Thunderstorms with heavy rain and a few strong wind gusts are expected this afternoon, particularly across the southeastern Finger Lakes.
Several factors are at play in the atmosphere, resulting in an enhanced, yet complex weather setup, with the primary concern being heavy rain and localized flash flooding.
The good news for most of the Finger Lakes region is that the greatest probability of flooding is east of the area. The Weather Prediction Center’s Excessive Rainfall Outlook has a Moderate risk for flash flooding just clipping the far southeastern Finger Lakes, across southern Cortland, far southeastern Tompkins, and most of Tioga counties. Much of the region is a category lower, in the Slight risk zone.
A flood watch is also in effect for Cortland, Tompkins, Schuyler, Chemung, and Tioga counties. These flood watches are on the edge of a much larger area of flood watches extending from North Carolina to New Hampshire.
Scattered to numerous showers and thunderstorms should start to develop over the region during the late morning and midday hours, and may continue to do so through the afternoon. Some areas may see multiple storm cells as they move slowly off to the northeast.
Torrential rainfall rates of 1-2 inches per hour, and maybe even briefly higher, will be possible. Any prolonged period of these rainfall rates will result in the risk of flash flooding. Significant and dangerous localized flooding is not out of the question, though the chances for that will be higher to our east, particularly in the Poconos, Catskills, and Vermont and New Hampshire.
An isolated strong to severe thunderstorm is possible, with strong winds and lightning the only other risks besides heavy rainfall.
The further north and west, the lower the chances for thunderstorms. Particularly from roughly Oswego to Newark to Letchworth and points north and west, it will probably be dry more than it will be rainy.
The heavy rain will come to an end this evening, but additional showers will be possible right into Monday morning. How much it rains on Monday is uncertain, but the most likely scenario will be for a drying trend to take hold and for much of the day to be rain-free.
Please remember that it is not possible to predict where individual storm cells will hit before they have developed, and that the more complex an atmospheric setup is, the higher the uncertainty runs.
My best advice, if you have outdoor plans today, is to watch the radar closely, have a backup plan in place, and of course, take any warnings seriously and obey local road closures and traffic restrictions. If you live in a known flood-prone area, especially if in the red Moderate zone in the southeastern Finger Lakes, have a plan in place to protect yourself and your property.