Alert archive / Colorado / Winter Storm Watches in 2012

Winter Storm Watch 1, NWS Denver/Boulder, CO

January 20, 20129 counties in Colorado

NWS Denver/Boulder, CO issued this winter storm watch at Jan 20, 2012, 4:31 AM MST for 9 counties in Colorado. It took effect at Jan 21, 2012, 12:00 PM MST. It was in force for .

The area

The counties it named.

The facts

Issued: Jan 20, 2012, 4:31 AM MST (11:31 UTC)
In effect from: Jan 21, 2012, 12:00 PM MST
Expired: Jan 20, 2012, 11:26 AM MST
In force
Issued by: NWS Denver/Boulder, CO

Counties Boulder County, CO, Clear Creek County, CO, Gilpin County, CO, Grand County, CO, Jackson County, CO, Jefferson County, CO, Larimer County, CO, Park County, CO, Summit County, CO

The radar

The Denver radar (KFTG), 102 km from the middle of the area, began a volume at 11:28 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 00:00Z, 11.5 hours before the alert went out and 254 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: 2418 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 178 m²/s²
0-3 km storm-relative helicity: 408 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 watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this winter storm watch went out at Jan 20, 3:26 AM MST, 1 hour 5 minutes earlier.

Area forecast discussion, Jan 20, 3:26 AM MST, 1 hour 5 minutes before

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Hazardous weather outlook, Jan 19, 10:54 AM MST, 17 hours 37 minutes before

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The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 19, 8:12 PM MST	Winter Weather Advisory	BOU	Boulder, Grand, Jackson, Larimer	15 hr
Jan 20, 11:26 AM MST	Winter Storm Warning	BOU	Boulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more	48 hr
Jan 20, 11:26 AM MST	Winter Weather Advisory	BOU	Grand, Jackson, Summit	43 hr
Jan 20, 11:30 AM MST	High Wind Warning	BOU	Boulder, Clear Creek, Douglas, Gilpin, Grand, Jackson and 4 more	28 hr

Nearby

Winter Storm Watches in Colorado, 2012 Every winter storm watch 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.