Alert archive / Idaho / Winter Storm Warnings in 2020

Winter Storm Warning 2, NWS Boise, ID

November 12, 20207 counties in Idaho

NWS Boise, ID issued this winter storm warning at Nov 12, 2020, 1:44 PM MST for 7 counties in Idaho. It took effect at Nov 13, 2020, 5:00 AM MST. It was in force for 16 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: Nov 12, 2020, 1:44 PM MST (20:44 UTC)
In effect from: Nov 13, 2020, 5:00 AM MST
Expired: Nov 13, 2020, 9:18 PM MST
In force: 16 hr
Issued by: NWS Boise, ID

Counties Adams County, ID, Boise County, ID, Camas County, ID, Elmore County, ID, Gem County, ID, Valley County, ID, Washington County, ID

The radar

The Boise radar (KCBX), 77 km from the middle of the area, began a volume at 20:42 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

Boise Airport, ID (KBOI), launched 12:00Z, 8.7 hours before the alert went out and 68 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: 1005 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 40 m²/s²
0-3 km storm-relative helicity: 167 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 Boise, ID wrote its last area forecast discussion before this winter storm warning went out at Nov 12, 10:04 AM MST, 3 hours 40 minutes earlier.

Area forecast discussion, Nov 12, 10:04 AM MST, 3 hours 40 minutes before

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The office that day

Everything else NWS Boise, ID issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Nov 12, 1:44 PM MST	Wind Advisory	BOI	Owyhee, Twin Falls	19 hr
Nov 12, 1:44 PM MST	Winter Weather Advisory	BOI	Adams, Camas, Elmore, Washington	32 hr

Nearby

Winter Storm Warnings in Idaho, 2020 Every 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.