It's not quite time to batten down the hatches in southwestern Pennsylvania. But with Tropical Storm Hanna heading toward the East Coast, you should prepare for a drenching this weekend.

The only question is: How wet will it get?

A key factor will be whether the storm veers west or east of the Appalachian Mountains as it heads north after making landfall late Friday or early Saturday.

Pittsburgh, which lies west of the Alleghenies, could see between 3 and 5 inches of rain over 48 hours if the storm tracks west, versus up to 2 inches if Hanna stays to the east of the range, said meteorologist Terry Parrish of the National Weather Service.

If the storm stays to the east, eastern Pennsylvania, Virginia, Maryland and Washington, D.C., could get hammered.

"You've got to be prepared for both scenarios. We'll get something out of it. Whether we get half inch to an inch or 3 to 5 inches might depend on just where that track goes," Mr. Parrish said. "We've got to keep our guard up for coming up the west side."

Right now, computer models are hedging their bets, placing Hanna on a northerly heading right along the ridge of the mountain range.

The good news, according to Mr. Parrish: "One side or the other, we're not going to get hurricane-force winds no matter what happens."

There is more good news. Even if the Pittsburgh region were clobbered by Hanna, flooding might be mitigated thanks to a dry summer and relatively low reservoir levels. "It depends how quickly it falls. Obviously, 3 to 5 inches if it fell in 12 hours could be more than streams and creeks could handle. But the big rivers and reservoirs are down. They could probably handle quite a bit of rain. But you get up near 5 inches, that's a lot," Mr. Parrish said.

Meteorologists should have a good idea by tomorrow where and when Hanna will make landfall and be able to update predictions for the impact on southwestern Pennsylvania.

While the National Weather Service is looking ahead, local residents volunteering in the South are dealing with Hurricane Gustav's aftermath.

Daniel Lopes, 55, of Fayette City, rode out the storm in an American Red Cross shelter in Covington, La., about 40 miles north of New Orleans. Yesterday he got down to business inspecting Red Cross shelters.

"It wasn't as bad as we all expected it to be," Mr. Lopes, a retired state corrections officer, said of the storm. "This is a lot better than [Hurricane] Katrina. I think they were more prepared this time."

Mr. Lopes is one of 10 volunteers from the region who have been deployed by the Red Cross to assist Gulf Coast residents. It is his fifth deployment with the organization, the first one having come three years ago in Katrina's wake.

"Katrina, that's what got me involved. I was sitting at home. I had my feet propped up watching the storm [on TV] and I thought 'I gotta do something,' so I called the toll-free number and took boot-camp training and here I am."

Private individuals and state government workers headed south to help.

Liz Carrier, 23, of Squirrel Hill, has been in New Orleans since January doing post-Katrina recovery as construction coordinator for the Office of Disaster Response of the Episcopal Diocese of Louisiana.

Ms. Carrier missed the storm far from the Big Easy. She was seeing college friends for the weekend in Grinnell, Iowa, home of her alma mater, but will return to Louisiana this week.

Meanwhile, Ms. Carrier's work colleagues have left New Orleans and are waiting inside a Baton Rouge church for clearance to return. Power is out at the church, she said, but that seems to be the worst of it.

Ms. Carrier plans to leave today for the journey back to New Orleans in her car, which already has 120,000 miles.

"It always feels meaningful," Ms. Carrier, a 2003 graduate of Sewickley Academy, said of her work. "There are all these big, overwhelming problems that I can't necessarily do anything about, but the people we build houses for, that makes all the difference in the world to them."