Alert archive / Virginia / Flood Watches in 2017

Flood Watch 5, NWS Blacksburg, VA

May 23, 201713 counties in Virginia; 9 counties in North Carolina

NWS Blacksburg, VA issued this flood watch at May 23, 2017, 3:22 AM EDT for 13 counties in Virginia; 9 counties in North Carolina. It was in force for 23 hr.

The area

The counties it named.

The facts

Issued
May 23, 2017, 3:22 AM EDT (07:22 UTC)
Expired
May 24, 2017, 2:00 AM EDT
In force
23 hr
Issued by
NWS Blacksburg, VA
Flood severity
None
All 22 counties

Alleghany County, NC, Ashe County, NC, Caswell County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Bland County, VA, Carroll County, VA, City of Danville, VA, City of Galax, VA, City of Martinsville, VA, Grayson County, VA, Halifax County, VA, Henry County, VA, Patrick County, VA, Pittsylvania County, VA, Smyth County, VA, Tazewell County, VA, Wythe County, VA

The radar

The Roanoke radar (KFCX), 52 km from the middle of the area, began a volume at 07:22 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

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 7.4 hours before the alert went out and 83 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, Greensboro/Hi Pt, NC at 00:00Z on 2017-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 163 joules per kilogram.LCLLFCEL10008507005003002001001 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, Greensboro/Hi Pt, NC at 00:00Z on 2017-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 square meters per square second.19395878Sfc1 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
163 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
1271 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
41 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

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 Blacksburg, VA wrote its last area forecast discussion before this flood watch went out at May 23, 3:11 AM EDT, 11 minutes earlier.

Area forecast discussion, May 23, 3:11 AM EDT, 11 minutes before
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Hazardous weather outlook, May 22, 3:58 AM EDT, 23 hours 24 minutes before
Hazardous Weather Outlook
National Weather Service Blacksburg VA
358 AM EDT Mon May 22 2017

VAZ007-009>014-018>020-022>024-035-WVZ042>044-507-508-230800-
Tazewell-Smyth-Bland-Giles-Wythe-Pulaski-Montgomery-Craig-
Alleghany VA-Bath-Roanoke-Botetourt-Rockbridge-Amherst-Mercer-
Summers-Monroe-Eastern Greenbrier-Western Greenbrier-
358 AM EDT Mon May 22 2017

This Hazardous Weather Outlook is for central Virginia, southwest
Virginia, west central Virginia and southeast West Virginia.

.DAY ONE...Today and tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

NCZ001>006-018>020-VAZ015>017-032>034-043>047-058-059-230800-
Ashe-Alleghany NC-Surry-Stokes-Rockingham-Caswell-Watauga-Wilkes-
Yadkin-Grayson-Carroll-Floyd-Patrick-Franklin-Bedford-Henry-
Pittsylvania-Campbell-Appomattox-Buckingham-Halifax-Charlotte-
358 AM EDT Mon May 22 2017

This Hazardous Weather Outlook is for north central North Carolina,
northwest North Carolina, central Virginia, south central Virginia,
southwest Virginia and west central Virginia.

.DAY ONE...Today and tonight.

There is a low probability for widespread hazardous weather.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Periods of heavy rain may cause flooding on Tuesday and Wednesday,
with the potential for river flooding extending through later in the
week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

The office that day

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

IssuedProductOfficeCountiesLasted
May 23, 1:20 AM EDTAreal Flood AdvisoryRNKHalifax3 hr
May 23, 7:12 AM EDTAreal Flood AdvisoryRNKHalifax, Pittsylvania3 hr
May 23, 7:41 AM EDTRiver Flood WarningRNKHalifax4 days
May 23, 10:09 AM EDTRiver Flood WarningRNKPittsylvania, City of Danville48 hr
May 23, 10:09 AM EDTRiver Flood WarningRNKHalifax3 days
May 23, 3:29 PM EDTAreal Flood AdvisoryRNKHalifax, Pittsylvania, City of Danville4 hr
May 23, 3:33 PM EDTAreal Flood AdvisoryRNKCharlotte, Halifax5 hr
May 22, 8:13 PM EDTSpecial Weather StatementRNKWilkes32 min
May 22, 8:44 PM EDTSpecial Weather StatementRNKWilkes31 min
May 22, 11:50 PM EDTAreal Flood AdvisoryRNKYadkin3 hr
May 23, 2:24 AM EDTAreal Flood AdvisoryRNKWilkes4 hr

Nearby

Flood Watches in Virginia, 2017Flood Watches in North Carolina, 2017Every 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.