High Surf in Hawaii, April 22 to 23, 2010

Name: High Surf in Hawaii, April 22 to 23, 2010
Start: 2010-04-22T06:00
End: 2010-04-23T03:00
Location: Hawaii

April 22 to 23, 2010 · NWS HFO · 10 events in 10 counties and zones

A swell from a strong low far northwest of the Aloha State generated surf of 10 to 15 feet along the north- and west-facing shores of Niihau, Kauai, Oahu, and Molokai; and the north-facing shores of Maui. No serious injuries or property damage were reported.

Where it happened

Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 10

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS HFO wrote it up.

What forecasters said that day

The local office's own words before the first event, 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 the first event at Apr 22, 4:00 AM HST, 2 hours earlier.

Area forecast discussion, Apr 22, 4:00 AM HST, 2 hours before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST THU APR 22 2010

.SYNOPSIS...
HIGH PRESSURE FAR TO THE NORTH WILL CONTINUE TO BRING BREEZY TRADES
THROUGH FRIDAY. WINDS WILL BECOME LIGHT TO MODERATE THIS
WEEKEND...AND THEN STRENGTHEN A BIT EARLY NEXT WEEK. SHOWERS WILL
FOCUS OVER WINDWARD AND MOUNTAIN AREAS...WITH SOME SHOWERS BEING
BLOWN TO LEEWARD AREAS.

&&

.DISCUSSION...
HIGH PRESSURE IS CURRENTLY ABOUT 700 MILES NORTH OF THE STATE...AND
CONTINUES TO BRING BREEZY TRADES. INFRARED SATELLITE IMAGERY SHOWS
SCATTERED LOW CLOUDS OVER THE ISLANDS...BRINGING SOME LIGHT SHOWERS
ALONG THE EASTERLY TRADE FLOW. THE 12Z SOUNDINGS AT LIHUE AND HILO
SHOW SLIGHTLY DRIER AIR...WITH PRECIPITABLE WATER VALUES AT 1.13 AND
1.05 INCHES RESPECTIVELY. THE SOUNDINGS ALSO SHOW WEAK INVERSIONS AT
AROUND 5000 FT...ALTHOUGH THE 00Z SOUNDINGS SHOWED HIGHER INVERSION
HEIGHTS. THE CAPPING INVERSION IS WEAK BECAUSE OF SOME UPPER LEVEL
TROUGHING OVER THE STATE OF WHICH SHOULD STRENGTHEN TODAY AND
FRIDAY. WITH THIS INSTABILITY...ISLAND WEATHER WILL CONTINUE TO BE
ON THE WET SIDE TODAY AND EARLY FRIDAY...BUT WITH LIGHT
ACCUMULATIONS AND SHOWERS MAINLY FOCUSING OVER WINDWARD AND MOUNTAIN
SLOPES. ALSO...EXPECT SOME SHOWERS TO CROSS INTO LEEWARD SECTIONS
DUE TO BREEZY TRADES. THE TROUGH MAY LIFT THE INVERSION ABOVE THE
BIG ISLAND SUMMITS TODAY...SO SOME SHOWERS ARE POSSIBLE IN THAT
AREA. IF TEMPERATURES GET LOW ENOUGH...SOME FREEZING PRECIPITATION
IS POSSIBLE AT THOSE ELEVATIONS AS WELL.

THE LOW LEVEL INVERSION WILL START TO STRENGTHEN AGAIN THIS WEEKEND
AS UPPER LEVEL RIDGING MOVES IN FROM THE WEST. THE 00Z GFS RUN
SUGGESTS THAT A FRONT OR SHEAR LINE MAY BRING SOME MORE MOISTURE TO
THE ISLANDS ON MONDAY AND THEN LINGERING AROUND THROUGH THE WEEK.
THIS COULD MAKE ISLAND WEATHER RELATIVELY WET IF THIS SOLUTION
VERIFIES. HOWEVER...THE 06Z RUN BACKS OFF IN THIS SOMEWHAT.

SUBTROPICAL RIDGING WILL START TO BE FORCED TO THE SOUTH ON FRIDAY
BY A STRONG LOW FAR TO THE NORTH...RESULTING IN WINDS DECREASING A
LITTLE FRIDAY...AND THEN WEAKENING FURTHER LATE THIS WEEKEND. A NEW
HIGH WILL MOVE IN NORTHWEST OF THE STATE BY EARLY MONDAY...WHICH
SHOULD BOOST THE TRADES ONCE AGAIN FOR MONDAY AND TUESDAY. MODELS
SHOW TRADES WEAKENING AGAIN LATE NEXT WEEK AS RIDGING MOVES CLOSE
TO THE ISLANDS.

&&

.MARINE...
A NEW NORTHWEST SWELL IS CURRENTLY BOOSTING SURF ALONG NORTH AND
WEST FACING SHORES. A HIGH SURF ADVISORY IS IN EFFECT UNTIL FRIDAY
MORNING FOR MOST NORTH AND WEST FACING SHORES. A SOUTH SWELL WILL
ARRIVE THIS WEEKEND...WITH SURF HEIGHTS EXPECTED TO REACH ADVISORY
LEVELS.

THE SMALL CRAFT ADVISORY HAS BEEN EXTENDED AND IS NOW IN EFFECT
UNTIL 6 PM TODAY FOR THE TYPICALLY WINDIER COASTAL ZONES...NEAR THE
BIG ISLAND AND MAUI COUNTY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 PM HST TODAY FOR MAALAEA
BAY...PAILOLO CHANNEL...ALENUIHAHA CHANNEL AND WATERS SOUTH OF THE
BIG ISLAND.

HIGH SURF ADVISORY UNTIL 6 AM HST FRIDAY FOR NORTH AND WEST FACING
SHORES NIIHAU...KAUAI...OAHU AND MOLOKAI AND FOR NORTH FACING SHORES
OF MAUI.

&&

HARRISON/BRENCHLEY

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

10 high surf. Local standard time, as filed.

High Surf, Niihau

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Niihau forecast zone
Reported by: Trained Spotter
Coordinates: 22.011, -159.705 (the zone’s center; the record gives no point)

High Surf, Kauai Windward

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Kauai Windward forecast zone
Reported by: Trained Spotter

High Surf, Kauai Leeward

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Kauai Leeward forecast zone
Reported by: Trained Spotter
Coordinates: 22.011, -159.705 (the zone’s center; the record gives no point)

High Surf, Waianae Coast

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Waianae Coast forecast zone
Reported by: Trained Spotter
Coordinates: 21.455, -157.961 (the zone’s center; the record gives no point)

High Surf, Oahu North Shore

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Oahu North Shore forecast zone
Reported by: Trained Spotter
Coordinates: 21.455, -157.961 (the zone’s center; the record gives no point)

High Surf, Oahu Koolau

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Oahu Koolau forecast zone
Reported by: Trained Spotter

High Surf, Molokai Windward

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Molokai Windward forecast zone
Reported by: Trained Spotter

High Surf, Molokai Leeward

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Molokai Leeward forecast zone
Reported by: Trained Spotter

High Surf, Maui Windward West

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Maui Windward West forecast zone
Reported by: Trained Spotter
Coordinates: 21.027, -156.788 (the zone’s center; the record gives no point)

High Surf, Windward Haleakala

When: April 22, 6:00 AM HST to April 23, 3:00 AM HST
Where: Windward Haleakala forecast zone
Reported by: Trained Spotter

What these are

High Surf: Large waves breaking on the shore that caused damage, erosion or casualties.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Hawaii in 2010 Every state in 2010 This day in weather history Warnings in Hawaii, April 2010

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 218666, 218667, 218668, 218669, 218670, 218671, 218672, 218673, 218674, 218675.