If you follow us on Twitter @SouthernCTWX, you may have noticed last night that I briefly mentioned the possibility of some snow on Friday morning from an anafrontal wave that some guidance brings far enough north to impact our area. While the modeled consensus for this event remains as a minor/non event for the state, considering that the trend ahs been to pull this system northwest, there are a couple pieces of reliable guidance showing a more substantial event, and that the timing could potentially impact the Friday morning commute, I thought that it would be worth outlining quickly here. \
The setup is fairly simple. As rain ends later today, a frontal boundary comes through the state from NW to SE, bringing cooler air and an end to the spring-like temperatures that we’ve had the past couple of days. Once the front clears our area and exits out into the Atlantic, it will stall, and remain in position for an extended period of time. During that time, an impulse of energy comes up along the coastline, allowing for interaction between the energy and the front. That will pull the front northwest, and cause precipitation to develop along it. Where the northwest edge of that new precipitation shield makes it to before pivoting east will determine how much, if any snow we see in Connecticut.
As is usual for a winter threat(or any threat, really), the modeling is all over the place. Some models, chiefly the NAM and GFS, are further southeast with the placement of the front, and as a result would result in little/no snow for the state. Some models, chiefly the GGEM and Euro(along with it’s ensembles), bring the front far enough northwest to bring a minor event to southeastern portions of the state, with the majority of the state only seeing flurries or sprinkles. And finally, some models, represented mainly by the UKMET, drive the system well northwest and bring the meat of the precipitation band into the state. This would result in a much more significant system, as it allows for the pivot of the band to take place in the state and as a result a much longer period of snow would take place, with significant accumulations possible. Images of the GFS, GGEM, and UKMET valid for 7 AM Friday morning are attached to this post.
The question then becomes which one do we believe? As of now, I’m inclined to lean towards the middle ground, which would bring some light snow, possibly mixed with rain, to eastern areas on Friday morning. However, I am hesitant to dismiss the higher impact solution, or at least some blend of it and the middle ground, for a couple of reasons. Firstly, the trend the past few model cycles has been undeniably to bring this system further north and west. There is a saying in meteorology that “the trend is your friend”, and I think that applies here. Secondly, anafrontal events, as this one is, have a habit of coming substantially northwest in the final day or two before verification. And finally, the seasonal trend this winter has been to model systems as impacts in the longrange, trend them away in the midrange, and then come back to some extent in the short term(Last month’s blizzard being a prime example of that). Combining those three factors, while they are not enough to make me believe the UKMET’s solution outright, makes me caution those who toss it completely. It’s worth noting that the stronger solutions are also a bit warmer, and would result in some rain to start across most of the state before shifting to snow for the second portion of the storm. The added precipitation would still result in substantial snow totals, however, and I’m not convinced that the temp profile would be as warm as advertised in such a setup.
As far as timing goes, any precipitation should break out overnight Thursday into Friday, with the snowier solutions keeping precipitation around through Friday morning, or, in the case of the UKMET, afternoon. I do think the morning commute could be impacted for eastern areas. Should a stronger solution verify, school and workplace impacts would be likely, however, at this time, I don’t have the confidence in that solution to be more gung-ho on potential closings/delays.
I’ll be keeping an eye on the models all day today, and if needed, will issue a snowmap in tonight’s forecast discussion. Regardless, we’ll have information tonight on this system(whether a miss or a hit) as well as your updated weekend forecast and more. Until then, have a great day and thanks for reading SCW!