Many fisherman missed it, but sandwiched between two recent heat waves was a week of cool, stable, fall-like weather.

The bass didn't miss it, and area bass fishing suddenly picked up for those who were on the lakes, as evidenced by the 45 1/4-pound stringer of Occoquan largemouths that was mentioned in last Thursday's fish report.

From that flurry of activity two lessons can be learned that will help guide us toward productive bass fishing this fall. One is that stable weather with no fronts passing through for three or four days brings a spurt of activity, even during the generally slow days of summer. The other is that cooler weather, which is not far way, will shake some life and hunger into the local bass population.

Autumn conditions often mandate light tackle. Within a few weeks cooler weather will reduce the growth rate of aquatic vegetation - for our purposes algae and plankton. That means the water will be clearer and high visibility 10-pound line and heavy tackle won't work so well along the shore-lines and in the coves where bass lurk.

During the fall, carry two rods. One should be that old lunker stick or worm rod you've used all summer to probe the depths. Use it when you want to fish deep and you need a rod with backbone to set a hook that is at the other end of a lot of stretchable line. Use the same rod when poking around lily pads or underwater structure. A fish hooked in such an area will try to tangle your line, so you can use the extra power in the rod to control the fish.

The other and more frequently used rod should weigh two to three ouces, should be 5 1/2 to six feet long and should carry a seven to nine-ounce spinning reel. Rig it with four-pound-test colorless monofilament. Such an ultralight outfil should be capable of tossing 1/16 to 1/4-ounce lures. A six-inch plastic worm, rigged on a 1/0 weedless hook so that it won't snag in the shallows, can be deadly. The hook should be exposed so it can be set with a light rod. Tie the hook directly to the line with a clinch knot, thereby avoiding the extra weight of a leader. Single piece or broken-back rebels, balsa or plastic plugs and spinner baits, all in small sizes, also work well.

One word of caution about ultralight tackle. A worn line snaps easily. Check the first few feet frequently and check the rod guides and the reel bail periodically. It is mighty painful to lose a big bass on light tackle when negligence is to blame.