Hawaii, 2020

Heavy Rain in Hawaii, December 18 to 19, 2020

December 18 to 19, 2020 · NWS HFO · 2 events in 1 county or zone

An upper air trough over the western part of the state and weak surface trough in the east triggered heavy showers over windward Big Island as moist trade winds swept the area. The precipitation caused ponding on roadways, and small stream and drainage ditch 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

Open the live radar over this ground

The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
2

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.

An upper air trough over the western part of the state and weak surface trough in the east triggered heavy showers over windward Big Island as moist trade winds swept the area. The precipitation caused ponding on roadways, and small stream and drainage ditch flooding. No serious 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 Dec 18, 3:31 AM HST, 12 minutes earlier.

Area forecast discussion, Dec 18, 3:31 AM HST, 12 minutes before
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The radar

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

Open the radar archive at this moment

Event by event

2 heavy rain. Local standard time, as filed.

Heavy Rain, Hawaii

When
December 18, 3:43 AM HST to 9:41 AM HST
Where
Hawaii County, 2.9 mi SW of Papaaloa to 5.79 mi ESE of Volcano
Reported by
Official NWS Observations
Coordinates
19.945, -155.256

Heavy Rain, Hawaii

When
December 18, 6:43 PM HST to December 19, 6:46 AM HST
Where
Hawaii County, 3.58 mi SW of Papaikou to 3.22 mi SW of Pahala
Reported by
Official NWS Observations
Coordinates
19.749, -155.144

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

More

Every storm in Hawaii in 2020Every state in 2020This day in weather historyWarnings in Hawaii, December 2020

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: 926995, 926996.