Low pressure north of the Finger Lakes will deliver a shot of cold air by midweek.
This is the same low pressure that brought the rain and thunderstorms to the region on Sunday. As disturbances rotate around the low pressure system, showers will occasionally move through the Finger Lakes. As is often the case with these types of systems, gauging when the subtle disturbances will move through is a low confidence task for anything more than a day or so in advance.
For Monday, though, it looks like the Finger Lakes will generally stay dry and mild. With a good deal of sunshine, temperatures should rise into the mid and upper 70s this afternoon. Showers are generally unlikely until one of these disturbances swings through tonight. A few showers will move across the region overnight, especially towards the midnight hour. Given the passage of this disturbance during the night, the shower activity will probably be limited due to the lack of daytime heating.
Another disturbance may make its way through the Finger Lakes Tuesday. At this time, it looks like the midday hours may have the best shot for more widespread showers, but this remains a bit uncertain. A couple of thunderstorms could also pop up within the showers, but severe weather is unlikely. Some very small hail could be possible due to cold air above the surface.
Temperatures will start to drop on Tuesday as well, with afternoon highs near or just below 70 degrees. Wednesday will be even cooler, with highs only near 60 degrees. Another disturbance may bring showers and storms on Wednesday, including the threat again for some small hail. Confidence, of course, is below normal, so check back for updates over the coming days.
The low pressure will finally start to pull away on Thursday. At this time, it looks like the showers on Thursday will mostly be east of the Finger Lakes. It will remain cool though, with highs again only near 60. Morning lows will be well into the 40s, but should remain much too warm for any late season frost concerns.
Heat will build across the Midwest late in the week, setting up a strong contrast in temperature over the Great Lakes. While very uncertain at this point, there could be another severe threat on Saturday somewhere in the general vicinity of the lower Great Lakes, Mid Atlantic or New England. Even now, six days out, the Storm Prediction Center is highlighting this potential, which is quite rare for our area. This is something that will have to be watched, but it is much too soon to know where or even if this threat will come to fruition.