Alert archive / Hawaii / High Surf Warnings in 2018

High Surf Warning 11, NWS Honolulu, HI

August 21, 20184 counties in Hawaii

NWS Honolulu, HI issued this high surf warning at Aug 21, 2018, 4:08 PM HST for 4 counties in Hawaii. It took effect at Aug 21, 2018, 6:00 PM HST. It was in force for 71 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
Aug 21, 2018, 4:08 PM HST (02:08 UTC)
In effect from
Aug 21, 2018, 6:00 PM HST
Expired
Aug 24, 2018, 4:53 PM HST
In force
71 hr
Issued by
NWS Honolulu, HI

Counties Hawaii County, HI, Honolulu County, HI, Kalawao County, HI, Kauai County, HI

The radar

The Molokai radar (PHMO), 38 km from the middle of the area, began a volume at 02:08 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

Hilo, (PITO), launched 00:00Z, 2.1 hours before the alert went out and 304 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, Hilo, at 00:00Z on 2018-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 107 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, Hilo, at 00:00Z on 2018-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -2 square meters per square second.1939Sfc1 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
107 J/kg
Mixed-layer CIN
-60 J/kg
Mixed-layer LCL
984 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
-2 m²/s²
0-3 km storm-relative helicity
46 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 high surf 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 high surf warning went out at Aug 21, 10:04 AM HST, 6 hours 4 minutes earlier.

Area forecast discussion, Aug 21, 10:04 AM HST, 6 hours 4 minutes before
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The office that day

Everything else NWS Honolulu, HI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 21, 4:08 PM HSTHigh Surf AdvisoryHFOHonolulu, Kauai, Kalawao38 hr
Aug 21, 5:11 PM HSTHurricane WarningHFOHawaii, Honolulu, Kalawao72 hr
Aug 21, 5:34 PM HSTTropical Storm WarningHFOHawaii, Honolulu, Kalawao4 days
Aug 22, 1:22 PM HSTAreal Flood AdvisoryHFOHawaii3 hr

Nearby

High Surf Warnings in Hawaii, 2018Every high surf warning in 2018

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.