Weather Forecast and Effects
First off for Virginia; it appears the system will be in deep southwest Va on Monday and be gone from the state by Wednesday, so depending on how fast this storm system is moving we could see rain in the morning in western Va and rain in the evening in the surburban areas of NOVA, Richmond and Tidewater. This probably has a net benefit of nothing since suburban voters typically vote in the morning; especially in NOVA whereas rural voters don't really care as much what time they vote. If however there is rain statewide all day or even just in the morning in NOVA, that should favor Allen (since people won't vote b/c they don't want to get out in the rain).
Rain in general should favor Allen since his strengths are the more rural areas that typically don't have long wait lines outside. Suburban areas on the other hand have long lines that people will not wait in; especially in bad weather.
The other dynamic here is age of voters. Most polls I have seen show Webb leading among the 65+ demographic, which will probably be the most unlikely to vote if there is bad weather (they aren't going to work, don't want to get out in the weather and get sick, etc). This bad weather should also benefit Allen is that way.
The third thing is overall turnout. With bad weather usually comes an overall lower turnout. The Allen people feel they are better off the lower the turnout is. Even so, the dems are more motivated so I think lower turnout statewide could actually hurt Allen in this race.
Best case scenario for Allen is rain in NOVA in the morning and nothing in Richmond or the Valley. Best case for Webb is basically the opposite; rain in the Valley and Richmond and clear skies in NOVA.
For Tennessee; it appears rain is only expected in the eastern part of the state while Memphis is clear. This could hurt Bob Corker in the Senate race as Memphis is a democratic stronghold and the GOP stronghold areas are the border counties in the easternmost part of the state.
In the northeast, rain could push turnout lower in many competitive House races in OH, PA, NY and CT. I still believe lower turnout favors democrats in this environment b/c they are more fired up and more likely to vote anyway. If these races are close, this weather could tip the balance (and the bulk of the competitive seats are on the east coast).
In Maryland, the same theory applies as Virginia. If rain comes in the morning in the DC suburbs; look for that to benefit Steele and Ehrlich in the statewide races there. If however the rain is only in the western part of the state; it could be bad news for the GOP candidates.
We will continue to monitor the weather forecasts and see if anything changes.