Alert archive / Virginia / Flood Watches in 2017

Flood Watch 2, NWS Baltimore/Washington

May 4, 201715 counties in Virginia

NWS Baltimore/Washington issued this flood watch at May 4, 2017, 11:48 AM EDT for 15 counties in Virginia. It took effect at May 5, 2017, 12:00 AM EDT. It was in force for 11 hr.

The area

The counties it named.

The facts

Issued: May 4, 2017, 11:48 AM EDT (15:48 UTC)
In effect from: May 5, 2017, 12:00 AM EDT
Expired: May 5, 2017, 10:33 AM EDT
In force: 11 hr
Issued by: NWS Baltimore/Washington
Flood severity: None

Counties Albemarle County, VA, Amherst County, VA, Augusta County, VA, City of Charlottesville, VA, City of Harrisonburg, VA, City of Staunton, VA, City of Waynesboro, VA, Greene County, VA, Madison County, VA, Nelson County, VA, Page County, VA, Rappahannock County, VA, Rockbridge County, VA, Rockingham County, VA, Warren County, VA

The radar

The Sterling radar (KLWX), 136 km from the middle of the area, began a volume at 15:48 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, 3.8 hours before the alert went out and 134 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: 1197 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 379 m²/s²
0-3 km storm-relative helicity: 428 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 flood watch 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 flood watch went out at May 4, 10:34 AM EDT, 1 hour 14 minutes earlier.

Area forecast discussion, May 4, 10:34 AM EDT, 1 hour 14 minutes before

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Hazardous weather outlook, May 4, 8:34 AM EDT, 3 hours 14 minutes before

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      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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        Please try again in a few minutes.
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The office that day

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

Issued	Product	Office	Counties	Lasted
May 4, 4:24 AM EDT	Gale Warning	LWX		33 hr
May 4, 3:42 PM EDT	Coastal Flood Advisory	LWX	Arlington, King George, City of Alexandria, City of Falls Church	58 hr

Nearby

Flood Watches in Virginia, 2017 Every flood watch in 2017

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.