Alert archive / Virginia / Freeze Warnings in 2012

Freeze Warning 9, NWS Baltimore/Washington

April 11, 20128 counties in Virginia; Allegany County, Maryland; 5 counties in West Virginia

NWS Baltimore/Washington issued this freeze warning at Apr 11, 2012, 1:45 PM EDT for 8 counties in Virginia; Allegany County, Maryland; 5 counties in West Virginia. It took effect at Apr 12, 2012, 2:00 AM EDT. It was in force for 7 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 11, 2012, 1:45 PM EDT (17:45 UTC)
In effect from: Apr 12, 2012, 2:00 AM EDT
Expired: Apr 12, 2012, 9:00 AM EDT
In force: 7 hr
Issued by: NWS Baltimore/Washington

Counties Allegany County, MD, City of Harrisonburg, VA, City of Staunton, VA, City of Waynesboro, VA, Highland County, VA, Nelson County, VA, Page County, VA, Rockingham County, VA, Shenandoah County, VA, Grant County, WV, Hampshire County, WV, Hardy County, WV, Mineral County, WV, Pendleton County, WV

The radar

The Sterling radar (KLWX), 127 km from the middle of the area, began a volume at 17:44 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

Roanoke, VA (KRNK), launched 12:00Z, 5.8 hours before the alert went out and 176 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: 1267 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 59 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 freeze warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Baltimore/Washington wrote its last area forecast discussion before this freeze warning went out at Apr 11, 12:30 PM EDT, 1 hour 15 minutes earlier.

Area forecast discussion, Apr 11, 12:30 PM EDT, 1 hour 15 minutes before

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Hazardous weather outlook, Apr 11, 9:01 AM EDT, 4 hours 44 minutes before

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In the hours before

Special weather statement, Apr 11, 9:47 AM EDT, 3 hours 58 minutes before

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Special weather statement, Apr 11, 10:00 AM EDT, 3 hours 45 minutes before

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Special weather statement, Apr 11, 10:33 AM EDT, 3 hours 12 minutes before

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The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 11, 1:29 AM EDT	Small Craft Advisory	LWX		13 hr
Apr 11, 5:06 AM EDT	Small Craft Advisory	LWX		39 hr
Apr 11, 6:51 AM EDT	Red Flag Warning	LWX	Albemarle, Augusta, Nelson, City of Staunton	13 hr
Apr 11, 1:45 PM EDT	Freeze Watch	LWX	Highland	15 hr
Apr 11, 2:05 PM EDT	Gale Warning	LWX		4 hr
Apr 11, 2:05 PM EDT	Small Craft Advisory	LWX		4 hr
Apr 11, 6:02 PM EDT	Gale Warning	LWX		4 hr
Apr 11, 6:02 PM EDT	Small Craft Advisory	LWX		26 hr

Nearby

Freeze Warnings in Virginia, 2012 Freeze Warnings in West Virginia, 2012 Freeze Warnings in Maryland, 2012 Every freeze warning in 2012

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.