First and foremost, we wish you a very happy new year and hope you had a wonderful first day of 2018. This month marks a milestone for us, as SCW will be celebrating five years of forecasting on January 22nd! We’re thankful for all of your support over the past five years and are looking forward to continuing to be your source for Connecticut meteorology for many more years to come. With that said, we’ve got an interesting forecast tonight, so let’s get right into it.
We’ll see the warmest conditions of the forecast period tomorrow and Wednesday as our arctic air mass briefly relaxes ahead of our next storm threat. Warmest, however, is a relative term in this case, as we’ll still be 10 degrees or so below normal on our temps, which translates to highs ranging through the 20s across the state. Unless we come in above forecast, we’ll continue our streak of days below freezing at all of the Connecticut climate sites, which currently stands at 7 days including today, to at least 13 days as we won’t go above freezing through Sunday at the latest. The record at Hartford is 19 days, which will likely stand as we should spike above 32 next week, but that's still an impressive stretch!
Very interesting setup on tap for our first system of 2018. Our next shot of arctic air is inbound for the weekend courtesy of the polar Jetstream, which is currently digging deep into the southeastern US. At the same time, energy comes onshore from the Pacific and traverses across the country, eventually phasing with the previously mentioned trough and producing a very strong system that then moves up the Atlantic coastline. While similar to a classic “Miller A” storm, this one is interesting in that we have anomalously strong high pressure to the west of the storm and therefore very cold temps along with a cold antecedent airmass in place. Combine that with the relatively warm ocean temperatures and you have a recipe for a very potent system; the models have caught onto this and are showing a rapidly deepening low that is producing impressively large precipitation and wind fields. Thus, while the main low could track far enough out to sea where it would not normally be a problem for our area, in that case we would likely still see some light snow simply due to the sheer size of the precipitation shield. Of course, should the system track close enough to get us into the main commahead of the storm, we could be looking at blizzard conditions across parts of the state. Unlikely, but not impossible.
Here’s a look at the upper air evolution as shown on the NAM. You can see the polar jet dropping down at the same time that the southern stream is moving southeast and the resulting interaction of the streams to create the coastal system.
However, there are a few pieces of guidance that bring the surface low further northwest, most notably the GGEM and the extended RGEM. In that solution, we would be close enough to the low to get into the commahead of heavy precipitation and the net result to us would be a significant snow event. That would look something like this, but I would be shocked if the thermal profile depicted on the model verified in that solution, instead favoring a colder solution that would keep all of Connecticut and southern New England as snow save for perhaps the Cape and Islands for parts of the event.
Wind is another thing to keep in mind for this event. The significant pressure gradient between the low and the arctic high to our west will create strong winds; even the offshore GFS has wind gusts in the 30-40 MPH range while the other models have some 40-50 MPH gusts along the shoreline. Those winds will likely magnify the impact of any snow that does fall, and as with the amount of snow, the eventual wind forecast will depend on the final track of the system.
We’ll have more on this storm tomorrow along with a first call snowmap, but this should give you a good idea of what we’re looking at. Timing looks like we’d have snow move in Thursday morning and last for much of the day before moving out Thursday evening.
The forecast for the extended can be summed up in one word; COLD! Another arctic high pressure arrives for next weekend and models say that this one will be even colder than the airmass that is currently exiting, with the Euro saying that we could see some interior areas in Connecticut fail to break zero on Saturday, which would be extraordinarily impressive. Warmer air begins to move in for Monday as low pressure slowly approaches the area; this will likely be our next system after Thursday and likely a much warmer one, but let’s get through Thursday first before we start to look at this one.
Tuesday: Mostly sunny, with highs in the mid 20s.
Wednesday: Mostly sunny, with highs in the mid to upper 20s.
Thursday: Snow likely, otherwise, mostly cloudy and windy, with highs in the low to mid 20s. Chance of precipitation is 70%.
Friday: Mostly sunny, with highs in the upper single digits to lower teens.
Saturday: Mostly sunny, with highs in the single digits.
Sunday: Mostly sunny, with highs in the mid teens.
Monday: A chance of rain or snow, otherwise, partly cloudy, with highs in the low to mid 30s. Chance of precipitation is 40%.
We’ll be back tomorrow evening with more on Thursday's system, until then, stay warm and thank you for reading SCW! Happy New Year!