A taste of winter coming with multiple storm threats

Hello everyone!

Back in the USA today with full access to data so let’s get to it. I will break down this post into two parts, the forecast, and the reasoning behind the forecast. I have done my best to keep things as non-technical as possible but if you are looking exclusively for the ‘sensible weather’, here it is.

Wednesday will feature lots of clouds and some showers especially north. Highs 50’s for most, 40’s north. Thursday will be a transition day with breezy NW winds and cooler temps, more sun, and highs in the 40’s. Friday will see more clouds with the chance for some flurries, highs in the 40’s for most, 30’s inland and mountains. Saturday will be another transition day, much like Thursday but quite a bit cooler with highs likely in the 30’s except SNE who still enjoy the 40’s. Sunday is still under debate but more clouds are likely with some rain/snow possibly moving in for the evening hours. Monday is also an uncertain forecast with rain/snow possible. Highs both days are largely dependant on the storm track but a mix of 30’s and 40’s looks likely. Tuesday will feature clearing out with breezy NW winds and cooler temps.

Read on to learn about the upcoming pattern and why the cold looks to stay a while. I’ll also break down each storm threat in more detail.

We have an interesting few weeks ahead with several storm threats to look at over the next 2 weeks. This upcoming Friday (Highly unlikely), Sun/Mon (Possible), Late next week (Possible). Despite much hype this week regarding Friday’s storm threat, I think that IF a storm forms, it shoots rapidly out to sea without much impact. That being said, I can easily see some rain and snow showers developing as the upper level energy moves through.

pos tilt trough

This map can look quite confusing at first but the thing you really need to look at is the position of the Purple/White area over Canada. New England is in the upper right for reference. All the models have this energy slipping through New England without much of an issue. The biggest impact will be more clouds with a flurry possible.

The much more interesting storm threats comes next week. After our flurries on Friday, much much colder air makes its way into the region with highs well below normal  (the Euro has a high of 35 for Wednesday). Anytime Arctic air is in place, you have to look at the potential for snow and we have two credible threats on tap this week, Sunday into Monday and sometime TBD late week.

stormsunmon

Here is the same GFS map for Monday Morning. Notice the difference between the two maps. The Monday morning map has the pocket of energy farther west and south and the overall energy much less positively tilted (at the 500mb level, the orientation of the trough is what matters when it comes to where the surface low will track. A trough that looks like / is pos tilted, | is neutral tilted and \ is negatively tilted). Notice how the reds and oranges on the map are much closer to being neutrally tilted than positively tilted. This allows for a storm to form somewhere offshore and have a much better chance at coming up the coast than if the trough were to be positively tilted like what is projected to happen on Friday.

Bottom line is that the upper air pattern is reasonably conducive for a storm to form and impact the region Sunday night into Monday. It is far too early at this point to start talking ptype/snow amounts but right  now I think that even though we have some decent cold air that will be in place after the Friday flurries, we likely don’t have enough to support snow at the coast. However, if the storm tracks a little further to the east, this could easily change. Still lots of details to be worked out.

Our final storm threat in the short term arrives at some point late next week. I usually don’t look to hard at stuff 7+ days out but this really catches my eye for a few reasons. First off, the cold air will really be in place after whatever comes Monday. Second, the upper air pattern on the larger scale supports it wholeheartedly. We are in what is known as an Omega block which is a type of upper air pattern that favors very cold weather across the east while the west, especially Alaska, bakes. While this threat is far beyond any reasonable model range, the ingredients are there for a storm to form so we’ll have to keep a close eye on things as time goes on.

I’d now like to look farther ahead into the future with far fewer specifics. The pattern we are in and are expected to stay in is very exciting for the east coast. One of the main drivers of this pattern is something I mentioned earlier called the Omega block. The name “Omega block” comes from the fact that the jet stream looks like the Greek letter Omega.

Omega block

Here are the 500mb height anomalies for this week and next from the CFS model. 500mb height anomaly is basically geek speak for where the cold is and where the warm is. Red is warm, blue is cold. Notice how the jet stream (red line) forms the shape of the Greek letter Omega over Alaska. The CFS keeps the same general pattern, slightly less amplified, for the forseeable future.

weakeromega

 

Here is the CFS for two weeks from now. Once again, the cold air is locked firmly in place over the Eastern US while Alaska is cooking (by their standards).

Overall, this pattern is highly conducive to snow in the northeast. The one big factor working against large Northeast snow is the lack of blocking over Greenland. This was the problem last year as well, no blocking over Greenland means that any storm that forms has a door wide open into the Atlantic so while the cold will certainly make its presence felt, big snow is far from a guarantee at this point.

bigcold

Here is the CPC forecast for the next 6-10  days…

bigbigcold

 

..and 8-14 days. The cold is here to stay.

Normal morning updates begin tomorrow.

-Jack

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