Hi all, sorry I have not posted in a while, but I do want to make this post much shorter than usual because of such a major storm we have at hand with major implications for the northeastern US. As I said all the way back in December, this worst of winter had yet to come, and based off of the northern hemisphere snowfall anomaly and the effects of the major stratospheric warming event still at hand, the worst of winter had yet to come and would be from late Jan-Feb. Many people had very doubts about this however, when one looks at what is actually happening, you can certainly see that the worst of winter is certainly upon us. Just look back at what we were dealing with in mid January with much of the US basking in well above normal temperatures and major snowmelt occurring nationwide.
Temperatures for the period roughly from the beginning of the 2nd week of January to about the 20th looked like this, with warm across the east, but very cold conditions across the intermountain west and into the southwestern US.
Now, many people thought at this point winter was over and spring was just around the corner, but did they even acknowledge that the great winter of 2009-10 also featured a formidable warm-up during the heart of winter, but most of that was soon forgotten by “snowmaggedon” that soon followed. Interestingly, you also notice that the warm-up in 2009-10 was much more widespread over the US, rather than what was observed this year with the warm-up being mainly confined to the east and central US while areas from the Rockies and points westward shivered.
Now, many people tried to say this was like last year, but as I explained in my last post, this winter has turned out be to nothing like last year, a simple temperature and snowfall comparison shows reality.
Temperatures for the first half of last winter looked like this, blowtorch warm over much of the US, only exception being towards the southwestern US, especially near west Texas, where they received a rare white Christmas even into El Paso, TX.
This year through mid January for roughly the same time period shows it is overall much cooler for the US
However, it could have been much worse than last year, take the winter of 2006-07 for example with even more overwhelmingly warm conditions over the US, especially for the eastern US, now this is what a “blowtorch” really looks like.
Even in the winter of 2006-07, conditions dramatically turned around in one of the greatest late winter comebacks ever, and this can be partially attributed to the warmer than normal waters that were present at that time over the deep tropical Atlantic, helping to enforce a an upward phase of the MJO, thus a cooler and stormier pattern, despite the overwhelming warmth the first half of winter.
Look at the Atlantic Ocean water temperatures during the winter of 2006-07 as we headed into February, notice how the tropical Atlantic relative to other tropical regions was comparatively warmer.
Also, look at what happened in 2009-10 in February, big time winter comeback with “snowmageddon” on this date back in 2010.
After the warm-up in the heart of the winter of 2009-10, within a few weeks what followed was one of the greatest winter storms ever to strike some areas of the mid-atlantic, with major snows through much of the northeast as well.
Look, at what happened a few days later on February 9-10, another major winter storm into some of the exact same areas of the mid-atlantic and northeast only hit a few days earlier with crippling snowfall, although the precise axis of snowfall very slightly to the north towards areas of southern PA and in towards Philadelphia.
As if that was not enough, yet another very powerful winter storm struck the northeast before February was over, this time for areas farther north, with lake effect snow very prevalent off of Lake Ontario and Erie, with a 30 inch + bulls eye near the Catskills of NY and very close to Albany.
The winter of 2009-10 as a whole ended up colder than normal, especially for areas further south with a very active subtropical jet stream in place, typical in el ninos, and the month of February certainly contributed very significantly to the colder and stormier than normal conditions for much of the US, especially for the eastern US.
Now, many people will remember this winter to be very cold and snowy, although I showed that like this year there was a period of mild conditions in the heart of winter, but what does February 2010 have in common with February 2007? Just look at the tropical Atlantic water temperatures, and you can see yet again, it is the warm waters present over the deep tropical Atlantic that are big reason as to why February was so cold and snowy because the warmer than normal waters over the deep tropical Atlantic force the surrounding air above to warm, thus inducing the air to rise. With rising motion being favored, this influences the upward phase of the MJO into the Atlantic, which is known to make the pattern cold and stormy over much of the US, especially towards octant 2 and 3.
Now, look at this year and compare to February 2007 and 2010, and you can see why I have been pushing since December for the worst of winter to be from late Jan-Feb, look at how warm the waters are over the deep tropical Atlantic. Knowing what happened in February of 2007 and 2010, one can certainly come to the conclusion that this month may not be too much different.
A good reason why warmer than normal waters over the tropical Atlantic have led to colder than normal Februarys in both 2007 and 2010 has been the MJO, and you can see when it is in the favorable Octants from generally 8-3, conditions are colder & stormier than normal over the US, especially the eastern US.
You might be wondering at this point, why do I talk about Octant 3 of the MJO being favorable, when it is warmer than normal from December through February, but look at what happens as we progress deep into the winter and start to approach spring how the MJO in Octant 3 becomes much colder than normal, with the temperature composite below from February through April showing this change in the effects of the MJO. You can also see just how dramatic this change is from December through February, the most favorable octants are 8 and 1, but this changes to 2 & 3 as get towards February and beyond, which is very interesting to say the least.
Now, another factor that will be helping out this situation for cold is the AO and NAO, both of which are going negative, which is fairly significant because both oscillations have maximum effect when they’re both working in tandem, and there’s a couple of reasons as to why they are going negative.
Of course one of the main culprits as to why the AO and NAO are going negative is because of the SOI (Southern Oscillation Index, a measure of the pressure differential between Tahiti, French Polynesia and Darwin, Australia), with values since the start of February as follows: Feb 1: -26.08, Feb 2: -47.31, Feb 3:-43.04, Feb 4:-32.95, Feb 5: – 31.85, Feb 6: -28.53. More SOI data is available here at the website, which updates once a day on the SOI http://www.longpaddock.qld.gov.au/seasonalclimateoutlook/southernoscillationindex/30daysoivalues/
Of course, the reason the SOI went negative has a lot to do with the MJO, and you could see this -SOI burst coming several weeks ago. It makes sense given that as the MJO sat over the western Pacific, not only did it produce ample amounts of thunderstorm, where these thunderstorms (as I’ve described in previous posts) create natural turbulence, which goes against the natural east to west flow of weather and winds over the tropics which is created naturally be the Coriolis Effect. Also what the upward MJO did was as these thunderstorms sat over the same region over an extended period of time (evidenced by the MJO stalling slightly in Octant 7) they cool down the surrounding air and water, and their turbulence also stirs up the surface waters, which cools them. As the waters and the surrounding air cools due to the increased and prolonged period of thunderstorm activity, the cooler air and water does not have the ability to lift as strongly as the previously warmer water. Thus over time, the waters cool, and since cooler air is naturally denser than warmer air due to the air molecules within colder air not moving as freely about in cool air, allowing them to stay more compact, which allows for air molecules to be packed in the same amount of space, which gives the air more “weight” thus pressures rise. As pressures rise in these areas over the western Pacific due to the moderated air and water from the increased thunderstorm activity and the MJO moving eastward, air pressures continue to rise, which begins to force regions of high pressure to form over this region. Since in areas of high pressure, air spreads out and goes outward in all directions, and since we are talking about the western Pacific, the only direction at which air can flow is eastward, thus the natural east to west air flow over the tropical Pacific becomes disturbed where air now flows from west to east. This air flowing against the natural east-west air flow and movement of weather over the tropics also disturbs the natural incline of water from east to west over the Pacific, which forces water in the eastern Pacific to rise in response to the sudden slowing of the natural east-west windflow. This creates a displacement of water, which can only be compensated for by large scale waves because of the vast size of the Pacific, and it is these waves which are called Kelvin Waves. Also, with lower pressures moving away from the western Pacific and moving towards the eastern Pacific, this causes the pressures towards Darwin, Australia in the western Pacific to rise, however, the pressures towards French Polynesia in the south-central Pacific begin to fall, thus with pressures higher towards Darwin, Australia as opposed to Tahiti in French Polynesia, the SOI goes negative, which is exactly what we have witnessed since the start of February as the MJO moved eastward across the Pacific.
The ECMWF MJO forecast from over a week ago showing this MJO heading towards the extremely favorable octants 2 and 3 in the long range, which makes sense given how warm the waters are in the deep tropical Atlantic to promote upward motion to support an upward MJO phase, and this supports the potential for a “Fun February” like what was observed in 2007 and 2010.
Now of course, when you have a -SOI, this helps to activate the subtropical jet stream, and when you activate the southern branch of the jet stream, this gives a better opportunity for phasing of other branches in the jet stream and allows for systems in the northern branch to dig deeper and strengthen fairly significantly, which is what we are beginning to see now, especially with this first major winter storm in the northeast. What the -SOI along with the upward MJO pulse does over the Atlantic is as the upward MJO pulse moves over the tropical Atlantic, it forces rising motion, causing thunderstorms to form over the tropics and atmospheric pressures to lower over the tropical Atlantic. As pressures lower in the tropics, this allows for the subtropical jet to strengthen and more troughiness to take over in the Atlantic. This also means that with the Azores High that is normally present northwest of Africa, this troughiness and low pressure influenced by the upward MJO forces the region of high pressure to weaken or even be replaced by an area of lower than normal pressure. This area of lower pressure here in the Azores also effects the area of low pressure normally present near Iceland & Greenland, and with lower pressures towards the Azores, this forces atmospheric pressures to rise towards Greenland, and when you have higher than normal pressures near Greenland “blocking” this means the NAO goes towards its negative state, which is exactly what we are seeing now as the models begin to respond to this.
This picture helps you to better understand how lower pressures are influencing the Azores High to weaken, thus allowing for blocking to begin to develop towards Greenland.
The GFS ensembles for several days now have been locked onto this idea of a -NAO developing as February progresses, thanks to the upward MJO, (especially as it heads towards octants 2 and 3 for maximum effect), and this along with the -SOI promoting low pressures towards the east Pacific, indicated by the troughiness (in blue) extending all the way back to Hawaii helps to promote deep mid-latitude troughs over the eastern and central US to go along with the active subtropical jet in place.
To make matters even better, we have the stratospheric warming event still ongoing below 50 millibars in the stratosphere, and although the temperatures in these levels of the atmosphere are cooling, they still remain high, with 70 millibar temperatures still near record levels. This continued warming at this level means air is expanding due to the warmer than normal temperatures, in doing so, this forces the lower layers of the atmosphere, like the troposphere to contract, thus being indicative of ongoing cooling and this forces pressures to rise in response, thus the AO has a tendency to go negative as well along with the NAO going negative due to the MJO forcing troughiness and pressures to lower near the Azores.
Here are the current 500 millibar temperatures, starting to cool finally, but still still quite warm, you can also see the red line, being this year how it surpassed the top black line, meaning we broke a record for all-time warmest since the beginning of the satellite era in 1970, for a period of time in this level of the stratosphere.
The 70 millibar temperatures show that it is still much warmer and near record warm conditions in the lower levels of the stratosphere as this warming event propagates its way to the surface. You can also see like in the 50 millibar chart above, the stratosphere in this level also broke a record for being warmest for a period of time during this warming event.
Also, let’s not forget about the 30 day sunspot cycle and its relation to the pattern and the PNA, and it is amazing to see, like what was observed in late December, how when we have a lull in sunspot activity that suddenly the pattern over the eastern US responds with periods of cold & snow, and it seems like we are seeing another one of those yet again as the sun oddly goes dormant near the peak of solar cycle 24. Also, the “Postdam Ap” when it is lower than normal, which is what we are seeing at this point in time, it pushes for more high latitude and arctic blocking, which along with the MJO and the stratospheric warming event, makes a whole lot of sense as to why the AO & NAO are going negative.
Taking all of this information into account, including the stratospheric warming event still ongoing in the lower stratosphere, the MJO and SOI support allowing for a stronger southern branch of the jet stream and helping to force the NAO & AO negative as a trough over the Atlantic where the upward MJO pulse is, subsequently forces pressure rises towards Greenland, thus it shouldn’t be a surprise to anyone as to why the NAO is going negative, despite what some of the models were saying only several days ago. With all of this information at hand considered along with the parallels with the warmer than normal water over the deep tropical Atlantic like what was observed in 2007 & 2010, not to mention the northern hemisphere snowfall anomaly for October which suggested a pattern like this would occur, it is no wonder this pattern has turned colder with the worst of winter currently upon us. The CFSv2 sub monthly ensembles seem to really like this pattern, and shows that even the southern US may get involved before this is all set and done.
Now that we know the conditions at hand let’s apply this to the models and see how these factors among many others are specifically influencing the pattern at hand. I am going to use the ECMWF for this model and pattern analysis as it has been by far the best performing model historically but also was the first model to catch this major snowstorm near the east coast, but will also show other models.
The current set-up reveals the last of the series of clippers departing off of the east coast of the US as it rotates around the very persistent gyre of low pressure visible just east of the Hudson Bay. Behind this clipper some cooler air is filtering in (also plays a part in this next storm’s development), with the real area of interest everyone in the northeast and New England has their attention on currently over the northern Rockies with the trough axis currently centered near Nevada, this will be the system in the northern branch of the jet that helps to lead to this large snowstorm near the east coast. Another notable feature is the region of troughiness visible over SW Texas in association with the active subtropical jet stream being influenced by the sudden -SOI burst and the upward MJO, both of which are helping to keep this disturbance energized. Also the next trough of low pressure about to come onshore over the Pacific northwest will play a large role in the system that comes out and produces snowfall over the northern plains and the Valentine’s Day system that could effect areas farther to the south and east of this current storm that will hit areas of New England and the northeast.
By 24 hours the clipper system that was off of the east coast of the US has moved towards Atlantic Canada and is moving away along with the gyre of low pressure just east of the Hudson Bay which is beginning to retreat northward. The main feature everyone will be watching is the trough that is currently over Nevada and the northern Rockies ejecting eastward out into the northern Plains here with the trough of low pressure near the west coast, which is digging southward into response to a building ridge over the Gulf of Alaska that is strengthening due in part to the subtropical jet stream underneath over the eastern Pacific forcing pressure rises to the north in this area, and of course the 30 day sunspot cycle which also favors a +PNA signature, which calls for a stronger ridge near northwestern North America. Also noticeable is the feature that was over Texas now moving eastward across the southern US, with this disturbance being noted on the ECMWF to be near Mississippi and Alabama, and this disturbance is producing heavy rains and some thunderstorms over this area, which is allowing to attain plenty of Gulf of Mexico moisture on its trek east-northeastward. Also what should be noted is the next trough barely visible in the top left corner of the screen near the Bearing Sea, and also with that trough over the northern plains that will help to produce the snow in the northeast, there is a shortwave disturbance just to its northwest over extreme northern Alberta and Saskatchewan (and Alberta Clipper) which is helping to add some energy into the trough from the northern branch of the jet stream.
At 48 hours, the main feature being the trough that was over the northern plains continues to move eastward along the mid-latitude westerlies towards the Great Lakes, and along with it is still somewhat of a shortwave disturbance that was over northern Alberta and Saskatchewan at hour 24 helping to add a little energy into this system, which is one good reason why the trough looks more pronounced at this time. However, a piece of that shortwave disturbance split off and is now centered over Nunavut and has got caught up into the gyre of low pressure now centered just north of the Labrador and Quebec Canadian provinces. Also, the shortwave disturbance that was over Texas at the initialization has shifted eastward and is now located off of the North Carolina coast and is beginning to form a nice surface low off of the coast. Also, another disturbance has entered the subtropical jet and is now visible over the southern plains and near the Arklatex region as the main feature being the trough of low pressure over the Great Lakes is moving at a faster speed than at its trough base, thus energy is getting left behind, giving the trough somewhat of a positive tilt, but this is dramatically changing as the trough over the Great Lakes begins to interact with the disturbance forming off of the Carolina coast. Also, the trough of low pressure that was off of the Pacific northwest coast at the beginning of the model run continues to dig southward along the west coast of the US in response to the strengthening ridge over the Gulf of Alaska which is indicative of a +PNA, and this ridge is likely being influenced by the lower 30 day sunspot cycle and the upward MJO pulse underneath forcing substantial pressure rises and causing dramatic changes in the pattern downstream.
At 72 hours, the moment of truth has arrived as the system rapidly intensifies near the east coast. The trough that was over the Great Lakes has merged with the disturbance that was over the southern US, helping to create a much stronger storm that is going through rapid intensification due to the unusually favorable environment at hand. When you look at what is occurring here, you can see how the conditions at hand like the MJO and the 30 day sunspot cycle are having specific effects on the pattern at hand. As the MJO and sudden -SOI burst forces troughiness over the east Pacific and pressure rises over the west Pacific, atmospheric heights are pumped directly to the north of it over the Gulf of Alaska, and to add to this, the 30 day sunspot cycle having an inverse relationship to the PNA means with the sunspot cycles remaining low and getting even lower, this forces the PNA to go towards its positive state. The PNA in its positive state means a region of high pressure is favored near northwestern North America and even in and around the Gulf of Alaska. A building ridge of high pressure here forces the next trough directly in front of it towards the west coast to dig deeper in response, thus pumping the heights out in front of it, and it is these stronger heights building in behind the trough of low pressure near the east coast which help to force air to rush into the system. Air rushing into the system at the surface is very crucial for this storm’s intensification, because in this instance we do not have at this particular time, a -NAO with higher than normal pressures near Greenland to feed these systems near the east coast, thus there must be another mechanism at which they can have air rush into them, and this occurs as the atmospheric heights rise behind the trough of low pressure. Also, another factor that has influence on this storm is the fact that cold air is being left behind in the wake of this most recent clipper system which has exited the east coast. This cold air is a big part to helping to force rapid cyclogenesis of mid-latitude cyclones, especially over water where the ocean has 1000x the energy capacity of air, thus more available fuel for any region of low pressure to rapidly intensify, and as the cold air gets left in the wake of the clipper system, the cold air forces the air near the surface to sink, however, in relation to the significantly warmer water below, large amounts of instability are created, yet no significant thunderstorms can form because of the high pressures being left in the wake of the trough helping to put a “cap” on any activity, however, as the next trough comes along, this begins to force pressures to lower, thus the “cap” breaks, sometimes violently and thunderstorms form, and as their processes continue over a period of time, this forces the surrounding air pressure to lower as latent heat is released. As more latent heat is released, the area of low pressure draws in more air at the surface, at least in our case with the ridge of high pressure sitting to the west of this system, this helps to feed the low pressure and allow for further intensification. Also helping to intensify this storm is the orientation of the storm system in the southern branch in accordance to the system in the northern branch that will be moving through the Great Lakes, and because the southern system is out ahead of the disturbance in the northern branch, this forces that disturbance to play catch up and lean towards the southern system, thus giving it a negative tilt, (orientated from SE to NW from trough base to the top of the trough), which is characteristic of strong troughs of low pressure.
Now, a similar storm that has been mentioned by professional meteorologists like Joe Bastardi at weatherbell who definitely deserves credit in pointing out this similarity (suggest getting a subscription to the premium site) is the “Lindsay Storm” of 1969, which came into and struck the northeast on almost the exact same date as this next storm is coming into the northeast with a very similar set-up and pattern going into the formation of the storm. This storm in 1969 which effected the exact same areas of the northeast under the gun with this next upcoming storm formed in a very similar manner as low pressure off of the Carolina coast met up with a disturbance in the northern branch which helped to form a storm off of the east coast. Now, this storm (as Joe Bastardi has said) did not have a considerable amount of blocking at the time to feed air at the surface into the storm, thus another mechanism triggered air to suddenly rush into the storm, and when you look at this picture below, you can clearly see the higher pressures indicated in shades of green, yellow, and orange buliding in the wake of the storm in response to the strong trough of low pressure near the west coast of the US. This ridge of high pressure allowed for air to rush into the intensifying storm off of the east coast, and although the trough off of the west coast of the US is a little farther to the west than the trough in our situation, it performs the same job as our current trough. Also notable is an active subtropical jet stream at this time indicative of the lower than normal pressures (in blue and purple) underneath the ridge over the US and just off of the Baja Peninsula and into Mexico, which tells me that the active southern branch of the jet stream helped to play a big part in this storm as well, not just the ridge in the central US being pumped by the trough off of the west coast.
Here’s another look at this storm using sea level pressure.
Here is a snowfall accumulation map of the “Lindsay Storm” which caught many off guard in the NYC area who were only expecting little to no snow at all, to turn around and be having to measure the snow in yardsticks.
The ECMWF’s depiction of this storm, as explained above seems to make the most sense to me as it appears to be correctly handling the pattern at hand, and not only that, but it was also the first model to pick up on this storm so definitely deserves a lot of attention in this case.
According to the latest ECMWF snowfall this is what it looks like in the northeast with it breaking down like this for some of the big cities on the I-95 corridor, not my forecast, just what this particular model is saying
Boston: 18-25 inches
Hartford: 18-24 inches
Providence: 18-24 inches
New York City: 10-14 inches
Philadelphia: 3-5 inches
Baltimore: 1-2 inches
Washington DC: flurries, perhaps a light coating in some areas
Here is the GFS’s depiction of the storm, as you can see it is a little bit flatter with the trough than the ECMWF (which can be anticipated), plus the model has had to correct towards the ECMWF solution, thus may get more aggressive with the snowfall totals later in time
The GFS’s thinking on snowfall totals in the big cities of the northeast
Boston: 10-15 inches
Hartford: 7-10 inches
Providence: 8-12 inches
New York City: 5-8 inches
Philadelphia: 2-4 inches
Baltimore: flurries, light coating up to 1 inch
Washington DC: flurries, perhaps a dusting or half an inch in spots
The CMC model’s depiction of snowfall, although I do not agree at all with this model, and think it has some serious adjusting to do, but even still, a good snowfall for southern New England
Here is the snowfall from the CMC, and I do not agree at all with this model, think it will be forced to adjust as we get closer to this storm
Boston: 7-12 inches
Hartford: 4-7 inches
Providence: 5-8 inches
New York City: 1-3 inches
Washington DC; none
The NAM’s depiction of this storm
Here is the NAM’s snowfall, although I do think it is too far north and will be required to adjust southward towards the ECMWF and GFS as time progresses.
Boston: 15-20 inches
Hartford: 1-3 inches
Providence: 3-6 inches
New York City: flurries, accumulations under 1 inch
Washington DC: none
Taking all of this information into account, and considering the conditions at hand and the solutions being provided by the models, here’s where I currently stand as far as snowfall goes for the big cities Boston 16-20 inches (2 feet or more in some areas) Hartford and Providence: 14-18 inches (some areas may approach 2 feet) New York City, very tough call at this point and likely to change, but going to go with 4-8 inches for now, Philadelphia at least some flurries, think a light accumulation of 1-3 inches certainly a possbility. Washington DC and Baltimore may end up with nothing but some flurries and a light accumulation of 1 inch of snow can not be ruled out, especially for areas farther to the north and east.
As we get beyond this storm by around 120 hours it has exited well out of the picture and is effecting Atlantic Canada as it gets absorbed into the polar jet and gets tangled in the gyre of low pressure that has now retrograded to just west of Greenland. Also of note is the trough that is currently off of the northwest coast of the US now entering into the plains as energy from this trough splits into two pieces. The reason for this is an alberta clipper shortwave will develop over the Rockies in Alberta and British Columbia, in doing so, it will influence the trough of low pressure in the western US to get tugged to the north, however, since the base of the trough extends very far to the south into the southwestern US, only a certain part of the trough can “feel” this shortwave disturbance, thus the trough splits with one piece moving northeastward and giving a large amount of snow to the northern plains and upper Great Lakes area early next week. The real feature that will begin to receive attention is towards the base of this trough over the southwestern US, because as it kicks eastward, we could see, yet again, another merging of two disturbances, thus there will be concern for yet another storm system in the eastern US, although this time farther to the south and east than the next system coming this Friday because the feedback from the snowpack will influence the surrounding air to cool, thus forcing the surrounding pressures to rise, and with higher pressures in place to the north of the developing low pressure system, these low pressures will tend to deflect the storm system farther south and east towards areas of the mid-atlantic and northeast rather than into New England. Also notice the ridge of high pressure near the Gulf of Alaska hanging tough as it continues to pump low pressure heights into the trough over the central US.
By the time we get to about a week from now, we can see this trough that went into the upper midwest exiting north America towards Atlantic Canada, not before producing potentially a little bit of light snowfall accumulation in the northeast, especially along and north of I-90. By this time though, attention will begin to shift to what is brewing over the southern US as the trough of low pressure that was over the midwest splits in two, the first piece already producing snowfall over the upper midwest, Great Lakes and into southern Canada, while the disturbance near the base of the trough over the southwestern US lays back some, however it soon kicks out and becomes energized from the increase in Gulf of Mexico moisture, the strong north-south distribution of temperatures and pressure over the central and eastern US that has been created in part by the snowfall, not to mention the upward phase of the MJO providing energy into the subtropical jet stream for this system to feed on, but now, all that is necessary for a big storm is some kind of phasing with a system in the northern branch. Also notice there is also more energy laying back behind this trough over the southwestern US, and although this can partially attributed to the ECMWF’s bias to withold energy in the southwestern US too long, it is a reasonable solution given the active subtropical jet stream. The ridge of high pressure near the Gulf of Alaska also still trying to stay intact, and it should do so as the MJO underneath forces pressure rises into this area and the low sunspot cycles continue to enforce a +PNA regime with higher than normal pressures near northwestern North America.
Just for fun, look at the ECMWF here as we get out towards the end of the run, and although nothing should be taken literally, you can see it does seem to hint at the potential for yet another system to come towards Valentine’s Day with a fully-developed trough just to the east of New England, and also as you look downstream there’s another system over the southern Rockies, which makes sense given the MJO and -SOI enhancing the subtropical jet stream and allowing for intensification of systems and merging with troughs in the northern branch. Also notice the ridge near the Gulf of Alaska is hanging tough, likely suggesting a +PNA regime will be in place for the foreseeable future, which will aid the east coast in getting big winter storms along with the AO and NAO which are going negative in response to the ongoing lower stratospheric warming event and the upward MJO pulse.
In general, if you are in the northeast, especially in southern New England, you should be anticipating a crippling snowstorm with strong winds heavy snow, and even the potential for thunder and lightning because of how dynamic the low pressure system is and the rate of intensification it will be undergoing as it bombs off of the east coast. From here, there will be another trough of low pressure to follow which will split in two, with the first piece of energy resulting in snowfall for the upper midwest and Great Lakes, while the second piece of energy stays behind and comes out to pose a significant threat for a major winter storm near the east coast around mid month, likely farther to the south and east from the current storm. Also, using the conditions at hand like the MJO, 30 day sunspot cycles and knowing their influence on factors like the NAO, AO, and PNA, one soon discovers this pattern is going to turn quite cold, and with historical relation with the warm waters over the deep tropical Atlantic to some cold and snowy Februarys like 2007 and 2010 there is even more evidence to support this. Of course this kind of pattern does have implications on spring and the tornado season, which I will discuss some of my thoughts on in upcoming posts, plus take another look into the hurricane season and hopefully give you a general idea of what to expect based off of what I am seeing at hand, history, and other forecasts, plus I hope to take an even deeper look into the AO/NAO and look at yet another factor that has strong relationship to how these oscillations behave from year to year and over longer periods of time.