Accumulating Snows Likely Across Connecticut Wednesday, March 21st, 2018

Our active string of winter weather looks to continue as we are tracking yet the possibility for another accumulating snowfall event on Wednesday. Forecast models have been rather consistent over the past week on this possibility, however, there have been some inconsistencies with the exact track of the storm. Like the last storm, however, it appears that there will be a rather large gradient across the state with regards to snowfall totals which will make constructing a snowfall map rather difficult. Anyone who gets under intense banding will get the most snowfall accumulations while anyone who doesn't get under the banding may not see a whole lot in terms of accumulations. Where the banding sets-up will be key!!

Currently, there is energy moving into the state of California. This energy will continue progressing into the southern Plains over the next few days before strengthening as a developing shortwave trough amplifies across the Gulf Coast states:

There is also a current piece of vigorous shortwave energy over the central Plains with an associated area of surface low pressure. This piece of energy and surface low will continue slowly progressing eastward over the next few days. As the energy across California moves west and amplifies, it will interact with the piece of energy and surface low pressure over the eastern United States. When this process happens the surface low pressure and system as a whole will begin to rapidly strengthen as it works towards the east coast:

One feature to watch which could result in a storm track further south is a vigorous piece of shortwave energy which hangs around across southeastern Canada. While forecast models this morning are suggesting the possibility for a big hit of snow across portions of Connecticut we still have to watch how the forecast models handle this energy in southeastern Canada because it could easily suppress the system further south which would mean less in the way of snow:

Latest forecast models seem to be in rather strong agreement that this system is going to really strengthen just south of Long Island and this is evident by forecast models becoming vertically stacked with the system south of Long Island. We can see this by looking at the 925mb, 850mb, 700mb, and 500mb charts and tightly closed contours (indicating closed off low pressure centers) which develop south of Long Island. This placement of the closed lows is a prime location for a band of extremely heavy snowfall to set-up right over Connecticut:

Forecast models are suggesting excellent snow growth over Connecticut along with sufficient moisture within the snowgrowth zone and excellent upward vertical motion within the snowgrowth zone. The graphic below from this morning's run of the GFS forecast model is showing forecast omega values along with the dendritic snow growth zone. This is showing a deep snowgrowth zone with the -12C to -18C zone extending from about 600mb to 500mb and a period of rather high omega values indicating very strong upward vertical motion. This suggests there would be a period of extremely heavy snowfall, likely within a potent band. We need to watch where this band sets-up as this is where the highest snowfall totals will occur along with the heaviest snowfall rates:

Over the next 24 hours the details should begin to become much more clear and the forecast will be able to become much more fine tuned. Also, there is a very small possibility we could see a period of light to perhaps moderate snow across the extreme southern Connecticut beginning mid-to-late tomorrow afternoon. If this does occur there is a possibility of some spots picking up as much as 1-3'' of snowfall from this. I will have a forecast update tomorrow afternoon.

In addition to the likelihood for accumulating snows, winds could be rather strong too, especially across coastal Connecticut on Wednesday where winds could gust upwards of 50-60 mph. This coupled with fairly wet and heavy snow could lead to scattered power outages and tree damage. This potential needs to be monitored very closely as well.

 Below is what I am thinking...but keep in mind the 8-14'' zone is with regards to the banding. This zone, along with totals will be adjusted and fine tuned once it becomes more clear where the banding will set-up and how intense the banding will be: