Alert archive / Illinois / Areal Flood Advisories in 2021

Areal Flood Advisory 55, NWS St. Louis, MO

July 15, 2021Adams County, Brown County, Pike County, Illinois

NWS St. Louis, MO issued this areal flood advisory at Jul 15, 2021, 3:18 PM CDT for Adams County, Brown County, Pike County, Illinois. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued: Jul 15, 2021, 3:18 PM CDT (20:18 UTC)
Expired: Jul 15, 2021, 6:30 PM CDT
In force: 3 hr
Issued by: NWS St. Louis, MO
Area: Storm-based polygon

Counties Adams County, IL, Brown County, IL, Pike County, IL

The radar

The St Louis radar (KLSX), 131 km from the middle of the area, began a volume at 20:18 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

Davenport, (KDVN), launched 12:00Z, 8.3 hours before the alert went out and 199 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: 78 J/kg
Mixed-layer CIN: -116 J/kg
Mixed-layer LCL: 688 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 106 m²/s²
0-3 km storm-relative helicity: 80 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS St. Louis, MO wrote its last area forecast discussion before this areal flood advisory went out at Jul 15, 12:54 PM CDT, 2 hours 24 minutes earlier.

Area forecast discussion, Jul 15, 12:54 PM CDT, 2 hours 24 minutes before

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Hazardous weather outlook, Jul 15, 4:43 AM CDT, 10 hours 35 minutes before

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</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.
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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 St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 15, 1:18 PM CDT	Areal Flood Advisory	LSX	Knox, Lewis, Marion, Shelby	3 hr
Jul 15, 4:47 PM CDT	Areal Flood Advisory	LSX	Boone, Callaway, Cole, Moniteau	3 hr

Nearby

Areal Flood Advisories in Illinois, 2021 Every areal flood advisory in 2021

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.