Surge of Warmth
Low pressure over the Midwest and high pressure directly to its north over Canada are battling over control of the Finger Lakes region today.
Warm air moving northward ahead of the low thanks to its counterclockwise winds are bumping up against cool air moving south around the clockwise flow of the high pressure. This is setting up a temperature gradient that will intensify through the day, then lift northward as a warm front overnight and into Friday.
A small impulse of energy is riding along this developing boundary this morning, bringing some scattered showers into the Finger Lakes. These showers are moving quickly to the southeast, so for the areas that see rain this morning, it should not be long lasting.
The chances for rain will decrease by midday, though a stray shower cannot be totally ruled out into the afternoon.
As the temperature gradient tightens up this afternoon, temperatures will range at least twenty degrees across the region. For areas in the Southern Tier west of Elmira, mid 70s are possible this afternoon. Meanwhile, along the shore of Lake Ontario, highs will only be in the mid 50s.
Overall, the temperatures have trended a bit cooler on the models, with much of the Finger Lakes somewhere between 60-65 degrees this afternoon.
With the front overhead, winds will be light and variable today with speeds generally under 5 mph.
The front will gradually lift northward tonight. At first, the front will stall roughly along the Thruway for several hours, allowing a sharp boundary between 50s to the south and 40s to the north. This boundary may linger into the predawn hours, but as the sun rises, the front will jump far to the north.
Warm air will quickly overspread the entire region Friday morning, with temperatures reaching the 70s before noon and topping out in the 80-85 degree range. A few higher elevations in the western Southern Tier may not quite make it to 80 degrees.
Skies will be a mix of sun and clouds throughout the day. Southwest winds will increase to around or slightly over 10 mph with a few gusts as high as 30 mph. The air will be dry in the afternoon with dewpoints around 40 degrees yielding relative humidity values of 20-30 percent. This dry air will combine with the sunshine and hot temperatures to raise the brush fire risk.
Dewpoints will rapidly rise late in the afternoon and some scattered showers and thunderstorms will be possible in the hours surrounding sunset. No severe weather is expected.
Temperatures will stick to the 50s Friday night and will easily rise back to the mid 70s on Saturday. Winds will turn to the southeast and clouds will be plentiful on Saturday, preventing it from being as hot as Friday.
Those winds will be on the blustery side, with speeds over 15 mph possible with gusts of 35-45 mph. The strongest winds will come late in the afternoon over roughly the southeastern half of the region.
Cool and Unsettled
Late Saturday, a slow moving band of rain will move into the area. The leading edge of this rain will serve as a strong cold front, knocking temperatures back through the 50s and into the 40s. Several hours of rain are expected, though the band will pick up speed during the evening, so eastern areas may see slightly less rain than western areas.
Most areas will probably see less than an inch of rain, but some localized heavier downpours could be possible. Severe weather, or even much in the way of thunder, is not expected with this cold front.
By Sunday morning, the steady rain will be east of the region and cooler air will be entrenching itself overhead. Morning lows will be around 40 degrees.
Much of Sunday will be dry, but some occasional showers will be possible, especially during the afternoon. Highs will be in the upper 40s and low 50s with light west and northwest winds.
Cool, unsettled weather looks like it will stick around for quite some time. Occasional showers, mainly during the daytime heating, will be possible Monday, Tuesday, and Wednesday next week. None of these days look like washouts, though.
Each day will have highs in the upper 40s or low 50s, which is slightly below average for late April. Nighttime temperatures will drop into the 30s, and there could be frost and freeze concerns for early budding fruit.
After a brief lull in the weather surrounding Thursday next week, even more active weather is possible next weekend and into early May. Temperatures should remain near or below average during this pattern.
This graphic represents an average over the entire Finger Lakes region. Localized variations should be expected.