Friday, December 26, 2025 southern New England Winter Storm

Low pressure es expected to develop within the mid-western states Friday morning along a surface warm front which will lift northeast across the Ohio Valley through the day. This results in blossoming precipitation across the Great Lakes region. Low pressure rapidly pushes east towards the Northeast through the day and into a very cold and dry Arctic airmass. As a 700mb warm front moves into the region and into the colder and drier Arctic air, combined with the left exit region of a strong upper-level jet stream, heavy precipitation is expected to blossom within Pennsylvania and southern New York. 

A strong zone of frontogenesis is expected to develop in the vicinity of the 700mb warm front, resulting in the development of an intense band of heavy snow across far northeast Pennsylvania, extreme northern New Jersey, and southeast New York during the early evening with this band moving across western Massachusetts and Connecticut during the mid-to-late evening. Bufkit soundings exhibit a 2-3 hour period of strong lift into the dendritic snow growth zone, indicating the potential for snowfall rates to approach or exceed 2 inches per hour with snowfall ratios upwards of 15:1 to 18:1. Outside of the banding, snowfall ratios and rates will be significantly less. 

Forecast Challenges: There are numerous forecasting challenges which exist and likely will not be resolved until the event unfolds, resulting in a nowcasting situation.

•  Pre-storm dry air: 
• The airmass ahead of the storm will be exceptionally dry with dewpoints into the single digits and perhaps even below zero. The atmosphere is expected to saturate quickly as the storm approaches, however, this will only be the case just out ahead of the main precipitation shield. On the fringes of the precipitation shield, dry air could be a major problem, and one factor which would net a very sharp gradient in snowfall totals. 
• Storm speed:
•  This storm will be flying across the region, with the heaviest snow occurring in a 2-3 to at most a 4 hour window. This will play a significant factor in the upper ceiling of the storms potential in terms of maximum accumulations. 
• Mid-level dry air punch: 
• Dry air will be racing in on the backside of the storm and it is still unclear as to exactly what influence or roll this will have. The current thinking is this will aid in the rapid cutoff of snow and negatively impact the upper ceiling of the storms maximum accumulation potential. However, this dry air may also help to enhance snowfall rates along the leading edge of the dry air. How so? Dry air is more dense than moist air, thus dry air moving into moist air will force that moist air to rise. 
• Where does the heaviest banding occur?
• This is the $1 million question and will ultimately determine where and who sees the most snowfall. Because of these uncertainties, it is extremely difficult, if not impossible to really fine tune the snowfall forecast. 

Storm timing

• Start Time:
• Snow is expected to breakout between 5:00 - 8:00 PM EST, from west to east across the region. 
• End Time:
• Snow rapidly begins to taper off from northwest to southeast after 10:00-11:00 PM. 

Forecast

• Where the heaviest banding occurs, it is possible there is a narrow swath of accumulations in the 6-9 inch range, however, it is unclear where that will occur and some of the uncertainties mentioned above regarding storm speed and mid-level dry air may hold this potential down. 
• Across far southeast Massachusetts there are some signals for some ocean enhancement as the storm is passing south and pulling away which could yield potential for a quick inch or two.