Alert archive / Maryland / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 28, NWS Baltimore/Washington

April 20, 20084 counties in Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at Apr 20, 2008, 3:07 PM EDT for 4 counties in Maryland. It was in force for 38 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 20, 2008, 3:07 PM EDT (19:07 UTC)
Expired: Apr 20, 2008, 3:45 PM EDT
In force: 38 min
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon

Counties Carroll County, MD, Frederick County, MD, Howard County, MD, Montgomery County, MD

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.1 hours before the alert went out and 50 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: 497 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 530 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 112 m²/s²
0-3 km storm-relative helicity: 154 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Apr 20, 10:51 AM EDT, 4 hours 16 minutes earlier.

Area forecast discussion, Apr 20, 10:51 AM EDT, 4 hours 16 minutes before

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Hazardous weather outlook, Apr 20, 10:57 AM EDT, 4 hours 10 minutes before

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In the hours before

Local storm report, Apr 20, 11:20 AM EDT, 3 hours 47 minutes before

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Local storm report, Apr 20, 1:43 PM EDT, 1 hour 24 minutes before

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Special weather statement, Apr 20, 2:11 PM EDT, 56 minutes before

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Local storm report, Apr 20, 2:25 PM EDT, 42 minutes before

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Special weather statement, Apr 20, 3:04 PM EDT, 3 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
Apr 20, 3:12 AM EDT	Flood Watch	LWX	Arlington, Clarke, Culpeper, Fairfax, Frederick, Greene and 19 more	27 hr
Apr 20, 9:20 AM EDT	Areal Flood Warning	LWX	Loudoun	6 hr
Apr 20, 2:33 PM EDT	Areal Flood Warning	LWX	Arlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church	6 hr
Apr 20, 3:31 PM EDT	Special Marine Warning	LWX		44 min
Apr 20, 2:17 PM EDT	Severe Thunderstorm Warning	LWX	Harford	44 min
Apr 20, 2:20 PM EDT	Severe Thunderstorm Warning	LWX	Howard, Montgomery, Prince George's	25 min
Apr 20, 5:51 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore, Carroll, City of Baltimore	54 min
Apr 20, 6:08 PM EDT	Tornado Warning	LWX	Baltimore	37 min
Apr 20, 6:24 PM EDT	Areal Flood Warning	LWX	Montgomery	6 hr
Apr 20, 7:38 PM EDT	Areal Flood Warning	LWX	Baltimore, Carroll	6 hr
Apr 20, 7:50 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore	20 min
Apr 20, 4:08 PM EDT	River Flood Warning	LWX	Berkeley	42 hr

Nearby

Severe Thunderstorm Warnings in Maryland, 2008 Every severe thunderstorm warning 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.