Alert archive / Colorado / Freeze Warnings in 2007

Freeze Warning 1, NWS Denver/Boulder, CO

October 21, 200716 counties in Colorado

NWS Denver/Boulder, CO issued this freeze warning at Oct 21, 2007, 2:56 PM MDT for 16 counties in Colorado. It took effect at Oct 21, 2007, 5:00 PM MDT. It was in force for 17 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: Oct 21, 2007, 2:56 PM MDT (20:56 UTC)
In effect from: Oct 21, 2007, 5:00 PM MDT
Expired: Oct 22, 2007, 10:00 AM MDT
In force: 17 hr
Issued by: NWS Denver/Boulder, CO

Counties Adams County, CO, Arapahoe County, CO, Boulder County, CO, Broomfield County, CO, Denver County, CO, Douglas County, CO, Elbert County, CO, Jefferson County, CO, Larimer County, CO, Lincoln County, CO, Logan County, CO, Morgan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 42 km from the middle of the area, began a volume at 21:02 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

Denver, CO (KDNR), launched 12:00Z, 8.9 hours before the alert went out and 80 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: 724 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: -190 m²/s²
0-3 km storm-relative helicity: -272 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 freeze warning 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 freeze warning went out at Oct 21, 2:50 PM MDT, 6 minutes earlier.

Area forecast discussion, Oct 21, 2:50 PM MDT, 6 minutes before

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Hazardous weather outlook, Oct 21, 11:25 AM MDT, 3 hours 31 minutes before

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In the hours before

Local storm report, Oct 21, 11:50 AM MDT, 3 hours 6 minutes before

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Local storm report, Oct 21, 12:40 PM MDT, 2 hours 16 minutes before

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Local storm report, Oct 21, 12:50 PM MDT, 2 hours 6 minutes before

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Local storm report, Oct 21, 12:58 PM MDT, 1 hour 58 minutes before

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Local storm report, Oct 21, 1:13 PM MDT, 1 hour 43 minutes before

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Local storm report, Oct 21, 1:48 PM MDT, 1 hour 8 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
Oct 20, 10:53 PM MDT	Snow Advisory	BOU	Grand, Jackson, Summit	12 hr
Oct 21, 11:17 AM MDT	Snow and Blowing Snow Advisory	BOU	Boulder, Clear Creek, Douglas, Gilpin, Grand, Jefferson and 3 more	4 hr

Nearby

Freeze Warnings in Colorado, 2007 Every freeze warning in 2007

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.