Polling and data guru Nate Silver said Wednesday that Vice President Kamala Harris is slightly favored to win the presidential election if it were held tomorrow, but cautioned the public against relying too much on polls, citing their record of getting it "wrong" when it comes to former President Trump.

"If you have the election tomorrow… I think Harris would be a slight favorite," Silver said Wednesday on "Special Report." "She has been ahead in most recent polling in the ‘blue wall’ states, Pennsylvania, Wisconsin, Michigan, Georgia, North Carolina, Arizona, Nevada all polling in the margin of error range."

FOX NEWS POLL: HARRIS, TRUMP TIED IN PENNSYLVANIA

"People should remember, though, two things," he added. "One, we have three more months to go. There will be more surprises. And two, the polls have been wrong before. In both the last two general elections they underestimated Trump."

The prominent elections analyst and statistician published a polling update on his Substack forecast page earlier Wednesday, noting a series of "strong swing state" polling for Harris.

"The race is still in what we’d consider the toss-up range, but Harris’s momentum has been steady and upward," he wrote.

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"Needless to say, stranger things have happened than a candidate who was behind in the polls winning," he added. "And in America’s polarized political climate, most elections are close, and a candidate is rarely out of the running."

Silver recently changed his election prediction to "toss-up" after initially predicting former President Trump was electorally favored to win the White House in November, with Harris winning the popular vote.

Announcing his updated prediction on Substack in early August, Silver wrote, "When we launched the presidential model on June 26 — in the lifetime ago when Joe Biden was the Democratic nominee — the headline in the post that introduced the model was that the election wasn’t a toss-up. Instead, Biden had persistently been behind in the states that were most likely to decide the Electoral College, enough so that he was about a 2:1 underdog in the election despite the uncertainties in the race. His situation wasn’t unrecoverable, or at least it wasn’t until the debate. But you’d rather have had Donald Trump’s hand to play every day of the week and twice on Sundays…"

"Now that the election is in Kamala mode, however, it’s far from clear whose position you’d rather be in, and I wouldn’t blame you if you wanted to bet either on Harris or on Trump," he added. 

Silver told Fox News chief political anchor Bret Baier on "Special Report" that his polling is based off models, reiterating that "sometimes models go wrong."

"So our view is that the polling bias is unpredictable and can go in either direction. If Pennsylvania is Harris plus 2 on Election Day, it could be Trump wins by 2 or Harris wins by 6, et cetera," he explained.

Silver, who authored a new book, "On The Edge," predicted a strong August finish for the Harris campaign, noting that the Democratic National Convention next week is likely to give her a temporary boost in the polls. He said he feels Trump has been "knocked off his campaign a little bit" after Biden withdrew from the race, with Harris taking his place.

"They were under-prepared for a change in the Democratic candidate," Silver argued. "They have been, in my view, making some tactical mistakes, focusing on things like her race, for example, instead of things like immigration or the economy."

"But September is a whole new month….you have a debate, at least one, maybe multiple debates. And she [Harris] will have higher expectations than she has right now," he added.

Fox News released a national survey Wednesday showing Harris trailing Trump by one percentage point, 49-50%. By that same figure, more Democrats back Harris (94%) than Republicans support Trump (93%), while the small subgroup of Independents goes for him by 8 points.

The poll found that equal numbers of those preferring Harris and Trump are extremely motivated about voting this year (68% each). Last month, Trump backers (66%) were 5 points more likely than Biden supporters (61%) to say they were extremely motivated.

The economy is clearly the top priority for voters, as 38% said it will be the most important issue in their vote for president. Next comes immigration and abortion, tied at 14% each, with all other issues tested in single digits.  

Silver said the new poll is "pretty good" news for Trump.

"That will help a little bit when we update our model tomorrow," he added.

Fox News' Dana Blanton contributed to this report.