ITHACA, N.Y. — Who needs a refrigerator for the leftovers on Thanksgiving when you can just set the food outside? Just kidding. It’ll be too cold. With the weather that’s coming our way, the air inside of your fridge will feel delightfully warm in comparison.

Already abnormally cold and unsettled weather will give way to a full-force arctic air mass on Thanksgiving Day, with temperatures struggling to make it into the 20s for highs. At least you’ll have some sunlight, so…icy silver lining?

Graphic courtesy of the NWS Eastern Region HQ.

Weather Recap

At the start of last week, it was noted that the forecast was on the cusp of a steady cold rain for Thursday night and Friday morning, or the first major snow storm of the year. Well, we all know how that turned out. Totals from the “main event” left 8-10″ of heavy wet snowman guts throughout the county. Final accumulations topped out at a foot in Caroline. This is a bit early for a double-digit accumulation, but not unheard of for mid-November. More than a hundred calls came in to the Tompkins County 911 Dispatch Center to report incidents ranging from vehicles sliding off the road to concerns about slippery conditions, and many schools and some business offices were closed Friday.

Somewhat more unexpected was the cold air damming that affected the East Coast in the run up to the snowstorm. A high pressure area, if moving equatorward East of the Appalachians, can create a jet stream-like flow that traps cold air at low-levels, while warmer air rides overhead (an inversion). This, combined with greater cold air intensity than first anticipated, resulted in favorable snow conditions in places that didn’t expect heavy snowfall – New York and Philadelphia, in particular. Central Park received 6″, the highest for a November snow since 1882, and some folks had a ten-hour commute, as the heaviest snow bands hit around evening rush hour. A real mess by any measure, but let’s glad it didn’t hit during the Thanksgiving travel rush.

On that note, the Voice will be bringing a special Thanksgiving travel weather forecast tomorrow, to keep folks up-to-date on any potential meteorological hazards they may encounter as they head out for the holiday. For those sticking around town, stick around for your usual weekly forecast, with unusual amounts of frigid air in store.

Precipitation, mean sea level pressure and 1000-500 mb thickness (temperature proxy) for 8 AM Thursday morning. Frigid air will pour into the region from the northwest as an Arctic high pressure area passes the region. GFS Model output courtesy tropicaltidbits.com.

Your Weekly Weather

The latest light snows in the area are thanks to a frontal boundary that has rather slowly moved into the region from the north. With a branch of the jet stream passing overhead, that allows pulses of energy (shortwaves) to ride along the jet and into the region, creating further instability in the atmosphere, and tapping into the moisture in the atmosphere to produce some light snows across the area. This pattern will largely continue for the first half of Thanksgiving week.

For your Monday, expect a dark, dreary day. Low, thick clouds will keep skies overcast, with temperatures barely budging from overnight lows in the low 30s. Expect highs to top out in the mid 30s in the more urban areas, with temperatures unlikely to break the freezing point in more rural or elevated locations. At the very least, with the frontal boundary sagging southward into central Pennsylvania, and with no shortwave energy pulses passing through, it’ll be fairly dry. Monday night will retain those thick clouds, and so temperatures will hardly cool off, with lows around 30 °F. Areas south of Ithaca might see a few flurries as a weak disturbance travels along the front.

Tuesday and Wednesday’s weather will be shaped by a combination of two systems – an area of low pressure (an “Alberta Clipper” system) moving in from the northwest, and a developing coastal low. The low is expected to developer too far eastward to bring precipitation to Tompkins County, but its counterclockwise circulation will tap into frigid air to our north and drag it southward. The Canadian low will only enhance that arctic flow further, meaning a bitterly cold air mass will be coming in by late Wednesday.

For your Tuesday, expect overcast skies with some scattered light snow showers ahead of the front, but nothing intense. Highs will be in the mid 30s. For Tuesday night, plan for mostly cloudy skies and relatively dry conditions, with lows in the low 20s. Temperatures should make their way to around 32 °F before the cold front passes through Wednesday afternoon with overcast skies and scattered snow showers, and with the cold air invading the region, temperatures will plunge to the low teens, with lows in the upper single-digits in the typically colder areas.

For your Thanksgiving…well, even if you don’t love your family, it’ll be better to stay indoors. On the bright side, the polar air will be very dry (very cold air has a much lower capacity to hold moisture), so skies should be partly cloudy, but highs will struggle to make it into the low 20s, and cool off into the single-digits – a good 20 to 25 degrees below normal. According to the Northeast Regional Climate Center, the record minimum for a high temperature on November 22nd in Ithaca was 20 °F in 1987, which also set the record low of 9 °F. Chances are very good we will set new low-temperature records this week.

For what it’s worth, it’ll moderate quickly as the core of the polar air mass shifts east. Friday will see partly sunny skies with highs around 30 °F, with lows Friday night in the low 20s under partly cloudy skies. A storm system moving through the mid-Atlantic will bring some clouds and maybe a few rain or snow showers for the weekend, but with some sunny periods in the mix. Temperatures Saturday and Sunday will be near 40 °F, with lows in the mid 30s.

Graphic courtesy of the NOAA Climate Prediction Center.

Extended Outlook

There’s some good news and some bad news, as we head into the start of December. The good news, temperatures are expected to moderate – conditions will be near normal to perhaps even a bit above normal, meaning highs regularly in the 40s. The trade-off is that we’ll be on the edge of a ridge next to the jet stream, meaning the jet stream will frequently be overhead. That will set up a veritable train of storm systems passing through the Northeast and New England. So it’ll be warmer, but it’ll be wet, and depending on the exact timing, there is potential for snow, though it’s much too early to say anything concrete.

Brian Crandall

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