Transcript for FiveThirtyEight Senate forecast update for Nov. 1, 2018

Yeah. The classic version of 538 senate. Currently gives Republicans six in seven or about an 85% chance of winning a majority. And it gives Democrats about a one in. That's the highest chance our model has given to Republicans to we in the city. According to our model and are currently three toss. And Democrats need to win them all. Even if they pulled off. Democrats would still need to pick up one more seat to control the chamber. In our previous episodes we focused on to toss in particular. Nevada and misery. So today let's take a closer look at Arizona it's slipped back and forth from the democratic to tossup model but right now we give democratic candidate Houston cinema three in five chance of beating Republican mark Salley. Polling in this race has been kind of all over the place with some giving cinema and nearly seven point. While others giving mixed Sally. Her south but the most recent Fox News poll has the two candidates dead. Our model does adjust these polls however and it seems as if cinema. Has the slight upper hand in recent poll Arizona -- nine points more Republican than the rest of the country. The Democrats will be hoping that their candidate can flip this open seat to. Visit 538 dot com slash senate forecast to explore the modeled partners and.

This transcript has been automatically generated and may not be 100% accurate.