Alert archive / Colorado / Winter Storm Warnings in 2020

Winter Storm Warning 13, NWS Grand Junction, CO

December 27, 20207 counties in Colorado

NWS Grand Junction, CO issued this winter storm warning at Dec 27, 2020, 2:41 PM MST for 7 counties in Colorado. It was in force for 48 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
Dec 27, 2020, 2:41 PM MST (21:41 UTC)
Expired
Dec 29, 2020, 2:27 PM MST
In force
48 hr
Issued by
NWS Grand Junction, CO

Counties Archuleta County, CO, Dolores County, CO, Hinsdale County, CO, La Plata County, CO, Montezuma County, CO, San Juan County, CO, San Miguel County, CO

The radar

The Grand Junction radar (KGJX), 165 km from the middle of the area, began a volume at 21:40 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, 9.7 hours before the alert went out and 178 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 2020-12-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 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 2020-12-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 square meters per square second.1939587897117136156Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1844 m above ground
0-6 km bulk shear
116 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
27 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 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 winter storm warning went out at Dec 27, 10:32 AM MST, 4 hours 9 minutes earlier.

Area forecast discussion, Dec 27, 10:32 AM MST, 4 hours 9 minutes before
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Hazardous weather outlook, Dec 27, 4:33 AM MST, 10 hours 8 minutes before
Hazardous Weather Outlook
National Weather Service Grand Junction CO
433 AM MST Sun Dec 27 2020

COZ001>014-017>023-UTZ022>025-027>029-281145-
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-
433 AM MST Sun Dec 27 2020

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

.DAY ONE...Today and Tonight

Light snow will linger across the northern Colorado mountains in
the morning while increasing across the southern mountains during
the late afternoon hours. Accumulations will be light but impacts
over mountain passes can be expected. Snowfall becomes more
widespread and heavy a times in the southern Colorado mountains
overnight.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

A stronger storm will impact the region Monday through late
Tuesday. Monday afternoon through early Tuesday will be the
timeframe of most concern with widespread areas of moderate to
heavy snowfall rates possible. Impacts to travel will be likely
during this timeframe. Snowfall could impact the some portion of
eastern Utah and western Colorado again by the end of the week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today.

In the hours before

Local storm report, Dec 27, 8:47 AM MST, 5 hours 54 minutes before
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Local storm report, Dec 27, 10:48 AM MST, 3 hours 53 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1048 AM MST SUN DEC 27 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0945 AM     SNOW             OAK CREEK               40.27N 106.96W
12/27/2020  M1.5 INCH        ROUTT              CO   COCORAHS

            COCORAHS STATION CO-RT-64 OAK CREEK 0.4 W.

0700 AM     SNOW             1 S MOUNT CRESTED BUTTE 38.89N 106.97W
12/27/2020  M1.0 INCH        GUNNISON           CO   COCORAHS

            COCORAHS STATION CO-GN-66 MOUNT CRESTED
            BUTTE.

0700 AM     SNOW             5 W TOPONAS             40.08N 106.89W
12/27/2020  M1.2 INCH        ROUTT              CO   COCORAHS

            COCORAHS STATION CO-RT-26 YAMPA 5.1S.

0700 AM     SNOW             1 NNW STEAMBOAT SPRINGS 40.49N 106.82W
12/27/2020  M1.7 INCH        ROUTT              CO   COCORAHS

            COCORAHS STATION CO-RT-28 STEAMBOAT SPRINGS
            0.6NNW.

&&
Local storm report, Dec 27, 1:28 PM MST, 1 hour 13 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
128 PM MST SUN DEC 27 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0500 AM     SNOW             4 ESE STEAMBOAT SPRINGS 40.45N 106.75W
12/27/2020  M3.0 INCH        ROUTT              CO   PUBLIC

&&

MMS

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 27, 3:24 AM MSTWinter Storm WatchGJTArchuleta, Dolores, Hinsdale, La Plata, Montezuma, San Juan and 1 more11 hr
Dec 27, 2:41 PM MSTWinter Weather AdvisoryGJTArchuleta, Delta, Eagle, Garfield, Gunnison, Hinsdale and 9 more48 hr

Nearby

Winter Storm Warnings in Colorado, 2020Every winter storm warning in 2020

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.