In December 2019, I described 10 housing and mortgage trends to watch for in 2020. But "deadly pandemic" was missing from my bingo card. Some of the trends I predicted are irrelevant now because COVID-19 disrupted the economy.

Time for a midyear update. In a world altered by the pandemic, here are trends that mortgage borrowers, and home buyers and sellers, will confront in the second half of 2020.

Trends that COVID-19 scrambled or made worse

One of the 2020 forecasts was that mortgage rates wouldn't change much, and the pandemic rendered that one flat-out wrong. Something more interesting happened to three other predictions: COVID-19 rendered them right but for unexpected reasons.

1. Mortgage rates would stabilize

Fannie Mae, Freddie Mac, the Mortgage Bankers Association and the National Association of Realtors all predicted that mortgage rates would barely move from the end of 2019 to the end of 2020. In November, Fannie Mae described the 2020 outlook as "mortgage rates normalizing." If you just let out a rueful chuckle, hey, same here.

What happened: Instead of normalizing, mortgage rates plunged in February as COVID-19 lurched from country to country, scattering fear and uncertainty wherever it spread. In NerdWallet's daily mortgage interest rates survey, the average rate on the 30-year fixed-rate mortgage fell almost half a percentage point in just 10 days, to 3.37% APR on Feb. 28.

After a spike in March, mortgage rates zigzagged downward. The average rate for the 30-year fixed-rate mortgage averaged 3.35% APR from April through June, compared with 4.24% APR in the same period in 2019.

Outlook for the rest of 2020: The average forecast among Fannie, Freddie, the MBA and NAR is for the 30-year fixed to fall about one-tenth of a percentage point from the second quarter to the fourth. If they're right, mortgage rates could average around 3.25% APR from October through December. But rates already were below that by mid-July, so I think the 30-year will fall even lower, averaging just over 3% APR in the fourth quarter.

2. It would be hard to find homes to buy

I forecast that home buyers would face a shortage of homes for sale, and the low inventory would continue through 2020 and beyond.

What happened: There were almost 20% fewer existing homes for sale in May 2020 than the same month in 2019. Would-be sellers took homes off the market or never listed them to reduce the health risk of strangers roaming through their homes.

Outlook for the rest of 2020: If COVID-19 continues to spread — and I think it will — sellers will be reluctant to open their homes to prospective buyers, dampening home sales

3. Lack of affordability would hold back home sales

At the beginning of the year, I predicted that scarcity of entry level-priced homes would persist, leaving many would-be first-time home buyers without a place of their own.

What happened: Home resales plunged more than 30% year-over-year in May, even as the median price rose 2.3% — meaning prices kept rising faster than incomes for many buyers. Both sellers and buyers were concerned about safety during the pandemic, and many first-time buyers wondered whether they should wait in case home prices fall.

Outlook for the rest of 2020: Lawrence Yun, chief economist for NAR, said home sales should pick up "with the economy reopening." But, he added, "New home construction needs to robustly ramp up in order to meet rising housing demand. Otherwise, home prices will rise too fast and hinder first-time buyers, even at a time of record-low mortgage rates.”

I'm not as optimistic as Yun about the economy reopening. If homeowners in hard-hit areas keep their homes off the market to ensure social distancing, it's unlikely that home sales can increase nationally. There's pent-up demand for homes at entry-level prices: 15% of new homes sold in May 2020 cost less than $200,000, compared with 10% in May 2019. Yet the pace of housing starts has slowed because of the pandemic.

An iBuyer is a company that lets you request an automated offer for your house. After you accept, the company buys your house as-is, on your schedule, then fixes it up and sells it. In December, I assumed iBuyers would continue their methodical spread into new markets.

What happened: At the outset of the pandemic, the biggest iBuyers, such as Opendoor, Zillow Offers, Offerpad and RedfinNow, suspended making offers, pausing their growth. By summer, they had resumed making offers.

Outlook for the rest of 2020: Most of the iBuyer companies have resumed their promise to expand to new markets, and are again making cash offers in most cases.

» MORE: The 7 steps to buying a home

Trends no one saw coming

5. Refinance boom

After mortgage rates fell, a refinancing wave swamped the mortgage industry in February and March. Lenders went through a period when they had more refinance applications than they could handle. They managed the workload by not cutting rates as much as they could have.

Outlook for the rest of 2020: The refinancing wave crested in spring, as the people who were most motivated to refinance had done so. Refinancing will continue to ebb, even if rates fall a little more, because the pool of potential refinancers has been drying up. They won't have much incentive to refinance again if rates fall just a small amount.

6. Housing insecurity

COVID-19 led to millions of layoffs and furloughs, and the unemployment rate rose from 3.5% in February to 14.7% in April.

The Coronavirus Aid, Relief and Economic Security Act was enacted March 27, providing mortgage relief to homeowners suffering from pandemic-related income loss. As of June 30, about 4.5 million homeowners were in mortgage forbearance plans, according to Black Knight, a real estate data provider.

The federal law instituted rental relief, including an eviction moratorium, for tenants of apartment buildings with federally backed mortgages. Those protections were scheduled to expire July 24.

Outlook for the rest of 2020: Homeowners will be able to request mortgage forbearance through the end of the year. Renters are vulnerable to the expiration of the eviction moratorium, with the potential of leaving millions unhoused.

7. Rise of 3D home tours

There was a jump in the use of 3D home tours, as lockdown orders, social distancing and fear discouraged home sellers from allowing potential buyers to visit their homes. The technology allows potential buyers — who haven't been eager to walk through strangers’ homes either — to explore homes virtually, using technology similar to Google Street View.

Outlook for the rest of 2020: 3D home tours will continue to grow in popularity because they allow buyers to virtually visit multiple homes and narrow down their lists of homes to tour in person.