ITHACA, N.Y. — It will be a cool and rather stormy week ahead as a pair of storm systems start and end of the week, with a brief respite in between. We’re in the unsettled, cloudy part of the year folks. Just be glad that most of you won’t be needing the snow shovel – for now, anyway.

Your Weekly Weather

For those traveling back or otherwise closing out their socially-distanced Thanksgiving holidays, it’s been a decent Sunday, with warmer-than-normal temperatures for late November, and mostly sunny skies overhead. This has been courtesy of an area of low pressure parked off the Mid-Atlantic Coast, and as it shifted eastward, modest southerly flow allowed temperatures to warm into the 50s on this late autumn Sunday.

However, all good things come to an end, and that’s especially true in meteorology. Our first storm system is really a two-pronged event. A Canadian clipper low moving southeastward across Ontario will merge with a second, stronger low moving northeastward from the Lower Mississippi River Valley. The resulting merged system will rapidly move northeastward across Upstate New York. However, the storm will become stalled over Canada thanks to the high controlling this weekend’s weather, which will strengthening and block the low from moving further northeastward. The system will spin in place and weaken over the middle of the week before the high breaks down enough to let its remnants move on to the northeast.

The cloud shield from the dominant southern low will begin to fill in this evening and overnight, but overall it should remain dry. With that increasing cloud cover and light southerly wind, lows will be on the warmer side for late November, in the upper 30s.

Rain should begin to move into the region around sunrise Monday morning, with areas southeast of Ithaca starting an hour or two earlier, say 5-6 AM instead of 7-8 AM. This system has Gulf moisture and is being advected quickly by a jet streak (a faster substream within the greater jet stream). That means there’s a lot of precipitable water vapor in the atmosphere to tap into, and moderate to heavy rain will continue through to around sunset – expect one-half to three-quarters of an inch from this system, with locally higher amounts near an inch. It will be overcast with highs in the upper 40s, with breezy winds from the south-southeast. Intermittent rain showers will persist into the overnight hours Monday into Tuesday as the system stalls to the north, but the showers will be light. Skies will be cloudy with lows around 40°F.

Tuesday will be an unsettled day, if not as rainy as Monday. Rain showers will persist throughout the day, with new rainfall amounts less than one-tenth of an inch. Plan for cloudy skies will highs in the mid 40s. As cold air begins to wrap in around the low, temperatures will cool Tuesday night, allowing some snow showers into the mix after 7-8 PM, though nothing more than a coating is expected. Skies will be mostly cloudy with lows in the low 30s.

Wednesday will be a quieter day as the storm system weakens and begins to move away to the northeast. There will be a stiff westerly breeze, skies will be mostly cloudy with a few isolated snow showers, and highs will top out in the upper 30s. Wednesday night will see the clouds break up with only a few passing clouds by sunrise Thursday, but with the breeze from the southwest, temperatures shouldn’t drop too much, with lows in the lower 30s.

Thursday is looking to be the most tolerable day of the week as high pressure builds in from the southeast, It will be mostly sunny with highs in the mid 40s. Thursday night will be partly cloudy as the high shifts eastward, with lows in the lower 30s.

Friday will be a little unsettled as a weak shortwave trough swings through the Southern Tier. This shortwave will merge with a developing low moving off the Mid-Atlantic coast to the northeast, and the system will develop into a small but notable Nor’Easter-type low as it moves towards Maine and Atlantic Canada. This won’t impact our weather too much, but it will create unsettled conditions for the weekend. Friday itself will be partly cloudy with a few scattered light rain showers and a high in the upper 40s. Friday night will see scattered rain showers and mostly cloudy skies as that coastal low develops, but lows will bottom out in the mid to upper 30s, and no significant snow is expected.

Saturday and Sunday aren’t terrible, but they won’t be great as that coastal storm continues to strengthen as it moves away, dragging air down from Canada and destabilizing the atmosphere (i.e. priming it for lake-enhanced showers). Saturday will be mostly cloudy with a chance of rain showers with highs in the mid 40s. Saturday night will also be mostly cloudy, with a mix of rain and show showers as colder air comes in on the backside of the low, and lows will be in the low 30s. Sunday will see a mix of light rain and snow showers with highs around 40°F.

Extended Outlook

Looking ahead into the second week of December, once the coastal low moves away, a dry, seasonably cold pattern is expected for the Southern Tier. A jet stream ridge will prevail over the Western United States and upper Midwest, while cooler and drier will be prevalent over the Southeastern United States. It’s not a good pattern for those hoping for a snowy white Christmas, but there’s still time for things to change as we head into the second half of the month.

Brian Crandall

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