High Surf in Hawaii, August 29 to 31, 2011

Name: High Surf in Hawaii, August 29 to 31, 2011
Start: 2011-08-29T09:00
End: 2011-08-31T23:59
Location: Hawaii

August 29 to 31, 2011 · NWS HFO · 16 events in 16 counties and zones

A swell from the southern hemisphere produced surf of 6 to 12 feet along the south-facing shores of all the islands. Lifeguards were busy with issuing warnings to swimmers and surfers, and performing rescues, as this unusually high surf affected the south shores.

Where it happened

Every event with a place to put it; 6 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: 16

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 Aug 29, 5:35 AM HST, 3 hours 25 minutes earlier.

Area forecast discussion, Aug 29, 5:35 AM HST, 3 hours 25 minutes before

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HONOLULU HI
535 AM HST MON AUG 29 2011

.UPDATE...
ISSUED A HIGH SURF ADVISORY FOR SOUTH FACING SHORES OF ALL HAWAIIAN
ISLANDS STARTING AT NOON HST FOR RISING SURF. UPDATED MARINE SECTION
BELOW.

&&

.SYNOPSIS...
SURFACE HIGH PRESSURE FAR NORTH OF THE ISLANDS WILL MAINTAIN
MODERATE TRADE WIND SPEEDS THROUGH FRIDAY...WITH LIGHTER WINDS
POSSIBLE NEXT WEEKEND. TRADE SHOWERS WILL FAVOR WINDWARD AND MAUKA
AREAS. AN UPPER LEVEL LOW PASSING JUST NORTH OF THE ALOHA STATE MAY
ENHANCE SHOWERS...WITH LOCALLY HEAVY RAINFALL POSSIBLE FROM TONIGHT
THROUGH TUESDAY NIGHT. EXPECT SLIGHTLY DRIER TRADE WIND WEATHER
DURING THE SECOND HALF OF THE WEEK.

&&

.DISCUSSION...
THE PRESSURE GRADIENT SOUTH OF A NEARLY EAST TO WEST ORIENTED
SUBTROPICAL RIDGE LOCATED ABOUT 850 MILES NORTH OF HONOLULU IS
MAINTAINING MODERATE TRADE WIND SPEEDS ACROSS THE STATE EARLY THIS
MORNING. PRESSURE TENDENCIES OVER THE PAST 24 HOURS AT OBSERVING
STATIONS ACROSS THE ALOHA STATE ARE DOWN ABOUT ONE-HALF MILLIBAR.
HOWEVER...WE EXPECT LITTLE CHANGE IN WIND SPEEDS THIS WEEK...WITH
MODERATE TRADE WINDS TO PREVAIL...AT LEAST THROUGH FRIDAY.

A TYPICAL TRADE WIND WEATHER PATTERN OF WINDWARD AND MAUKA SHOWERS
CONTINUES. MID-LEVEL RIDGING IS MAINTAINING A SUBSIDENCE INVERSION
NEAR 7 TO 8 THOUSAND FEET ACCORDING TO THE EARLY MORNING BALLOON
SOUNDINGS FROM HILO AND LIHUE. PRECIPITABLE WATER VALUES IN THESE
SOUNDINGS RANGED FROM 1.3 TO 1.4 INCHES. SINCE THERE IS CURRENTLY A
LACK OF ORGANIZED FEATURES IN THE CLOUDS UPSTREAM OF THE ISLANDS...
WE EXPECT THE AREAL COVERAGE OF LOW CLOUDS AND SHOWERS TO REMAIN
SIMILAR TO THE DISTRIBUTIONS WE HAVE BEEN SEEING RECENTLY. SOME
LEEWARD AREAS OF THE SMALLER ISLANDS MAY EXPERIENCE BRIEF PASSING
SHOWERS EARLY THIS MORNING...WITH MOST LINGERING LEEWARD SHOWERS
LIKELY TAPERING OFF A FEW HOURS AFTER SUNRISE.

ALOFT...AN UPPER TROPOSPHERIC LOW IS CENTERED NEAR 26.5N 154W...OR
ABOUT 480 MILES NORTH NORTHEAST OF HILO. THIS FEATURE...WHICH IS
MOVING SOUTH SOUTHWESTWARD AT NEARLY 20 MPH...WILL PASS JUST NORTH
OF THE ISLANDS TONIGHT AND TUESDAY. ONCE THIS FEATURE IS CLOSE
ENOUGH...THERE IS A POSSIBILITY OF ENHANCED TRADE SHOWER COVERAGE
AND INTENSITY STARTING TONIGHT AND CONTINUING INTO TUESDAY NIGHT.
THE GREATEST INSTABILITY AND COLDEST TEMPERATURES ALOFT ASSOCIATED
WITH THE UPPER LEVEL LOW ARE EXPECTED TO REMAIN JUST NORTH OF THE
ISLANDS. HOWEVER...LOWER TROPOSPHERIC RIDGING WILL PERSIST...WHILE
THE MODELS DO NOT APPEAR TO BRING IN ANY SIGNIFICANT MOISTURE
SOURCES. BASED ON ALL OF THIS EVIDENCE...IT IS ASSUMED THERE WILL BE
A WEAKENED SUBSIDENCE INVERSION OVER THE STATE WITH A MODEST
INCREASE IN SHOWER COVERAGE AS SOME SHOWERS MAY BE CARRIED OVER TO
LEEWARD SECTIONS OF THE SMALLER ISLANDS. THERE IS A POSSIBILITY
SHOWERS COULD BE BRIEFLY HEAVY...SO THE MENTION OF LOCALLY HEAVY
SHOWERS REMAINS IN THE LATEST FORECAST. A SLIGHT CHANCE OF
THUNDERSTORMS REMAINS IN THE FORECAST FOR PORTIONS OF THE COASTAL
AND OFFSHORE WATERS IMMEDIATELY NORTH OF KAUAI AND OAHU.

ONCE THE UPPER LEVEL LOW MOVES TO THE NORTHWEST AWAY FROM THE MAIN
HAWAIIAN ISLANDS...RIDGING ALOFT WILL GRADUALLY REBUILD FROM EAST TO
WEST OVER THE ISLANDS BY MID-WEEK. THEREFORE...EXPECT STABLE
ATMOSPHERIC CONDITIONS TO RETURN STARTING WEDNESDAY. FORECAST MODELS
ALSO SUGGEST SLIGHTLY DRIER CONDITIONS WITH BELOW NORMAL
PRECIPITATION EXPECTED.

BASED ON THE LATEST FORECAST MODEL OUTPUT...HIGH PRESSURE CENTERED
FAR NORTHEAST OF THE STATE WILL BE SLOWLY DRIFTING SOUTHEASTWARD AND
WEAKENING BY THIS WEEKEND. AS A RESULT...TRADE WIND SPEEDS MAY
BECOME LIGHTER HEADING INTO THE WEEKEND.

&&

.AVIATION...
PERIODS OF MVFR CONDITIONS DUE TO LOW CEILINGS AND REDUCED
VISIBILITIES IN SHOWERS ARE EXPECTED OVER WINDWARD AREAS...
INCLUDING THE PHTO VICINITY...THIS MORNING. VFR CONDITIONS WILL
CONTINUE TO PREVAIL OVER NEARLY ALL LEEWARD AREAS OF THE STATE.

&&

.MARINE...
NO SMALL CRAFT ADVISORIES...SCA...ARE POSTED OVER ANY HAWAIIAN
WATERS. HOWEVER...TRADE WIND SPEEDS ACROSS THE TYPICALLY WINDY
WATERS AND CHANNELS ADJACENT TO THE ISLANDS OF MAUI COUNTY AND THE
BIG ISLAND WILL LIKELY REMAIN JUST BELOW THE SCA CRITERIA THROUGH
TONIGHT. A SLIGHT DECREASE IN TRADE WIND SPEEDS IS POSSIBLE TUESDAY
AND WEDNESDAY DUE TO THE PRESENCE OF THE UPPER LEVEL LOW TO THE
NORTH OF THE ISLANDS. OTHERWISE...NO SIGNIFICANT CHANGES ARE
ANTICIPATED THROUGH THE REMAINDER OF THE WORK WEEK.

SOUTHERN HEMISPHERE SWELL SOURCES WILL PRODUCE A NOTICEABLE BOOST IN
SURF HEIGHTS ALONG SOUTH FACING SHORES OF THE STATE THIS WEEK. SURF
FROM A BUILDING SOUTH SWELL WILL REACH THE HIGH SURF ADVISORY
THRESHOLD OF 8 FEET AFTER NOON HST TODAY. A LARGER...LONG-PERIOD
REINFORCING SOUTH SWELL IS EXPECTED TO INCREASE SURF HEIGHTS ALONG
SOUTH FACING SHORES OF THE STATE WELL ABOVE THE HIGH SURF ADVISORY
CRITERIA FROM LATER TONIGHT THROUGH WEDNESDAY. THIS SOUTH SWELL WILL
GRADUALLY SUBSIDE THURSDAY AND FRIDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY STARTING AT NOON HST FOR RISING SURF ALONG SOUTH
FACING SHORES OF ALL HAWAIIAN ISLANDS.

&&

HOUSTON

The radar

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

Open the radar archive at this moment

Event by event

16 high surf. Local standard time, as filed.

High Surf, Niihau

When: August 29, 9:00 AM HST to August 31, 11:59 PM 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: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Kauai Windward forecast zone
Reported by: Trained Spotter

High Surf, Kauai Leeward

When: August 29, 9:00 AM HST to August 31, 11:59 PM 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, Oahu South Shore

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Oahu South Shore forecast zone
Reported by: Trained Spotter

High Surf, Waianae Coast

When: August 29, 9:00 AM HST to August 31, 11:59 PM 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, Molokai Windward

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Molokai Windward forecast zone
Reported by: Trained Spotter

High Surf, Molokai Leeward

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Molokai Leeward forecast zone
Reported by: Trained Spotter

High Surf, Lanai Makai

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Lanai Makai forecast zone
Reported by: Trained Spotter

High Surf, Kahoolawe

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Kahoolawe forecast zone
Reported by: Trained Spotter
Coordinates: 21.027, -156.788 (the zone’s center; the record gives no point)

High Surf, Maui Leeward West

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Maui Leeward West forecast zone
Reported by: Trained Spotter
Coordinates: 21.027, -156.788 (the zone’s center; the record gives no point)

High Surf, Maui Central Valley

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Maui Central Valley forecast zone
Reported by: Trained Spotter

High Surf, Windward Haleakala

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Windward Haleakala forecast zone
Reported by: Trained Spotter

High Surf, Leeward Haleakala

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Leeward Haleakala forecast zone
Reported by: Trained Spotter

High Surf, Kona

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Kona forecast zone
Reported by: Trained Spotter
Coordinates: 19.602, -155.523 (the zone’s center; the record gives no point)

High Surf, South Big Island

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: South Big Island forecast zone
Reported by: Trained Spotter

High Surf, Big Island North and East

When: August 29, 9:00 AM HST to August 31, 11:59 PM HST
Where: Big Island North and East 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 2011 Every state in 2011 This day in weather history Warnings in Hawaii, August 2011

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: 333184, 333185, 333186, 333187, 333188, 333189, 333190, 333191, 333192, 333193, 333194, 333195, 333196, 333197, 333198, 333199.