Welcome to Health Reform Watch, Sarah Kliff’s regular look at how the Affordable Care Act is changing the American health-care system — and being changed by it. You can reach Sarah with questions, comments and suggestions here. Check back every Monday, Wednesday and Friday afternoon for the latest edition or sign up here to receive it straight from your inbox. Read previous columns here.

(Jon Elswick/AP)

Brian Lynch has a very, very busy day ahead of him.

The New Hampshire-based insurance broker works with about 300 local clients, many of whom are trying to buy coverage through HealthCare.gov. With a midnight deadline to enroll in coverage that begins January, Lynch's calendar for the afternoon is filling up quickly.

"I so far have appointments at 2:30, 3:30, 5:30, and 8 p.m. so there will be some after-hours work tonight," Lynch told me this morning. "If I'm helping someone on their application at 11 p.m., I'm not going to stop with that. I always try to accommodate people as much as possible, but today is probably an extreme example of that."

The Obama administration had initially set a Dec. 15 deadline for purchasing January coverage, but pushed it back to Dec. 23 due to the technical hurdles facing hundreds of thousands of shoppers. The White House announced a last minute change Monday, first reported by The Washington Post: It would extend the deadline another day, allowing those who purchase coverage by midnight on Christmas Eve to start their plans in January.

Still, the public-facing deadline of Dec. 23 has many HealthCare.gov shoppers scrambling to enroll — not all with successful results.

The HealthCare.gov Twitter handle tweeted mid-morning that the site was having a "record day" with "thousands visiting and enrolling." Around 11 a.m., the Obama administration deployed the site's queuing system, which kicks in when the site has reached its maximum capacity for visitors.

Navigators around the country say they have been deluged with phone calls, and that a lot of people are walking into their offices, hoping to get help signing up for coverage despite the navigators’ packed schedule of appointments.

Some reported being able to enroll people at a rapid clip: about 30 minutes for someone on Medicaid, and perhaps an hour for people getting private plans. But others reported difficulty getting consumers’ identities verified and being booted off the system as they browsed plan options.

“Our office hours are until 5, but if someone needs to be enrolled we have to do what we have to do,” says Tiffany Green, a navigator for Sinai Health System in Chicago. Her office already had enrolled about 25 people by midday. “It’s been pretty busy. Everyone’s trying to hurry up and get it done, because they’re under pressure because it’s the last day.”

Many of the HealthCare.gov shoppers enrolling Monday had already tried to buy insurance. Many started shopping Oct. 1, when the HealthCare.gov site launched. With the deadline looming, they decided to take another shot at signing up.

"I jumped on the day it opened and was part of the group that experienced the great crash," says Bryan Williams, a 44-year-old software developer in Cary, N.C. "I checked back every couple of days. This morning I decided to pull the trigger."

Williams picked a high-deductible plan with Blue Cross and Blue Shield of North Carolina that will cost $855 per month. He's still trying to confirm that his plan has received his enrollment forms and make a first premium payment, after running into difficulties doing so online.

"It was definitely a sense of relief," says David Graff, a 45-year-old consultant in Western Pennsylvania who has been shopping since October. He picked a plan around 6 a.m. this morning, when he had some quiet time before his 3-year-old son woke up. "It was a little bit frustrating having to spend a lot of time trying to get insurance. I know a lot of people have had harder problems than I did."

Others have not gotten that far, still stuck in the process of sorting out who in their family qualifies for which programs — and doubtful they will have coverage by Jan. 1.

Jim McMullen, an independent consultant and father of five in Overland Park, Kan., says he's been shopping for coverage since the site launched in October. His application shows himself and his wife as eligible for tax credits, but not his children.

"I don't really know if I'll have coverage on January 1," McMullen says. "Obviously, I'm pushing to get there. But my experience has been disappointing, so I'm dubious."

He spent three hours on the phone Saturday with the HealthCare.gov call center. McMullen called a local navigator group right at 9 a.m. this morning, when they opened, who guessed it had something to do with the prior tax returns he filed online.

"Unfortunately I'm on the road for meetings all day, so I can't go in and change it," he says. "I'll try and go through and change it if I get to the hotel in time tonight."

Still others are battling a different challenge: Ensuring that an earlier enrollment has actually made it to the plan they selected. The Obama administration has previously said that approximately 15,000 enrollment files were not transmitted to insurers, although the error rate has dropped dramatically in recent weeks.

But for Brett Barry, a real estate agent in Arizona, those low error rates do not provide much comfort. He has made numerous calls to the insurance plan he selected weeks ago, but has so far not received a response. A call center representative helped him submit a new application Friday, which he has not yet confirmed his plan has received.

"I have to pay them, but I don't know how to get in touch with them," Barry says. "I'm definitely trying. I'm a parent of two kids, I'm as healthy as could be, but I don't want to go without health insurance."

With reporting from Sandhya Somashekhar

KLIFF NOTES: Top health policy reads from around the Web.

White House quietly extends Obamacare's sign-up deadline. "Without any public announcement, Obama administration officials have changed the rules so that people will have an extra day to enroll, according to two individuals with knowledge of the switch. Over the weekend, government officials and outside IT contractors working on the online marketplace’s computer system made a software change that automatically gives people a Jan. 1 start date for their coverage as long as they enroll by 11:59 p.m. Christmas Eve." Amy Goldstein and Juliet Eilperin in the Washington Post.

Even with robust funding, Colorado faces enrollment challenges. "There are navigators working at 57 assistance organizations across Colorado – everyone from county health departments to local clinics to the state trucking association. Neighboring states Nebraska and Arizona aren't embracing the health-care law like Colorado is. They have just two navigator organizations each and about $2 per uninsured person to spend on assisters. Colorado has almost $24 per person. But all the effort had netted about 23,000 customers for private insurance in the state's marketplace as of Dec. 14 – only about 17 percent of the way to the state's goal of enrolling 136,000 people by the end of March." Eric Whitney for NPR.

A federal court rules against the health law's contraceptives mandate.  "A federal judge granted an injunction Friday that prohibits the government from enforcing the federal health-care law's requirement that insurance coverage include access to the morning-after pill and similar contraceptives on almost 200 religious organizations that have filed a class-action lawsuit to block the mandate." Tim Talley for the Associated Press.