As Alaska continues to count and report votes weeks after Election Day, it is increasingly unlikely that Republican Sen. Dan S. Sullivan will hang on to his job.

His Democratic challenger, Mary Peltola, is on track to win the still-unresolved Senate race under either possible scenario — with an outright majority, or if the race goes to ranked choice ballots, according to an NBC News Decision Desk analysis of outstanding and tabulated votes.

Peltola currently leads Sullivan by 3.7 percentage points, or just over 10,000 votes. With 96% of the expected vote in, NBC News’ Decision Desk now believes Peltola is likely to win this race, though we may need to wait until Wednesday, Nov. 18, to know the final result.

If no candidate receives over 50% of the vote, Alaska uses ranked choice voting, in which the lowest-ranked candidates are eliminated one by one and their votes are redistributed according to each voter’s ranked preferences. If a voter did not rank the remaining candidates, their ballots are considered “exhausted” and are excluded from the final vote count.

Wednesday is Alaska’s deadline for final mail absentee ballots to be received by election officials, one reason why this close race has lingered for so long. Alaska reports its votes unevenly, and NBC News expects to receive the remainder of these votes early next week.

Nov. 18 is also the day the state Division of Elections would run the ranked choice tabulation, if needed.

If Peltola receives over 50% of the vote, she will win the election without needing to go through the ranked choice tabulation process. She needs to win just 53.8% of the remaining ballots to clear this mark — a real possibility given her strength in recent vote reports. On Friday night, she received 58% of the newly reported votes.

Sullivan, the incumbent, has two separate paths to gain ground and win the election: making up the gap with first-choice rankings, or making up the gap via the ranked choice process. An NBC News Decision Desk analysis of the ballots already tabulated shows that the first route is highly improbable and that the second route is likely impossible.

The first route that Sullivan could use to come back would be passing Peltola in first-choice rankings. With approximately 12,000 votes outstanding, Sullivan would need to win around 92% of those in order to tie with Peltola. That would amount to about 46 points better than he has performed in the vote counted so far, and far above the percentage either candidate has achieved in any batch of ballots received up to this point. On Friday night, he received just 38% of newly reported votes.

The second route for Sullivan to retake the lead is through the ranked choice process, but analysis of the ballots shows why this route is effectively closed to him.

There are currently 11,300 tallied ballots with first-choice votes for candidates other than Peltola and Sullivan. Those ballots may be redistributed in the ranked choice process. With 4% of the total vote outstanding, the number of ballots with first-choice votes for candidates other than Peltola and Sullivan could rise to around 12,000. For Sullivan to net 10,400 ballots out of a pool of 12,000 and close the gap with Peltola, he would need to win around 93% of redistributed votes.

However, even that steep figure is misleadingly optimistic for Sullivan because of what we already know about how people are ranking the candidates.

The Alaska Division of Elections posts a “Cast Vote Record” for the over-270,000 ballots currently tabulated. These records show exactly how each candidate is ranked on each ballot.

Our analysis of those ballots shows that Sullivan does gain some votes from the ranked choice process, receiving a large transfer of votes from voters who backed Republican Gerald Heikes, who is in third place. But the most important thing about these votes is that a large percentage of ballots from those who backed other candidates are “exhausted” in the ranked choice tabulation process.

Over 45% of voters who ranked Heikes, Dan J. Sullivan Jr., or a write-in candidate did not rank Peltola or Sen. Dan S. Sullivan as a later choice, which means that these ballots will play no role in the ranked choice tabulation.