Alert archive / West Virginia / Flash Flood Warnings in 2009

Flash Flood Warning 33, NWS Baltimore/Washington

August 19, 2009Morgan County, West Virginia

NWS Baltimore/Washington issued this flash flood warning at Aug 19, 2009, 7:10 PM EDT for Morgan County, West Virginia. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 19, 2009, 7:10 PM EDT (23:10 UTC)
Expired: Aug 19, 2009, 10:00 PM EDT
In force: 3 hr
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Flood severity: None

County Morgan County, WV

The radar

The Sterling radar (KLWX), 93 km from the middle of the area, began a volume at 23:13 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 11.2 hours before the alert went out and 185 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: 277 J/kg
Mixed-layer CIN: -81 J/kg
Mixed-layer LCL: 953 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 57 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning 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 warning went out at Aug 19, 5:53 PM EDT, 1 hour 17 minutes earlier.

Area forecast discussion, Aug 19, 5:53 PM EDT, 1 hour 17 minutes before

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Hazardous weather outlook, Aug 19, 2:42 PM EDT, 4 hours 28 minutes before

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In the hours before

Special weather statement, Aug 19, 3:17 PM EDT, 3 hours 53 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
317 PM EDT WED AUG 19 2009

MDZ013-016-VAZ052-053-192045-
PRINCE GEORGES MD-CHARLES MD-PRINCE WILLIAM/MANASSAS/MANASSAS PARK VA-
FAIRFAX VA-
317 PM EDT WED AUG 19 2009

...THUNDERSTORMS WITH HEAVY RAIN TO AFFECT PRINCE GEORGES...
CHARLES...PRINCE WILLIAM/MANASSAS/MANASSAS PARK AND FAIRFAX
COUNTIES...

AT 316 PM EDT...DOPPLER RADAR INDICATED A CLUSTER OF THUNDERSTORMS
WITH HEAVY RAIN OVER WOODBRIDGE AND LORTON...MOVING EAST AT 15 MPH.

LOCATIONS THAT WILL LIKELY BE AFFECTED BY THESE STORMS INCLUDE MASON
NECK...POTOMAC HEIGHTS...BRYANS ROAD...ACCOKEEK...NORTHWOOD...WALDORF
AND BADEN.

RAINFALL OF ONE TO TWO INCHES WILL BE POSSIBLE IN AN HOUR. HEAVY
DOWNPOURS MAY REDUCE VISIBILITY BELOW A MILE AND CAUSE PONDING OF
WATER ON ROADWAYS.

HTS

Special weather statement, Aug 19, 3:21 PM EDT, 3 hours 49 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
321 PM EDT WED AUG 19 2009

VAZ037-192045-
ALBEMARLE VA-
321 PM EDT WED AUG 19 2009

...THUNDERSTORMS WITH HEAVY RAIN TO AFFECT ALBEMARLE COUNTY...

AT 319 PM EDT...DOPPLER RADAR INDICATED A THUNDERSTORM WITH HEAVY
RAIN OVER NORTH GARDEN...MOVING EAST AT 15 MPH.

LOCATIONS THAT WILL LIKELY BE AFFECTED BY THIS STORM INCLUDE
OVERTON...MONTICELLO...SHADWELL...BOYD TAVERN...KESWICK AND CAMPBELL.

RAINFALL OF AN INCH TO AN INCH AND A HALF WILL BE POSSIBLE IN AN
HOUR OR LESS. HEAVY DOWNPOURS MAY REDUCE VISIBILITY BELOW A MILE AND
CAUSE PONDING OF WATER ON ROADWAYS.

HTS

Special weather statement, Aug 19, 3:45 PM EDT, 3 hours 25 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
345 PM EDT WED AUG 19 2009

VAZ056-192030-
SPOTSYLVANIA VA-
345 PM EDT WED AUG 19 2009

...THUNDERSTORMS WITH HEAVY RAIN TO AFFECT SPOTSYLVANIA COUNTY...

AT 343 PM EDT...DOPPLER RADAR INDICATED SHOWERS AND THUNDERSTORMS
WITH HEAVY RAIN 3 MILES WEST OF GATEWOOD...MOVING EAST AT 20 MPH.

LOCATIONS THAT WILL LIKELY BE AFFECTED BY THIS STORM INCLUDE
MASSAPONAX AND PARTLOW.

HEAVY DOWNPOURS MAY REDUCE VISIBILITY BELOW A MILE AND CAUSE PONDING
OF WATER ON ROADWAYS.

BJL

Local storm report, Aug 19, 5:02 PM EDT, 2 hours 8 minutes before

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Local storm report, Aug 19, 6:00 PM EDT, 1 hour 10 minutes before

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Special weather statement, Aug 19, 6:22 PM EDT, 48 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 18, 8:25 PM EDT	Special Marine Warning	LWX		65 min
Aug 19, 4:30 PM EDT	Special Marine Warning	LWX		2 hr
Aug 19, 5:45 PM EDT	Special Marine Warning	LWX		90 min
Aug 19, 4:19 PM EDT	Severe Thunderstorm Warning	LWX	Saint Mary's	41 min
Aug 19, 4:35 PM EDT	Tornado Warning	LWX	Saint Mary's	40 min
Aug 19, 5:15 PM EDT	Severe Thunderstorm Warning	LWX	Saint Mary's	45 min

Nearby

Flash Flood Warnings in West Virginia, 2009 Every flash flood warning in 2009

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.