...Today and tonight.

Isolated storms will linger through early morning with redevelopment
of scattered to numerous showers and thunderstorms this afternoon and
evening. Storms will be capable of producing gusty outflow winds,
small hail, and brief bouts of heavy rainfall. Localized flash
flooding and debris flows are possible, mainly along and south of the
I-70 corridor today and tonight.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Chances for daily showers and storms continue into the coming week.
The potential for heavy rainfall is a threat through mid week with
localized flash flooding and debris flows possible across the region.

.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.

In the hours before

Special weather statement, Aug 11, 3:53 PM MDT, 3 hours 48 minutes before

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Special weather statement, Aug 11, 4:14 PM MDT, 3 hours 27 minutes before

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Special weather statement, Aug 11, 5:36 PM MDT, 2 hours 5 minutes before

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Special weather statement, Aug 11, 5:42 PM MDT, 1 hour 59 minutes before

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Special weather statement, Aug 11, 5:58 PM MDT, 1 hour 43 minutes before

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Local storm report, Aug 11, 5:59 PM MDT, 1 hour 42 minutes before

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The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 11, 6:20 PM MDT	Special Weather Statement	GJT		40 min
Aug 12, 2:15 AM MDT	Special Weather Statement	GJT	La Plata	30 min
Aug 12, 2:32 PM MDT	Special Weather Statement	GJT	Mesa	28 min
Aug 11, 6:06 PM MDT	Special Weather Statement	GJT	Grand	24 min
Aug 11, 7:05 PM MDT	Flash Flood Warning	GJT	San Juan	115 min
Aug 11, 7:17 PM MDT	Areal Flood Advisory	GJT	San Juan	101 min
Aug 12, 2:14 PM MDT	Special Weather Statement	GJT	Daggett	31 min
Aug 12, 2:26 PM MDT	Special Weather Statement	GJT	San Juan	34 min
Aug 12, 2:59 PM MDT	Areal Flood Advisory	GJT	San Juan	112 min

Nearby

Flash Flood Warnings in Colorado, 2024 Every flash flood warning in 2024

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.