Oho will hit parts of British Columbia and Alaska with drenching rain, gusty winds and pounding seas before the week comes to an end.
Oho reached Category 2 hurricane strength on Wednesday, but it will gradually lose most tropical characteristics during the latter half of this week as it tracks northeastward over the eastern Pacific Ocean.
According to AccuWeather Senior Meteorologist John Gresiak, even though the system will lose tropical traits, it is likely to remain a system to be reckoned with.
"The storm will actually get stronger as it transitions to a tropical rainstorm and approaches British Columbia and part of the Alaska Panhandle," Gresiak said.
Areas of soaking rain will precede the main storm through Thursday.
Very heavy rain and strong winds are likely to target areas from near Juneau, Alaska, to Prince Rupert and Port McNeill, British Columbia, beginning Thursday night and continuing Friday into Saturday.
The rain will be heavy enough to cause flash flooding and rock slides. The risk of flash flooding and mudslides will be greatest in recent burn areas.
According to AccuWeather Senior Meteorologist and Canada Weather Expert Brett Anderson, "From 3 to 5 inches [75-125 mm] of rain is likely with wind gusts of 60-80 mph [95-130 kph] along the coast Thursday night and Friday."
In a narrow zone along the upper British Columbia and lower Alaska coast, winds and rain can be more intense with the potential for significant damage and flooding.
"The core of the strongest winds (hurricane-force gusts) may impact the island of Haida Gwaii, British Columbia, during late Thursday night and early Friday, resulting in extensive tree and property damage, coastal flooding and power outages," Anderson said.
As winds shift from the southeast to the southwest, not only will there be the potential for trees to topple with minor property damage, but also the likelihood of building seas.
"Seas will rapidly build to 20-30 feet [6-9 m] as the storm approaches later Thursday," Anderson said.
Commercial shipping, fishing and cruise interests should closely monitor the track of Oho, even after it is no longer considered to be a hurricane or tropical storm. Captains may need to keep their vessels in port during the event.
"Oho will be but part of a big gyre over the Gulf of Alaska containing multiple storms," Gresiak said.
Rounds of rain and locally gusty winds from the giant spinning system will extend more than 2,000 miles (3,200 km) from coastal Washington to the Aleutian Islands.