1 heavy rain, as filed by the National Weather Service.
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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 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 May 11, 10:00 AM HST, 1 hour 50 minutes earlier.
HAWAIIAN ISLANDS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 1000 AM HST TUE MAY 11 2004 .SYNOPSIS...AFTER RETURNING TODAY...TRADE WINDS WILL DIMINISH AGAIN BY FRIDAY AS A LOW FORMS NEAR KAUAI. THE COMING WEEKEND WILL BE A WET ONE FOR KAUAI AND OAHU AS AN ASSOCIATED SHEARLINE SETTLES OVER THE WESTERN ISLANDS. TRADES WILL BEGIN TO RETURN NEXT WEEK. && .DISCUSSION...PRESSURE RISES OVER THE PAST 24 HOURS INDICATE A RIDGE IS SLOWLY BUILDING BETWEEN THE ISLANDS AND A LOW 900 MILES TO THE NORTH. THIS TREND...ALONG WITH MODEL DATA...SHOWS THAT MODERATE TRADES WILL RETURN TODAY. THE WET REMNANTS OF AN OLD SHEARLINE REMAIN IN OUR AREA...MAINLY OVER THE WESTERN ISLANDS. INSTABILITY ASSOCIATED WITH A NEARBY UPPER TROUGH TRIGGERED ISOLATED THUNDERSTORMS OVER KAU DISTRICT OF THE BIG ISLAND...WEST MAUI...AND OVER HAWAIIAN WATERS JUST EAST OF OAHU OVERNIGHT. THE ACTIVITY EAST OF OAHU PERSISTS AT THIS HOUR. AS WE TRANSITION FROM A CONVECTIVE PATTERN TO A TRADE WIND PATTERN...WE WILL SEE CLOUDS AND SHOWERS INCREASINGLY FAVOR WINDWARD AREAS. OVER THE NEXT THREE DAYS...THE LOW NORTH OF US WILL MOVE NORTH BEYOND 40N...GIVING THE RIDGE TEMPORARY UNFETTERED SWAY OVER OUR WEATHER. THE ABUNDANCE OF MOISTURE UPWIND WILL BE SUFFICIENT TO FUEL AT LEAST SCATTERED SHOWERS OVER WINDWARD AREAS. CONTINUED TROUGHING ALOFT WILL INDUCE THE FORMATION OF A SURFACE LOW VERY NEAR KAUAI ON FRIDAY. WHILE THIS LOW IS EXPECTED TO MOVE NORTH QUICKLY OVER THE COMING WEEKEND...A SURFACE TROUGH TRAILING SOUTH OF THE LOW WILL PASS OVER THE WESTERN ISLANDS AND TEMPORARILY STALL. THE 12Z GFS IS RATHER GENEROUS WITH RAINFALL EXPECTED OVER KAUAI AND OAHU LATE FRIDAY THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. GFS SHOWS THE TROUGH WILL BEGIN TO MOVE SLOWLY SOUTHEAST AGAIN SUNDAY...REACHING MAUI BEFORE WASHING OUT SOMETIME NEXT WEEK. WINDS WILL DROP OFF QUICKLY AFTER THE LOW FORMS...REMAINING LIGHT UNTIL MODERATE NORTHEAST TRADES BEGIN TO RETURN NEXT MONDAY TO KAUAI. && .WATCHES/WARNINGS/ADVISORIES...NONE. POWELL
The national radar mosaic for the moment the first event began.
1 heavy rain. Local standard time, as filed.
Heavy showers and steady rain produced small stream and drainage ditch flooding and ponding of raodways in windward and central parts of the island of Oahu. This included communities from Kahuku to Mililani to Waimanalo. No serious property damage or injuries were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Hawaii in 2004Every state in 2004This day in weather historyWarnings in Hawaii, May 2004
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: 5431468.