Active Weather
Hawaii carries the item that matters most in this brief, and it has moved since yesterday. Watches are now posted.
The National Weather Service office in Honolulu has issued a tropical storm watch for Kauai East, Kauai Mountains, Kauai North, Kauai South, Kauai Southwest, and Niihau. A tropical storm watch means tropical storm force winds are possible somewhere in that area within 48 hours. The peak wind forecast in the watch is 30 to 40 mph with gusts to 60 mph, and the window given for tropical storm force winds is Monday afternoon until early Tuesday morning.
The storm information in Honolulu's 5 PM Hawaii time statement places the eye of Hurricane Lowell about 630 miles south-southwest of Lihue and about 640 miles southwest of Honolulu, at 13.7 north and 163.4 west, with maximum sustained winds of 130 mph and movement toward the west-northwest at 5 mph. That is a category 4 hurricane. It was a category 5 with 160 mph winds in yesterday's brief, so the trend over the past day has been weakening, and the forecast calls for gradual further weakening Sunday into Monday.
The forecast track is the part to read carefully. Honolulu expects Lowell to continue turning toward the north or north-northeast overnight into Sunday, then to speed up Sunday night and Monday, with the eye making its closest approach to the main Hawaiian islands Monday night, passing just west of them.
A flood watch is now in effect for all main Hawaiian islands, from Sunday evening through Tuesday afternoon. Honolulu's reasoning is that moisture along the eastern flank of Lowell will bring periods of heavy rain to the islands late Sunday through Tuesday, with the threat highest along windward and mountain areas at first and spreading everywhere as the winds turn more southerly on Monday.
Surf is already elevated and is forecast to climb. A high surf advisory is in effect until 6 AM Hawaii time Tuesday for south and east facing shores of all islands and west facing shores of the Big Island, with surf up to 14 feet on east facing shores and up to 12 feet on south facing shores rising to 14 feet by Sunday night. Honolulu states plainly that the advisory is expected to be upgraded to a warning for south and west facing shores Sunday night into Monday. A separate east swell from Tropical Storm Karina is contributing on the east-facing side.
On the mainland, the San Diego office has a high surf advisory and a coastal flood advisory in effect until 11 PM Pacific Tuesday for the San Diego and Orange county coastlines. The Reno office has a lake wind advisory until 3 PM Pacific for the greater Lake Tahoe area, the greater Reno and Carson City area, Mono, Mineral and southern Lyon counties, and the Lassen, eastern Plumas, and eastern Sierra counties of California.
Arizona and Guam carry no active alerts this morning.
Infrastructure
Two uncontained fires continue burning in southern California. The Plaskett fire stands at 29,768 acres and 23 percent contained, with one structure threatened and evacuations in effect. The Timber fire is at 25,346 acres and 23 percent contained, also with one structure threatened. Those figures come from the National Interagency Fire Center report dated September 5 at 7:30 AM Mountain time and are about a day behind this morning.
In northern California and along the Nevada line, the S 1 Vya fire is at 9,692 acres and 94 percent contained with four structures threatened, and the MP18 fire is at 7,601 acres and 95 percent contained. In Nevada proper, the McConnell fire is at 33,231 acres and 81 percent contained and the Calico fire at 18,319 acres and 98 percent contained with residences threatened. In Arizona, the Mount Emma fire is at 368 acres and 70 percent contained with structures threatened, and the Paddy Creek fire at 668 acres and 63 percent contained.
The national wildfire preparedness level is 4 of 5, with 53,030 fires and 8,307,707 acres year to date.
The Hawaii infrastructure question ahead of Monday night is the one that makes island outages different from mainland outages. An island grid is self-contained. Power cannot be imported from a neighboring state the way it often is on the mainland, and restoration depends on local crews and materials that arrive by ship. That is the reason a Hawaii household plans for a longer outage than a mainland household of the same size would, and it is the reason the preparation window that exists today is worth using.
If you run a generator during an outage, the Consumer Product Safety Commission's guidance is to operate it outdoors only, at least 20 feet from the house, with the exhaust directed away from windows, doors, and vents. Working carbon monoxide alarms belong on every level of the home and outside sleeping areas, and should be tested monthly. If a carbon monoxide alarm sounds, get outside first, then call 911.
No grid emergencies or water system disruptions are reported across the region this morning.
Public Health
No heat alerts are active in California, Arizona, Nevada, Hawaii, or Guam this morning.
The water is the health item in Hawaii today, and it is active now rather than Monday. Honolulu's high surf advisory describes strong breaking waves and strong currents making swimming dangerous, and its instruction is direct: heed all advice from ocean safety officials, and when in doubt, do not go out. Surf from a distant hurricane arrives days ahead of the storm and looks ordinary from the sand, which is precisely why it catches people. That gap between how it looks and what it does is the hazard.
Air quality is the item that varies by address in California, where two uncontained fires are still burning. The Environmental Protection Agency's Fire and Smoke Map at fire.airnow.gov answers that question for a specific location better than any regional statement.
The Centers for Disease Control and Prevention's Health Alert Network archive could not be read this run, so this brief makes no claim about national health advisories in either direction.
Watch Item
This is the section that matters today, and its subject is the 36 hours between now and Monday evening.
The situation has firmed up since yesterday in a way that is worth naming plainly. Yesterday there were no watches and the honest advice was to prepare rather than predict. Today there is a tropical storm watch for Kauai and Niihau, a flood watch for every island, and a stated expectation that surf reaches warning levels Monday. The forecast has not become alarming. It has become specific, which is what a household actually needs.
The wind window for Kauai and Niihau is Monday afternoon into early Tuesday. That leaves Sunday and most of Monday, which is more preparation time than most households anywhere get for anything. Nothing about this calls for hurrying today. It calls for using a day and a half well.
The work worth doing is the work that stores run thin on later. Drinking water at about one gallon per person per day for several days. Food that needs no cooking. A flashlight per person rather than per household, with batteries. A battery or hand crank radio, because a phone network is not guaranteed and a radio does not depend on one. Prescription refills brought forward rather than left for Monday. Cash in small bills, because card readers need both power and a network. Vehicle fuel tanks filled Sunday rather than Monday.
Around the house, the outdoor work is the part that becomes impossible once the wind arrives. Anything loose in a yard or on a lanai becomes a projectile at 60 mph. Clearing gutters and drains is what decides whether several inches of rain leaves through the downspout or through a wall, and the flood watch language is explicit that flood prone roads and low lying areas may close and that urban areas may see more significant flooding from rapid runoff.
The documentation step costs twenty minutes and only pays if it is done first. Photograph each room, including inside closets and cabinets, and put the photographs somewhere other than the phone in your pocket.
Then stop watching. The next real decision point is whether the tropical storm watch becomes a warning, and whether Oahu and Maui get products of their own. Those are Honolulu's calls to make and announce, and checking their advisories twice a day is the right amount of attention. Watching a track map hourly will not change what your household should do, and the forecast Monday morning will be better than the forecast today. A track that passes just west of the islands is a track where a small shift matters, which is an argument for being ready rather than for refreshing a map.
For California, the surf and coastal flood advisories on the San Diego and Orange county coasts run into Tuesday, and the fire picture is the slower story. Drought is the background condition: the United States Drought Monitor map valid September 1 notes moderate drought expanding in northern California on hot, dry weather and poor snowpack.
Explore Today
The step by step version of what a household does with a day and a half of warning, written to be worked through rather than skimmed.
What a household covers on its own before help is routine. Especially relevant where the grid is an island grid.
For California and Nevada households, the work around the house that matters while fires are still burning.