Major Winter Storm on Tap for CT Saturday, January 18, 2020

We have been relatively quiet in the winter weather department across CT since ringing in the new year. In fact, we have seen temperatures quite a bit above-average. That is all about to change, however, as a potent weather system looks to deliver some snow...and potentially quite a bit this upcoming weekend.

A potent piece of shortwave energy forecast to enter the Pacific-Northwest Thursday evening will quickly traverse the fast flow aloft through the end of the week and enter the Ohio Valley region by Saturday morning:

A vigorous 110+ knot 500mb jet rounding the base of the trough will result in further strengthening of the system; including the surface low pressure:

There is pretty strong agreement within the computer model world the surface low pressure tracks through the upper-tier of the Ohio Valley, through southeastern Canada, and across northern New England. Typically this type of storm track results in warmer air flooding into the region...especially when the surface low continues to strengthen to our west. While there will be warmer air that works in which will likely result in snow changing to sleet/freezing rain or rain there are a few features which yield potential for major snow totals;

1) Strong surface high just north of Maine. This feature is departing to the northeast as Saturday progresses, however, it looks to have control long enough for the return flow (winds at the surface more north-northeast) to keep lower-level and surface cold air locked in:

2) Strong warm-air advection. Strong surge of warm-air advection results in very strong upward vertical motion resulting potential for moderate-to-heavy precipitation...in this case snow. This also helps provide the moisture needed for the generating of snow:

It is still a bit too far out to get into details and there are still some uncertainties, especially regarding the potential for mixed-precipitation and any changeover to rain and whether this will impact potential totals. Anyways, as it stands right now this could be a major snowstorm for a large portion of CT.