Tonight's game against the Los Angeles Express on a cool, clear California evening proved even stormier to the Washington Federals than last week's loss to George Allen and the Chicago Blitz in a Washington downpour.

Not only did the Federals absorb a disconcerting 20-3 loss, they also lost to injuries their three most potent offensive weapons--running back Craig James, starting quarterback Mike Hohensee and wide receiver Reggie Smith.

James (sprained back) and Hohensee (bruised sternum) both left in the second quarter, severely diminishing Washington's offense. There was no indication whether they would play in Sunday's game against the Boston Breakers. Smith's injury, a dislocated left foot, is expected to keep him out a month or longer.

Playing before 22,453 at Los Angeles Memorial Coliseum, the Express outplayed the Federals in nearly every aspect. Last week, the Express defeated Herschel Walker and the New Jersey Generals, 20-15, here. It played even better tonight. Only the attendance appeared diminished; the Express drew 11,549 more fans to the opener.

Quarterback Mike Rae played only the first half for the Express, but he threw 14 times for eight completions, 110 yards and two touchdowns, both to tight end Ricky Ellis.

Kim McQuilken, who opened the season as the Federals' starting quarterback, replaced Hohensee. He was 15 for 30, but threw two interceptions and was under heavy pressure when it counted.

"We had key people taken of out there," said McQuilken. "We're such a young team and we're not executing the fundamentals. There's no way we can afford to lose whatever depth we may have."

In the first drive, Hohensee looked as if he would give the Federals the offensive consistency they lacked in their opener. Hohensee completed passes to Smith, William Wall, James and Mike Holmes to get to the Los Angeles four (Holmes, who led the Canadian Football League's Winnipeg Blue Bombers in receptions in 1979 and 1980, signed with the Federals Saturday.)

But when James was dropped for a one-yard loss on a sweep and Hohensee was sacked by defensive back Alvin Burleson for a 13-yard loss, the 15-play drive stalled. Obed Ariri kicked a 28-yard field goal with 6:25 left in the first quarter to give Washington a 3-0 lead.

Smith injured his foot on the drive and did not return.Los Angeles' opening drive reaped equal benefits.

Playing behind one of the biggest, most skilled offensive lines in the USFL, Rae completed his first pass to Lonnie Turner for a quick 30-yard gain.

A 20-yard completion to LaRue Harrington put the Express within field-goal range, and Vince Abbott kicked a 30-yarder to tie the game with 55 seconds left in the first period.

In the second quarter, any thoughts of parity between the two teams disappeared as Los Angeles began to dominate. On its first possession of the period, the Express took command as Harrington's 44-yard run behind the blocking of left tackle Gus Coppens took Los Angeles to the Washington 17.

On the next play, Rae threw a out pattern to Ellis for a score and a 10-3 lead with 11:55 left in the first half.

For the Federals, disaster followed misfortune.

Running back Eric Robinson fumbled Abbott's kickoff and Ron Seawell of the Express recovered on the Washington 13.

Two plays later, on what appeared to be a replay of the previous score, Rae again threw to Ellis, this time for an 18-yard scoring pass. Los Angeles led, 17-3, with 11:20 left in the half.

As if the widening gap were not enough for Washington, fate added injury to impasse. On the first play from scrimmage following Rae's second touchdown pass, Hohensee was hit hard after releasing a pass and left the game for good.

And with time running out in the first half, James left with a jammed upper back after he was upended on a sweep around right end.

The Express held James to 17 yards on eight carries in the first half. Harrington gained 45 yards on five carries.

Hugh Campbell, the Los Angeles coach, continued to do well against Ray Jauch, the Federals coach. When they were both coaching in Canada, Campbell for Edmonton and Jauch for Winnipeg, Campbell held a 13-4 edge.

"We want to gear our team around our defense handling the opponent," said Campbell. "We weren't there yet, but we got a little closer tonight."

Los Angeles showed confidence in its 17-3 lead. Although Rae was eight of 12 for 110 yards and two touchdowns in the first half, Tom Ramsey, the rookie from UCLA, opened the second half.

A 17-yard completion from Ramsey to Harrington and a pass interference call against the Federals set up Abbott's second field goal, a 28-yarder, for a 20-3 lead with 2:08 left in the third quarter.

With Hohensee, James and Smith all out, the Federals lost whatever chance they had to catch up. As the third quarter ended, the Federals had not scored a touchdown and McQuilken had completed only seven of 17 passes.

"I can't move my torso at all," said Hohensee. "When I was laying there on the ground, I couldn't even contract my stomach muscles and get up."