Alert archive / Colorado / Winter Storm Watches in 2021

Winter Storm Watch 4, NWS Grand Junction, CO

December 7, 202118 counties in Colorado; 4 counties in Utah

NWS Grand Junction, CO issued this winter storm watch at Dec 7, 2021, 2:56 PM MST for 18 counties in Colorado; 4 counties in Utah. It took effect at Dec 8, 2021, 6:00 PM MST. It was in force for .

The area

The counties it named.

The facts

Issued: Dec 7, 2021, 2:56 PM MST (21:56 UTC)
In effect from: Dec 8, 2021, 6:00 PM MST
Expired: Dec 8, 2021, 12:16 PM MST
In force
Issued by: NWS Grand Junction, CO

All 22 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, Mesa 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, Daggett County, UT, Grand County, UT, San Juan County, UT, Uintah County, UT

The radar

The Grand Junction radar (KGJX), 32 km from the middle of the area, began a volume at 21:53 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, 9.9 hours before the alert went out and 51 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: 700 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 138 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 winter storm 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 winter storm watch went out at Dec 7, 12:10 PM MST, 2 hours 46 minutes earlier.

Area forecast discussion, Dec 7, 12:10 PM MST, 2 hours 46 minutes before

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Hazardous weather outlook, Dec 7, 3:08 AM MST, 11 hours 48 minutes before

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In the hours before

Local storm report, Dec 7, 9:34 AM MST, 5 hours 22 minutes before

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Local storm report, Dec 7, 9:42 AM MST, 5 hours 14 minutes before

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Local storm report, Dec 7, 9:43 AM MST, 5 hours 13 minutes before

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Local storm report, Dec 7, 9:44 AM MST, 5 hours 12 minutes before

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Local storm report, Dec 7, 9:45 AM MST, 5 hours 11 minutes before

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Nearby

Winter Storm Watches in Colorado, 2021 Winter Storm Watches in Utah, 2021 Every winter storm 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.