Heavy Rain, Honolulu
- When
- September 19, 6:24 AM HST to 8:52 AM HST
- Where
- Honolulu County, 1.88 mi SSE of Kahuku to 0.73 mi ESE of Kaaawa
- Reported by
- Official NWS Observations
- Coordinates
- 21.654, -157.942
Heavy Rain in Hawaii, September 19, 2012
Another upper low in September, moving from the northwest, produced heavy rain over parts of East Oahu. There was ponding on roadways, and minor drainage ditch and small stream flooding.
Where it happened
Every event with a place to put it. 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
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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.
Another upper low in September, moving from the northwest, produced heavy rain over parts of East Oahu. There was ponding on roadways, and minor drainage ditch and small stream flooding. No significant injuries or property damage were reported.
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 Sep 19, 4:00 AM HST, 2 hours 24 minutes earlier.
Area forecast discussion, Sep 19, 4:00 AM HST, 2 hours 24 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 400 AM HST WED SEP 19 2012 .SYNOPSIS... LIGHT TRADE WINDS WILL ALLOW DAYTIME SEA BREEZES AND NIGHTTIME LAND BREEZES TO FORM TODAY THROUGH FRIDAY. THE TRADES WILL BRING SHOWERS TO WINDWARD AREAS...WHILE THE SEA BREEZES WILL BRING AFTERNOON SHOWERS TO LEEWARD AREAS. SOME OF THE SHOWERS WILL BE BRIEFLY HEAVY. HIGH PRESSURE WILL BUILD NORTH OF HERE...BRINGING STRONGER TRADE WINDS TO THE ISLANDS THIS WEEKEND. THE TRADES MAY BE WET ON SUNDAY. && .DISCUSSION... GUIDANCE SHOWS SEVERAL FRONTS MOVING EAST AND SOUTHEAST ACROSS THE NORTH PACIFIC THE NEXT FEW DAYS. THE FRONTS WILL ERODE THE SURFACE RIDGE JUST NORTH OF THE ISLANDS...KEEPING THE TRADES LIGHT THROUGH FRIDAY. THE LIGHT TRADES WILL ALLOW LAND AND SEA BREEZES TO FORM. THE SEA BREEZES WILL BRING SOME CLOUDS AND SHOWERS TO INTERIOR AND LEEWARD SECTIONS IN THE AFTERNOON...WHILE THE LAND BREEZES WILL FLUSH OUT A GOOD DEAL OF THE MOISTURE AT NIGHT. THE LIGHT TRADES WILL CONTINUE TO CARRY SHOWERS ACROSS WINDWARD AREAS. SOME SHOWERS WILL BE HEAVY...DUE TO A SLIGHTLY UNSTABLE ATMOSPHERE AND A WEAK AND HIGH SUBSIDENCE CAP ASSOCIATED WITH A MID-LEVEL TROUGH OVERHEAD. SATELLITE IMAGERY SHOWS A LARGE AREA OF WESTWARD MOVING MOISTURE EXTENDING FROM THE BIG ISLAND EASTWARD SOME 600 MILES. MODELS INDICATE THAT MOST OF THE MOISTURE WILL SLIDE NORTH OF THE ISLANDS TODAY AND THURSDAY. SOME OF THE WET STUFF MAY PASS OVER THE ISLANDS HOWEVER...POSSIBLY BOOSTING SHOWER ACTIVITY. WIDESPREAD HEAVY RAIN IS HIGHLY UNLIKELY...BUT LOCAL DOWNPOURS ARE CERTAINLY POSSIBLE. A SURFACE HIGH WILL FORM FAR NORTHWEST OF HAWAII FRIDAY...THEN STRENGTHEN AND MOVE TO THE EAST. THE RETURN OF MODERATE TRADES WILL SHUT DOWN THE LAND AND SEA BREEZES THIS WEEKEND THROUGH EARLY NEXT WEEK. THE ATMOSPHERE SHOULD BE DRYER SATURDAY...BUT A SECOND SLUG OF TROPICAL MOISTURE MAY MOVE IN FROM THE EAST ON SUNDAY. && .AVIATION... VFR CONDITIONS WILL PREVAIL ACROSS THE STATE...EXCEPT FOR MVFR CEILINGS AND VISIBILITIES ACCOMPANYING SHOWERS. SOME VISIBILITIES MAY DROP BELOW THREE MILES IN ISOLATED HEAVY SHOWERS...MAINLY IN THE AFTERNOON. && .MARINE... WINDS AND SEAS WILL REMAIN BELOW ADVISORY THRESHOLDS THROUGH SATURDAY AFTERNOON. THE TRADE WINDS WILL LIKELY STRENGTHEN TO 25 KT IN THE WINDY AREAS AROUND THE BIG ISLAND AND MAUI BY SATURDAY NIGHT. SOUTH SOUTHWEST SWELLS WILL PRODUCE MODERATE SURF ALONG SOUTH FACING SHORES THROUGH TODAY...WITH SMALL SURF EXPECTED THE REST OF THIS WEEK. A LOW DEEPENING FAR NORTH NORTHWEST OF THE ISLANDS TODAY WILL SEND A NORTHWEST SWELL IN OUR DIRECTION. THE SWELL COULD BOOST SURF TO ADVISORY LEVELS ALONG NORTH AND WEST FACING SHORES THIS WEEKEND. && .HFO WATCHES/WARNINGS/ADVISORIES... NONE. && CRAIG
The radar
The national radar mosaic for the moment the first event began.
Event by event
1 heavy rain. Local standard time, as filed.
What these are
- Heavy Rain
- Rainfall totals unusual for the place and season that did not produce a flood.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Hail and Damaging Winds in Wisconsin, September 19, 2012
- Flooding in New Hampshire, September 19, 2012
- Strong Wind in Wisconsin, September 19, 2012
- Marine Thunderstorm Winds in Lake Michigan, September 19, 2012
- Waterspout in Lake Ontario, September 19, 2012
- Marine Thunderstorm Wind in South Atlantic Coastal Waters, September 19, 2012
- Damaging Wind in Florida, September 19, 2012
More
Every storm in Hawaii in 2012Every state in 2012This day in weather historyWarnings in Hawaii, September 2012
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: 407362.