Economics as the dismal science? Not in some quarters.

In the midst of the deepest recession in the experience of most Americans, many professional forecasters are optimistically heading into the new year declaring that the worst may soon be over.

For this rosy picture to play out, they are counting on the Obama administration and Congress to come through with a substantial stimulus package, at least $675 billion over two years.

They say that will get the economy moving again in the face of persistently weak spending by consumers and businesses, not to mention banks that are reluctant to extend credit.

If the dominoes fall the right way, the economy should bottom out and start growing again in small steps by July, according to the December survey of 50 professional forecasters by Blue Chip Economic Indicators. Investors seemed to be in a similarly optimistic mood on Friday, bidding up stocks by about 3 percent.