ITHACA, N.Y. — It’s something of a mixed bag this week when it comes to weather. The start of the week will be grey and damp thanks to the remnants of Hurricane Delta and a frontal boundary. A high pressure will provide milder and drier conditions for a few days before a cold front sweeps in and leaves a brisk if mostly sunny weekend in its wake.

Your Weekly Weather

It’s been quite a temperature change from Saturday to Sunday, following the passage of a cold front Saturday evening. Whereas highs at the Ithaca Tompkins airport were in the low 80s yesterday, today it and most of the county are recording highs in the upper 50s with increasing clouds as the day has gone on.

Currently, upstate New York is the edge of two weather systems – a Canadian high pressure area responsible for today’s cooler temperatures, and the remnants of Hurricane Delta, which are passing over the Southern Appalachians northeastward into the Mid-Atlantic; those clouds overhead are part of its cloud shield slowly eating into the southern edge of the high.

The bulk of Delta’s moisture will remain to the south and east of Tompkins County, but some periods of light rain will be possible overnight as the remnants pass to our southeast. It will be a cloudy night between those batches of rain, and that will help keep temperatures on the mild side, with lows in the low 50s. Any new rainfall will be less than one-tenth of an inch.

Monday’s going to feel rather cool as the remnant low of Delta helps drive a stiff northwest breeze on the rear flank of its counterclockwise circulation. Even as Delta moves away from us during the morning hours, skies will remain overcast as a frontal trough pushes in from the west. In fact, the instability in the atmosphere created by both the trough and the tropical remnants are in close enough proximity to complement each other and allow for more rain showers to develop between them, and so through Monday afternoon and evening, expect overcast skies with periods of light rain. Highs Monday will be in the mid 50s, with new rainfall amounts between one-tenth and one-quarter of an inch. Monday night will see the rain showers continue with overcast skies and northwest winds, with a low in the low 50s.

As the trough moves eastward, the rain will taper off and skies should begin to clear out Tuesday morning. Once those clouds clear out, it’s looking like a rather pleasant autumn day as high pressure builds in from the southwest, with partly cloudy skies and highs in the mid 60s. Tuesday night will host mostly clear skies, which would allows for substantial radiational cooling, and lows will be in the mid 40s.

Wednesday will be a pleasant day, as high pressure over the Central Appalachians will keep the air stable, as well as advect mild air from the lower Mississippi River Valley. Plan for mostly sunny skies and highs in the upper 60s. Wednesday night will see a few more clouds build in as that high shifts eastward, but otherwise it’ll be a quiet night with lows in the low 50s.

Thursday is likely to be the warmest day of the week, as southerly flow is enhanced ahead of a rather potent area of low pressure that’ll move across the Upper Midwest and into Canada – in fact, the models show snow will be possible in parts of Minnesota, Wisconsin and upper Michigan. Thankfully, we will be far enough south from it so that we only receive a much weaker push of cold air. Highs will be in the low 70s with partly cloudy skies turning mostly cloudy as the cold front associated with that low approaches the Southern Tier. Rain is likely to arrive around or a little after sunset Thursday, and Thursday night will be cloudy with periods of rain and lows in the mid 40s.

The front will push through Friday morning, but showers will linger through the afternoon while skies begin to clear out. It will be mostly cloudy with highs in the mid to upper 50s. Friday night will be chilly as the high pressure behind the front will advect cold Canadian air into the Great Lakes region. Lows Friday night will be in the upper 30s, with some lake enhanced rain showers to the north (and for now those are looking to remain rain showers).

Saturday and Sunday will be cool but sunny. A few lake effect will taper off as the northwest winds weaken early Saturday, and Saturday will top out in the mid 50s with partly sunny skies. It will be partly cloudy and dry Saturday night with lows in the mid to upper 30s, and Sunday will be sunny and a tad warmer as the high shifts eastward and the flow of cooler air weakens, with highs near 60°F.

Graphics courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking ahead into the final third of the month, a widespread cool air mass centered on the Upper Midwest will bring colder-than-normal conditions to much of the continental United States, as a large ridge keeps Alaska and the West Coast mild, and the next ridge downstream keeps New England, Florida and the fringes of the East Coast on the mild side. In that narrow band between the ridges and wide trough will be near-normal temperatures (on average, it can vary from one day to the next), and that band includes Tompkins County. Precipitation is likely to be a little above normal as the jet stream oscillates overhead from day to day, and transient storm systems track along its flow to keep conditions unsettled as we push forward towards Halloween.

Brian Crandall

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