Nov 17, 2010: Colder Weekend, Next Week Starts Mild

Today was a mostly cloudy and windy day for the area, with high temperatures peaking early in the morning in the lower to mid 60s across most of the area. There were some heavy showers and thunderstorms last night, however the storms in the Mid Atlantic into parts of New Jersey and Pennsylvania were stronger than expected, and produced wind damage. The rest of the day was windy across the area, and the wind is expected to weaken later tonight.

After another day of comfortable temperatures, a chilly weekend is expected for the area with warmer temperatures for next week, however this will be the start of a stormier and colder pattern that may set up for Thanksgiving weekend.


Tomorrow's Outlook:

Tomorrow will start out with mostly sunny skies but with increasing clouds later in the day across the area with a west wind expected. High temperatures will be in the mid to upper 50s inland, mid to upper 50s in Long Island/S CT, and in the upper 50s in the immediate NYC area. An isolated shower is possible in the late afternoon in the western parts of the area.

The leftover precipitation and cloud cover from a weak storm that is expected to dissipate tomorrow will reach the area tomorrow night, which will lead to mainly cloudy skies and the potential of an isolated shower. With 850 mb temperatures could enough and surface temperatures in the 30s, a few snow showers could fall north and west of NYC.


Friday - Sunday: Chilly

On Friday, the colder 850 mb temperatures will be over the area, which will lead to chilly conditions. High temperatures will be in the lower to mid 40s inland, mid to upper 40s for the immediate NYC area, and mid to upper 40s in Long Island/S CT.

For Saturday, the cold air mass will briefly lift out of the area with slightly warmer temperatures, however a weak low pressure will be moving through Maine, bringing light snow into these areas, and an even colder air mass will follow behind this storm. The air mass, however, won't be able to dig far south, and will generally move east, if not slightly ESE, with a boundary setting up near the area with chilly temperatures to the north and warmer temperatures to the south. As a result, Sunday's high temperatures are likely to be similar to those of Friday, with low temperatures for Sunday morning a little colder than those of tomorrow night, in the 20s away from the immediate coast, and lows in the lower 20s are possible inland.


Monday - Tuesday: Warming Up

On Monday, a low pressure moving through the Great Lakes will pull the trough out of the Northeast, with a high pressure moving towards the SE US, leading to warmer temperatures with a SW wind developing. 850 mb temperatures will start to warm up as the SE ridge builds itself, however the main thing preventing this from being a large spell of above average temperatures is the negative NAO, which will block the ridge from extending too far north, leaving the area with at least slightly above average temperature.

By Tuesday, a strong polar air mass will be dropping into Montana and the Dakotas, and with the SE ridge persisting, a storm is expected in between, near the Great Lakes, with its cold front slowly pushing east. Temperatures on Tuesday will be the warmest of this time frame, potentially in the lower to mid 60s in the immediate NYC area.


Thanksgiving Weekend: Colder, Stormier?

Afterwards, uncertainty increases as there are differences with the models, however there are two main solutions at this time. The first is that the cold front slowly moves eastward, with weak waves of low pressures developing along the front, until a stronger storm will form and pull in the cold air mass into the region, leading to a cold Thanksgiving weekend. Another possible scenario is that the cold quickly moves into the Northeast for Wednesday, then moves out as the next storm develops, leading to an inland storm track for Thanksgiving weekend, which is shown by the 06z GFS and 12z ECMWF, which still bring in the colder air behind the storm.

While there are large differences, what is known at this time is that there will likely be a large cold air mass in the north central US, at least a weak southeast ridge, and there could be a storm around November 25-27, and while it is still too early to determine the exact track, my first thoughts on the potential track given the set up and the pattern is a potential track between the Mid Atlantic and the Great Lakes, though this could change as details become clearer. With plenty of cold air available, snow could fall to the north of the storm. Stay tuned for more details on this time frame and any storm potential for Thanksgiving weekend.