Alert archive / Montana / Winter Weather Advisories in 2012

Winter Weather Advisory 32, NWS Missoula, MT

March 31, 20125 counties in Montana; Idaho County, Idaho

NWS Missoula, MT issued this winter weather advisory at Mar 31, 2012, 2:45 PM MDT for 5 counties in Montana; Idaho County, Idaho. It took effect at Mar 31, 2012, 9:00 PM MDT. It was in force for 17 hr.

The area

The counties it named.

The facts

Issued: Mar 31, 2012, 2:45 PM MDT (20:45 UTC)
In effect from: Mar 31, 2012, 9:00 PM MDT
Expired: Apr 1, 2012, 2:12 PM MDT
In force: 17 hr
Issued by: NWS Missoula, MT

Counties Idaho County, ID, Granite County, MT, Mineral County, MT, Missoula County, MT, Ravalli County, MT, Sanders County, MT

The radar

The Missoula radar (KMSX), 55 km from the middle of the area, began a volume at 20:49 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

Boise Airport, ID (KBOI), launched 12:00Z, 8.8 hours before the alert went out and 372 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: 7 J/kg
Mixed-layer CIN: -162 J/kg
Mixed-layer LCL: 1675 m above ground
0-6 km bulk shear: 76 kt
0-1 km storm-relative helicity: 192 m²/s²
0-3 km storm-relative helicity: 256 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 Missoula, MT wrote its last area forecast discussion before this winter weather advisory went out at Mar 31, 11:50 AM MDT, 2 hours 55 minutes earlier.

Area forecast discussion, Mar 31, 11:50 AM MDT, 2 hours 55 minutes before

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The office that day

Everything else NWS Missoula, MT issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 30, 6:20 PM MDT	Wind Advisory	MSO	Lemhi	2 hr
Mar 31, 4:27 PM MDT	Special Weather Statement	MSO	Lemhi	63 min

Nearby

Winter Weather Advisories in Montana, 2012 Winter Weather Advisories in Idaho, 2012 Every winter weather advisory in 2012

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.