Alert archive / Virginia / Flash Flood Watches in 2008

Flash Flood Watch 2, NWS Wakefield, VA

April 21, 200816 counties in Virginia; 9 counties in North Carolina

NWS Wakefield, VA issued this flash flood watch at Apr 21, 2008, 12:08 AM EDT for 16 counties in Virginia; 9 counties in North Carolina. It was in force for 20 hr.

The area

The counties it named.

The facts

Issued: Apr 21, 2008, 12:08 AM EDT (04:08 UTC)
Expired: Apr 21, 2008, 8:00 PM EDT
In force: 20 hr
Issued by: NWS Wakefield, VA
Flood severity: None

All 25 counties

Bertie County, NC, Camden County, NC, Chowan County, NC, Currituck County, NC, Gates County, NC, Hertford County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, Brunswick County, VA, Charles City County, VA, City of Chesapeake, VA, City of Emporia, VA, City of Franklin, VA, City of Hopewell, VA, City of Petersburg, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Dinwiddie County, VA, Greensville County, VA, James City County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA

The radar

The Norfolk radar (KAKQ), 29 km from the middle of the area, began a volume at 04:08 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

Wallops Is Stn, VA (KWAL), launched 00:00Z, 4.1 hours before the alert went out and 189 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: 871 J/kg
Mixed-layer CIN: -10 J/kg
Mixed-layer LCL: 721 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 96 m²/s²
0-3 km storm-relative helicity: 101 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.8

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch 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 flash flood watch went out at Apr 20, 8:05 PM EDT, 4 hours 3 minutes earlier.

Area forecast discussion, Apr 20, 8:05 PM EDT, 4 hours 3 minutes before

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Hazardous weather outlook, Apr 20, 10:45 PM EDT, 1 hour 23 minutes before

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In the hours before

Special weather statement, Apr 20, 6:37 PM EDT, 5 hours 31 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WAKEFIELD VA
637 PM EDT SUN APR 20 2008

NCZ012-202330-
NORTHAMPTON NC-
637 PM EDT SUN APR 20 2008

...STRONG THUNDERSTORM MOVING INTO EASTERN NORTHAMPTON COUNTY...

AT 637 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 7 MILES WEST OF RICH SQUARE...MOVING NORTH AT 24
MPH. THE STRONG THUNDERSTORMS WILL BE NEAR JACKSON AT 650 PM EDT...
PLEASANT GROVE AT 700 PM EDT...SEABOARD...AND...GUMBERRY AT 705 PM
EDT...MARGARETTSVILLE AT 715 PM EDT.

WIND GUSTS TO 45 MPH AND FREQUENT CLOUD TO GROUND LIGHTNING ARE
EXPECTED IN THE PATH OF THESE STORMS. IF YOU HEAR THUNDER...YOU ARE
CLOSE ENOUGH TO BE STRUCK BY LIGHTNING. MOVE INTO A SAFE SHELTER
BEFORE THESE STORMS REACH YOUR AREA. REMAIN INDOORS UNTIL THE STORMS
HAVE PASSED.

RAINFALL RATES OF ONE TO TWO INCHES PER HOUR WILL CAUSE PONDING OF
WATER ON ROADWAYS...AND POSSIBLE LOCALIZED FLOODING IN LOW LYING AND
FLOOD PRONE AREAS.

MCNATT

Local storm report, Apr 20, 6:52 PM EDT, 5 hours 16 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
Apr 21, 4:24 AM EDT	Coastal Flood Statement	AKQ	Accomack, Gloucester, Lancaster, Mathews, Middlesex, Northampton and 4 more	20 hr
Apr 21, 10:36 AM EDT	Flash Flood Warning	AKQ	Isle of Wight, Southampton, City of Chesapeake, City of Norfolk, City of Portsmouth, City of Suffolk and 1 more	9 hr
Apr 21, 1:05 PM EDT	Areal Flood Advisory	AKQ	Charles City, Chesterfield, Hanover, Henrico, James City, King William and 12 more	6 hr
Apr 21, 3:11 PM EDT	Areal Flood Advisory	AKQ	Essex, Gloucester, King and Queen, King William, Mathews, Middlesex and 1 more	6 hr
Apr 20, 8:12 PM EDT	Severe Thunderstorm Warning	AKQ	Bertie, Gates, Hertford, Northampton	33 min
Apr 21, 9:06 AM EDT	Areal Flood Advisory	AKQ	Camden, Gates, Pasquotank, Perquimans	3 hr

Nearby

Flash Flood Watches in Virginia, 2008 Flash Flood Watches in North Carolina, 2008 Every flash flood watch in 2008

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.