Alert archive / Louisiana / Dense Fog Advisories in 2021

Dense Fog Advisory 8, NWS New Orleans, LA

February 9, 20214 parishes in Louisiana

NWS New Orleans, LA issued this dense fog advisory at Feb 9, 2021, 4:55 AM CST for 4 parishes in Louisiana. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued: Feb 9, 2021, 4:55 AM CST (10:55 UTC)
Expired: Feb 9, 2021, 9:00 AM CST
In force: 4 hr
Issued by: NWS New Orleans, LA

Counties Assumption Parish, LA, Saint Bernard Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 10.9 hours before the alert went out and 86 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: 568 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 290 m²/s²
0-3 km storm-relative helicity: 334 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 New Orleans, LA wrote its last area forecast discussion before this dense fog advisory went out at Feb 9, 3:11 AM CST, 1 hour 44 minutes earlier.

Area forecast discussion, Feb 9, 3:11 AM CST, 1 hour 44 minutes before

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The office that day

Everything else NWS New Orleans, LA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 9, 4:05 AM CST	Special Marine Warning	LIX		40 min
Feb 9, 4:55 AM CST	Marine Dense Fog Advisory	LIX		4 hr

Nearby

Dense Fog Advisories in Louisiana, 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.