Alert archive / South Carolina / Dense Fog Advisories in 2021

Dense Fog Advisory 10, NWS Charleston, SC

November 22, 20214 counties in South Carolina; Effingham County, Long County, Georgia

NWS Charleston, SC issued this dense fog advisory at Nov 22, 2021, 4:50 AM EST for 4 counties in South Carolina; Effingham County, Long County, Georgia. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued: Nov 22, 2021, 4:50 AM EST (09:50 UTC)
Expired: Nov 22, 2021, 9:00 AM EST
In force: 4 hr
Issued by: NWS Charleston, SC

Counties Effingham County, GA, Long County, GA, Berkeley County, SC, Colleton County, SC, Dorchester County, SC, Hampton County, SC

The radar

The Charleston,SC radar (KCLX), 16 km from the middle of the area, began a volume at 09:51 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

Charleston AFB, SC (KCHS), launched 00:00Z, 9.8 hours before the alert went out and 85 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: 1210 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: -5 m²/s²
0-3 km storm-relative helicity: 115 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 Charleston, SC wrote its last area forecast discussion before this dense fog advisory went out at Nov 22, 4:05 AM EST, 45 minutes earlier.

Area forecast discussion, Nov 22, 4:05 AM EST, 45 minutes before

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Hazardous weather outlook, Nov 22, 4:34 AM EST, 16 minutes before

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In the hours before

Special weather statement, Nov 22, 2:02 AM EST, 2 hours 48 minutes before

Special Weather Statement
National Weather Service Charleston SC
202 AM EST Mon Nov 22 2021

GAZ114>119-137>141-221000-
Tattnall-Evans-Inland Bryan-Coastal Bryan-Inland Chatham-
Coastal Chatham-Long-Inland Liberty-Coastal Liberty-
Inland McIntosh-Coastal McIntosh-
202 AM EST Mon Nov 22 2021

...PATCHY DENSE FOG THIS MORNING...

Patchy dense fog will impact areas of Southeast Georgia through
sunrise, mainly along and south of Interstate 16, including the
Savannah Metro Area. The nature of the fog is such that conditions
could change rapidly over very short distances with visibilities
dropping to 1/4 mile or less at times. Motorists should remain
alert to these conditions. The risk for fog will quickly end at
daybreak.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If driving, slow down and leave extra distance ahead of you in
case a sudden stop is needed.

&&

Special weather statement, Nov 22, 3:26 AM EST, 1 hour 24 minutes before

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The office that day

Everything else NWS Charleston, SC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Nov 21, 9:58 PM EST	Small Craft Advisory	CHS		57 hr
Nov 22, 3:12 AM EST	Gale Watch	CHS		12 hr
Nov 22, 3:15 AM EST	Freeze Watch	CHS	Allendale, Berkeley, Colleton, Dorchester, Hampton	24 hr
Nov 22, 3:06 PM EST	Lake Wind Advisory	CHS	Berkeley	20 hr
Nov 22, 3:11 PM EST	Gale Warning	CHS		20 hr

Nearby

Dense Fog Advisories in South Carolina, 2021 Dense Fog Advisories in Georgia, 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.