Alert archive / Montana / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 121, NWS Great Falls, MT

September 6, 2013Cascade County, Lewis and Clark County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Sep 6, 2013, 3:26 PM MDT for Cascade County, Lewis and Clark County, Montana. It was in force for 49 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 6, 2013, 3:26 PM MDT (21:26 UTC)
Expired
Sep 6, 2013, 4:15 PM MDT
In force
49 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon

Counties Cascade County, MT, Lewis and Clark County, MT

The radar

The Great Falls radar (KTFX), 45 km from the middle of the area, began a volume at 21:27 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 6, 2:09 PM MDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 9.4 hours before the alert went out and 345 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, Spokane, WA at 12:00Z on 2013-09-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 78 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, Spokane, WA at 12:00Z on 2013-09-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -63 square meters per square second.1939587897Sfc1 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
78 J/kg
Mixed-layer CIN
-106 J/kg
Mixed-layer LCL
504 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
-63 m²/s²
0-3 km storm-relative helicity
146 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 Great Falls, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 5, 4:30 PM MDT, 22 hours 56 minutes earlier.

Area forecast discussion, Sep 5, 4:30 PM MDT, 22 hours 56 minutes before
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Hazardous weather outlook, Sep 5, 4:21 PM MDT, 23 hours 5 minutes before
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<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<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.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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    </section>
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  <script src="index.js"></script>
</body>
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The office that day

Everything else NWS Great Falls, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 5, 6:03 PM MDTSpecial Weather StatementTFXLiberty42 min
Sep 5, 6:05 PM MDTSpecial Weather StatementTFX40 min
Sep 5, 6:08 PM MDTSevere Thunderstorm WarningTFXBeaverhead, Madison52 min
Sep 5, 6:13 PM MDTSevere Thunderstorm WarningTFXBeaverhead47 min
Sep 5, 6:40 PM MDTSpecial Weather StatementTFXBlaine50 min
Sep 5, 6:41 PM MDTSpecial Weather StatementTFXHill49 min
Sep 5, 7:15 PM MDTSevere Thunderstorm WarningTFXHill, Liberty30 min
Sep 5, 7:18 PM MDTSpecial Weather StatementTFXJefferson42 min
Sep 5, 7:37 PM MDTSevere Thunderstorm WarningTFXBroadwater, Jefferson38 min
Sep 5, 7:56 PM MDTSpecial Weather StatementTFXGallatin64 min
Sep 5, 8:00 PM MDTSpecial Weather StatementTFXBlaine60 min
Sep 5, 8:17 PM MDTSpecial Weather StatementTFXBroadwater43 min
Sep 5, 8:37 PM MDTSpecial Weather StatementTFXBeaverhead53 min
Sep 5, 10:38 PM MDTSpecial Weather StatementTFXGallatin52 min
Sep 5, 11:35 PM MDTSpecial Weather StatementTFXFergus55 min
Sep 6, 12:09 AM MDTSpecial Weather StatementTFXBroadwater, Meagher51 min
Sep 6, 12:29 AM MDTSpecial Weather StatementTFXPetroleum46 min
Sep 6, 2:17 PM MDTSpecial Weather StatementTFXLewis and Clark43 min
Sep 6, 2:27 PM MDTSpecial Weather StatementTFXJudith Basin48 min
Sep 6, 3:03 PM MDTSpecial Weather StatementTFXLewis and Clark42 min
Sep 6, 3:10 PM MDTSpecial Weather StatementTFXGlacier50 min
Sep 6, 3:25 PM MDTSpecial Weather StatementTFXGlacier50 min
Sep 6, 3:29 PM MDTSpecial Weather StatementTFXGlacier46 min
Sep 6, 3:40 PM MDTSpecial Weather StatementTFXTeton50 min
Sep 6, 3:41 PM MDTSpecial Weather StatementTFXJudith Basin49 min
Sep 6, 3:48 PM MDTSpecial Weather StatementTFXCascade42 min
Sep 6, 3:55 PM MDTSevere Thunderstorm WarningTFXCascade, Lewis and Clark50 min
Sep 6, 4:04 PM MDTSpecial Weather StatementTFXGlacier41 min
Sep 6, 4:09 PM MDTSevere Thunderstorm WarningTFXCascade66 min
Sep 6, 4:15 PM MDTSpecial Weather StatementTFXGlacier45 min
Sep 6, 4:27 PM MDTSevere Thunderstorm WarningTFXFergus63 min
Sep 6, 4:34 PM MDTSevere Thunderstorm WarningTFXCascade41 min
Sep 6, 4:35 PM MDTSpecial Weather StatementTFX40 min
Sep 6, 4:37 PM MDTSpecial Weather StatementTFXTeton38 min
Sep 6, 5:05 PM MDTSpecial Weather StatementTFXGlacier40 min
Sep 6, 5:09 PM MDTSpecial Weather StatementTFXTeton51 min
Sep 6, 5:11 PM MDTSevere Thunderstorm WarningTFXCascade, Chouteau, Judith Basin49 min
Sep 6, 5:20 PM MDTSpecial Weather StatementTFXLewis and Clark40 min
Sep 6, 5:23 PM MDTSpecial Weather StatementTFXTeton52 min
Sep 6, 5:55 PM MDTSevere Thunderstorm WarningTFXChouteau, Judith Basin65 min

Nearby

Severe Thunderstorm Warnings in Montana, 2013Every severe thunderstorm warning in 2013

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.