Weekend Storm to Bring Heavy Mixed Precipitation

A potentially significant storm system looks to blow through New York and Connecticut this weekend that could impact travel Saturday night into Sunday morning.  Our computer weather models have been all over the place with this recent storm, resulting in a large range of forecasts with a number of scenarios.  In this post, I’m going to break down my expectations for the storm and also briefly touch on the next storm threat on January 6th.  Should you wish to purchase the premium, 3,300 word forecast on the two storms and the expected January pattern, you can do so here.  Similarly, should you wish to prepare for either of these storms by getting daily email updates with detailed forecasts, do consider signing up for our Premium service here.  If not, I’ll dive right in now to my expectations for this upcoming storm, with snippets of the earlier released Premium forecast.

WEEKEND STORM: I do believe we see some wintry precipitation to start off with this storm, and that the heaviest precipitation and the bulk of the storm will be rain.  Recent changed in our weather models have, however, eliminated the possibility that this storm is all wintry precipitation for the area, and this should keep significant wintry precipitation accumulations from being possible unless there is a major change in our weather models.  What it now all comes down is the interaction between these two pieces of energy that I have outlined.  If they phase quickly into a larger piece of energy, we end up with a scenario like the Canadian weather model shows, where a stronger low pressure center moves much further to our west, that brings more wind and rain and less snow.  If, like the GFS weather model, the two pieces of upper level energy (one diving into the upper Midwest, the other an upper level low in southern California) stay separate a little longer, the cold front moves through quicker on Sunday, the storm stays as wintry precipitation a little bit longer, and the precipitation is not as heavy with winds that are not quite as bad.  In the extreme scenario where the two pieces of energy stay separate, there is still a small chance of significant wintry precipitation accumulations, but that is getting smaller by the hour at this point.  The main point is that models have trended back towards the original solution of a stronger primary low cutting up to our west, and that is entirely made possible by the upper level low moving slower allowing the block it was supposed to move into to move east, so that energy can phase with another shortwave.  So don’t let anyone ever tell you that forecasting storms like this is easy!  Right when models were beginning to hone in on all the variables, another one was thrown on the table.

This leads to the final question: is this the final solution?  Honestly, I am still not entirely sold.  The upper level low could throw one more wrench in this forecast, speeding up to miss the connection or slowing down to a point where it phases even earlier, eliminating snowfall from the equation entirely.  The low is just now diving over southern California and will be wandering around there for a couple days, and so there is time for it do something else strange.  At the same time, it is now being properly sampled by out weather balloons, meaning the info being put into our computer models is more accurate, thus raising my confidence in the new updated forecast.  I’ll continue to watch the scenarios closely, but I have a feeling that we are honing in on what will be closer to the final scenario here, though the details will need to be continuously worked out over the coming days.

So, to conclude this section, I want to go over what I see for real conditions.  The going forecast is for snow to start across the region between 5 and 7 PM on Saturday.  Snow starts light but quickly picks up.  By 10 PM, snow begins to mix with sleet/rain at the coast, and by around midnight it is likely the entire area has turned over to a sleet/rain mix that rapidly becomes just plain rain.  Total snow accumulations of a couple inches at the coast to a few inches inland will probably be entirely washed away by morning, as up to an inch of rain falls overnight.  Then, rain moves out of the area Sunday morning, and by Sunday afternoon I expect we see some clearing as the cold front moves through Saturday night to allow colder weather to flood into the region on Monday.  Winds look to be strongest on Sunday ahead of the passage of the cold front, though models again vary on strength.  This is what I will be spending the majority of my future analysis on with this storm, so be sure to stay tuned for the latest.

JANUARY 6-7: The Premium post has model analysis, but here is a summary for this long-range feature:

Because this is such a small-scale feature, it is too early to get your hopes up for too much.  This is likely to be a weak Alberta Clipper that will dive down to the coast and strengthen as it hits the water.  Some variables that are at play are the fact that the air over the region will be fresh dry, frigid arctic air, enabling the entire storm to be snow unless it is drastically different than modeled.  Also, water temperatures are much warmer than normal due to a very mild December, allowing the storm to potentially strengthen more rapidly than normal when it leaves the land and hits the water.  This could enhance snowfall across the region should the storm take a proper track.  I’m going to keep a very close eye on this storm, especially because of the strong weather model agreement that we have currently.

LONG-RANGE ANALYSIS: This is main Premium feature, but I wanted to also offer a sneak-peak into what I see coming in the future:

MJO forecasts and teleconnection forecasts have remained relatively the same.  MJO forecasts are all over the place, with the recent MJO moving slightly closer to the center circle, indicating even less of an influence in the overall pattern.  This is how we are able to get such cold weather when it is in its warm cycle.  The AO is still forecast to remain positive, while the NAO is expected to flip positive, and the PNA will remain slightly negative.  It is the negative EPO that will continue allow us to see colder weather.  It briefly breaks down in mid January, but I expect the negative EPO to return later in the month, which is one of the things that will help to re-establish the cold.  And the CFSv2 climate model (the sub-monthly version that I prefer) finally flipped and showed, after the mid-month warmth, a very cold ending to January, even colder than I was expecting.  I still don’t like the model very much, but it is encouraging when it backs up the central broad ideas of my forecast.

CONCLUSION: Overall, these are the storm threats that I am tracking as winter really heats up.  We have one cold blast over the next couple of days, another January 5th/6th before the 6/7 storm threat, and then another the 7-11 as the coldest air of the season blasts into the area.  With accumulating snow looking more likely in the coming days and potentially widespread impacts from multiple storm systems, I definitely encourage you to stay tuned for the latest, and potentially consider signing up for a Premium membership to get more detailed forecasts emailed to you nightly alongside natural gas market analysis, 15-day forecasts, 7-day regional forecasts, and impact analysis including school delay/closure forecasts.  Stay tuned for the latest!

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