Active Weather
Hurricane Lowell is the story in this region, and it is the most consequential item in today's brief nationally.
As of public advisory 44, issued at 5:00 PM Hawaii time Sunday and current on the National Hurricane Center page at 5:01 AM Eastern today, Lowell was centered near 15.9 degrees north and 163.5 degrees west, moving north at 9 mph with maximum sustained winds of 120 mph and a minimum central pressure of 948 millibars. The advisory headline reads that a hurricane watch has been issued for Kauai and Niihau.
A hurricane watch means hurricane conditions are possible within the watch area, generally within 48 hours. It is the step that exists to give households time to act, not the step that says conditions have arrived. A warning is the one that says they are expected.
The Hawaii Emergency Management Agency's forecast, in its update posted at 4:40 PM Hawaii time Friday, has Lowell passing just west of Niihau and Kauai overnight Monday into early Tuesday. Its stated hazard figures are wind gusts up to 75 mph in Kauai County and up to 50 mph on Oahu Monday into Tuesday, isolated maximum rainfall of ten inches for Niihau, Kauai, and the southeast Big Island, eight inches for windward Maui, and two to six inches elsewhere, along with extremely dangerous surf on south and west facing shores and high surf statewide Monday and Tuesday.
The National Weather Service public alert feed, read at about 1 AM Eastern this morning, counts twenty active alerts across Hawaii, distributed across every main island rather than only Kauai. That is consistent with a system whose surf and rainfall reach much further than its wind field.
In the eastern Pacific, Tropical Storm Marie was centered near 24.2 north and 123.2 west as of 8:00 PM Pacific Sunday, with maximum sustained winds of 70 mph, moving northwest at 6 mph. The National Hurricane Center's headline states that Marie is expected to continue producing dangerous beach conditions along the coast of Baja California and Southern California for another couple of days. Marie is not forecast to bring wind or rain to the mainland. The hazard is entirely in the water.
The alert feed counts ten active alerts in California and one in Nevada. Arizona shows none at that hour.
Infrastructure
Two named large fires are burning in California, according to the National Interagency Fire Center situation report dated Sunday September 6 at 7:30 AM Mountain time. The Plaskett fire stands at 29,831 acres and 31 percent containment with evacuations in place, and the Timber fire is at 25,357 acres and 27 percent containment. Both are below a third contained, which means most of the perimeter is still open.
The national wildfire preparedness level is 4 on a five-step scale, according to the National Interagency Fire Center situation report dated Sunday September 6 at 7:30 AM Mountain time. That report counts 75 uncontained large fires nationally, with 53,165 fires and 8,302,657 acres burned so far this year, running at 125 percent and 158 percent of the ten-year average.
For Hawaii, the infrastructure question this week is the grid rather than fire. Wind gusts in the 50 to 75 mph range are in the band that brings down distribution lines and tree limbs onto them. Kauai in particular runs on a small island grid with limited redundancy, which means restoration after a wind event depends on crews reaching poles on roads that may be blocked.
The Federal Emergency Management Agency's declarations page could not be read this run, so this brief reports no change either way on open declarations.
Public Health
The national AirNow site carries a standing notice this morning that wildfire smoke is affecting air quality in multiple states. Specific readings near the Plaskett and Timber fires were not obtained this run. The Fire and Smoke Map at fire.airnow.gov gives a current local number.
For Hawaii households, the health item that matters this week is carbon monoxide, because power outages are the conditions under which portable generators come out. This is the one piece of guidance in today's brief that is worth reading in full: operate portable generators outdoors only, at least 20 feet from homes and buildings, with exhaust directed away from windows, doors, and vents. Install working carbon monoxide alarms on every level of the home and outside sleeping areas, and test them monthly. If a carbon monoxide alarm sounds, get outside immediately, then call 911. That guidance is from the Consumer Product Safety Commission.
Carbon monoxide has no smell and no color, and generator poisoning is one of the more common causes of harm after a storm rather than during it. The alarm is what makes the difference, and it is the item people most often plan to buy after the storm passes.
No boil-water advisories were identified across the region.
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
The next 36 hours are the ones that matter for Kauai and Niihau. Lowell's closest approach is forecast for overnight Monday into early Tuesday, and the watch may be upgraded, downgraded, or allowed to expire depending on how the track resolves. The Central Pacific Hurricane Center issues advisories on a fixed schedule, and its 5:00 AM and 11:00 AM Hawaii time products today are the ones that will settle the question.
The preparation that still fits inside that window is the ordinary list, and today is the day for it rather than tomorrow. Water at one gallon per person per day for several days. Food that needs no cooking. Prescriptions filled. Phones and battery banks charged tonight while the power is on. Anything outdoors that becomes airborne in a 75 mph gust brought in or tied down. A vehicle with fuel in it.
The rainfall figure deserves its own note. Ten inches on Kauai is a flooding number rather than a wind number, and on steep island terrain it moves fast. Roads wash out, culverts back up, and the low crossing that is fine in ordinary rain is the one that fails. Do not drive into water across a road, per the National Weather Service's Turn Around, Don't Drown guidance.
For Oahu, Maui, and the Big Island, the forecast is a strong weather day rather than a hurricane day: gusts to 50 mph on Oahu, up to eight inches of rain on windward Maui, ten inches possible on the southeast Big Island, and high surf statewide. The surf item is the one that hurts people who are otherwise unaffected. Stay off south and west facing shores Monday and Tuesday.
On the mainland, the equivalent note is Marie's swell along Southern California. Dangerous beach conditions for another couple of days, in warm water under clear skies, which is exactly the combination that puts swimmers in the water on a day the water is not safe. Swim where a lifeguard is watching or do not swim.
The California fire picture is the slower item. Plaskett at thirty-one percent and Timber at twenty-seven percent are both fires with more open edge than held edge, and September in California is the month when offshore wind events begin. Nothing in the current outlook points at one this week.
Explore Today
What to do inside a watch window, in the order that makes sense when you have hours rather than days.
Generator safety, food safety during an outage, and how to cover the first three days without power.
Defensible space and evacuation readiness for households near an open fire perimeter.