Alert archive / Utah / Flash Flood Warnings in 2018

Flash Flood Warning 17, NWS Grand Junction, CO

July 16, 2018Grand County, Utah

NWS Grand Junction, CO issued this flash flood warning at Jul 16, 2018, 5:45 PM MDT for Grand County, Utah. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 16, 2018, 5:45 PM MDT (23:45 UTC)
Expired: Jul 16, 2018, 8:45 PM MDT
In force: 3 hr
Issued by: NWS Grand Junction, CO
Area: Storm-based polygon
Flood severity: None

County Grand County, UT

The radar

The Grand Junction radar (KGJX), 118 km from the middle of the area, began a volume at 23:45 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

Elko, NV (KLKN), launched 12:00Z, 11.8 hours before the alert went out and 447 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: 77 J/kg
Mixed-layer CIN: -383 J/kg
Mixed-layer LCL: 2137 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 33 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 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 Jul 16, 5:40 PM MDT, 5 minutes earlier.

Area forecast discussion, Jul 16, 5:40 PM MDT, 5 minutes before

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Hazardous weather outlook, Jul 16, 4:52 AM MDT, 12 hours 53 minutes before

Hazardous Weather Outlook
National Weather Service Grand Junction CO
452 AM MDT Mon Jul 16 2018

COZ001>014-017>023-UTZ022>025-027>029-171100-
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-
452 AM MDT Mon Jul 16 2018

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

.DAY ONE...Today and Tonight

Scattered to numerous thunderstorms will develop over the higher
terrain from late morning into the afternoon and are expected to
linger well into the evening. Severe weather is not expected,
however some cells will be capable of generating excessive
rainfall which may lead to rock fall and debris flows in steep
terrain. Fresh burn scars, most notably from the 416, Burro and
Lake Christine fires are particularly susceptible to debris flows
and flash flooding.

A Flash Flood Watch is in effect for the 416 and Burro burn
scars.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Isolated to scattered afternoon and evening thunderstorms will be
possible each day the rest of the week, mainly over the mountains.

.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, Jul 16, 2:21 PM MDT, 3 hours 24 minutes before

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Special weather statement, Jul 16, 2:24 PM MDT, 3 hours 21 minutes before

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Special weather statement, Jul 16, 2:31 PM MDT, 3 hours 14 minutes before

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Special weather statement, Jul 16, 4:01 PM MDT, 1 hour 44 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
Jul 16, 1:26 PM MDT	Flash Flood Warning	GJT	La Plata	4 hr
Jul 16, 2:21 PM MDT	Special Weather Statement	GJT	La Plata	24 min
Jul 16, 2:24 PM MDT	Special Weather Statement	GJT	La Plata	36 min
Jul 16, 2:44 PM MDT	Flash Flood Watch	GJT	Archuleta, Dolores, Hinsdale, La Plata, Montezuma, San Juan and 1 more	30 hr
Jul 16, 4:01 PM MDT	Special Weather Statement	GJT	Montezuma	44 min
Jul 16, 5:16 PM MDT	Areal Flood Advisory	GJT	Montezuma	93 min
Jul 16, 2:31 PM MDT	Special Weather Statement	GJT	Uintah	44 min

Nearby

Flash Flood Warnings in Utah, 2018 Every flash flood warning in 2018

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.