Alert archive / Virginia / Frost Advisories in 2018

Frost Advisory 2, NWS Wakefield, VA

October 21, 201833 counties in Virginia; Bertie County, Hertford County, Northampton County, North Carolina

NWS Wakefield, VA issued this frost advisory at Oct 21, 2018, 3:39 AM EDT for 33 counties in Virginia; Bertie County, Hertford County, Northampton County, North Carolina. It took effect at Oct 22, 2018, 2:00 AM EDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued: Oct 21, 2018, 3:39 AM EDT (07:39 UTC)
In effect from: Oct 22, 2018, 2:00 AM EDT
Expired: Oct 22, 2018, 8:00 AM EDT
In force: 6 hr
Issued by: NWS Wakefield, VA

All 36 counties

Bertie County, NC, Hertford County, NC, Northampton County, NC, Amelia County, VA, Brunswick County, VA, Caroline County, VA, Charles City County, VA, Chesterfield County, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Franklin, VA, City of Hopewell, VA, City of Petersburg, VA, City of Richmond, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fluvanna County, VA, Goochland County, VA, Greensville County, VA, Hanover County, VA, Henrico County, VA, King and Queen County, VA, King William County, VA, Louisa County, VA, Lunenburg County, VA, Mecklenburg County, VA, New Kent County, VA, Nottoway County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Sussex County, VA, Westmoreland County, VA

The radar

The Norfolk radar (KAKQ), 53 km from the middle of the area, began a volume at 07:43 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 7.7 hours before the alert went out and 187 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: 24 J/kg
Mixed-layer CIN: -68 J/kg
Mixed-layer LCL: 1927 m above ground
0-6 km bulk shear: 115 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 102 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 frost advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Wakefield, VA wrote its last area forecast discussion before this frost advisory went out at Oct 20, 7:29 PM EDT, 8 hours 10 minutes earlier.

Area forecast discussion, Oct 20, 7:29 PM EDT, 8 hours 10 minutes before

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Hazardous weather outlook, Oct 20, 7:40 PM EDT, 7 hours 59 minutes before

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The office that day

Everything else NWS Wakefield, VA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 21, 2:12 PM EDT	Freeze Warning	AKQ	Caroline, Fluvanna, Goochland, Hanover, Louisa	18 hr

Nearby

Frost Advisories in Virginia, 2018 Frost Advisories in North Carolina, 2018 Every frost advisory in 2018

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.