Flood potential centers on Chemung County on final rainy day

finger lakes weather forecast wednesday july 25 2018 flash flood elmira chemung county heavy rain
With over 5 inches of rain falling so far this week, Chemung County can take very little extra rainfall.

Last Day of Heavy Rain

Wednesday will be another rainy day, but the rain will come to an end tonight as the storm system finally begins to move along.

Rain is once again widespread across the Finger Lakes region this morning. Most of the rain is light to moderate in nature and much more beneficial than problematic.

This rain will push off to the northeast later this morning, leaving some scattered showers around midday.

The risk for flooding will increase this afternoon as additional rain and thunderstorms develop as a front moves through. These areas of heavier downpours are most likely over the eastern half of the Finger Lakes.

These storms will be capable of producing over an inch of rain in an hour with total rain amounts of 1 to 2 inches for many areas east of Keuka Lake.

This evening, the heavier downpours will transition to more of a widespread, lighter rain, similar to this morning. That rain should then exit the region to the east around or shortly after midnight, ending our multi-day rain event.

Thursday will be dry for the most part with a little sun breaking through from time to time.

Elmira Area Flood Concern

The Elmira area once again ended up with some of the highest 24-hour rain totals in the region on Tuesday, thanks to some heavier rain that fell overnight, prompting a flash flood warning.

Chemung County has been repeatedly hit with heavy rain over the last few days. Since Sunday morning, rain totals in the area range between 4-7 inches. For comparison, most of the rest of the Finger Lakes has seen a beneficial 1-3 inches during that same time.

24 Hour Rain Estimates

finger lakes weather rain amounts tuesday july 24 2018
Another 2-4 inches of rain fell on Tuesday across Chemung County with some flash flooding reported. Click to enlarge.

3-Day Rain Estimates

finger lakes weather three day rain fall sunday july 22 2018 monday july 23 2018 tuesday july 24 2018
Sunday to Tuesday rain amounts have gone over 5 inches across Chemung County with 1 to 3 inches for most of the rest of the Finger Lakes. Click to enlarge.

Flash flood simulations project that flooding will occur in this area if between a half-inch and one-inch of rain falls over a six-hour period. A one hour rain of a half-inch or even slightly less would also produce flooding.

Given the likelihood of additional heavy downpours this afternoon, it seems only a matter of time this afternoon before additional flash flooding will occur and warnings will be needed. The flood risk may continue even after the rain has ended due to runoff, so be aware even into Thursday morning.

The threat for flash flooding is slightly less to east across the Southern Tier, but still a very real possibility. Some sporadic flooding will also be possible further north towards Penn Yan, Ithaca, and Cortland, but the chances for heavy enough rain for flooding is less.

Across the northern and western Finger Lakes, there is little to no risk for flooding today.

Friday and the Weekend

Rain will be back in the forecast on Friday, though not at all to the same extent as the rain we have seen this week so far.

A new front will drop southeast across the region. Scattered showers and thunderstorms will likely accompany the front.

The Storm Prediction Center already has a slight risk area issued for severe thunderstorms across Southeastern New York. This will have to be watched in case it is adjusted further northwest. I do not anticipate a big severe weather event for the Finger Lakes, though, with the front passing through during the late morning and early afternoon.

A few showers may linger around the region on Saturday. Sunday, however, looks mostly dry with a good deal of sunshine.

Temperatures will continue to hold in the 70s through the weekend.

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Meteorologist Drew Montreuil
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.). When not forecasting, he can be found working at the local library, making goat milk soap, running until his legs burn, or playing with his three young boys.