ITHACA, N.Y. — Call it “Indian Summer”, call it “halcyon days”, “second summer”, or by whatever is your preferred nomenclature. An unseasonable warm spell will result in relatively quiet conditions with above-normal temperatures for the upcoming week, though temperatures will moderate closer to normal as we head into next weekend.
Your Weekly Weather
Some high clouds have been streaming northward across Tompkins County today, exhaust flow from a counterclockwise-circulating low pressure storm system off the Carolina coast. With clockwise-flowing high pressure to its northeast over Atlantic Canada, the large-scale flow over the Southern Tier and Finger Lakes is east-southeasterly. This is amenable to milder but higher moisture conditions, as the air wicks oceanic moisture into its flow upstream.
Practically speaking, more buoyant moist air tends to make the atmosphere somewhat more unstable and amenable to cloudiness and showers. As the low pressure system moves northward into Delmarva and disintegrates, there could be a few showers later this evening, primarily east and south of Ithaca, but the air over Ithaca itself appears to be too dry and stable to allow for anything but some additional cloud cover.
For the rest of your Sunday, expect a dry and mild October day, great for your outdoor fall activities. Highs across the area will top out in the upper 60s with increasing clouds as the day progresses. The cloud cover will persist into the overnight tonight, staying dry unless you’re heading to New York or perhaps Albany; the rain will try to move northwestward, but the dry air will eat away and evaporate it before it can get this far out. The cloud cover will work as a light blanket, keeping overnight lows a little milder, in the mid 40s by sunrise Monday.
High pressure should keep the remnants of the low away from Ithaca Monday, while a sprawling, powerful low pressure storm system over Central Canada reinforces the ridge of warm air over much of the Mid-Atlantic and Northeast (remember, its counterclockwise flow, so it’s pulling lots of air from its south and ushering it northeastward). It will be a lovely day. There will be decreasing cloud cover, light winds, and highs in the low 70s, 10-15 degrees above normal. Monday night will host partly cloudy skies, perhaps a little cloudier towards daybreak, with lows in the upper 40s.
The Canadian storm system develops a secondary low along its cold frontal boundary Tuesday, and that will track up the Mississippi River Valley. This will reinforce the ridge, with another day of mild, dry conditions. Skies will be partly to mostly cloudy with highs in the low 70s. Tuesday night will be mostly cloudy and mild with lows in the mid 50s.
The core of the secondary low will separate from its parent and track northeastward across Lake Erie and Lake Ontario, into the St. Lawrence Valley. This keeps Tompkins County in the warm sector of the low. Secondly, because of the orientation of the, the slot of dry air that will become wrapped around it, will be drawn into the Southern Tier. This means light, limited rainfall. At this point, only a few light showers are expected during the day Wednesday. Skies will be mostly cloudy with highs in the low 70s. As the low crosses Ithaca’s longitude Wednesday night, showers will end and winds will turn to the northwest, but it won’t be strong – lows will fall back to the upper 40s by sunrise Thursday.
Thursday will be cooler, though still a little above normal as Canadian high pressure northerly flow, become more northeasterly later on. Skies will be partly sunny with highs around 60. Thursday night will be tranquil, with partly cloudy skies and lows around 40.
Heading into Friday, temperature may be a touch warm with a weaker northerly component to the wind, otherwise it’ll be much the same as Thursday. Skies will be partly sunny with highs in the low 60s. Friday night will be partly cloudy with lows in the mid 40s.
Looking into next weekend, temperatures may warm up a ltitle more as the high moves east and the southerly components of its clockwise circulation moved overhead. It’s looking pleasant with partly cloudy skies and highs in the mid 60s both days. Lows will be in the mid 40s.
Looking towards Halloween and the start of November, the large-scale weather pattern favors a persistent, strong ridge of warm air over the eastern half of the continental United States, with temperatures likely to run well above normal as we head into early November. The synoptic flow will also draw in moist, rather unstable air from the Southern U.S. and the Gulf of Mexico, resulting in slightly elevated chances for above-normal precipitation during the period.