UPDATE 10:45 PM, MONDAY: There’s really not much reason to start a new thread, as little has changed, other than to slightly boost the amounts with 2-plus inches expected to be widespread over the region. Flash flood watches are in effect, as locally heavy rain, particularly Tuesday afternoon and evening, could lead to localized flooding from runoff, despite recent weeks of dry weather. The strong upper atmospheric winds aloft with this system are driving a geyser of thick moisture northward from the Gulf of Mexico to the Great Lakes — you can follow its progress on national radar linked here. By Wednesday another windy push of cold air will move in — there may be some snow showers, mainly west of the Blue Ridge. This storm will act as a pattern-changer, leading to several days in which a southerly dipping jet stream is likely to bring colder-than-normal weather (but not really extreme cold) to the region. There is some potential by the mid to late portion of next week for a disturbance moving through that southerly diving jet to bring a chance of wintry precipitation to the region, but that’s still too far off now to consider too many specifics. END UPDATE
A soaking appears very likely throughout the region, as a strong surface low-pressure system moves through the Ohio Valley, dragging a cold front that will contain secondary ripples of low pressure that will move northward along the eastward moving front. Intense winds aloft will help steer abundant Gulf of Mexico moisture northward, which will be squeezed out by a variety of factors Tuesday into early Wednesday — overrunning a shallow dome of cooler air trapped against the mountains, upslope flow blowing from the southeast over the mountain ridges, and the lifting action of the strong cold front. Expect rainfall amounts to top an inch over almost all of Southwest, Southside and Western Virginia — and several amounts could top 2 inches. Here is the way the National Weather Service at Blacksburg sees the rainfall developing. Additionally, strong winds could gust over 50 mph from the southeast along the ridges of far Southwest Virginia — generally west of I-77 — on Tuesday, and then over a much wider area from the west and northwest on Wednesday after the front passes.
Though things have been dry of late, I would not be surprised to see a flood watch or flash flood watch issued, given the level of rain that could fall in a short time particularly Tuesday evening. If there were more instability, severe weather could be an issue with the intense winds aloft, but the threat of severe thunderstorms and tornadoes will probably be more of a problem over the eastern half of our state south into the Carolinas.