ITHACA, N.Y. — There’s a distinct chill in the air today as the days grow shorter and the season grows colder. Throw on the flannels and pour the hot drinks as showery, cool conditions prevail for the first couple days of the week. You’ll have more pleasant weather for late-week outdoor activities as high pressure provides sunnier, milder conditions. Unfortunately, another round of cool, rainy weather appears likely for next weekend.

Your Weekly Weather

A large and potent low pressure storm system is moving northeastward from the Atlantic seaboard and into Atlantic Canada. An upper-level disturbance is being dragged in the low’s counterclockwise circulation, and surface heat flux destabilization of cool air passing over the warmer waters of Lake Ontario. These two factors are providing plenty of atmospheric instability for widespread showers streaming from north to south across the Finger Lakes and Central New York this dreary Sunday.

With northerly flow and generally grey skies, temperatures will be on the cool side for mid-October today, with highs only in the lower 50s across Tompkins County. If you want to consider a potential silver lining, a hard frost is very unlikely. The clouds and moisture will also keep temperatures from dropping too much overnight, with lows in the lower 40s tonight as rain showers persist on northerly winds. New rainfall amounts today and tonight should be light, generally <0.10″.

Continued northerly flow and instability around the now-Canadian low will make for an unsettled Monday, though somewhat lighter north winds and a few more breaks in the clouds will allow temperature to warm a little closer to normal. Expect weak, thin bands of lake effect rain showers and highs in the mid and upper 50s. Monday night will see lake effect rain showers, mostly cloudy skies and lows in the low to mid 40s. New rainfall amounts Monday and Monday night will be <0.10″.

As the low moves to the east Tuesday, showers will become less numerous, since northerly flow over Lake Ontario will slacken and the atmospheric will become more stable. A few scattered light rain showers will persist, but sunshine should increase as the day progresses. Highs will be in the upper 50s. Tuesday night will be cooler as skies continue to clear, winds become light, and the dewpoint decreases with drier air building across Tompkins County. Lows Tuesday night will be in the upper 30s in Ithaca and along the lakeshore, with some mid 30s likely on the hilltops outside Ithaca.

A meteorological regime change begins Wednesday, as high pressure builds in from the Southern Appalachians. Modest southwesterly flow will perk the thermometer into the low 60s for highs, with partly cloudy, agreeable conditions across the area. Wednesday night will host partly cloudy skies and lows in the lower 40s.

High pressure moves northeastward off the Atlantic Coast Thursday, as a developing Canadian storm system to the northeast begins to dig into the Western Great Lakes. Enhanced southerly flow and some atmospheric instability will result in a few more clouds, probably more clouds than sun overall, with mild daytime highs in the mid 60s. Rain showers begin to move in from the west Thursday night. Skies will become mostly cloudy with lows in the upper 40s.

The cold front associated with the Canadian will be slow to move in, and the daylight hours Friday will be mild, if rainy. Showers will increase in coverage during the afternoon, with overcast skies, south breezes, and highs in the lower 60s. Friday night will see the front finally push through well after midnight, close to sunrise Saturday. Expect periods of rain during the overnight hours and lows in the upper 40s.

Peering into next weekend, models consistently show a secondary low developing at the tail end of the front will strengthen and likely cover much of the Mid-Atlantic and Northeast with rain and clouds. Plan for another rainy weekend with highs in the upper 50s Saturday, and perhaps only around 50 next Sunday as colder air wraps around the low as it heads northeastward.

Graphics courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking into the run-up towards Halloween, the large-scale pattern shows a broad ridge over the Central and Western United States, with more neutral, weak troughing over the Eastern part of the country. Some storm systems may slide around the ridge and cross the Northeast, but these are likely to be moisture-starved. The overall effect is fairly normal temperatures and precipitation for the last weeks of October.

Brian Crandall reports on housing and development for the Ithaca Voice. He can be reached at bcrandall@ithacavoice.org.