Widespread rain arrives Thursday evening after sunny start

finger lakes weather forecast thursday december 20 2018 rain wind snow above normal temperatures
After a rather nice day, widespread steady rain will move into the Finger Lakes this evening, kicking off a wild ride through Friday. [Photo by Meteorologist Drew Montreuil]

Nice Day Turns Rainy, Windy

Much of Thursday will be a nice day, but an area of widespread rain will move in from the south this evening.

Skies are starting the day clear with temperatures mostly in the upper 20s and low 30s. There are a few colder pockets where temperatures are in the teens.

Sunshine will be abundant early on. Temperatures should quickly rise into the 40s before noon.

Thin cloud cover will work in by midday and will become thicker as the afternoon goes on. This will slow the warming, but high temperatures should still be near 50 degrees for most.

Rain will overspread the area from south to north in the hours immediately following sunset. By 7 or 8 pm, it should be raining over all the area.

Steady rain will continue throughout the night with strong winds kicking up after midnight. The highest gusts will be over the hilltops where 40 mph gusts will be possible.

The heaviest amounts of rain should remain to the southeast and west of the Finger Lakes. Locally, totals will be on the order of a half-inch through the morning hours.

Temperatures will drop into the low 40s this evening but rise back towards 50 degrees by dawn Friday.

Very Warm Friday, Quick Turn to Cold Saturday

The storm system responsible for the rain Thursday night will take a path directly over the Finger Lakes on Friday.

This will result in a period of dry, very warm weather for much of Friday.

Temperatures could approach or exceed 60 degrees, especially if the sun comes out. This is most likely over the eastern Finger Lakes in valley locations. Widespread mid and upper 50s are likely elsewhere.

The warm weather may even be enough to trigger a few rumbles of thunder late in the day as a cold front creeps east across the Finger Lakes. Regardless of any thunder, this front will bring another period of rain to the area Friday evening.

Cold air will flood in behind the front and by midnight, most areas will be back in the 30s. There will be a narrow window of opportunity as the cold air moves in and the precipitation moves out for snow. Depending on how long the two overlap, anywhere from a dusting to a couple inches will be possible.

Flurries will continue behind the storm system through Saturday morning as blustery northwest winds continue to pump cold air into the region.

Temperatures Saturday will hover near 30 degrees all day. With wind gusts over 30 mph, it will feel more like 20 degrees.

White Christmas Odds Increasing

Winds will go calm Sunday morning and skies will clear as a small area of high pressure moves overhead.

High temperatures will top out in just the low 30s, so any snow that falls Saturday will stick around.

Clouds will increase Sunday afternoon as the next weather system moves in.

This system is small and not overly powerful, yet the models are trending towards a higher precipitation output centered on the Finger Lakes.

The result could be a surprisingly generous snow event with several inches possible Sunday night and into early Christmas Eve. Uncertainties remain, however, as models often have a difficult time with these types of small systems.

Skies will remain cloudy Monday with some limited lake effect to the east of the Great Lakes.

Temperatures will be in the low and mid 30s.

Christmas Day will have mostly cloudy skies but a few breaks of sun from time to time. Most of the day should be dry, but there is a chance for another small system to work in late in the evening.

High temperatures will remain cool, topping out around 30 degrees.

There are indications of another large storm system late next week. Whether that brings us snow or another warm up is far too uncertain.

Beyond that, I have noticed strong signals of a dome of very cold air building over central Canada. This should begin to spill into the northern United States during the final days of 2018. What this means for us at the start of 2019 is still uncertain.

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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.