Alert archive / Colorado / High Wind Watches in 2020

High Wind Watch 5, NWS Denver/Boulder, CO

December 18, 202010 counties in Colorado

NWS Denver/Boulder, CO issued this high wind watch at Dec 18, 2020, 3:19 PM MST for 10 counties in Colorado. It took effect at Dec 19, 2020, 5:00 PM MST. It was in force for .

The area

The counties it named.

The facts

Issued
Dec 18, 2020, 3:19 PM MST (22:19 UTC)
In effect from
Dec 19, 2020, 5:00 PM MST
Expired
Dec 19, 2020, 10:30 AM MST
In force
Issued by
NWS Denver/Boulder, CO

Counties Boulder County, CO, Clear Creek County, CO, Douglas 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), 94 km from the middle of the area, began a volume at 22:21 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

Riverton, WY (KRIW), launched 12:00Z, 10.3 hours before the alert went out and 423 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-pSkew-T log-p diagram, Riverton, WY at 12:00Z on 2020-12-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 12:00Z on 2020-12-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -47 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1230 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
-47 m²/s²
0-3 km storm-relative helicity
33 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 high wind 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 high wind watch went out at Dec 18, 10:44 AM MST, 4 hours 35 minutes earlier.

Area forecast discussion, Dec 18, 10:44 AM MST, 4 hours 35 minutes before
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Hazardous weather outlook, Dec 18, 11:05 AM MST, 4 hours 14 minutes before
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In the hours before

Local storm report, Dec 18, 12:51 PM MST, 2 hours 28 minutes before
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Local storm report, Dec 18, 1:19 PM MST, 2 hours before
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Local storm report, Dec 18, 2:27 PM MST, 52 minutes before
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Local storm report, Dec 18, 2:59 PM MST, 20 minutes before
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Local storm report, Dec 18, 3:00 PM MST, 19 minutes before
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Nearby

High Wind Watches in Colorado, 2020Every high wind watch 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.