Currently: Sprawling high pressure from VA to Central Quebec is responsible for the cool air across the area. Low pressure organizing from Texas to the Quad Cities will be our next weather maker.
Tonight: Temperatures will be a little tricky tonight, since low temperatures will depend on how quickly it gets cloudy and how much radiational cooling occurs. For now, the thinking is clouds will spread in from Southwest to Northeast as the night goes on. All in all, this should result in low temperatures ranging from the mid 20s to the mid 30s.
Tomorrow: Another interesting aspect of this storm is timing the arrival of precipitation. With these types of systems, it' s always a race between when the air can saturate enough to allow precipitation to fall and how fast the overrunning precipitation can arrive, which usually does come in faster than models suggest. In addition, if it begins precipitating heavy enough into the dry air, evaporational cooling can temporary cool the air. Although temporary, this can have an effect on precipitation type, mainly talking about rain vs. freezing rain. As far as sleet and snow go, that is more determined by upper level temperatures, which wouldn't change based on what's going on at the surface. Going by a model consensus, most places in the state will see precipitation develop too late to have anything substantial in terms of accumulating snow. The best chance for any accumulations would be in the NW hills, and even there, the accumulations would probably be only on the order of 1-2". Right now, I am thinking that precipitation arrives during the second half of the morning rush hour in the SW, to just after lunch in the NE. There could be some freezing rain in the sheltered valley locations if it starts early enough. A lot of this may have to be watched right up to the last minute. Rain should then fall pretty much all day, not ending until midnight in the SW and a few hours later than that in the NE. Rainfall amounts should be around one inch on average, which is good, because we need the rain. Most of the state is in a moderate to severe drought. As far as temperatures, they will be chilly, given the cool start, clouds, and precipitation. High temperatures should be around 50 degrees throughout the state, though some of those high temperatures may not occur until late at night.
Tomorrow Night and Friday... Tomorrow night was pretty much already covered above. Rain tapers off from midnight in the SW to a few hours later in the NE. Temperatures probably don't drop too much tomorrow night. As mentioned, high temperatures will probably occur towards midnight, After the rain ends and the cold front goes through, temperatures will begin to fall. Low temperatures will likely be in the 40s throughout the state.
Longer Term- the weekend and beyond: The weekend's weather will be largely determined by the position of a back door type cold front. Basically, with these fronts, when they are south of you, it's cool, often with drizzle and fog, and when they are north of you, it gets warmer and sunny. When the front is near overhead, you can get periods of rain. In addition, back door cold fronts are very difficult to forecast. Right now, I will use a model consensus to determine the position of the front over the weekend, since that's the best tool we have at this juncture. However, these back door cold fronts have generally ended up south of where models have them at this range.
Based on the above, I'll have the back door cold front to the north of the state on Saturday, with some peaks of sun and temperatures getting into the 60 to 65 degree range. I'll then show the back door front moving through later on Saturday, with a quick shower, and then cooler temperatures, in the mid 50s, for most places, on Sunday.
Looking beyond the weekend, Monday should stay in the same general air mass as Sunday, with similar conditions expected. As ridging moves in, expect temperatures to be 5 to 7 degrees warmer on Tuesday and Wednesday. With ridging overhead, do not expect any precipitation until beyond the long term- maybe around the end of next week, and that brings us into the...
Long Range: As we head into the first week of November, it appears the overall hemispheric pattern begins to truly shift into one that would feature more frequent intrusions of cold air, and perhaps east coast storminess. While it may still be too early to start talking about widespread snow threats, for those of us who like winter weather, it may be a good thing that we're starting to see this pattern shift, as the first or second week of November us generally when you want to see the pattern to start lining up favorably.
That's all for the "textual" portion of this discussion. Now let's take a look graphically at the system slated to affect the state tomorrow. Generally, I'll just focus on rainfall amounts. This is the GFS model, although other models have been wetter, in general, but not by a tremendous amount. You can also see that precipitation is very uniform throughout the state, and a nice, soaking rainfall for the state.