A period of light winds with plenty of low-level moisture and transiting upper disturbances produced heavy showers and isolated thunderstorms over much of the Aloha State. There were also flash flood events as time went along.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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.
The episode as NWS HFO wrote it up.
A period of light winds with plenty of low-level moisture and transiting upper disturbances produced heavy showers and isolated thunderstorms over much of the Aloha State. There were also flash flood events as time went along. No serious injuries were reported.
The costs of any damages from the heavy downpours were not available, including damages to a barge, the Wade K, that went aground at the Wailua Marina on Kauai in the early morning hours of the 25th (after the Wailua River had flooded).
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 Mar 21, 10:10 AM HST, 4 hours 24 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 1010 AM HST MON MAR 21 2016 .SYNOPSIS... SOUTHEAST TO SOUTH WINDS WILL BRING INCREASED MOISTURE THROUGH TOMORROW...WITH AFTERNOON SEA BREEZES BRINGING CLOUDS AND SHOWERS TO LEEWARD AND INTERIOR AREAS TODAY. INSTABILITY WILL ALSO INCREASE TONIGHT AND TUESDAY AS DISTURBANCE ALOFT MOVES OVER THE ISLANDS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE LATE TONIGHT ON KAUAI...AND ACROSS THE ENTIRE STATE ON TUESDAY...WITH A SLIGHT CHANCE FOR AFTERNOON AND EVENING THUNDERSTORMS. HIGH MOISTURE AND LIGHT WINDS WILL LINGER OVER THE STATE THROUGH THE REST OF THE WORK WEEK...WITH LOCALIZED HEAVY DOWNPOURS POSSIBLE...MAINLY IN THE AFTERNOONS AND EVENINGS. A DRIER WEATHER PATTERN MAY DEVELOP DURING THE UPCOMING WEEKEND...WITH GENTLE TRADE WINDS POSSIBLY RETURNING. && .DISCUSSION... CURRENTLY...AREAS OF CLOUDS AND SHOWERS ARE MOVING NW OVER WINDWARD WATERS N AND NE OF THE ISLANDS FROM KAUAI TO MOLOKAI...AND OVER WATERS WELL SW OF KAUAI COUNTY AND NIIHAU. OTHERWISE SMALLER PATCHES OF SHOWERY LOW CLOUDS ARE MOVING NW OVER THE CENTRAL PART OF THE ISLAND CHAIN...WITH SOME OF THIS MOISTURE APPROACHING OAHU. SURFACE ANALYSIS DEPICTS HIGH PRESSURE FAR NE OF THE STATE...AN ASSOCIATED RIDGE ABOUT 200 MILES N OF KAUAI...AND A COLD FRONT ABOUT 750 MILES NW OF KAUAI. SCATTERED THUNDERSTORMS ARE CURRENTLY ACTIVE ALONG AND AHEAD OF THIS FRONT N OF 22N. WATER VAPOR IMAGERY SHOWS A LARGE MID/UPPER LEVEL TROUGH ALONG 175W THAT IS ADVANCING E AND PROVIDING SUPPORT FOR THE SURFACE FRONT. THE EXPECTATION FOR TODAY IS THAT AFTERNOON SEA BREEZES WILL LEAD TO INCREASED CLOUDS AND A FEW SHOWERS OVER THE ISLANDS...ESPECIALLY OVER LEEWARD AND INTERIOR AREAS. THESE ARE EXPECTED TO CONTINUE INTO THE EVENING HOURS...WITH GENERAL CLEARING THEREAFTER AS LIGHT LARGE- SCALE WINDS ALLOW SEA BREEZES TO CLEAR SKIES OVER LAND. THE EXCEPTION MAY OCCUR ON KAUAI COUNTY WHERE LIGHT S FLOW MAY ADVECT MOISTURE OVER LAND FROM THE S AND SW. THE APPROACHING TROUGH ALOFT MAY HELP TO TRIGGER HEAVIER SHOWERS FROM THIS MOISTURE FIELD...AND THE CURRENT FORECAST ALLUDES TO HEAVY SHOWER POTENTIAL OVER KAUAI LATE TONIGHT. THE SURFACE RIDGE WILL REMAIN OVER THE ISLANDS FOR MOST OF THE UPCOMING WEEK...KEEPING LARGE SCALE WINDS LIGHT BUT FROM A SOUTHERLY DIRECTION. THIS WILL KEEP A MOIST AIR MASS IN PLACE OVER THE ISLANDS...BUT A LARGE SCALE TRIGGER TO ACTIVATE THIS MOISTURE APPEARS TO BE ABSENT IN MOST RECENT MODEL RUNS...WITH SOME CAVEATS. THE MID- AND UPPER-LEVEL TROUGH SEEN APPROACHING FROM THE W MAY PROVIDE SUFFICIENT LIFT TO TRIGGER AVAILABLE MOISTURE FROM LATE TONIGHT THROUGH TUESDAY...WITH THE GREATEST IMPACT FROM THIS TROUGH BEING FELT ON KAUAI AND OAHU...WHERE MID-LEVEL TEMPERATURES WILL COOL THE MOST. ANOTHER TROUGH PASSING AROUND FRIDAY MAY HAVE THE SAME EFFECT. OTHERWISE...THE LIGHT WINDS WILL ALLOW SEA BREEZES TO DEVELOP OVER THE ISLANDS EACH AFTERNOON...WHICH WOULD POTENTIALLY TRIGGER THE DEVELOPMENT OF SPOTTY HEAVY SHOWERS OVER INTERIOR AND LEEWARD AREAS. THESE SAME LIGHT WINDS WOULD THEN ALLOW SKIES TO CLEAR OVER THE ISLANDS EACH NIGHT AND MORNING. SHOWERS SHOULD INCREASE ACROSS WESTERN PORTIONS OF THE STATE TONIGHT AS MOISTURE/INSTABILITY CONTINUES TO INCREASE...THEN EXPECT SOMEWHAT ACTIVE WEATHER CONDITIONS ACROSS THE ENTIRE STATE ON TUESDAY AS A SHORTWAVE TROUGH APPROACHES AND MID LEVEL TEMPS DROP TO AROUND -12C. LOCALLY HEAVY RAINFALL IS MENTIONED IN THE FORECAST BEGINNING ON TUESDAY...WITH A SLIGHT CHANCE OF THUNDERSTORMS FOR TUESDAY AFTERNOON/EVENING AS WELL. MOISTURE MAY BE DEEP ENOUGH AND TEMPERATURES COLD ENOUGH FOR SOME SNOW SHOWERS AT TIMES FROM TUESDAY THROUGH FRIDAY ON THE HIGHEST ELEVATIONS OF THE BIG ISLAND SUMMITS. IT IS UNCLEAR AT THIS TIME IF ANY SIGNIFICANT SNOW ACCUMULATION WILL OCCUR. BY THE END OF THE WORK WEEK INTO THE WEEKEND...MODELS SHIFT THE UPPER LEVEL LONGWAVE TROUGH AND DEEP MOISTURE TO THE EAST OF THE STATE...ALTHOUGH THE GFS KEEPS THE UPPER TROUGH CLOSER TO THE ISLANDS THAN DOES THE ECMWF. HIGH PRESSURE TO OUR NORTH MAY ALLOW GENTLE TRADES TO RESUME BY THAT TIME. && .AVIATION... CONDITIONS OVER THE ISLANDS HAVE IMPROVED THIS MORNING AND ALL AIRMETS FOR MTN OBSC HAVE BEEN DROPPED AS OF 20Z. THE BACKGROUND SE FLOW WILL ALLOW SEA BREEZES TO DEVELOP AND PROMOTE INTERIOR CLOUDS AND SHOWERS THIS AFTERNOON. ENHANCED MOISTURE EMBEDDED IN THE FLOW WILL CONTINUE TO BE PULLED OVER THE ISLANDS AND SOME SHOWERS THIS AFTERNOON COULD BE HEAVY AT TIMES CARRYING REDUCED CIGS/VIS. IF NECESSARY...AIRMET SIERRA FOR MTN OBSC MAY NEED TO BE RE-ISSUED. A COLD FRONT A SEVERAL HUNDRED MILES NW OF KAUAI WILL CONTINUE TO APPROACH THE ISLANDS...AND CLOUDS AND SHOWER COVERAGE TONIGHT IS EXPECTED TO INCREASE FURTHER. && .MARINE... A HIGH SURF ADVISORY REMAINS IN EFFECT FOR EXPOSED N AND W FACING SHORES UNTIL NOON TODAY. THE ONGOING N AND NW SWELLS ARE DECLINING... WITH THE WAIMEA BAY CDIP BUOY RECENTLY REPORTING COMBINED SEAS OF 7-8 FEET WITH A PERIOD OF 14 SECONDS...WHILE THE HILO BUOY IS REPORTING SLIGHTER HIGHER SEAS AND PERIODS. UPSTREAM OF THE ISLANDS...SWELL HEIGHTS AT BUOYS 51001/51101 NW OF KAUAI HAVE DROPPED DRAMATICALLY OVER THE PAST SEVERAL HOURS...AND RESULTANT SURF ALONG EXPOSED N AND W FACING SHORES SHOULD FALL BELOW ADVISORY LEVELS BY THIS AFTERNOON. SWELLS AND SURF WILL CONTINUE TO DIMINISH THROUGH WEDNESDAY...AT WHICH TIME SURF ALONG N AND W FACING SHORES WILL BE THE SMALLEST IT HAS BEEN IN AWHILE. ALTHOUGH A SMALL NNW SWELL IS POSSIBLE THURSDAY AND FRIDAY...SURF WILL REMAIN RATHER SMALL INTO NEXT WEEKEND...WHEN A SLIGHTLY LARGER NW SWELL IS POSSIBLE. NO OTHER SIGNIFICANT SWELLS ARE EXPECTED. A SMALL CRAFT ADVISORY /SCA/ IS IN EFFECT FOR SELECT WATERS AROUND MAUI COUNTY AND THE BIG ISLAND...DUE TO A COMBINATION OF FRESH E/SE WINDS AND LINGERING SEAS. SCA LEVEL WINDS MAY CONTINUE AROUND PARTS OF THE BIG ISLAND TONIGHT...BUT BY TUESDAY WE EXPECT WINDS AND SEAS TO BE BELOW SCA CRITERIA ACROSS ALL WATERS AS A SURFACE RIDGE MOVES OVER THE ISLANDS. WINDS/SEAS ARE THEN FORECAST TO REMAIN BELOW SCA LEVELS THROUGH THE REST OF THIS WEEK. && .HFO WATCHES/WARNINGS/ADVISORIES... HIGH SURF ADVISORY UNTIL NOON HST TODAY FOR NORTH AND WEST FACING SHORES OF NIIHAU KAUAI AND MOLOKAI AND FOR NORTH FACING SHORES OF OAHU MAUI AND THE BIG ISLAND. SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR MAUI COUNTY WINDWARD WATERS-ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD WATERS- BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS. && DISCUSSION/MARINE...BIRCHARD AVIATION...EATON
The Molokai radar (PHMO), 61 km away, was scanning. The volume nearest the first event began at 00:35 UTC.
11 heavy rain, 8 flash flood, 1 wildfire, 1 thunderstorm wind. Local standard time, as filed.
More than a dozen hikers were stranded for a time because of high water levels in the Makamakaole Gulch.
A lightning strike started a wildfire that consumed nearly 1800 acres of mainly brush around Puuanahulu along Highway 190 in North Kona on the lee side of the Big Island. Most of the fire was extinguished or contained by 1500 HST on the 24th. There were no reports of serious injuries or property damage.
Kuhio Highway closed near the Hanalei Bridge due to water over the roadway from an overflowing Hanalei River.
An overflowing Wailua River along Kuamoo Road in Wailua forced tourists to evacuate their vehicle due to water covering the roadway.
Water from heavy rain was reported to be entering the Waimea Theater building.
A greenhouse roof was blown off its structure, a fixed goat shelter was blown into another pasture, and a storage shed was was severely damaged, according to a report from KHON-2 news.
Highway 19 on the Big Island of Hawaii was closed between mile markers 9 and 10 due to high water, with levels reported to be as deep as five feet. Several vehicles became stranded.
Maui Civil Defense reported a swift water rescue of a family of eight in Halawa Valley at the east end of Molokai. Another party of 12 was also located and helped to leave the area. The groups had been trapped by high water rising in a stream and waited for the water to subside before exiting the valley. When firefighters arrived on the scene, everyone had already successfully crossed the stream.
A hiker requested a rescue at the Bamboo Forest near Huelo on Maui because of flash flooding conditions.
Civil defense reported flooding on Highway 190 between mile markers 6 and 8, with barricades being placed around the flood waters.
Civil defense reported flooding on Highway 270 at mile marker 12 in the leeward part of the Big Island.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Hawaii in 2016Every state in 2016This day in weather historyWarnings in Hawaii, March 2016
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: 618294, 618295, 618296, 618297, 618298, 618299, 618484, 618300, 618301, 618302, 618303, 619011, 619012, 618304, 618482, 618477, 618480, 618305, 618481, 618478, 618479.