Alert archive / Virginia / Frost Advisories in 2015

Frost Advisory 3, NWS Baltimore/Washington

April 24, 201520 counties in Virginia; 4 counties in Maryland

NWS Baltimore/Washington issued this frost advisory at Apr 24, 2015, 2:35 PM EDT for 20 counties in Virginia; 4 counties in Maryland. It took effect at Apr 25, 2015, 2:00 AM EDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Apr 24, 2015, 2:35 PM EDT (18:35 UTC)
In effect from
Apr 25, 2015, 2:00 AM EDT
Expired
Apr 25, 2015, 8:15 AM EDT
In force
6 hr
Issued by
NWS Baltimore/Washington
All 24 counties

Baltimore County, MD, City of Baltimore, MD, Howard County, MD, Montgomery County, MD, Albemarle County, VA, Amherst County, VA, Augusta County, VA, City of Fairfax, VA, City of Harrisonburg, VA, City of Staunton, VA, City of Waynesboro, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Greene County, VA, Loudoun County, VA, Madison County, VA, Nelson County, VA, Page County, VA, Rappahannock County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Warren County, VA

The radar

The Sterling radar (KLWX), 76 km from the middle of the area, began a volume at 18:34 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 12:00Z, 6.6 hours before the alert went out and 80 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2015-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2015-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 116 square meters per square second.1939587897117136Sfc1 km3 km6 km9 kmRMLM
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
1636 m above ground
0-6 km bulk shear
94 kt
0-1 km storm-relative helicity
116 m²/s²
0-3 km storm-relative helicity
195 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 23, 8:17 PM EDTFrost AdvisoryLWXCulpeper, Fauquier, Greene, Madison, Nelson, Orange and 2 more11 hr
Apr 24, 3:23 AM EDTFreeze WatchLWXAlbemarle, Amherst, Augusta, Clarke, Frederick, Greene and 13 more11 hr
Apr 24, 2:35 PM EDTFreeze WarningLWXClarke, Frederick, Loudoun, City of Winchester18 hr

Nearby

Frost Advisories in Virginia, 2015Frost Advisories in Maryland, 2015Every frost advisory in 2015

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.