The remnants of Hurricane Ivan could bring 3 to 5 inches of rain to the Baltimore region over the next few days, along with the danger of stream and tidal flooding.
Then again, forecasters said, it might not.
Next week, whatever rain and flooding we do get from Ivan could be compounded by Jeanne, a tropical storm now headed for the Bahamas.
"The track it's taking certainly would bring it up the eastern seaboard. Potentially, it could have an impact," said Steven Zubrick, science and operations officer at the National Weather Service forecast office in Sterling, Va.
But, "it's too early to say if that would happen," he added.
In the meantime, forecasters posted flood watches yesterday for most eastern states as far north as Pennsylvania and New Jersey, including all Maryland counties west of the Chesapeake Bay, and on the Lower Eastern Shore.
"Dealing with any tropical system's remnants in our area always leaves us open for the potential for heavy rain. There's a lot of moisture in the air," Zubrick said.
Ivan, which had been downgraded to a tropical storm, was trying yesterday to work its way north from the Alabama-Florida coast. But it faced two blocking highs, over New England and over the Great Lakes.
Forecasters could not say for sure whether it would muscle its way between the highs or run out of steam over the southern Appalachians.
Even if the storm stalls, its moisture will spread out ahead. Ivan's wind circulation will draw in Atlantic moisture and drop it on the eastern slopes of the mountains. An approaching cold front could squeeze even more rain from the tropical air.
"Right now, in the Baltimore area we're expecting anywhere from 3 to 5 inches of rainfall," Zubrick said. "We're looking at a potential for significant problems with the rivers."
"Certainly the Potomac and any of the rivers that feed into the bay region are susceptible to flooding, given these rainfall forecasts," he said.
Up to 10 inches of rain is possible in the Shenendoah Valley and southwestern Virginia. Emergency management officials have advised those along flood-prone rivers to leave sandbags - piled up against Frances' deluge - where they are.
Low pressure from Ivan, combined with high pressure to the north, is likely to produce increased winds from the southeast that could blow water up the Chesapeake Bay, with potential for tidal flooding this weekend in Baltimore and Annapolis harbors and other low spots along the shore, Zubrick said. The high water could be aggravated by runoff from heavy rain.
Forecasters warned of further tidal flooding along the bay next week as Jeanne approaches.
Still, there are scenarios that might cut the Baltimore area a break, Zubrick said.
"There is some potential for the [cold] front from the Great Lakes to punch through here and shunt [Ivan's] moisture to our south," he said. "That could lessen considerably the amount of rain.
"If we didn't have Ivan, we'd be forecasting a great weekend," he said. "Unfortunately, we do."