A cold front advancing across Kauai induced southeast winds over Oahu. The winds interacted with the Koolau Range and generated heavy downpours on the windward side of the isle.
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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 cold front advancing across Kauai induced southeast winds over Oahu. The winds interacted with the Koolau Range and generated heavy downpours on the windward side of the isle. There were no reports of serious injuries. Any property damage costs were not available.
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 Feb 19, 8:30 PM HST, 3 hours 29 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 830 PM HST SAT FEB 19 2011 .SYNOPSIS... LOW PRESSURE REMAINING FAR TO THE NORTHWEST WILL PRODUCE CLOUDY CONDITIONS THROUGH THE FIRST HALF OF THE WEEK...MUCH OF THE CLOUDINESS WILL BE HIGH LEVEL CLOUDS. DEEPER MOISTURE AND ATMOSPHERIC INSTABILITY WILL AFFECT PRIMARILY KAUAI THROUGH MONDAY NIGHT. AN UPPER LOW FORMS JUST NORTH OF THE CENTRAL ISLANDS BY THE MIDDLE OF THE WEEK. THE PERSISTENT GENTLE SOUTHEASTERLY WINDS MAY THEN BECOME VARIABLE WHILE WEATHER REMAINS UNSETTLED. && .DISCUSSION... THE UPPER LOW TO THE WEST WILL DIRECT ENOUGH UPPER CLOUDS TO COVER ALL THE MAIN HAWAIIAN ISLANDS FOR THE NEXT SEVERAL DAYS. THE DEEPER MOISTURE WILL REMAIN WEST OF MAUI COUNTY...ESPECIALLY NEAR KAUAI WHERE COLDER AIR ALOFT WILL PRODUCE THE MOST INSTABILITY THROUGH MONDAY. THE OLD STATIONARY FRONT THAT HAS BEEN NEAR KAUAI WILL SHIFT FARTHER WEST AND THE UPPER LOW...PRESENTLY 1000 MILES NORTHWEST... WILL ADVANCE EASTWARD...AND BY MONDAY MORNING DEVELOP A NEW SURFACE LOW AND NEW FRONT ABOUT 400 MILES NORTHWEST OF KAUAI. FOR THE PRESENT...WEATHER RADAR INDICATES ISOLATED SHOWERS WEST OF THE BIG ISLAND. A FEW SHOWERS MAY BE HEAVY DUE TO THE MODERATELY UNSTABLE ATMOSPHERE. THE GENTLE SOUTHEASTERLY WIND FLOW WILL CONTINUE FOR THE NEXT FEW DAYS. THE MOST MOISTURE AND INSTABILITY WILL REMAIN NEAR KAUAI HENCE THE THE MOST PRECIPITATION EXPECTED FOR THAT ISLAND. OTHERWISE THE OTHER ISLANDS WILL EXPERIENCE AFTERNOON SEA BREEZES WHICH WILL AID THE BUILD UP OF CLOUDS BUT THE PATTERN WILL BE ONLY WEAKLY CONVECTIVE DUE TO HIGH CLOUDS INHIBITING THE AFTERNOON HEATING OF THE LAND. .PREV DISCUSSION... A TROUGH ALOFT WILL DIG TOWARD THE ISLANDS FROM THE NORTHWEST OVER THE NEXT FEW DAYS. THE DIGGING TROUGH WILL MAKE THE ATMOSPHERE UNSTABLE ENOUGH TO PRODUCE A THREAT OF HEAVY SHOWERS AROUND KAUAI... POSSIBLY AS EARLY AS SUNDAY NIGHT...AND MORE LIKELY ON MONDAY. THE CHANCE OF HEAVY SHOWERS WILL SUBSIDE ON TUESDAY AS LOW LEVEL MOISTURE SHIFTS FARTHER WEST AND THE TROUGH ALOFT LIFTS OUT TO THE NORTHEAST. THE MODELS CONTINUE TO SHOW A LOW ALOFT DEVELOPING NORTH OF THE ISLANDS WEDNESDAY...THEN DIGGING SOUTH TOWARD THE ISLANDS. AS THE LOW APPROACHES...TEMPERATURES ALOFT WILL COOL AND THE ATMOSPHERE WILL BECOME MORE UNSTABLE AGAIN. THIS INSTABILITY COULD PRODUCE MORE HEAVY SHOWERS BY THE END OF NEXT WEEK...HOWEVER THE MODELS DIFFER ON THE DETAILS. && .HFO WATCHES/WARNINGS/ADVISORIES... NONE. HOAG/DONALDSON
The Molokai radar (PHMO), 80 km away, was scanning. The volume nearest the first event began at 09:59 UTC.
1 flash flood. Local standard time, as filed.
Heavy rain forced Waikane Stream over its banks, which then flooded a portion of Kamehameha Highway for a time on the windward side of Oahu.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Hawaii in 2011Every state in 2011This day in weather historyWarnings in Hawaii, February 2011
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: 277090.