CoastalWx Posted December 16, 2014 Share Posted December 16, 2014 So I thought I would post the pattern transition coming up and the associated look. As you recall, the pattern after Thanksgiving has been mediocre at best across SNE, esp east of ORH-BDL. Frankly, it sucks in ern areas with little in the way of snow near BOS. The culprit has been a GOAK trough and lower heights near AK that is both climo for Ninos and also driven by a strong MJP wave that created an enhanced Pacific jet the flooded the CONUS with mild temps. The pattern across NNE has been real nice with marginal temps able to work with significantly above normal storminess. Going forward, a significant change is likely to take place, one that may be similar to the pattern this past November and even last year with cross polar flow developing. Now, as is usually the case in New England, this will not be felt right away. Normally when these patterns develop, cold air is first to plunge south into the Plains, carving out a trough. This creates low pressure developing across the srn Plains and allowing movement to the northeast. This usually results in 2-3 storms that are a mix and even rain if the storms cut west. These are your "transition" storms. Sometimes they slide out south of SNE and can result in a more wintry pattern, but my guess is that we may get 2-3 storms that perhaps aren't pretty until maybe the 26-28 or so. This does not include the 17th. Below are images starting at hr 120. Notice at hr 120, the fast Pacific flow is evident. Low heights near AK and a strong jet plowing into the west. You can also see the storm over the deep south take shape with a weak bootleg block over Ontario. Fast forward 3 days. Notice now at hr 192 the ridging developing over the West Coast. You can also see the deep trough I spoke about into the Plains, The height response is higher heights in the east. Finally now at hr 240 you can see the pattern really take shape. The potential 12/25 storm now forces ridging into the Davis STraits in the form of a 500mb ridge, and the -EPO is becoming established with baked AK. The pattern continues to get established at hr 300. Notice the heights dip SW as the trough digs over the Plains. This may be the catalyst to eject s/w's coming out of the Plains to give is anything from Miller As to SWFE. All are possible. And finally hr 384. Now what is causing this? Notice the EC VP 200mb plots. You can see the eastward movement of various features, but the thing to take home is that the blues and greens represent areas of potentially rising air at 200mb and hence convection. Notice a surge of these greens pushing to 150E by the New Year. This is what helps force the ridge in AK. Convection here will cause heights to build downwind which is what we see in AK. This may weaken a bit heading to mid Jan, but by then who knows how things will continue. Could be a fun ride. Link to comment Share on other sites More sharing options...
alex Posted December 16, 2014 Share Posted December 16, 2014 This is why I love this forum. Awesome explanation. Thanks! Link to comment Share on other sites More sharing options...
Cold Miser Posted December 16, 2014 Share Posted December 16, 2014 Thanks Scott. Was a good read. Looking forward to the possibility of some good snow chances. Link to comment Share on other sites More sharing options...
SlantStickers Anonymous Posted December 16, 2014 Share Posted December 16, 2014 Very nice, thanks for posting. Link to comment Share on other sites More sharing options...
SnoSki14 Posted December 16, 2014 Share Posted December 16, 2014 Great explanation; a lot to look forward to if you're a winter weather lover. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 16, 2014 Share Posted December 16, 2014 No more Ray smash? What does that mean? Link to comment Share on other sites More sharing options...
Ginx snewx Posted December 16, 2014 Share Posted December 16, 2014 Biggest red flag would be cutoff of STJ in that LR depiction. Seems the sudden tendency for a Nino fade could be an issue otherwise game on. Biggest fear all along has been STJ going absent. Cold for sure and that's great. Link to comment Share on other sites More sharing options...
Met1985 Posted December 16, 2014 Share Posted December 16, 2014 Great analysis Scott! Thanks for putting is together. Link to comment Share on other sites More sharing options...
WxUSAF Posted December 16, 2014 Share Posted December 16, 2014 Great post, Scott. Link to comment Share on other sites More sharing options...
CoastalWx Posted December 16, 2014 Author Share Posted December 16, 2014 No more Ray smash? What does that mean? Ever see the Incredible Hulk get mad? You were bordering tearing open your purple shorts this morning lol. It's just a joke. Link to comment Share on other sites More sharing options...
CoastalWx Posted December 16, 2014 Author Share Posted December 16, 2014 Biggest red flag would be cutoff of STJ in that LR depiction. Seems the sudden tendency for a Nino fade could be an issue otherwise game on. Biggest fear all along has been STJ going absent. Cold for sure and that's great. If can go absent and we would be ok I think. That trough in the SW could eject shortwaves. Link to comment Share on other sites More sharing options...
CT Valley Snowman Posted December 16, 2014 Share Posted December 16, 2014 excellent job Scott. very good layout with the appropriate maps and data to support your hypothesis, a great example of using the scientific method. Link to comment Share on other sites More sharing options...
dryslot Posted December 16, 2014 Share Posted December 16, 2014 Well laid out and explained Scott, Looks good going forward Link to comment Share on other sites More sharing options...
Ginx snewx Posted December 16, 2014 Share Posted December 16, 2014 excellent job Scott. very good layout with the appropriate maps and data to support your hypothesis, a great example of using the scientific method.it's not hypothetical though. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 16, 2014 Share Posted December 16, 2014 Good stuff. But I still don't understand the last graph. A dumb Polak ftl. Link to comment Share on other sites More sharing options...
Rainman Posted December 16, 2014 Share Posted December 16, 2014 Outstanding write-up. You note that AK ridging may ease toward mid-Jan, but by then we may be getting into the favorable time range for an SSW. Link to comment Share on other sites More sharing options...
CT Valley Snowman Posted December 16, 2014 Share Posted December 16, 2014 yes you're right hypothesis may not be the right word because the science is already provenbut nevertheless it is a good job of showing the cause and effect of how we transition from our current pattern to the next one Link to comment Share on other sites More sharing options...
Rainman Posted December 16, 2014 Share Posted December 16, 2014 Good stuff. But I still don't understand the last graph. A dumb Polak ftl. To get a view of what is happening in the tropics at a given time, you read the graph left to right. If you scroll down with your eyes, you are moving forward in time. So that slanted green color that Scott mentioned is literally moving left to right with time. You know this because it moves right as you scroll down the chart. No idea if I helped you at all here Link to comment Share on other sites More sharing options...
Ginx snewx Posted December 16, 2014 Share Posted December 16, 2014 yes you're right hypothesis may not be the right word because the science is already provenbut nevertheless it is a good job of showing the cause and effect of how we transition from our current pattern to the next oneyes Link to comment Share on other sites More sharing options...
CoastalWx Posted December 16, 2014 Author Share Posted December 16, 2014 Good stuff. But I still don't understand the last graph. Dumb blonde ftl.Yeah that's not easy to explain. So we know there are waves in the atmosphere. You may have heard of Kelvin or MJO waves being tossed around here. That graph shows you velocity potential at 200mb. The greens and blues are showing you areas where we have divergence and potentially lift at 200mb. The browns and yellows are the opposite. Think subsidence. The left side is the calendar date. The Brits like doing it that style, but the forecast starts at 12/15. This takes into account the forcing from the MJO and kelvin waves. A better way to see these waves instead of those dynamic models on the CPC page. Mike V had some better stuff, but it's his proprietary stuff, so can't really post. In any case, you can see the east propagation towards the dateline heading towards mid January. The signal weakens then, but it's there. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 16, 2014 Share Posted December 16, 2014 To get a view of what is happening in the tropics at a given time, you read the graph left to right. If you scroll down with your eyes, you are moving forward in time. So that slanted green color that Scott mentioned is literally moving left to right with time. You know this because it moves right as you scroll down the chart. No idea if I helped you at all here Actually. It did. Lol. Link to comment Share on other sites More sharing options...
ROOSTA Posted December 16, 2014 Share Posted December 16, 2014 Excellent Scott. I do believe the learning curve has increased exponentially for many, myself included. LOL never to old to learn from a great teacher of the science. Thank you. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 16, 2014 Share Posted December 16, 2014 I get it now, thanks. Link to comment Share on other sites More sharing options...
TheSnowman Posted December 16, 2014 Share Posted December 16, 2014 Awesome Awwesome post. Link to comment Share on other sites More sharing options...
CoastalWx Posted December 16, 2014 Author Share Posted December 16, 2014 If I am not clear, that forcing I was speaking of pushing to the dateline can be thought of as convection. Convection releases heat and can build downstream heights up like we are seeing in AK on the models. Link to comment Share on other sites More sharing options...
HoarfrostHubb Posted December 16, 2014 Share Posted December 16, 2014 Thank you Scooter. No more smash we hope Link to comment Share on other sites More sharing options...
Randy4Confluence Posted December 16, 2014 Share Posted December 16, 2014 Great post and easy to follow for those of us who are hobbyists. Thank you. Link to comment Share on other sites More sharing options...
weathafella Posted December 16, 2014 Share Posted December 16, 2014 Weeklies? Link to comment Share on other sites More sharing options...
SR Airglow Posted December 16, 2014 Share Posted December 16, 2014 Clear and well written as always, thanks! Link to comment Share on other sites More sharing options...
jamesnichols89 Posted December 16, 2014 Share Posted December 16, 2014 The first legitimate threat is still 10 days away if we want a very cold solution with snow to the coastline including cape and ACK. The GEFS means show a clipper impacting the Great Lakes then redeveloping southeast of Long Island and south of ACK between the 25-27th, the means already have the surface low down to 995mb. This could be the first sub 980mb low of the young winter season. Arctic jet involvement could mean a chance at a triple jet structure if the arctic jet gets involved. Link to comment Share on other sites More sharing options...
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