Alert archive / Oregon / Flash Flood Warnings in 2017

Flash Flood Warning 1, NWS Portland, OR

September 20, 2017Hood River County, Multnomah County, Oregon; Skamania County, Washington

NWS Portland, OR issued this flash flood warning at Sep 20, 2017, 4:28 AM PDT for Hood River County, Multnomah County, Oregon; Skamania County, Washington. It was in force for 62 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 20, 2017, 4:28 AM PDT (11:28 UTC)
Expired: Sep 20, 2017, 5:30 AM PDT
In force: 62 min
Issued by: NWS Portland, OR
Area: Storm-based polygon
Flood severity: None

Counties Hood River County, OR, Multnomah County, OR, Skamania County, WA

The radar

The Portland,OR radar (KRTX), 75 km from the middle of the area, began a volume at 11:30 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

Medford/Jackson, OR (KMFR), launched 00:00Z, 11.5 hours before the alert went out and 375 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: 16 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 1080 m above ground
0-6 km bulk shear: 78 kt
0-1 km storm-relative helicity: 201 m²/s²
0-3 km storm-relative helicity: 257 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 flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Portland, OR wrote its last area forecast discussion before this flash flood warning went out at Sep 20, 3:08 AM PDT, 1 hour 20 minutes earlier.

Area forecast discussion, Sep 20, 3:08 AM PDT, 1 hour 20 minutes before

<!doctype html>
<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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

In the hours before

Local storm report, Sep 19, 11:26 PM PDT, 5 hours 2 minutes before

<!doctype html>
<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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

The office that day

Everything else NWS Portland, OR issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 19, 7:27 PM PDT	Special Weather Statement	PQR	Clackamas	33 min
Sep 20, 2:02 AM PDT	Winter Weather Advisory	PQR		17 hr
Sep 20, 2:04 PM PDT	Flash Flood Warning	PQR	Hood River, Multnomah	3 hr
Sep 20, 2:34 PM PDT	Small Craft Advisory for Hazardous Seas	PQR		14 hr

Nearby

Flash Flood Warnings in Oregon, 2017 Flash Flood Warnings in Washington, 2017 Every flash flood warning in 2017

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.