Alert archive / West Virginia / Flash Flood Watches in 2011

Flash Flood Watch 4, NWS Baltimore/Washington

May 13, 2011Highland County, Virginia; Allegany County, Maryland; 5 counties in West Virginia

NWS Baltimore/Washington issued this flash flood watch at May 13, 2011, 9:00 AM EDT for Highland County, Virginia; Allegany County, Maryland; 5 counties in West Virginia. It was in force for 12 hr.

The area

The counties it named.

The facts

Issued: May 13, 2011, 9:00 AM EDT (13:00 UTC)
Expired: May 13, 2011, 9:23 PM EDT
In force: 12 hr
Issued by: NWS Baltimore/Washington
Flood severity: None

Counties Allegany County, MD, Highland County, VA, Grant County, WV, Hampshire County, WV, Hardy County, WV, Mineral County, WV, Pendleton County, WV

The radar

The Sterling radar (KLWX), 134 km from the middle of the area, began a volume at 13:01 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, 1.0 hours before the alert went out and 142 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: 6 J/kg
Mixed-layer CIN: -13 J/kg
Mixed-layer LCL: 476 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 125 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 flash 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 flash flood watch went out at May 13, 6:02 AM EDT, 2 hours 58 minutes earlier.

Area forecast discussion, May 13, 6:02 AM EDT, 2 hours 58 minutes before

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Hazardous weather outlook, May 13, 5:18 AM EDT, 3 hours 42 minutes before

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In the hours before

Special weather statement, May 13, 7:58 AM EDT, 1 hour 2 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
758 AM EDT FRI MAY 13 2011

WVZ050-055-501>504-131230-
HARDY WV-HAMPSHIRE WV-WESTERN GRANT WV-EASTERN GRANT WV-
WESTERN MINERAL WV-EASTERN MINERAL WV-
758 AM EDT FRI MAY 13 2011

...STRONG THUNDERSTORM TO AFFECT HARDY...HAMPSHIRE...GRANT... AND
MINERAL COUNTIES...

AT 756 AM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 5 MILES
NORTH OF GORMANIA...MOVING SOUTHEAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE WILLIAMSPORT... BISMARCK AND MEDLEY.

HEAVY RAIN WITH THIS STORM MAY REDUCE VISIBILITIES TO BELOW ONE MILE
AND MAY CAUSE PONDING OF WATER ON ROADWAYS.

SMALL HAIL CAN ALSO BE EXPECTED WITH THIS STORM.

&&

LAT...LON 3930 7934 3931 7930 3935 7926 3937 7922
      3941 7916 3928 7869 3892 7895 3916 7933
      3919 7930 3921 7931 3920 7939 3923 7944
TIME...MOT...LOC 1156Z 293DEG 20KT 3935 7935

The office that day

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

Issued	Product	Office	Counties	Lasted
May 13, 1:36 AM EDT	Special Weather Statement	LWX	Albemarle, City of Charlottesville	39 min
May 13, 1:43 PM EDT	Severe Thunderstorm Warning	LWX	Rockingham	33 min
May 13, 2:31 PM EDT	Flash Flood Warning	LWX	Rockingham	5 hr
May 13, 6:15 PM EDT	Special Weather Statement	LWX	Augusta	30 min
May 13, 1:57 PM EDT	Coastal Flood Warning	LWX	Anne Arundel	14 hr
May 13, 1:57 PM EDT	Coastal Flood Advisory	LWX	Anne Arundel	68 hr
May 12, 11:24 PM EDT	Special Weather Statement	LWX	Grant	51 min
May 13, 7:58 AM EDT	Special Weather Statement	LWX	Grant	32 min
May 13, 1:15 PM EDT	Special Weather Statement	LWX	Pendleton	30 min
May 13, 1:48 PM EDT	Special Weather Statement	LWX	Pendleton	27 min
May 13, 2:11 PM EDT	Special Weather Statement	LWX	Pendleton	34 min
May 13, 2:36 PM EDT	Special Weather Statement	LWX	Grant	39 min
May 13, 3:38 PM EDT	Flash Flood Warning	LWX	Grant	2 hr

Nearby

Flash Flood Watches in West Virginia, 2011 Flash Flood Watches in Virginia, 2011 Flash Flood Watches in Maryland, 2011 Every flash flood watch in 2011

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.