Another round of showers and scattered thunderstorms is expected to move across the Finger Lakes and Central New York on Sunday before a cooler, more persistent lake-driven pattern settles in and keeps periods of rain around into Tuesday.
The National Weather Service forecasters from Buffalo and Binghamton point to the most active part of Sunday’s forecast developing from late morning into the afternoon, when a cold front and an upper-level low could help a few storms turn stronger, especially from the Finger Lakes east into Central New York. Highs are still expected to reach the 70s before cooler air begins to take hold.
The broader pattern then changes quickly. Forecast confidence is higher on the cooler stretch than on the exact placement of every rain band, but both offices expect lake-enhanced and lake-effect showers to become a larger part of the forecast tonight through at least Tuesday, with Monday shaping up as the coolest day of the stretch and Wednesday offering the clearest break before another late-week system approaches.
Sunday turns active again
Showers already moving through early Sunday are expected to push east through the morning, but the forecast does not end with that first round. As winds turn more westerly behind the front and the upper-level low drops over the eastern Great Lakes, additional showers and thunderstorms are expected to redevelop across the region during the afternoon.
That is where the forecast carries its most notable uncertainty and its highest-impact risk. Neither Buffalo nor Binghamton is signaling a widespread severe outbreak, but both offices say a few storms could become strong enough to produce damaging wind gusts, with hail also possible in taller storms. The stronger risk appears to lean from the Finger Lakes eastward toward Syracuse and nearby parts of Central New York, where daytime heating and better storm organization may overlap for a few hours.
Rain coverage is not expected to be uniform all day. Some communities will see breaks between rounds, while others pick up a quick downpour or thunderstorm as the front clears. Even so, Sunday still looks unsettled enough across the region that the day transitions away from the warmer, more humid feel of late Saturday and toward a cooler start to the workweek.
Cooler air arrives tonight
The larger shift begins after sunset. Once the front moves east and surface heating fades, the severe threat should diminish, but the atmosphere behind it becomes much more favorable for scattered rain showers to continue, especially as cooler air pours over the still-warm lakes.
That setup matters for the Finger Lakes because it changes the character of the forecast from frontal showers and storms to a more lake-driven pattern. Buffalo forecasters expect southwest flow tonight to start organizing bands near Lake Erie and Lake Ontario, while Binghamton forecasters expect at least spotty showers to return late as the upper low settles overhead. Overnight lows are forecast to fall into the upper 40s to mid-50s by daybreak Monday, a noticeably cooler feel for late August.
Monday stays unsettled and cooler
Monday is expected to be the coolest day in the coming week, with highs generally held in the 60s to lower 70s. Buffalo says temperatures in western and central New York may run 10 to 15 degrees below late-August normals, and Binghamton also points to a much cooler air mass settling over the region as 850-millibar temperatures drop into the single digits Celsius.
The challenge on Monday is not whether showers will develop, but where they become most persistent. Lake-enhanced and lake-effect rain is expected east and southeast of the lakes, though Binghamton also notes that this pattern often sends coverage farther south than some guidance first suggests. That is why shower chances were pushed deeper into the Twin Tiers Monday afternoon, while parts of the western and northern Finger Lakes could also see repeated rounds depending on how individual bands set up.
There is also enough cold air aloft for a few thunderstorms to redevelop during the day, though the setup looks more scattered and less organized than Sunday’s frontal activity. Communities closer to Lake Ontario and downwind lake corridors may spend more time under thicker clouds and steadier showers, while inland spots farther from the organized bands could see a broken mix of clouds, brief dry periods and passing rain.
Tuesday begins to ease
Tuesday does not look fully dry, but it should mark the start of a gradual improvement. As the upper low lifts northeast, both forecast offices indicate that the lingering shower coverage should start to shrink, with the most persistent rain more likely to remain tied to areas downwind of Lake Ontario and the eastern Great Lakes.
That means the Finger Lakes and Central New York may still deal with spotty showers at times, particularly early or wherever leftover lake bands hold together, but the overall trend is toward less widespread rain than Monday. Temperatures should recover slightly from Monday’s levels, though the region is still expected to stay on the cooler side of normal through the day.
Tuesday night appears to be the real turning point in the forecast. Binghamton expects high pressure to begin building in, while Buffalo projects lake-effect rain diminishing first off Lake Erie Monday night and later off Lake Ontario by Tuesday night. The result should be a quieter setup heading into midweek.
Wednesday offers the clearest break
Wednesday is shaping up as the cleanest day in this stretch of the forecast. Both offices point to high pressure and mainly dry weather, giving the Finger Lakes and Central New York a better chance to string together a more stable day after several rounds of showers and cooler air.
The forecast discussions do not suggest a major heat surge returning right away, but they do support a break in the unsettled pattern. If the current timing holds, Wednesday should bring the most dependable dry window between Sunday’s storm risk and the next late-week disturbance.
Late week turns less certain again
Forecast confidence drops some by Thursday and Friday, but the pattern does not stay quiet for long. Binghamton expects another system to approach from the south and west late in the week, while Buffalo also points to scattered showers and thunderstorms returning Thursday afternoon as the next disturbance reaches the eastern Great Lakes.
The important detail for now is timing. Some guidance leans toward the activity arriving later Thursday, which would keep more of the day dry before shower and thunderstorm chances build. The late-week system also looks more progressive than the one affecting the region now, so the current expectation is for it to move through rather than stall overhead into next weekend.
That leaves the late-week forecast in a familiar August position: not a washout signal, but not a locked-in dry stretch either. After Sunday’s stronger storm potential and the cooler lake-driven stretch through Tuesday, Wednesday still stands out as the best-defined break before shower and thunderstorm chances increase again heading toward Thursday and Friday.
Check the latest forecast at the FingerLakes1.com Weather Center.
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