A Pattern Of Potential...

Hello this is Junior Meteorologist Kyle Elliott...and there are several things of interest as far as East Coast Snowstorm possibilities that are ahead in the next several weeks that I feel are worth discussing and posting my thoughts on. The January thaw that has been in the eastern half of the nation for the past week or so is going to end this Monday and Tuesday, and the storm that cuts into the Lakes will bring a pattern change that will affect not only the United States, but the teleconnections between the PNA, AO, and NAO and the pattern in general from the U.S. to Canada to Greenland. I believe that the changes ahead will set the stage for an snowstorm on the East Coast around January 29th, and there are three reasons why I believe this. First, though, I want to give some background information about several issues first. The first piece of information that I want to state is that I mentioned the possibility of a snowstorm between the 28-30 of January way back on the 14th of the month...before the GFS even hinted at a storm during this time period. I stated that the pattern would become more favorable for storms in the East, and I also mentioned about how the pattern is one I have seen before and recognize. That leads into the second piece of information I want to talk about...and that is pattern recognition in itself. Some meteorologists look at analogs, teleconnections, and upper air anomalies to make their forecasts...and some use all three. Others, like myself, tend to look at the pattern in general, the placement of high and low pressure systems, and the steering currents of the Jet Stream and upper air winds. Using these tools, what I refer to as "pattern recognition," I try to make the most logically guess as to when and where storms will occur up to 2 weeks before they happen. The downfall to pattern recognition is that it limits about to see storm potential more than 10-14 days before the storm occurs...but on the other hand, it can also be of utmost benefit when trying to pin down the most likely track of a storm up to 2 weeks before it happens. If one knows the general movements of high and low pressure systems in a pattern like the one that is upcoming, they can pick out model errors and adjust them...and they can use those adjustements to theorize how the misplacement of those systems will affect the ultimate outcome of a potential storm threat. Everything in the meteorologically world is connected, and if the model has an error say on an arctic high in Canada, for example, then that would ultimately affect the track of a potential storm system during that time frame. This general approach to solving storm track issues and pinning down a given scenario when three are available, as is the case for the 29th storm, gives a much more clear picture of why one solution would be much more likely than all the rest...even if the models favor the wrong one. The models' weakness is that a small error in the near term leads to bigger and bigger errors as the model is run; therefore, models can cling to a wrong forecast track for days on end before errors finally become resolved and the model finally shifts to the right path. Having said all this, I am now going to point out a few model errors of the GFS in regards to the 29th storm and give my reasoning for why the storm, I think, will end up on the East Coast. I see how the storm may ultimately end up tracking into the Lakes though too at the same time, and I will also present how that may happen. So, without further adieu, let me present my points on the 29th storm...keeping in mind what I've said above.

1) The first reason I doubt that the storm will either get suppressed or track into the Great Lakes is due to the storm coming this Sunday/Monday. If you notice, the storm on Sunday/Monday takes a track into the Lakes itself...very near to Chicago. At the same time, a secondary, much weaker low pressure system (modeled by the 18z NAM of this evening) forms along the Appalachians and heads northward through Pennsylvania. At the same time, a blizzard will develop in the northern Plains through Minnesota on the backside of the storm, while heavy rains, warm temperatures and thunderstorms reach as far north as Pennsylvania and New Jersey. This storm, in effect, is a pattern changer. Recently, there has been a blocking high pressure system north of NY State over southeastern Canada...and the entire pattern is locked up as the northern Jet Stream has been confined to Canada while the southern Jet Stream remains separate from the northern branch. Therefore, a generally calm pattern with weak steering currents has been plaguing the East Coast...which is why storms have been moving slowly and unable to charge up the East Coast. Even though warmth is abundant relative to the time of year, there are no negatively tilted troughs to quickly intensify storm systems that come along. Also, the temperature gradient between north and south has been very spread out...therefore resulting in little instability for a snowstorm. Granted, the southern stream jet has caused an outbreak of severe weather in the south...but its failure to combine with the northern jet has ultimate led to why snowstorms have been evaded in the Mid-Atlantic and most of the Northeast except for far northern New England. The storm coming on Monday, though, will change all that as it will cut up west of the Arctic high...ultimately booting it out of the way and clearing the pattern out. At the same time, the northern Jet Stream will will plunge southward as a blast of cold air rides the whole way to the Eastern Seaboard by Tuesday. Here is where things, in my opinion, are modeled wrong by the GFS. How can one storm cut into Chicago and move the trough 500-700 miles eastward to the Coast...and the next storm follow that up and track only 150 miles east of that through Detroit? Looking at pattern recognition, this tells me that the model has a fallacy somewhere...and that the storm will ultimately end up tracking about 500 miles east of Chicago...producing a storm that cuts from Oklahoma to the Tennessee Valley to Richmond and ends up off Cape Cod. Granted, I do not see this storm as one that will wrap itself up into a true blizzard off the Cape...but I do believe it will be a more flat track from OK to VA with moderate intensification on the coast. Having said this, though, I do figure that a moderate snowstorm will affect areas from Kansas to Illinois to Maryland, Pennsylvania, and ultimately all of New England. Instead of a track into the Lakes, I believe the storm will ride the new placement of the trough and therefore end up along the East Coast. That is the background to reason number 1.

2) Secondly, I believe the GFS is handling the situation with the high pressure system in Canada wrong. On one of the ensembles members from 18z, the member showed a high pressure system just north of Lakes Huron and Michigan. I believe that that member is the one member that is correct...because I do not believe that the high pressure over the western provinces will sit there and waddle around for three days straight while the storm develops in the southern Rockies and tracks across the country. Instead, the high will track to a position north of Lake Huron as is modeled by the ensemble member...and we all know that a storm cannot attack an arctic high that is anchored north of the Lakes. Instead, the storm will follow the path of least resistance which, in this case, will be the East Coast. So, in effect, we have sufficiently thrown out the scenario of a storm that cuts straight into the Lakes and ends up in a position over Quebec, Canada. Now...to disprove the suppression scenario...in my third point.

3) Finally, there will be a high pressure system that moves off the East Coast behind the Sunday/Monday storm and ends up somewhere near Bermuda. With that happening, the flow will turn southerly in the East and, as a result, the 29th storm will not be able to attack that high either. Therefore, it will have to go up and around that high pressure system and track west of its center. So...with all of this being said...what is the past of least resistance? Obviously, the storm cannot track into the Lakes due to the high centered over Huron...and it cannot track out-to-sea off of South Carolina because it would run headlong into another high pressure system. Therefore, it must end up somewhere between Harrisburg, PA, and 200 miles off the Jersey Coast. What is the mean of that? The benchmark track...need I say more?

So, there you have it...my theory and reasoning behind why I believe the 29th storm is the first real snow threat that the East Coast has seen since the Blizzard of 2009. I do have one significant concern, though, of why the storm will not track through the benchmark...and that concern is this. In nearly all cases of storms that have tracked through the benchmark, there has been a high pressure system just north of New England and a negatively tilted trough along the East Coast. The high pressure system is not pressing southward to suppress the storm, but is rather holding its ground and merely giving away ground slowly to allow for the storm's unhindered track up the coast. Cold air comes down from New England, and no warming is felt from a high pressure near Bermuda which would turn snow to rain in the I-95 corridor. And that is where my concern comes with this storm: the high pressure is not north of Lake Ontario...instead, the arctic high is north of Lake Huron. Also, the high pressure near Bermuda would in essence block the storm from taking a perfect benchmark track. My concern is this: even though the storm will not be a Lakes Cutter, could it end up tracking through the I-95 corridor and produce a snowstorm for only those folks west of I-95? If the upper air pattern is how I described it above and what I think it may end up being, we will see a track either along I-95 or through the benchmark. The ultimate reason I am leaning toward the benchmark is because I believe the high pressure north of Lake Huron will dominate the high over Bermuda as I think it will be much stronger. My guess is that the Bermuda high is about a 1022 millibar high, while the one north of Huron ends up around a 1031 millibar high. If the high north of Huron were weaker, though, and the one in the Atlantic stronger...then that would lead to another disappointment for I-95 corridor snow geese. So in the end, only time will tell. Yes, I have my leanings now and know what has happened in the past from patterns resembling this one, but no one pattern is alike and factors can change. At this point, though, this is my best guess on the storm. With a relatively neutral PNA index, storm systems will be more inclined to come onshore in California instead of diving down from the Northwest...resulting in a flatter storm track across the country. With a slightly negative NAO, storms will most likely not bomb out into a historic blizzard along the East Coast...but at the same time, they will not be inclined to track into the Lakes. Therefore, I have gone with what I know should result on the 29th as a result of the pattern...and that's why this time I have gone with a track that is favoring a storm that winds up on the East Coast off of the Delmarva. Things may change, but let's just say that this is a "Pattern of Potential." That's all I have for now, so have a great evening and look forward to further updates on this upcoming winter storm event as I will be watching the pattern like a hawk over the next week. And, by the way, the fun does not stop there as I see yet another storm following the 29th storm sometime around the 3rd to the 4th of February. Let's put it this way: if the storm on the 29th goes awry and does not end up on the coast, the one of the 3rd of February definitely will. So don't give up hope is the 29th storm does not come about the way I see it now, because the next one would have to. This is Junior Meteorologist Kyle Elliott reporting for the AKStormtracker Forecasting Center.

P.S. In regards to my final snowfall map I made yesterday evening, it busted miserably. I tried to bring the precipitation too far north, and I overlooked a marginal 850 mb situation which also feature a warm mid-level surge of air...so my map busted miserably. Overall, I'd give myself a D on the forecast as nobody in the Susquehanna Valley saw snow, and the most I saw that any given location got was just over an inch. I made a meteorological error, and for that I deserve to have busted this time. I'll cut my losses, and move on. The pattern of late has been very difficult to forecast, and I'm honestly glad that I even got one out of two storms correct. Calling the storm on the 17th was a confidence boost, and I am really not that disappointed that the forecast last night failed...as the pattern has been locked up of late and has been highly dependent on exact tracks (to the mile basically) of high pressure systems and the storm systems themselves. Anyway, that makes me 5 for 7 overall and 4 for 7 locally this year. Not what I was hoping for, but around 60-70 percent accuracy...so I'm not complaining.