The 5-Day Forecast was updated for the interior parts of the area and the immediate NYC area, with the forecast for Long Island/southern Connecticut to be updated late tomorrow morning.
In addition, either tomorrow or Monday, an update to the winter outlook will be posted, with revisions to the original forecast, especially for January.
As the warmest of the mild spell took place today, temperatures were even warmer than expected, surging into the lower to mid 50s across most of the area. The NAM and GFS models significantly underestimated the warmth due to the snow pack, and even the GGEM model, which was much warmer than the NAM and GFS, still underestimated the warm up, showing high temperatures only in the upper 40s.
Temperatures tonight will remain steady, if not slightly rise in some places, and will peak tomorrow in the mid to upper 40s with a few 50 degree readings possible. A cold air mass will then take hold, as a cold pattern becomes established for a good part of January.
After some scattered showers tonight, which will be light with rainfall amounts up to 0.1 inch, potentially up to 0.2 inch in the wetter scenario, tomorrow will be drier but with mainly cloudy skies and an isolated shower possible. Temperatures will peak early in the day in the mid to upper 40s with a few 50 degree readings possible before starting to drop in the afternoon hours. A west wind is expected.
Monday – Thursday: Chilly And Dry
On Monday, a cold air mass will return with 850 mb temperatures near -10c, with high temperatures expected to be in the upper 20s to mid 30s across the area. On Tuesday, the cold air mass will slightly weaken as a low pressure moves east through the Great Lakes, bringing high temperatures in the mid 30s to lower 40s across the area. An isolated rain or snow shower is possible in the northern parts of the area, but the best chance for that will be to the north and east of the area, with otherwise mostly cloudy skies expected.
Colder temperatures will return by Wednesday and Thursday, with high temperatures expected to be in the upper 20s to mid 30s again, slightly warmer on Wednesday and slightly colder on Thursday, however cloud cover will start to increase due to a storm which despite a lot of uncertainty, appears that it may bring at least some snow to the area.
Friday – Saturday: Potential Snow Storm?
Over the last few days, I mentioned the potential for a storm to affect the area in the January 7-9 time frame. The models are now consistent with showing a storm, but each one develops it in a different way. The highlight of today’s model runs was the 12z GFS which showed yet another 12+ inch blizzard for parts of the area, with the ECMWF keeping most of the snow to the north of the area. As this is in the longer range, it is too early to take each individual solution more seriously until we reach at least the medium range when the list of scenarios should start to be narrowed down.
While there is uncertainty with the exact scenario, we are likely looking at a weak low pressure that originates near the Great Lakes moving east, and from there it appears that intensification may take place off the coast, but where and when that happens is uncertain. At this time, it appears that the best chance for a significant snowstorm may be to the north and northeast of the area, however that is still uncertain and is subject to change. Stay tuned for more information over the next few days on this storm and how it may affect the area.
Regardless of what the storm does, however, it appears that there will be an arctic air mass behind the storm, and in the days after the storm, temperatures will be below average, with high temperatures potentially returning into the 20s for parts of, if not most of the area according to the latest models.