Alert archive / Maryland / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 237, NWS Baltimore/Washington

September 2, 2014Howard County, Montgomery County, Prince George's County, Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at Sep 2, 2014, 4:39 PM EDT for Howard County, Montgomery County, Prince George's County, Maryland. It was in force for 36 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
Sep 2, 2014, 4:39 PM EDT (20:39 UTC)
Expired
Sep 2, 2014, 5:15 PM EDT
In force
36 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon

Counties Howard County, MD, Montgomery County, MD, Prince George's County, MD

The radar

The Sterling radar (KLWX), 44 km from the middle of the area, began a volume at 20:42 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 2, 4:39 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.7 hours before the alert went out and 38 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2014-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 497 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2014-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 68 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
-108 J/kg
Mixed-layer LCL
1408 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
90 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 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 Sep 2, 3:15 PM EDT, 1 hour 24 minutes earlier.

Area forecast discussion, Sep 2, 3:15 PM EDT, 1 hour 24 minutes before
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Hazardous weather outlook, Sep 2, 4:28 PM EDT, 11 minutes before
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In the hours before

Local storm report, Sep 2, 4:10 PM EDT, 29 minutes before
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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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Local storm report, Sep 2, 4:11 PM EDT, 28 minutes before
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<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
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        Please try again in a few minutes.
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        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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The office that day

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

IssuedProductOfficeCountiesLasted
Sep 2, 12:33 AM EDTSpecial Marine WarningLWX57 min
Sep 2, 3:08 PM EDTSevere Thunderstorm WarningLWXClarke, Loudoun52 min
Sep 2, 3:30 PM EDTSevere Thunderstorm WarningLWXLoudoun45 min
Sep 2, 3:52 PM EDTSevere Thunderstorm WarningLWXFairfax, Loudoun38 min
Sep 2, 4:04 PM EDTSevere Thunderstorm WarningLWXFrederick41 min
Sep 2, 4:49 PM EDTSevere Thunderstorm WarningLWXClarke, Loudoun41 min
Sep 2, 5:11 PM EDTSpecial Marine WarningLWX64 min
Sep 2, 6:20 PM EDTSevere Thunderstorm WarningLWXClarke, Loudoun40 min
Sep 2, 6:29 PM EDTSpecial Marine WarningLWX46 min
Sep 2, 6:46 PM EDTSevere Thunderstorm WarningLWXLoudoun44 min
Sep 2, 7:08 PM EDTSpecial Marine WarningLWX52 min
Sep 2, 7:32 PM EDTSpecial Marine WarningLWX58 min
Sep 2, 7:54 PM EDTSpecial Marine WarningLWX51 min
Sep 2, 2:50 PM EDTSevere Thunderstorm WarningLWXAllegany40 min
Sep 2, 4:11 PM EDTSevere Thunderstorm WarningLWXMontgomery49 min
Sep 2, 4:31 PM EDTSevere Thunderstorm WarningLWXFrederick, Washington44 min
Sep 2, 5:15 PM EDTSevere Thunderstorm WarningLWXBaltimore, Carroll, Frederick, Howard, Montgomery45 min
Sep 2, 6:55 PM EDTSevere Thunderstorm WarningLWXFrederick, Howard, Montgomery35 min
Sep 2, 7:39 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Baltimore, Howard, City of Baltimore51 min
Sep 2, 7:51 PM EDTSevere Thunderstorm WarningLWXBaltimore, Harford, City of Baltimore39 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2014Every severe thunderstorm warning in 2014

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.