Alert archive / Idaho / Winter Weather Advisories in 2021

Winter Weather Advisory 45, NWS Spokane, WA

December 21, 20214 counties in Idaho

NWS Spokane, WA issued this winter weather advisory at Dec 21, 2021, 2:48 PM PST for 4 counties in Idaho. It took effect at Dec 22, 2021, 4:00 PM PST. It was in force for .

The area

The counties it named.

The facts

Issued
Dec 21, 2021, 2:48 PM PST (22:48 UTC)
In effect from
Dec 22, 2021, 4:00 PM PST
Expired
Dec 22, 2021, 4:04 AM PST
In force
Issued by
NWS Spokane, WA

Counties Benewah County, ID, Kootenai County, ID, Latah County, ID, Shoshone County, ID

The radar

The Spokane radar (KOTX), 97 km from the middle of the area, began a volume at 22:49 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

Spokane, WA (KOTX), launched 12:00Z, 10.8 hours before the alert went out and 49 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, Spokane, WA at 12:00Z on 2021-12-21Temperature 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 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 12:00Z on 2021-12-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
645 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
171 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 weather advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Spokane, WA wrote its last area forecast discussion before this winter weather advisory went out at Dec 21, 11:41 AM PST, 3 hours 7 minutes earlier.

Area forecast discussion, Dec 21, 11:41 AM PST, 3 hours 7 minutes before
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Hazardous weather outlook, Dec 21, 5:18 AM PST, 9 hours 30 minutes before
Hazardous Weather Outlook
National Weather Service Spokane WA
518 AM PST Tue Dec 21 2021

IDZ002>004-026-027-WAZ031>036-038-041-043-044-047-049-221330-
Coeur d'Alene Area-Idaho Palouse-Central Panhandle Mountains-
Lewiston Area-Lewis and Southern Nez Perce Counties-
Northeast Blue Mountains-Lower Garfield and Asotin Counties-
Washington Palouse-Moses Lake Area-Upper Columbia Basin-
Spokane Area-Okanogan Highlands-Wenatchee Area-Okanogan Valley-
Waterville Plateau-Central Chelan County-Western Okanogan County-
518 AM PST Tue Dec 21 2021

This Hazardous Weather Outlook is for portions of North Idaho...
North Central Idaho...Central Washington...East Central
Washington...North Central Washington...Northeast Washington and
Southeast Washington.

.DAY ONE...TODAY AND TONIGHT

Precipitation will return as snow late this evening bringing light
widespread snow accumulations.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Most precipitation will transition to rain Wednesday morning.
There will be multiple rounds of light snow through the week into
the weekend, along with much colder temperatures.

IDZ001-WAZ037-048-221330-
Northern Panhandle-Northeast Mountains-Western Chelan County-
518 AM PST Tue Dec 21 2021

This Hazardous Weather Outlook is for portions of North Idaho...
North Central Washington and Northeast Washington.

.DAY ONE...TODAY AND TONIGHT

Precipitation will return as snow late this evening bringing
moderate snow accumulations. The heaviest snow will be for the
Cascades, northeastern Washington mountains, and northern Idaho.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Snow accumulations will continue into the early afternoon on
Wednesday. There will be multiple rounds of light snow throughout
the week into the weekend, along with much colder temperatures.

The office that day

Everything else NWS Spokane, WA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 21, 4:33 AM PSTWinter Storm WatchOTXChelan, Pend Oreille, Spokane, Stevens10 hr
Dec 21, 2:33 PM PSTWinter Storm WarningOTXChelan61 hr
Dec 21, 2:33 PM PSTWinter Weather AdvisoryOTXAdams, Douglas, Grant, Lincoln, Okanogan, Pend Oreille and 2 more15 hr

Nearby

Winter Weather Advisories in Idaho, 2021Every winter weather advisory 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.