Alert archive / Idaho / Winter Weather Advisories in 2021

Winter Weather Advisory 40, NWS Spokane, WA

December 12, 2021Lewis County, Nez Perce County, Idaho

NWS Spokane, WA issued this winter weather advisory at Dec 12, 2021, 9:54 AM PST for Lewis County, Nez Perce County, Idaho. It took effect at Dec 12, 2021, 10:00 AM PST. It was in force for 19 hr.

The area

The counties it named.

The facts

Issued: Dec 12, 2021, 9:54 AM PST (17:54 UTC)
In effect from: Dec 12, 2021, 10:00 AM PST
Expired: Dec 13, 2021, 5:00 AM PST
In force: 19 hr
Issued by: NWS Spokane, WA

Counties Lewis County, ID, Nez Perce County, ID

The radar

The Spokane radar (KOTX), 174 km from the middle of the area, began a volume at 17:55 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, 5.9 hours before the alert went out and 158 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: 807 m above ground
0-6 km bulk shear: 83 kt
0-1 km storm-relative helicity: 102 m²/s²
0-3 km storm-relative helicity: 129 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 12, 4:26 AM PST, 5 hours 28 minutes earlier.

Area forecast discussion, Dec 12, 4:26 AM PST, 5 hours 28 minutes before

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Hazardous weather outlook, Dec 12, 4:05 AM PST, 5 hours 49 minutes before

Hazardous Weather Outlook
National Weather Service Spokane WA
405 AM PST Sun Dec 12 2021

IDZ001>004-026-027-WAZ031>038-041-043-044-047>049-131315-
Northern Panhandle-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-
Northeast Mountains-Okanogan Highlands-Wenatchee Area-
Okanogan Valley-Waterville Plateau-Central Chelan County-
Western Chelan County-Western Okanogan County-
405 AM PST Sun Dec 12 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

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

Snow will move into central Washington early Monday morning with
the threat spreading east through the afternoon and overnight
hours. This will provide a good chance of widespread light snow
accumulations to many of the lowlands through Tuesday morning.

In the hours before

Local storm report, Dec 12, 8:48 AM PST, 1 hour 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SPOKANE WA
848 AM PST SUN DEC 12 2021

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

0846 AM     SNOW             4 SE VIOLA              46.79N 116.96W
12/12/2021  M5.0 INCH        LATAH              ID   TRAINED SPOTTER

            SNOW STARTED ACCUMULATING SOME TIME BEFORE
            4AM AND STOPPED NEAR 845AM.

&&

RP

The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 12, 2:32 PM PST	Winter Weather Advisory	OTX	Chelan, Douglas, Ferry, Grant, Okanogan	43 hr

Nearby

Winter Weather Advisories in Idaho, 2021 Every 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.