Alert archive / Missouri / Dense Fog Advisories in 2011

Dense Fog Advisory 3, NWS St. Louis, MO

February 23, 20116 counties in Missouri; Adams County, Brown County, Pike County, Illinois

NWS St. Louis, MO issued this dense fog advisory at Feb 23, 2011, 10:30 PM CST for 6 counties in Missouri; Adams County, Brown County, Pike County, Illinois. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued: Feb 23, 2011, 10:30 PM CST (04:30 UTC)
Expired: Feb 24, 2011, 6:22 AM CST
In force: 8 hr
Issued by: NWS St. Louis, MO

Counties Adams County, IL, Brown County, IL, Pike County, IL, Knox County, MO, Lewis County, MO, Marion County, MO, Monroe County, MO, Ralls County, MO, Shelby County, MO

The radar

The St Louis radar (KLSX), 146 km from the middle of the area, began a volume at 04:29 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

Davenport, (KDVN), launched 00:00Z, 4.5 hours before the alert went out and 218 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: 671 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 330 m²/s²
0-3 km storm-relative helicity: 336 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 St. Louis, MO wrote its last area forecast discussion before this dense fog advisory went out at Feb 23, 6:12 PM CST, 4 hours 18 minutes earlier.

Area forecast discussion, Feb 23, 6:12 PM CST, 4 hours 18 minutes before

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In the hours before

Local storm report, Feb 23, 7:27 PM CST, 3 hours 3 minutes before

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Local storm report, Feb 23, 10:17 PM CST, 13 minutes before

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The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 24, 3:57 AM CST	Winter Storm Warning	LSX	Audrain, Knox, Lewis, Marion, Monroe, Pike and 2 more	24 hr

Nearby

Dense Fog Advisories in Missouri, 2011 Dense Fog Advisories in Illinois, 2011 Every dense fog advisory in 2011

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.