Alert archive / Maryland / Flash Flood Warnings in 2011

Flash Flood Warning 137, NWS Baltimore/Washington

September 7, 2011Charles County, Prince George's County, Saint Mary's County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Sep 7, 2011, 12:18 PM EDT for Charles County, Prince George's County, Saint Mary's County, Maryland. It was in force for 5 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: Sep 7, 2011, 12:18 PM EDT (16:18 UTC)
Expired: Sep 7, 2011, 5:30 PM EDT
In force: 5 hr
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Flood severity: None

Counties Charles County, MD, Prince George's County, MD, Saint Mary's County, MD

The radar

The Sterling radar (KLWX), 79 km from the middle of the area, began a volume at 16:20 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, 4.3 hours before the alert went out and 72 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: 1 J/kg
Mixed-layer CIN: -270 J/kg
Mixed-layer LCL: 448 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 154 m²/s²
0-3 km storm-relative helicity: 184 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 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 Sep 7, 11:32 AM EDT, 46 minutes earlier.

Area forecast discussion, Sep 7, 11:32 AM EDT, 46 minutes before

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Hazardous weather outlook, Sep 7, 11:25 AM EDT, 53 minutes before

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In the hours before

Special weather statement, Sep 7, 10:57 AM EDT, 1 hour 21 minutes before

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Special weather statement, Sep 7, 11:28 AM EDT, 50 minutes before

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Special weather statement, Sep 7, 11:46 AM EDT, 32 minutes before

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Local storm report, Sep 7, 12:09 PM EDT, 9 minutes before

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Special weather statement, Sep 7, 12:14 PM EDT, 4 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
Sep 6, 10:54 PM EDT	Areal Flood Warning	LWX	Albemarle, Greene, Nelson, Orange, City of Charlottesville	4 hr
Sep 7, 12:21 AM EDT	Flash Flood Warning	LWX	Albemarle, Nelson, City of Charlottesville	3 hr
Sep 7, 10:47 AM EDT	Flash Flood Warning	LWX	Arlington, Fairfax, City of Alexandria, City of Falls Church	7 hr
Sep 7, 11:11 AM EDT	Small Craft Advisory	LWX		7 hr
Sep 7, 11:38 AM EDT	Flash Flood Warning	LWX	Fairfax, King George, Prince William, Spotsylvania, Stafford, City of Fairfax and 2 more	3 hr
Sep 7, 12:37 PM EDT	Coastal Flood Advisory	LWX	Arlington, Fairfax, King George, Stafford, City of Alexandria, City of Fairfax and 1 more	70 hr
Sep 7, 1:23 PM EDT	Special Marine Warning	LWX		2 hr
Sep 7, 1:26 PM EDT	Special Marine Warning	LWX		78 min
Sep 7, 1:30 PM EDT	Special Marine Warning	LWX		95 min
Sep 7, 4:31 PM EDT	Special Marine Warning	LWX		119 min
Sep 7, 5:25 PM EDT	Areal Flood Warning	LWX	Arlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church	6 hr
Sep 7, 6:20 PM EDT	Special Marine Warning	LWX		115 min
Sep 6, 9:07 PM EDT	River Flood Warning	LWX	Garrett	7 hr
Sep 6, 10:17 PM EDT	River Flood Warning	LWX	Montgomery	19 hr
Sep 7, 1:19 AM EDT	Special Weather Statement	LWX	Baltimore, Carroll	56 min
Sep 7, 9:51 AM EDT	Flash Flood Warning	LWX	Baltimore, City of Baltimore	12 hr
Sep 7, 10:57 AM EDT	Special Weather Statement	LWX	Prince George's	33 min
Sep 7, 11:28 AM EDT	Special Weather Statement	LWX	Charles, Prince George's	32 min
Sep 7, 11:33 AM EDT	Flash Flood Warning Emergency	LWX	Anne Arundel, Baltimore, Carroll, Howard, Prince George's	10 hr
Sep 7, 11:46 AM EDT	Special Weather Statement	LWX	Howard	44 min
Sep 7, 12:14 PM EDT	Special Weather Statement	LWX	Charles	31 min
Sep 7, 12:39 PM EDT	Special Weather Statement	LWX	Prince George's	51 min
Sep 7, 1:03 PM EDT	Special Weather Statement	LWX	Montgomery	27 min
Sep 7, 1:14 PM EDT	Flash Flood Warning	LWX	Carroll, Howard, Montgomery	3 hr
Sep 7, 1:28 PM EDT	Flash Flood Warning	LWX	Anne Arundel, Calvert, Prince George's, Saint Mary's	3 hr
Sep 7, 1:32 PM EDT	Special Weather Statement	LWX	Baltimore, City of Baltimore	28 min
Sep 7, 1:58 PM EDT	Flash Flood Warning	LWX	Baltimore, Harford	8 hr
Sep 7, 4:19 PM EDT	Areal Flood Warning	LWX	Anne Arundel, Calvert, Saint Mary's	6 hr
Sep 7, 5:03 PM EDT	Special Weather Statement	LWX	Calvert	22 min
Sep 7, 6:12 PM EDT	Special Weather Statement	LWX	Baltimore, City of Baltimore	48 min
Sep 7, 6:55 PM EDT	Special Weather Statement	LWX	Saint Mary's	35 min
Sep 7, 7:23 PM EDT	Tornado Warning	LWX	Saint Mary's	37 min
Sep 7, 7:50 PM EDT	Tornado Warning	LWX	Calvert, Saint Mary's	25 min

Nearby

Flash Flood Warnings in Maryland, 2011 Every flash flood warning 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.