Pennsylvania's Republicans vote today in a choice between one of their party's most liberal Senators and one of its most conservative Congressmen: For months, it appeared that Specter would win the nomination easily. But Toomey, boosted by millions in contributions from conservative donors, narrowed the gap dramatically this month. Specter and Toomey had spent more than $15 million as of this month's filings, not including money spent on their behalf by independent groups...Behind the scenes, Toomey volunteers were making phone calls and canvassing neighborhoods, while Specter's campaign was relying on the state Republican Party - which endorsed him - to rally voters. The Specter team was also calling voters with recorded messages... Weather forecasts appeared to favor Specter. Cool conditions are expected across the state, with the possibility of spotty showers in the Philadelphia and Pittsburgh areas, where Specter is expected to do well. Heavier rain was expected in Toomey's strongholds of north and central Pennsylvania. An independent poll released yesterday showed Specter halting Toomey's strong recent gains. With 10 percent of those surveyed still undecided, Specter led Toomey by 6 percentage points in the poll from Quinnipiac University, a Connecticut school that tracks elections in the Northeast. That is virtually unchanged from last week.