ITHACA, N.Y. — It’s probably the last thing folks want in the lead-up to the Christmas holiday, but it is what it is. A cold, snow showery start to the week will get increasingly warmer as the work week progresses, with rain and temperatures likely in the 50s for Friday.

Weather Recap

Last week was a fairly dry if cold week for Ithaca and Tompkins County. The real news marker of the week is the coastal low currently pushing off the Mid-Atlantic to the northeast. Ithaca was on the cusp of that precipitation line for much of the past three days, but the system has encroached as its moisture ate away at the dry air, and with temperatures right around 32 °F in the hills, there has been a variety of mixed precipitation in the more elevated areas, including thin coats of sleet and freezing rain.

Precipitation, mean sea level pressure and 1000-500 mb thickness (temperature proxy) for 7 PM Monday night. A pulse of instability will fire off scattered snow showers during the day Tuesday. GFS Model output courtesy tropicaltidbits.com.

Your Weekly Weather

The rain/sleet/snow medley should be coming to an end by midnight as the coastal low continues its trek eastward. With thick clouds and abundantly soaked ground (meaning a high dewpoint, and a limited ability for the air to cool off), temperature should be fairly mild tonight by winter standards. Expect low 30s in Ithaca proper, to around 30 °F in elevated areas or places with slightly more clearing, with cloudy if dry conditions. On the back side of that low, a cold breeze will prevail from the northwest.

Monday will be cold and a bit unsettled. Temperatures will be right around 32 °F with overcast skies and scattered snow showers as a strong if brief pulse of instability (a shortwave trough) passes through during the day. However, with limited water vapor in the atmosphere, its ability to produce snow will be limited; some pop-up showers are likely, but don’t expect more than half an inch to an inch, unless you’re heading up towards lake effect country near Lake Ontario.

Monday night will be chilly as cold air is driven into the region by strong northwest winds, but the snow showers will taper off and skies will begin to clear up by morning. Temperatures will bottom out in the mid 20s.

Tuesday during the day will basically just hold steady in that mid 20s range, with the cold, stiff breeze preventing much of a warm-up. You’ll at least get some sun under those partly cloudy skies. The wind dying down later Tuesday will allow for optimal radiational cooling conditions, and lows Tuesday night will be around 20 °F under mostly cloudy skies.

Wednesday will be much nicer. An area of high pressure will slide off the Virginia/Carolina coast into the Atlantic, and as it does, its clockwise circulation will draw in milder air to the Southern Tier. With a light south breeze in place of the northwest vlow, temperatures will quickly warm Wednesday. It’s a fairly pleasant December day in store, partly cloudy skies and temperatures in the low 40s. Wednesday night will be mostly cloudy, with lows in the upper 20s to around 30 °F.

Thursday will be similar, and a bit warmer. A tighter pressure gradient will drive the southerly wind just a little more, and with that extra warm air advection, temperatures will climb into the mid 40s under partly cloudy skies, turning mostly cloudy by sunset.

The forecast takes a turn for the wet by Thursday night, as a low pressure area forming in the Deep South will begin to journey northeastward. Ahead of the low, mild but moist air will be channeled into the region, and rain will arrive with it. Rain will kick in by late evening and continue through morning, and lows will be in the upper 30s early, warming up through the 40s during the night. Needless to say, under these mild conditions, no snow is expected.

Friday will be warm and wet as the low approaches from the southeast. With the channeling of warm air ahead of the low, temperature will be quite mild, topping out in the low to mid 50s. It will also be cloudy, however, with periods of rain. As the low passes overhead and continues northeastward, temperatures will cool but not especially much Friday night, not bad for those traveling early for the holiday – expect mostly cloudy skies and scattered rain showers with lows in the upper 30s.

The weekend is looking to be on the warm side of seasonable, though unsettled with scattered rain and showers. Saturday will be mostly cloudy, scattered rain showers during the day, and in the low 40s. Saturday night could see a few snow showers, with lows around 30 °F. Sunday will be drier, with mostly cloudy skies and a high in the upper 30s.

Image courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Sorry folks, but a White Christmas just doesn’t appear to be in the cards for this year. It’s looking like temperatures will be a bit above normal, with precipitation chances near normal for the holiday week. While that doesn’t mean there’s no chance of a nice Christmas Day snow, it’s just looking less likely than usual thanks to a broad ridge of warm air over the Central United States. This warm ridge will shift eastward for New Year’s, so it’s looking like this year’s celebrations will be much nicre than the subzero cold snap we had last year, though chances for greater than normal precipitation will be slightly elevated.

Brian Crandall

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