Sunday, January 19, 2025 Winter Storm

 Technical Discussion:

Low pressure develops within the mid-Atlantic region Sunday afternoon ahead of a southeastward advancing cold front. Computer forecast models are all in great agreement in shortwave energy rounding the base of an amplifying upper-level trough aiding in the development and strength of the low pressure. However, there are some uncertainties on the strength of this shortwave energy, however, there is a consensus towards this piece of energy to be on the stronger side:

Low pressure is then expected to pass to the south and east of Connecticut, a very favorable track for moderate-to-heavy snow to traverse much of the state. However, with some warmer in place out ahead of this system; particularly along the shoreline and southeastern Connecticut, this will ultimately cut down on snow potentials there:

Despite being so close to the storm, there are some uncertainties regarding the overall track and this could have a big impact on snowfall totals; particularly across south and eastern sections which are on the line between colder and warmer temperatures and where the heaviest banding and subsequent totals may reside. One of the more consistent forecast models with the evolution of this system has been the GFS. The GFS advertises potential for some heavy banding to traverse much of southern New England:

In fact, the latest 12z GFS bufkit for Worcester, MA (ORH) exhibits a crosshair signature with as much as -40 to -50 ubar/second within the dendritic snow growth zone. This is indicative of tremendous lift and would likely result in snowfall rates in the 2-3 inch per hour range with snowfall ratios of 15:1:

Forecast:

• Light snow begins to breakout across western Connecticut and western Massachusetts between 1-3 PM Sunday and the remainder of the region by 5-6 PM. 
• Snowfall rates intensify rapidly during the evening with the heaviest snowfall rates between 7-10 PM (hold on as late as 12-1 AM across northeast Massachusetts). Snowfall rates will approach 1 inch per hour and as much as 2-3 inches per hour under the heaviest banding. 
• Snow tapers off during the early overnight. 
• This will be a quick hitting and fast moving storm.
• There are some uncertainties; particularly around the Boston market and where the heaviest banding occurs. 
• Where the heaviest banding occurs, we will likely see a swath of snowfall accumulations more in the 8-12 inch range. 
• There will also be some mesoscale subsidence zones where snow growth and intensities struggle. Where this occurs totals will end up closer to the lower ends of the ranges. 
• Frigid temperatures and dangerously cold wind chills build in for Sunday night and Monday behind the system. 
• Below is what I am currently thinking. Keep in mind, where the heaviest banding snowfall occurs, totals will be in the 8-12 inch range, however, it is very difficult to determine where that will occur.