Alert archive / Wyoming / Dense Fog Advisories in 2021

Dense Fog Advisory 6, NWS Cheyenne, WY

May 17, 2021Albany County, Laramie County, Wyoming; Scotts Bluff County, Nebraska

NWS Cheyenne, WY issued this dense fog advisory at May 17, 2021, 5:36 AM MDT for Albany County, Laramie County, Wyoming; Scotts Bluff County, Nebraska. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued: May 17, 2021, 5:36 AM MDT (11:36 UTC)
Expired: May 17, 2021, 11:00 AM MDT
In force: 5 hr
Issued by: NWS Cheyenne, WY

Counties Scotts Bluff County, NE, Albany County, WY, Laramie County, WY

The radar

The Cheyenne radar (KCYS), 51 km from the middle of the area, began a volume at 11:35 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 00:00Z, 11.6 hours before the alert went out and 230 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: 143 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 685 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: -15 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 dense fog advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Cheyenne, WY wrote its last area forecast discussion before this dense fog advisory went out at May 17, 5:27 AM MDT, 9 minutes earlier.

Area forecast discussion, May 17, 5:27 AM MDT, 9 minutes before

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Hazardous weather outlook, May 17, 4:20 AM MDT, 1 hour 16 minutes before

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In the hours before

Special weather statement, May 17, 12:57 AM MDT, 4 hours 39 minutes before

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      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 17, 1:34 PM MDT	Special Weather Statement	CYS	Laramie	26 min
May 17, 1:48 PM MDT	Areal Flood Advisory	CYS	Albany, Carbon	3 hr
May 17, 2:05 PM MDT	Flash Flood Warning	CYS	Albany, Carbon	2 hr
May 17, 4:47 PM MDT	Special Weather Statement	CYS	Laramie	28 min
May 17, 5:22 PM MDT	Special Weather Statement	CYS		38 min

Nearby

Dense Fog Advisories in Wyoming, 2021 Dense Fog Advisories in Nebraska, 2021 Every dense fog advisory in 2021

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.