An area of low pressure is moving through the southeastern United States, while over eastern Canada, high pressure is in control.
The spheres of influence of these two opposite pressure systems are meeting over the Finger Lakes, creating a subtle, weak atmospheric boundary. This boundary will sit over the area for a day or two, bringing some clouds and a few sporadic showers.
Already this morning, there are a few blips on the radar with showers drifting from north to south. This will continue to be the case this morning, but most areas will remain dry.
More activity is expected this afternoon as the instability in the atmosphere rises with the daytime heating cycle. Scattered pop-up showers will spread across the southern half of the Finger Lakes, while precipitation to the north will be harder to come by, but not impossible.
The individual shower cells should be small and fairly short-lived for any one location. The rain may come down heavily for a brief time, and a couple rumbles of thunder are not completely out of the question.
Winds will be light and from the east with the boundary overhead. The boundary will drift southward with time, so northern areas may end the day with more of a northeasterly wind.
Temperatures will mostly be in the upper 70s and low 80s today. Some urban and valley locations could sneak towards 85 degrees if some sun pokes out and showers remain elsewhere.
The shower activity should diminish quickly this evening, and some northern areas may even see skies clear as the boundary drops to near the NY-PA state line. The clouds should diminish more overnight, leading to an increase in areas seeing clear skies.
Nighttime temperatures will remain mild, with lows between 55-60 degrees, but mostly in the upper half of that range.
The boundary will remain overhead tomorrow but will be weaker. A few pop up showers will still be possible, but the overall coverage should be less than today. There should be a bit more in the way of sunshine tomorrow as well.
Winds will be from the east and southeast with speeds near or just over 5 mph. Afternoon highs will be near or just under 80 degrees for most areas except the I-90 region, which will see low 80s.
More Chances for Showers
A small piece of low pressure will try to nose its way northward into the Mid-Atlantic region on Thursday. As this happens, a broader area of rain showers will spread north toward the Finger Lakes.
The models are handling this area of rain differently, with some bringing it directly into the area, while others favor more of a glancing impact with most of the rain heading east.
Either way, at least a few showers should meander into the area on Thursday, but there is a chance for more widespread precipitation. Lightning seems unlikely, and most of the rain should be light. The second half of the day seems to be more favorable for the rain.
Temperatures will take a small hit with the clouds and showers, and highs should mostly be in the mid 70s. A steadier rain could lead to lower temperatures. Winds will remain easterly, with similar speeds to today and tomorrow.
Uncertainty remains higher than usual as we head into Friday and Saturday. Both days have chances for showers and a few rumbles of thunder. Saturday seems to have a higher chance of rain than Friday, though it is easily conceivable that a few areas could see rain on Friday and then get missed on Saturday. OVerall, the coverage of the rain, and the potential rain amounts, look higher Friday and Saturday than today, tomorrow, and possibly Thursday.
The uncertainty in the forecast comes from a lack of any significant, well-defined disturbance or front in the area for the models to lock in on this far out. I would expect the forecast to clarify more over the next couple of days.
Temperatures should get a small boost back into the upper 70s with some low 80s mixing in. it will be humid as well, with dewpoints well into the 60s. The humid air will also keep nighttime temperatures mild, with overnight lows only in the mid 60s.
Sunday looks like our best chance for a completely dry day, though this far in advance with this overall weather pattern, it isn’t something to rely too heavily on. Assuming it does stay dry, temperatures should poke up into the low 80s.
If Sunday is the best chance for dry weather, Monday is the best chance for thunderstorms. Warm temperatures and humid air will provide an unstable atmosphere, and a cold front will be approaching from the west. But it is too early to tell if these two factors will match up at the proper time or not.
With the frontal passage, temperatures should go from the low 80s Monday to the mid 70s Tuesday and most of next week. The weather will likely remain unsettled, with more chances for rain.
This graphic represents an average over the entire Finger Lakes region. Localized variations should be expected.