Heavy thunderstorms bring flooding, some severe threat this afternoon and evening

Flash Flood Watches

Let’s start the day off with the good news first, as there isn’t a whole lot of it in this post, unfortunately.

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Southeast winds have pushed the weekend’s wildfire smoke out of the area. Clean air from over the Atlantic Ocean has moved in, bringing air quality levels back to their typical no-concern levels.

On the Air Quality Index map, Green “Good” levels are throughout the Finger Lakes, with the Syracuse area just above the threshold into the yellow “Moderate” category.

Air quality will not be a concern for the rest of today and tonight, but heavy rain and thunderstorms will.

Another slow moving front will work its way into the region with multiple waves of rain and thunderstorms.

The first wave will impact the northwestern parts of the Finger Lakes by the mid-afternoon. Wayne, Ontario, Monroe, Livingston, Genesee, Wyoming and northern Allegany counties will be most likely to experience this first round.

Activity will slowly spread eastward during the late afternoon. The southeastern Finger Lakes, such as Chemung, Tioga, Cortland, and parts of Tompkins County, may not see much at all before sunset.

Widespread heavy rain and thunderstorms will then be possible through the evening.

For severe weather, the threat will be highest during the afternoon hours, especially for areas about from Penn Yan westward. Damaging winds will be the primary severe threat, though hail and possibly even a brief tornado cannot be ruled out.

The bigger threat, however, will likely be flash flooding, with that threat peaking during the evening hours as the rain slows down over the middle and eastern thirds of the region.

It is likely that there will be at least some areas of flash flooding and I am concerned that there could be some significant flash flooding, closing roads and causing damage.

This is probably most likely across the southern half of the region, where soils are less capable of holding onto the rainfall and the terrain is more complex. However, the whole region is at risk.

Nighttime flooding is even more dangerous than daytime flooding due to the lack of visibility, which makes risk assessment even more difficult.

Rain should taper off during the overnight, but a few showers may linger into Tuesday morning.

There is a bit of uncertainty with how this all unfolds, so there is at least a chance that we will avoid the worst this pattern has the potential to produce.

Temperatures today will reach the mid and upper 70s for most areas, though a few higher elevations may stick to the low 70s. Overnight lows will be around 60 degrees.

Weather Staying Active

Behind the front, a new plume of wildfire smoke will likely move in tomorrow. This will include some near-surface smoke, likely impacting air quality at least somewhat. While the air quality has the potential to match this past weekend, it shouldn’t be worse than that and may not reach that level at all.

Temperatures will be in the mid 70s tomorrow with a few more stray showers possible here or there. Most areas will be dry most of the day.

Smoke should decrease again late Tuesday and Tuesday night, allowing air quality to improve. Confidence in smoke behavior drastically drops after 24-36 hours, but this will likely continue to be something we have to deal with on and off throughout the week.

Wednesday is looking dry with sun and clouds. Highs will reach the upper 70s to near 80 degrees.

Late showers will return on Thursday, with scattered showers likely Friday and Saturday. Temperatures will drop, with mid 70s Thursday, highs near 70 on Friday, and in the upper 60s on Saturday.

I do not see anything encouraging as far as a pattern shift goes, with continued frequent rain chances into late June. Temperatures will generally remain in the 70s with some both warmer spikes and cooler drops as weather systems pass through.

Meanwhile, over central Canada, precipitation chances will be more limited, meaning the fires supplying our smoke will likely persist, keeping air quality something to monitor for the foreseeable future.

More Information:

» Finger Lakes Weather Radar

» Finger Lakes Weather Radar

» Zip Code Forecasts

» Your Forecast

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This graphic represents an average over the entire Finger Lakes region. Localized variations should be expected.

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