ITHACA, N.Y. — We head into astronomical winter this week as thoughts turn to December and the holiday season. While no major snow storms are in the forecast, multiple storm systems will impact the area over the next several days, and Wednesday and Thursday could be rather dicey as strong winds send your inflatable Santa for a sleigh ride across town.

Your Weekly Weather

Following Saturday’s rather mild and tranquil weather, a low pressure storm system is tracking northwestward across the Ohio River Valley, across Upstate New York and eastward into New England and Canada. Ithaca and Tompkins County will stay in the warm sector (southeast side) of the low through the day today, so precipitation will stay in the form of rain. Most communities in and around Tompkins can expect around 0.25-0.50″ of rain, the vast majority of which will fall this afternoon and evening. So for the rest of your Sunday, expect periods of moderate to heavy rain to taper to showers, with overcast skies and highs around 50. Tonight will see scattered rain showers, near-overcast skies and lows in the upper 30s. Winds will become breezy out of the northwest after midnight as the cold front passes.

Monday will be a raw and rather unpleasant day with northwest flow behind the low. Expect scattered light rain showers, primarily in the morning, with northwest breezes and highs in the low 40s. Monday night will see showers ending, with decreasing winds and cloud cover as high pressure builds in from the southwest. Lows Monday night will be around 30.

Tuesday sees high pressure briefly in control, providing for a mild day for late November with light southerly flow. Skies will be partly cloudy with highs in the upper 40s. Tuesday night will see increasing clouds and a strengthening southerly wind, with showers moving in after midnight. Lows will be in the mid 30s.

Wednesday’s storm system is rather complicated but will be quite large and potent. Two developing lows, one in the lee of the Colorado Rockies, the other an Alberta Clipper in Canada. The Canadian low will help draw the Colorado low northeastward, and impart its energy onto that storm. This will create a strong storm system that will be centered over the Western Great Lakes by Wednesday morning, but stretch from the polar latitudes down to the Gulf of Mexico.

As the low continues to strengthen while moving northeastward Wednesday, it will be a nasty day to be outdoors – grey, and damp with strong winds. Expect 0.50-1.00″ of rain, heavier in the PM hours, with wind gusts of 40 MPH possible throughout the day. Use caution if travelling. The combination of soaking rain and high winds tends to weaken tree roots and make them more likely to topple. If you have any Christmas decorations outdoors, secure them very tightly now or move them inside. It’s also not a bad to check on your backup power generator if you have one. Those gusty south winds ahead of the wind will keep this a rain event in the warm sector (southeast) of the low, with highs in the mid 50s.

As for Wednesday night, the rain becomes more sporadic showers, and turns to a few isolated snow showers after midnight as the wind begins to turn clockwise to the west and then to the northwest, while still gusting to 30-35 MPH. Temperatures will bottom out in the upper 20s by morning, but that wind chills will make it feel more like the teens.

Thursday will be drier, with partly cloudy skies as high pressure begins to work in from the southwest. However, the storm system, now over Eastern Quebec, will have a core of low pressure as intense as many hurricanes (~970 mb). This large, tight gradient will keep windspeeds elevated. Winds will be sustained at 20+ MPH most of the day with gusts of 40-45 MPH. Wind fetch of this speed has difficulty in tapping lake heat energy for strong lake effect snowbands, though some showers will still be possible north of Ithaca. The strong winds will also keep temperatures in the upper 30s for highs. The winds will slacken as the low moves away later Thursday, with mostly clear skies overnight and lows in the mid 20s.

Friday will be a seasonably cool and quiet day as high pressure passes to the south. It will be dry with increasing clouds and highs in the mid 40s. Friday night will see mostly cloudy skies with lows in the lower 30s.

Another storm system will impact Ithaca/Tompkins Saturday, but this one will pass further to the north and be weaker than Wednesday’s event. Expect a few scattered rain showers and mostly cloudy skies with highs around 50. Saturday night will see showers ending with mostly cloudy skies and lows in the mid 30s. With high pressure builds in from the Midwest Sunday is looking to be partly cloudy with highs in the mid 40s.

Graphics courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking into the second week of December, the large-scale pattern suggests a persistent jet stream trough in the northwestern United States, and a ridge centered over the Southeast. While this pattern is favorable for modestly above-normal temperatures, the jet stream itself will be oriented to carry storm systems through the Ohio River Valley and Great Lakes, meaning above-normal precipitation is also likely. Some slight risks for a cold snap are noted in the 12/6-12/9 time range, though the only real certainly is a cold snap in that period for the Pacific Northwest and Northern Great Plains.

Brian Crandall

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