Busy weather through the weekend with heat, storms

finger lakes weather forecast friday may 20 2022 showers thunderstorms heat humidity
Hazards from both high heat and scattered thunderstorms will be present through the weekend. Here are the latest no-hype details. [Photo by Meteorologist Drew Montreuil]

Thunderstorm Risks

An active weather pattern is setting up for the Finger Lakes region throughout the weekend with both thunderstorms and an early season blast of heat.

While the chances for thunderstorms Saturday and especially Sunday have been well advertised for days now, the thunderstorm threat today only started to just show up on the models yesterday. This is because, as I explained yesterday, the threat for storms today depended on thunderstorm development nearly 1000 miles away in Missouri yesterday.

Thunderstorms did indeed develop yesterday, including a weak tornado in the St. Louis suburbs. This storm complex has persisted through the night and is currently moving through Ohio. Several other clusters of rain and thunderstorms left over from yesterday also exist in southern Pennsylvania and moving across Lake Erie.

Our first chance for rain and thunder today will come from the Lake Erie complex. This should weaken as it moves into the area for the second half of this morning. Still, a few showers and perhaps a rumble of thunder will quickly move through between 10 AM and 1 PM.

Meanwhile, the Ohio cluster will move northeast into Pennsylvania. Most of the action should stay to the south, but some parts of the Southern Tier could see some thunderstorms. This cluster, unlike the Lake Erie cluster, may strengthen again this afternoon.

Both clusters should be quick moving, with rain lasting an hour, or much less, for most locations.

finger lakes weather forecast friday may 20 2022 thunderstorm threat
The yellow and green shading show the most likely areas for thunderstorms on Friday and Saturday, respectively. Any storm will have a chance for frequent lightning, strong winds, or hail. Click or tap to enlarge.

Overall, the severe storm risk is minimal across the region, with the best chance for thunderstorms coming across the far southern reaches of the region. Most areas will probably not see a thunderstorm today.

I will say, though, that the weather models can often perform poorly in situations like this, where the storm threat is dependent not on large-scale features, but small clusters of preexisting storms. As such, be weather aware throughout the day, realizing that showers and storms could pop up at almost any time and that some isolated severe weather is not out of the question.

The thunderstorm threat for Saturday will be highest across the western and northern Finger Lakes. Again, there is a lack of a large-scale event to trigger thunderstorm development, and the thunderstorms that develop tomorrow may have their roots in storms that pop up today in the Midwest.

With the heat and humidity, which I will get to momentarily, any storms that develop tomorrow will have a potential for strong winds and hail, not to mention frequent to continuous lightning.

Thunderstorms Saturday are most likely very late in the afternoon or in the evening, roughly between 6-10 PM.

The greatest overall threat for severe thunderstorms will come on Sunday, though that is still far enough out that the details are still coming into focus.

A strong cold front will push into the region, providing the trigger for thunderstorm development. The timing of the front will determine how hot and humid it gets before the storms develop.

A line of thunderstorms should develop over the Finger Lakes sometime during the midday or afternoon hours. Parameters continue to look favorable for damaging winds and lots of lightning. This is a threat I will continue to monitor closely with updates throughout the weekend.

finger lakes weather 7-day forecast friday may 20 2022
This graphic represents an average over the entire Finger Lakes region. Localized variations should be expected. Click to enlarge.

Heat and Humidity

Blustery south winds will push warm, humid air into our region today. Winds may gust as high as 40 mph today.

The extra clouds and showers today may keep temperatures a degree or two lower than they would be otherwise, but most areas should still work their way into the 80s today. Highs in the mid 80s are likely in the I-90 corridor, while lower 80s will be more common south of the Thruway. Higher elevations and the Southern Tier, where the afternoon thunderstorms are most likely, will top out in the upper 70s.

Tonight will be warm and muggy, with lows mostly in the 65-70 degree range. The best chance for temperatures sticking near 70 will be in the Syracuse and Rochester areas.

With thunderstorms not expected until late Saturday, most of the day will have a mix of sun and clouds, allowing temperatures to really rise. Most areas should be near or above 90 degrees, though mid 90s are looking less likely than they were a few days ago. Even higher elevations may get close to 90 degrees.

Dewpoints on Saturday will rise into the mid 60s. While not the oppressive mid-summer dewpoints in the 70s, the combination of heat and humidity this early in the season can be hazardous. Heat index values will be in the mid to locally upper 90s. Be smart with the heat on Saturday.

Saturday night will have widespread mid 60s for temperatures, with a quick rise expected Sunday morning. How warm it ultimately gets will depend on the timing of the front and thunderstorms. Mid and upper 80s are a good bet, even with an earlier, midday frontal passage.

The weather will quiet and cool down behind the cold front Sunday. Mainly dry conditions are expected Monday, Tuesday, and possibly Wednesday, though a stray shower here or there cannot be ruled out, especially early Monday and late Wednesday.

Monday will be cool, with highs in the low 60s. Temperatures will rise to around 70 on Tuesday, with upper 60s or low 70s on Wednesday, depending on cloud cover and any showers.

Unsettled weather looks likely toward the end of next week with temperatures remaining mostly in the 70s.

More Information:

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finger lakes weather 7-day forecast friday may 20 2022
This graphic represents an average over the entire Finger Lakes region. Localized variations should be expected.

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Follow Meteorologist Drew Montreuil:
Meteorologist Drew Montreuil has been forecasting the weather in the Finger Lakes region since 2006 and has degrees in meteorology from SUNY Oswego (B.S. with Honors) and Cornell (M.S.). Drew and his wife have four young boys. When not working or playing with the boys, he is probably out for a run through the countryside.