Alert archive / Iowa / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 81, NWS La Crosse, WI

July 27, 1999Floyd County, Iowa

NWS La Crosse, WI issued this severe thunderstorm warning at Jul 27, 1999, 11:40 PM CDT for Floyd County, Iowa. It was in force for 60 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: Jul 27, 1999, 11:40 PM CDT (04:40 UTC)
Expired: Jul 28, 1999, 12:40 AM CDT
In force: 60 min
Issued by: NWS La Crosse, WI
Area: Whole counties

County Floyd County, IA

The radar

The La Crosse radar (KARX), 154 km from the middle of the area, began a volume at 04:43 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.

Issued	Product	Office	Lasted
Jul 27, 10:45 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 4.7 hours before the alert went out and 209 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: 2389 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 1083 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 71 m²/s²
0-3 km storm-relative helicity: 133 m²/s²
Significant tornado parameter: 1.6
Supercell composite: 9.3

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 La Crosse, WI wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 27, 2:04 PM CDT, 9 hours 36 minutes earlier.

Area forecast discussion, Jul 27, 2:04 PM CDT, 9 hours 36 minutes before

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Hazardous weather outlook, Jul 27, 5:50 AM CDT, 17 hours 50 minutes before

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In the hours before

Special weather statement, Jul 27, 6:45 PM CDT, 4 hours 55 minutes before

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  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
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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.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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      <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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The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 28, 6:29 AM CDT	Severe Thunderstorm Warning	ARX	Trempealeau	31 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1999 Every severe thunderstorm warning in 1999

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.