IF YOU REALLY want some fish this weekend, there are only two places that are sure bets -- the fish section of your local supermarket and the Chesapeake Bay off Deale, Md.

"There are acres of baitfish on the surface," says Capt. Tim Johnson of Deale. And where there's bait, there are blues.

The charters are coming back with "boatloads" of four- pound bluefish, Johnson reports. "There were four acres of baitfish on the surface, with the blues cutting them up" at marker No. 1, off Deale, last weekend, he says.

Johnson recommends trolling green and red surgical hose from marker 8B to 10B, especially near markers 9B and 10B, and across the Bay to marker 70. Troll down to 60 feet, he suggests. Johnson recommends Deale, because it's only a 45- minute drive from Washington "and then a short boat ride to a lot of fish." (To get there from the Beltway, take Route 4 (Pennsylvania Avenue) to Route 258 and follow the signs.)

"This is the best July I can remember," he says. He uses words like "unbelievable" to describe the condition of the Bay and the plentitude of the grass shrimp, which are up to an inch long, and other baitfish on the surface right now.

This is welcome news these dog- day mornings and afternoons of late July. Storms have scattered the fish off the Atlantic, and there are not many nice things to say about freshwater fishing now except that it can't get any worse.

But the Bay is offering "the best chumming that I've seen in about five years," says Capt. Bruce Scheible, who runs Scheible's Fishing Center near Point Lookout, south of Deale. "It's a spinning tackle dream right now. You can anchor in 20 feet of water and you can fish all day long," he said.

Johnson says he's talked to other Bay charter captains, "and a lot of the oldtimers say it reminds them of the old days" of 20 years ago when there were albacore and kingfish in the Bay.

"The cleanup of the Bay must be working," he says. If the grass shrimp and other baitfish stay plentiful, "eventually they'll bring flounder in and everything else" -- maybe even the albacore and kingfish.

So why go to the supermarket when you can go to Deale. It beats standing in line, and you'll probably go home with more fish. WHAT'S THE CATCH? D.C. AND VICINITY

Dan Ward of Fletcher's Boat House has a novel way of fishing for bass -- by riding your bicycle along the C&O Canal. He calls it "hunting for fish."

"Just ride along the canal and look for bass," Ward says. "I used to do it as a kid." Bass in the canal "like to sun themselves this time of year, and you can see them on the surface," Ward says. "If you don't ride too close to the edge, they won't see you. When you see one, just get off your bike and cast out to them. You might catch one."

The bass in the canal are usually small, Ward says, because the water is drained out periodically. But you may be able to land a larger bass. Ward says he caught a five- pounder in the canal: "But that was a long time ago."

Besides bass, you can catch bluegill and catfish in the canal. You may as well give it a try, because the canal is one of the few places in this vicinity where fishermen are having any luck, Ward says.

"Occasionally a nice fish is caught" in the Potomac, Ward says. For example, "a nice walleye" was taken a few days ago by trolling with a deep-diving lure. But that is the exception, not the rule, these days. MARYLAND

UPPER POTOMAC -- The water is high and muddy right now, but "if there are no more storms, the fishing is going to get better," says fish guide Mark Kovach, who operates an unusual "whitewater bass boat" guided tour from the upper Potomac just above Harpers Ferry and on into the Shenandoah as far as Brunswick.

That stretch of the Potomac and Shenandoah are full of smallmouth bass and red-breasted sunfish, Kovach says, but "the fisherman has to work pretty hard." Tiny torpedoes and buzz baits are having the most success, he says.

The most productive time to fish here is in the evenings, he says -- and be sure to use a surface lure. The white miller fly is hatching, so all the action is going to be on the surface. But Kovach advises against trying to duplicate the miller fly with an artificial fly. The fish are gobbling up those bugs all day, so one more in the water isn't going to turn any heads. The only thing that seems to be getting their attention enough to strike is a bigger, noisier surface lure.

For more information about Kovach's combination bass-fishing, whitewater rapids trip, give him a call at 588-8742.

LOWER POTOMAC -- "This past week is just about the best fishing we've had all year," says Jack Yates of Capt. John's Marina on Cobb Island.

The jumbo perch and jumbo spot "starting last week have been really good," he says, and the catches have been "about as big as your hand." Use bloodworms for the perch and softshell crab for the spot, Yates says. VIRGINIA

BURKE LAKE -- "The lake is hot -- and make sure you use that word -- hot," says Phillip Mello of The Lynn Co. in Occoquan. A lot of muskellunge (musky) are being caught and some "good-sized bass," he says.

If you decide to do some musky fishing at the lake this weekend, get some very large minnows or use big spoons or spinners, Mello advises. An 11-pound musky was caught last week -- and that was just small potatoes compared to the 26-pounder caught in the lake earlier this month.

Mello says Burke Lake has suddenly "turned on, after five years of waiting for it to." He says the water level of the lake was lowered this year "to work on the dam," and he thinks that has made the fish more "congregated in one place, and more accessible" to fishermen.

OCCOQUAN RIVER -- There has been "some bass activity down here on the river -- bass and stripers," Mello reports. "And, of course, plenty of catfish."

White or chartreuse spinnerbaits and purple or motor-oil plastic worms are bringing out the bass, Mello says. The evening fishing here should be picking up dramatically, depending on how long the current "cool spell" lasts, he says.

RAPPAHANNOCK -- "There hasn't been a whole lot going on this past week," says Charlie Wingard at Chesley's Tackle Shop in Fredericksburg. Downriver from town "quite a few" largemouth are being caught, and upriver the smallmouth are hitting, "but no one's brought anything large" into the shop to be weighed, he says.

"The river is in excellent shape," Wingard says. It's clear and low, "and everything's concentrated," and the fishing should be excellent this weekend if the weather holds up, he says.

LAKE OF THE WOODS -- The catch of the week is a 5-pound, 6-ounce chain pickerel, taken in this lake near Fredericksburg, in Orange County. "That's large for a chain pickerel," Wingard says. ATLANTIC OCEAN

OCEAN CITY -- "It's been pretty bad," says Tom Detig of the Ocean City fishing pier. "A few flounder, a few bluefish, a few trout, but that's about all."

Detig attributes the bad fishing of late "to the storms we've had. The thunder and lightning drive the fish out to deep water." The storms were followed by a couple of days of hot, windless, almost waveless weather, "which also drives the fish away."

"Usually it's air-conditioned on the pier," Detig says. "Honest. You usually have to wear a jacket. But it's been too hot for most people to stay out on the pier," he says. As soon as the weather improves, so too should the fisng.

CHINCOTEAGUE -- The flounder fishing is "in A-1 shape if the weather's pretty," says Capt. Bob Pohlmeyer, who operates Capt. Bob's Marina.

"If you know what you're doing," you can expect to catch up to 30 good-sized flounder, he says. If you don't know what you're doing, sorry, you'll have to settle for only eight of them. Minnows and silver-sides are working best on the flounder, he says.

Some sea bass also are available in the back bay part of Chincoteague (as opposed to oceanside, off Assateague Island). Pohlmeyer advises using squid for the sea bass.