With an amplified set up over the region, the strongest trough so far this winter dropped into the region yesterday, producing widespread lake effect snows and colder temperatures in the area. As the arctic front moved through last night, widespread light snow showers affected parts of the area, especially north and west of NYC, this morning, with most locations receiving these flurries generally seeing a trace to a coating of snow. Although this morning’s snow was very light, it is remarkable that some areas that received flurries today have not seen any snow at all throughout December. Central Park has seen its third snowless December on record, and has not officially recorded snow today. The two other years this has happened, 2006 and 1877, ended up with well below average snow for the entire winter; both winters, however, had most of their snows focused later into January and February. More on the impact the current pattern has on the rest of the winter will be posted with the updated winter outlook to be posted this Friday.
With the front behind the area, the area is now seeing the peak of the cold air mass, with 850mb temperatures near -20 degrees Celsius. As a result, temperatures will drop into the single digits across most of the area north and west of NYC, getting close to zero degrees inland. Along with breezy conditions, wind chills are expected to drop into the single digits across the entire area and below zero further north/west from NYC. Temperatures will quickly warm up late this week into the weekend, although another wave of low pressure will move through on Sunday, bringing another risk of rain, followed by slightly above average temperatures once again.
After the very cold morning, temperatures will warm up by the afternoon into the mid 20s inland and the mid to upper 20s across the rest of the area. Mostly sunny skies are expected in the morning, although cloud cover will increase by the afternoon and evening hours as another shortwave approaches from the west. This shortwave will bring scattered snow showers across a larger part of the area for tomorrow evening into the overnight hours, with another dusting of snow possible. Due to the cloud cover and snow showers, temperatures will only slightly drop tomorrow night, remaining steady in the upper 10s to mid 20s across most of the area.
Thursday – Saturday: Back To Warmer Weather
The cold spell the region is seeing is only temporary, and will quickly be replaced by another approaching warmer air mass. Although there are still no large scale changes with the pattern as a result of this cold spell, the difference from the current pattern and the one in most of December is that the ridge in the southeastern US has significantly weakened. This ridge has been present through most of November and December, keeping storms to the north/west of the area along with persistent above average temperatures. Over the last week or so, however, the ridge has significantly weakened, and although some ridging in the southeastern US is expected over the next 1-2 weeks, it will be weaker and less frequent than we have previously seen; as a result, temperatures from January 5, when the cold spell ends, through about January 15, will still likely end up slightly above average, but not as mild as December has been, with more frequent cool spells and troughs in the region.
One of these brief warm spells will affect the region late this week into the weekend, with temperatures warming back up into the upper 30s to lower 40s on Thursday. Partly sunny skies will continue through Saturday with high temperatures warming into the mid to upper 40s across the area on Friday, with slightly warmer temperatures possible for Saturday, reaching the upper 40s to lower 50s across most of the area.
Sunday – Next Week: Colder, Stormier?
A wave of low pressure is expected to move into the region on Sunday as a colder air mass returns. There is uncertainty with the storm, with impacts ranging from the GFS showing a weak storm with scattered light precipitation, the CMC showing moderate rain, and the ECM showing a significant storm with moderate to locally heavy rain along with heavy snows in the Northeast. Given this pattern, no significant amplification is expected with any storm that comes through, and the ECM’s solution appears to be too extreme given this set up, although not completely impossible. For now, I am siding with a scenario where the wave of low pressure moves through, bringing light to moderate rain for Sunday with temperatures in the 40s, although it is possible that the storm ends up stronger with more rain, or weaker with isolated precipitation. Stay tuned for more information on this storm.
After Sunday, colder temperatures will briefly return into the region, although the models are showing the potential for another storm towards the end of next week. The ECMWF shows an intense storm moving through the region, while the GFS is still showing a range of different solutions but most of them siding with a weak storm. While details are still uncertain, the potential is there for rain to affect the area towards the second half of next week, followed by colder temperatures towards next weekend. Some snow could be possible if the storm takes a track supportive of such a scenario, although given the pattern in place, the Northeast is still favored over the area for any decent snow event. Stay tuned for more information on next week’s outlook.