Alert archive / Hawaii / Flash Flood Warnings in 2025

Flash Flood Warning 11, NWS Honolulu, HI

April 18, 2025Kalawao County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Apr 18, 2025, 1:18 PM HST for Kalawao County, Hawaii. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 18, 2025, 1:18 PM HST (23:18 UTC)
Expired: Apr 18, 2025, 4:12 PM HST
In force: 3 hr
Issued by: NWS Honolulu, HI
Area: Storm-based polygon
Flood severity: None

County Kalawao County, HI

The radar

The Molokai radar (PHMO), 24 km from the middle of the area, began a volume at 23:18 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

Lihue, (PHLI), launched 12:00Z, 11.3 hours before the alert went out and 263 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: 1369 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 632 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 29 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.6

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 Honolulu, HI wrote its last area forecast discussion before this flash flood warning went out at Apr 18, 10:10 AM HST, 3 hours 8 minutes earlier.

Area forecast discussion, Apr 18, 10:10 AM HST, 3 hours 8 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

Special weather statement, Apr 18, 1:06 PM HST, 12 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 Honolulu, HI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 17, 3:19 PM HST	High Surf Advisory	HFO	Honolulu, Kauai, Kalawao	12 hr
Apr 17, 4:51 PM HST	Areal Flood Advisory	HFO	Kalawao	3 hr
Apr 17, 7:20 PM HST	Areal Flood Advisory	HFO	Kalawao	2 hr
Apr 17, 8:36 PM HST	Areal Flood Advisory	HFO	Honolulu	3 hr
Apr 18, 2:01 AM HST	Areal Flood Advisory	HFO	Kauai	6 hr
Apr 18, 8:17 AM HST	Flash Flood Warning	HFO	Kauai	3 hr
Apr 18, 11:56 AM HST	Areal Flood Advisory	HFO	Kalawao	4 hr
Apr 18, 11:59 AM HST	Areal Flood Advisory	HFO	Honolulu	65 min
Apr 18, 12:26 PM HST	Areal Flood Advisory	HFO	Kalawao	4 hr
Apr 18, 12:35 PM HST	Special Marine Warning	HFO		55 min
Apr 18, 12:37 PM HST	Areal Flood Advisory	HFO	Kalawao	3 hr
Apr 18, 1:04 PM HST	Flash Flood Warning	HFO	Honolulu	105 min
Apr 18, 1:06 PM HST	Special Weather Statement	HFO	Honolulu	24 min
Apr 18, 1:15 PM HST	Areal Flood Advisory	HFO	Honolulu	12 min
Apr 18, 1:27 PM HST	Flash Flood Warning	HFO	Honolulu	3 hr
Apr 18, 1:27 PM HST	Special Marine Warning	HFO		63 min
Apr 18, 1:55 PM HST	Special Marine Warning	HFO		65 min

Nearby

Flash Flood Warnings in Hawaii, 2025 Every flash flood warning in 2025

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.