Increasingly rainy Thursday into Friday for the Finger Lakes

Minor Rain Showers Thursday

A slow moving frontal system will approach and move through the Finger Lakes over the next couple of days. As it does so, the chances for rain will gradually increase across the area.

An area of rain showers and thunderstorms over Michigan early this morning will head towards the Finger Lakes region for the midday and early afternoon hours today.

This area of rain is expected to weaken to just a few scattered showers by the time it arrives. Little in the way of rain is expected across the southeastern regions, while areas further north and west could see a relatively short period of steadier showers.

Outside of that batch of showers, most of Thursday should remain dry with the front still lagging well to the northwest. Temperatures will push into the upper 70s this afternoon.

The chances for rain will start to increase again this evening and especially overnight. Still, showers should be scattered and some areas may not see any rain at all between now and Friday morning.

Monitoring Flash Flood Potential Friday

The weather for Friday is rather complex.

As the front slowly makes its way towards the region, moisture from Tropical Storm Cindy will be sucked northeast. While the most copious amounts of moisture will likely remain south across Pennsylvania, the atmosphere will still be very moist and capable of heavy downpours.

The computer models are among their worst when dealing with tropical systems moving inland. The structures and mechanisms of a tropical system differ significantly from a typical low pressure, so when these two types of systems interact, surprises are not uncommon.

Given that the front will be moving through the area during the afternoon and evening hours, there has to be concern for heavy rain and potential flash flooding. Just because the models do not currently show that occurring is not a reason to think that there is no risk.

Flash flood guidance indicates that as little as 1-2 inches in a span of one to three hours would be enough for some areas to flood in the Finger Lakes. That is certainly attainable given the atmosphere tomorrow.

In addition to the flash flood risk, there may also be a small risk of severe wind gusts from the thunderstorms and possibly a minor tornado risk as well.

This will be something I will be monitoring continuously on Friday.

Temperatures Head Below Normal

Behind this system, a cool weather pattern will set up across the Finger Lakes once again.

Temperatures on Saturday will top out in the mid 70s, but this will likely be as warm as it gets for quite some time.

Starting Sunday, daily temperatures should be at or below 70 degrees for most of next week.

Saturday will also be the driest upcoming day.

With the sun angle at its highest, surface heating is maximized. With cold air aloft, strong surface heating will create an unbalance in the atmosphere.

This should result in daily showers and thunderstorms developing during the late morning hours and persisting through the afternoon before dissipating by evening. This daily pattern should start on Sunday.