Alert archive / Maryland / Flash Flood Watches in 2012

Flash Flood Watch 3, NWS Baltimore/Washington

May 27, 2012Allegany County, Maryland; Mineral County, West Virginia

NWS Baltimore/Washington issued this flash flood watch at May 27, 2012, 10:32 PM EDT for Allegany County, Maryland; Mineral County, West Virginia. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued: May 27, 2012, 10:32 PM EDT (02:32 UTC)
Expired: May 28, 2012, 1:31 AM EDT
In force: 3 hr
Issued by: NWS Baltimore/Washington
Flood severity: None

Counties Allegany County, MD, Mineral County, WV

The radar

The Sterling radar (KLWX), 130 km from the middle of the area, began a volume at 02:35 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 00:00Z, 2.5 hours before the alert went out and 138 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: 319 J/kg
Mixed-layer CIN: -81 J/kg
Mixed-layer LCL: 1455 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -16 m²/s²
0-3 km storm-relative helicity: 72 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 27, 10:16 PM EDT, 16 minutes earlier.

Area forecast discussion, May 27, 10:16 PM EDT, 16 minutes before

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Hazardous weather outlook, May 27, 9:56 PM EDT, 36 minutes before

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In the hours before

Local storm report, May 27, 8:40 PM EDT, 1 hour 52 minutes before

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Special weather statement, May 27, 8:42 PM EDT, 1 hour 50 minutes before

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Special weather statement, May 27, 8:59 PM EDT, 1 hour 33 minutes before

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Special weather statement, May 27, 9:06 PM EDT, 1 hour 26 minutes before

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Local storm report, May 27, 10:16 PM EDT, 16 minutes before

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Local storm report, May 27, 10:17 PM EDT, 15 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
May 27, 8:02 PM EDT	Special Weather Statement	LWX	Frederick, City of Winchester	28 min
May 27, 8:08 PM EDT	Severe Thunderstorm Warning	LWX	Clarke, Loudoun	37 min
May 27, 8:13 PM EDT	Special Marine Warning	LWX		97 min
May 27, 8:23 PM EDT	Special Marine Warning	LWX		82 min
May 27, 8:42 PM EDT	Special Weather Statement	LWX	Arlington, Fairfax, Loudoun, Prince William, City of Alexandria, City of Fairfax and 3 more	18 min
May 27, 9:06 PM EDT	Special Weather Statement	LWX	Arlington, Fairfax, Prince William, City of Alexandria, City of Fairfax, City of Falls Church and 2 more	39 min
May 27, 9:38 PM EDT	Special Marine Warning	LWX		52 min
May 28, 1:02 AM EDT	Special Weather Statement	LWX	Clarke, Frederick, Warren, City of Winchester	43 min
May 28, 4:16 AM EDT	Heat Advisory	LWX	Arlington, Culpeper, Fairfax, Fauquier, King George, Orange and 6 more	17 hr
May 28, 6:39 PM EDT	Small Craft Advisory	LWX		28 hr
May 27, 8:59 PM EDT	Special Weather Statement	LWX	Anne Arundel, City of Baltimore	46 min
May 27, 11:25 PM EDT	Special Weather Statement	LWX	Allegany	35 min
May 27, 11:52 PM EDT	Special Weather Statement	LWX	Allegany	23 min
May 28, 4:21 PM EDT	Special Weather Statement	LWX	Allegany	54 min
May 28, 4:39 PM EDT	Flash Flood Warning	LWX	Allegany	62 min

Nearby

Flash Flood Watches in Maryland, 2012 Flash Flood Watches in West Virginia, 2012 Every flash flood watch in 2012

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.