When the gate dropped for the first moto, though, the sun was out, and the track was drying out quickly.
Geico Powersports Honda's Jake Weimer (30) grabbed the holeshot to start the first Lites moto.
Even though he led the first few turns, Weimer began to make mistakes immediately and handed the lead to MDK KTM's Martin Davalos (577).
Davalos led the first lap, just ahead of Rockstar/Makita Suzuki's Nico Izzi, Weimer, Villopoto and Ryan Sipes.
Izzi ran second early in his first race back from a concussion.
Villopoto (1) officially led lap two, even though he didn't finish off the pass on Davalos (577). Heading to the finish-line jump on lap two, Villopoto split Davalos and Izzi (behind Villopoto) and jumped out to the flat.
Davalos (577) fought to stay in front of Villopoto (1), but it only lasted a couple more turns before Villopoto made the pass for the lead stick. Davalos eventually faded to 16th by the finish.
Despite his early mistakes that caused Weimer to fall back to fifth on lap two, he pulled it back together and began working his way back through the field, eventually passing Izzi for second on lap 13 of 15, where he would finish - his best National moto finish ever.
Izzi (341) ran second for much of the first moto before finishing third.
Boost Mobile/Yamaha of Troy's Jason Lawrence (338) passed Sipes (57) for fourth on the last lap of the first moto. The final finishing order was Villopoto, Weimer, Izzi, Lawrence, Sipes.
Rockstar/Makita Suzuki's Mike Alessi picked up where he left off in Texas, with another holeshot, to start the first 450cc moto.
Despite the blazing start, Monster Energy Kawasaki's James Stewart (7) was quickly all over Alessi...
Alessi (800) fought it, but eventually Stewart (7) made the pass stick and quickly began to pull away.
Brawndo Honda's Ryan Clark started third in the first 450cc moto, but eventually finished 11th with a hole in his engine case. The hole wasn't found until about 10 minutes before the second moto began. In order to fix it, Clark's crack staff drilled the hole out, grabbed a cork from a bottle of whiskey they had in the rig (you know, for just such an occasion - ahem), and plugged the hole with the cork, holding it in place with a brush. It lasted the whole second moto.
Honda Red Bull Racing's Davi Millsaps (118) worked his way from a start just outside the top five to third by moto's end, while his teammate Andrew Short (29) eventually finished fifth.
Monster Energy Kawasaki's Timmy Ferry finished fourth in the opening moto.
Stewart took a convincing win - his seventh moto win of the seven run thus far this season.
The second Lites moto heads up the hill.
Motosport/Xtreme Kawasaki's Andrew McFarlane (38) grabbed the holeshot, followed by Weimer (30), Villopoto (1) and the rest of the field.
Villopoto quickly passed McFarlane and checked out, taking his seventh moto win in a row.
Along with Villopoto, Rockstar/Makita Suzuki's Ryan Dungey was jumping the track's infield triple in the second moto. Dungey was sixth in the first moto after starting around midpack...
...but in moto two, Dungey started much nearer to the front and finished second. However, he was never that close to Villopoto (1).
Villopoto's teammate Austin Stroupe was third in moto two, and when averaged with his ninth from moto one, he was fourth overall.
Brett Metcalfe was fourth in the second moto, and seventh in the first, finishing fifth overall.
Weimer started and finished fifth after battling for much of the moto with Metcalfe, who eventually passed him. However, his 2-5 was good for second overall - his first-ever AMA National podium finish.
But no one got too close to Villopoto, who went 1-1 for the third-straight race.
Weimer (left), Villopoto (middle) and Dungey (right) celebrate on the podium.
Stewart (7) leaves the line alongside teammate Timmy Ferry (left), Jeff Alessi (801) and Millsaps (118), but...
...it was Alessi who got another massive holeshot - his fourth straight.
Early on the first lap, a pileup claimed a lot of riders, including Jeff Alessi, who eventually caught up to 15th.
Honda Red Bull Racing's Ivan Tedesco came into the event nursing a hurt ankle, and then reportedly re-aggravated the injury in a second-turn fall and pulled out of moto two.
Alessi led the first lap, but quickly came under fire - again - from Stewart.
Stewart caught and passed Alessi on the second lap, and that was it for the battle for the win.
Millsaps again raced his way onto the podium, finishing with a 3-3 and third overall.
Alessi's 2-2 was good enough for second overall.
Stewart is undefeated one third of the way through the AMA Nationals.
Alessi (left), Stewart (middle) and Millsaps (right) celebrate on the podium.