6:37 p.m. ET: Final Sprint Cup practice is underway! Follow along.
6:35 p.m. ET: Our drivers get to give their takes on road courses.
5:59 p.m. ET: Definitely something to watch for this weekend.
5:54 p.m. ET: "Hey, Harv. Check out the NASCAR Mobile '13 app. It's awesome."
5:36 p.m. ET: Awesome.
5:34 p.m. ET: Qualifying order for tomorrow's Nationwide race has been announced. Check it out.
5:27 p.m. ET: Tune in to Press Pass to catch up on what your favorite drivers have to say.
4:45 p.m. ET: First practice has wrapped up at Sonoma Raceway. Top five: Marcos Ambrose, Juan Pablo Montoya, Casey Mears, Kurt Busch, Jamie McMurray. Drivers will hit the track again at 6:30 p.m. ET for the final practice.
4:37 p.m. ET: A strong prediction by our loop data analyst.
4:30 p.m. ET: Some shakeup in the top five. Juan Pablo Montoya takes the top spot with 93.890 mph; Joey Logano moves into fifth.
4:25 p.m. ET: Full results for the Nationwide practices are up here.
4:22 p.m. ET: Some teams seeing struggles in California today.
KH had a hard time turning right that run, thinks he killed the tire. The team confirmed once he pulled into the garage. — RCR 29 Cup Team (@RCR29KHarvick) June 21, 2013
1-hour into practice and a few shunts and mishaps for some. Thankfully, no one needed carriage back to paddock on lorry. — Stewart-Haas Racing (@StewartHaasRcng) June 21, 2013
4:15 p.m. ET: Owen Kelly, Billy Johnson, AJ Allmendinger, Michael McDowell, Sam Hornish Jr. top the charts in Nationwide practice.
4:09 p.m. ET: Denny Hamlin hasn't had a finish better than 34 in the past three years, but he's running fifth in practice. Ambrose still leads, with Bowyer and Kurt Busch behind.
3:58 p.m. ET: Danica Patrick and Ricky Stenhouse Jr. are both making their first outing at Sonoma, running 37th and 34th, respectively.
3:50 p.m. ET: The track's ready for the Toyota/Save Mart 350.
3:40 p.m. ET: Last year's Coors Light Pole winner Marcos Ambrose returns to the top of the speed charts as the No. 24 heads to the track.
3:32 p.m. ET: Currently running 26th in practice.
3:25 p.m. ET: Some bad news at Road America for Elliott Sadler.
3:20 p.m. ET: Team strategy talk.
3:15 p.m. ET: With an hour left in Nationwide practice, Cole Whitt leads. Michael McDowell is second and Mike Wallace third.
3:11 p.m. ET: Almirola and Johnson have already gotten turned around.
Caution out early after the No. 43 and No.48 cars spin. — HDR (@HomeDepotRacing) June 21, 2013
3:07 p.m. ET: Teams are rolling onto the track at Sonoma.
3 p.m. ET: Sprint Cup practice is live now at Sonoma Raceway. Follow the live leaderboard here.
2:54 p.m. ET: Cars switching over from rain tires to race tires soon at Road America.
First initial laps went well, good practice with rain tires, now sitting in the pits waiting for rest of track to dry and put on slicks. — RAB Racing (@RAB_Racing) June 21, 2013
CC Shane Wilson calls Brendan to the garage to switch over to race tires and remove the rain tires — RCR 62 CWTS Team (@RCR62BGaughan) June 21, 2013
2:50 p.m. ET: Nationwide practice update: Mike Wallace, Billy Johnson, Owen Kelly, Parker Kligerman and Nelson Piquet Jr. lead the practice board.
2:44 p.m. ET: So many turns!
2:37 p.m. ET: Parker Kligerman currently leading practice with Nelson Piquet Jr. and AJ Allmendinger just behind.
Plan for the No. 2 team is to make one run on rain tires then get ready to practice on race tires. — RCR 2 NNS Team (@RCR2BScott) June 21, 2013
Brendan reports the track is too in between wet and dry to get a good feel for the handling but swifts really clean — RCR 62 CWTS Team (@RCR62BGaughan) June 21, 2013
2:28 p.m. ET: Get inside the garage in five minutes, or head over to GarageCam now to get your requests in early.
2:24 p.m. ET: Only a few cars on the track so far, with Michael McDowell atop the speed chart. Drivers are slowly making their way out.
2:20 p.m. ET: In case you missed it, Clint Bowyer is speaking live now in Press Pass.
2:02 p.m. ET: Something you don't see too often!
1:47 p.m. ET: There's sunny Sonoma, and then there's this.
1:42 p.m. ET: Things are looking a little brighter on the West Coast.
1:37 p.m. ET: Cars will be heading to the track shotly.
1:23 p.m. ET: Teams are keeping busy during the delay... mostly by tweeting pictures of their haulers.
12:59 p.m. ET: Tires will be working hard today.
12:51 p.m. ET: Lots of eyes on the radar at the track.
12:48 p.m. ET: Thankful for those tents, I bet.
12:43 p.m. ET: Official tweet update from NASCAR.
12:31 p.m. ET: Weather conditions are 65 and stormy in Wisconsin, keeping cars off the track for now.
12:16 p.m. ET: Teams are going to have a hard time staying dry today, but cars will run in the rain.
12:12 p.m. ET: Keep up with practice laps using our live leaderboard. Here, you'll see what's going on in social media as cars hit the track.
12:06 p.m. ET: Thanks for joining for today's practices at Sonoma and Road America. First up on track is Nationwide Series practice at 12:30 p.m. ET, where the track is seeing some rain.