Dozens of states are reporting rising numbers of COVID-19 cases in what could be the first signs of a long and difficult winter.

Even states that had the lowest case numbers in the country in recent months — such as New Jersey and New York — are seeing spikes in infections, while states in the Midwest and Great Plains are becoming new hot spots. 

The U.S. is now recording an average of 47,000 new cases per day — a 12 percent increase from two weeks ago. It’s a dangerous spot to be in ahead of the colder winter months, when the virus’s spread will be aided by dry air and people spending more time indoors. 

“We still have tens of thousands of known cases, probably hundreds of thousands of actual cases, happening every day, and what that means is that we have a tremendous number of small little outbreaks ready to burst,” said Michael Mina, assistant professor at Harvard’s Center for Communicable Disease Dynamics.

New cases began increasing again in September, which some experts attribute to the reopening of college campuses and schools, increased activity around Labor Day, fatigue with social distancing and mask-wearing, colder weather moving some people indoors, and the lifting of restrictions on businesses in certain states.

Experts had hoped to have fewer daily cases by the fall. Having such high levels of transmission now provides more avenues for the virus to spread in the winter, when respiratory viruses spread more easily.

“We’re likely to see massive explosions of cases and outbreaks that could potentially make what we’ve seen so far look like it hasn’t been much,” Mina said.

Youyang Gu, a data scientist who developed a frequently cited COVID-19 model, projects nearly 231,000 deaths by Nov. 1. 

A University of Washington model projects nearly 363,000 deaths by Jan. 1, with daily deaths topping what was seen at the peak in the spring.

There are currently about 213,000 confirmed COVID-19 deaths in the U.S., according to Johns Hopkins University.

Midwest and Great Plains states, in particular, have been hit hardest in the latest surge after evading large outbreaks earlier in the pandemic that were focused in the Northeast, South and West.

The percentage of tests coming back positive is 5 percent or higher in 32 states, according to Johns Hopkins University, an indication of growing community spread, according to the World Health Organization. 

North Dakota, South Dakota, Wisconsin, Montana, Utah, Idaho, Nebraska, Iowa, Missouri, Oklahoma, Arkansas, Wyoming, Tennessee and more than a dozen other states have large outbreaks that are continuing to grow, according to tracker from The New York Times.

“Unfortunately, Wisconsin is one of the hottest of all the COVID hotspots in the United States,” said Mark Kaufman, chief medical officer of the Wisconsin Hospital Association. 

The state has reported nearly 17,500 confirmed cases in the past seven days, trailing only Texas and California, which have much larger populations than Wisconsin. 

“All geographic regions are experiencing record or near-record numbers of hospitalized COVID patients. Many Wisconsin hospitals are operating at or near capacity,” Kaufman said. 

Wisconsin recently opened a field hospital at the state fair park for patients with COVID-19 who don’t need hospital-level care.

Democratic Gov. Tony Evers’s administration also issued an emergency order limiting public gatherings to 25 percent of a room's or building’s capacity, including at bars and restaurants.

North Dakota has confirmed more new cases of COVID-19 per capita than any other state: 416 per 100,000 people, 

South Dakota, where Gov. Kristi Noem (R) has downplayed the virus and called lockdowns “useless,” is not far behind, with 374 confirmed cases per 100,000 people. 

States that previously had lower case numbers are also seeing increases, including New York, New Jersey, New Mexico, Delaware, Ohio, Michigan, Washington, D.C., Pennsylvania and others, according to the Times's tracker.

In an effort to drive case numbers back down, new restrictions have taken effect in several parts of New York City, including the closure of nonessential businesses in parts of Brooklyn and Queens. 

New Jersey, which was hit hard in the early days of the pandemic, is again seeing a spike in COVID-19 cases, with Gov. Phil Murphy (D) suggesting new restrictions on indoor gatherings. 

“We do see slight upticks and test positivity, slight upticks in cases, and that often is just the earliest indicator that there’s ongoing asymptomatic spread in the communities,” Deborah Birx, the White House coronavirus task force response coordinator, said Thursday regarding states in the Northeast while speaking at an event with Connecticut Gov. Ned Lamont (D).

In New Mexico, Gov. Michelle Lujan Grisham (D) warned of new restrictions if the virus isn’t controlled soon. 

“We are at extreme risk of uncontrollable spread,” she said during a virtual press conference Thursday.