Alert archive / Florida / Dense Fog Advisories in 2021

Dense Fog Advisory 36, NWS Tallahassee, FL

December 30, 202112 counties in Florida

NWS Tallahassee, FL issued this dense fog advisory at Dec 30, 2021, 8:30 PM CST for 12 counties in Florida. It was in force for 13 hr.

The area

The counties it named.

The facts

Issued: Dec 30, 2021, 8:30 PM CST (02:30 UTC)
Expired: Dec 31, 2021, 9:00 AM CST
In force: 13 hr
Issued by: NWS Tallahassee, FL

Counties Bay County, FL, Calhoun County, FL, Dixie County, FL, Franklin County, FL, Gulf County, FL, Holmes County, FL, Jefferson County, FL, Lafayette County, FL, Taylor County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL

The radar

The Tallahassee radar (KTLH), 44 km from the middle of the area, began a volume at 02:33 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

Jacksonville, FL (KJAX), launched 00:00Z, 2.5 hours before the alert went out and 293 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: 805 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 864 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 162 m²/s²
0-3 km storm-relative helicity: 172 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 3.2

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 Tallahassee, FL wrote its last area forecast discussion before this dense fog advisory went out at Dec 30, 5:27 PM CST, 3 hours 3 minutes earlier.

Area forecast discussion, Dec 30, 5:27 PM CST, 3 hours 3 minutes before

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In the hours before

Special weather statement, Dec 30, 4:31 PM CST, 3 hours 59 minutes before

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Local storm report, Dec 30, 4:39 PM CST, 3 hours 51 minutes before

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Special weather statement, Dec 30, 4:56 PM CST, 3 hours 34 minutes before

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Special weather statement, Dec 30, 5:08 PM CST, 3 hours 22 minutes before

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Special weather statement, Dec 30, 5:30 PM CST, 3 hours before

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Special weather statement, Dec 30, 5:52 PM CST, 2 hours 38 minutes before

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The office that day

Everything else NWS Tallahassee, FL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 30, 6:10 PM CST	Special Weather Statement	TAE	Dougherty	35 min
Dec 30, 10:27 PM CST	Special Weather Statement	TAE	Irwin	18 min
Dec 30, 11:43 PM CST	Special Weather Statement	TAE	Irwin	32 min
Dec 31, 12:19 AM CST	Special Weather Statement	TAE	Irwin	26 min
Dec 31, 12:25 AM CST	Severe Thunderstorm Warning	TAE	Irwin	20 min

Nearby

Dense Fog Advisories in Florida, 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.