Archive replay · live forecasts → CPHC
The two words are a schedule, not a severity scale. A watch says hurricane conditions are possible in your area; a warning says they are expected. The watch arrives about 48 hours before tropical-storm-force winds are anticipated, the warning about 36 — and that clock deliberately counts down to the first dangerous winds, not to the eye, because outdoor preparation has to be finished before the wind arrives, not before the centre does.
Tropical storm watches and warnings run on the same 48- and 36-hour schedule, for sustained winds of 39–73 mph. The definitions are the National Weather Service's, published here.
A warning does not rely on you watching the news. Hawaiʻi's statewide outdoor siren system sounds a steady attention tone — if you hear it outside the scheduled test on the first business day of each month, tune to local radio or TV for official instructions. Wireless Emergency Alerts push the same warnings to phones, and NOAA Weather Radio carries the Central Pacific Hurricane Center's advisories continuously. The centre issues a full advisory every six hours and intermediate ones every three once watches are up.
A 36-hour forecast today misses the storm's eventual position by less than half of what it did in the 1988–1999 era — a two-thirds radius of 48 nautical miles now against 117 then, measured from every forecast in this archive. When a warning covers your island, it is drawn on the best forecast track there has ever been. It is still a forecast: Iniki in 1992 was expected to pass south until roughly a day before it turned north into Kauai. The system has improved most exactly where that hurt — treat a watch as the moment to act, not as a maybe.
Watches, warnings and evacuation orders come only from the Central Pacific Hurricane Center and your county. This page explains the system; it is not part of it.
Watch and warning definitions: National Weather Service. Alerting and sirens: Hawaiʻi Emergency Management Agency. Forecast accuracy: measured from this archive. Checked against the official pages on 14 August 2026.