SteveB Posted December 21, 2010 Share Posted December 21, 2010 this thing is going south. look at that confluence off the eastern seaboard. that is a big change since 18Z Strongly agree. That confluence zone is rather far South and off the coast at 84 on NAM. Link to comment Share on other sites More sharing options...
Colin Posted December 21, 2010 Share Posted December 21, 2010 this thing is going south. look at that confluence off the eastern seaboard. that is a big change since 18Z yeah, that's what i was thinking too. Link to comment Share on other sites More sharing options...
LVblizzard Posted December 21, 2010 Share Posted December 21, 2010 this thing is going south. look at that confluence off the eastern seaboard. that is a big change since 18Z The s/w is moving slower, though, so that could make the confluence be unimportant. Link to comment Share on other sites More sharing options...
hazwoper Posted December 21, 2010 Share Posted December 21, 2010 yeah, that's what i was thinking too. I am not worried about it at this point. Still a long ways to go. Looking forward to the GFS. Next. Link to comment Share on other sites More sharing options...
CooL Posted December 21, 2010 Share Posted December 21, 2010 The s/w is moving slower, though, so that could make the confluence be unimportant. Agree, the slower movement of the shortwave compensates the increased confluence over the northeast.. Keep in mind how fragile the NAM can be in its long range guys...Onto the GFS Link to comment Share on other sites More sharing options...
Parsley Posted December 21, 2010 Share Posted December 21, 2010 Incredible post. Agreed! One issue though.. Being born and raised on Long Island, I take offense to those maps not having Long Island depicted at all. Link to comment Share on other sites More sharing options...
nzucker Posted December 21, 2010 Share Posted December 21, 2010 John, wonderful write-up and a happy holiday to you and your loved ones. I think that the ridge axis being a bit too far east may be less of a concern because of the strong connection between the developing +PNA and the high height field left behind near Baffin Island. The amplitude of this ridge argues for a very powerful trough underneath it, especially given that energy is being sucked down from the polar low on Greenland due to the ridge's tilt. Certainly a very unusual blocking pattern that could produce a large snowfall followed by very cold air. Link to comment Share on other sites More sharing options...
Quakertown needs snow Posted December 21, 2010 Share Posted December 21, 2010 John, love the write up. Thank You. ENS MEAN really showing the cold drainage after the storm pulls out. Link to comment Share on other sites More sharing options...
chubbs Posted December 21, 2010 Share Posted December 21, 2010 Agree with others. Nice write-up. That is a massive 50/50 low at the end of the NAM run Link to comment Share on other sites More sharing options...
Chris L Posted December 21, 2010 Share Posted December 21, 2010 John, you are going to make a heck of a meteorologist someday, givne your expansive knowlege already of the systems of weather. Well Done. Link to comment Share on other sites More sharing options...
Isotherm Posted December 21, 2010 Share Posted December 21, 2010 John, Nice analysis of the upcoming potential. I was looking through some H5 maps prior/during our big storms since 2000, and wanted to share an interesting finding regarding the orientation of the PNA ridge out West (don't worry, it's good news). For 30 DEC 00, 05 DEC 03, 22-23 JAN 05, 11 FEB 06, 19 DEC 09, 25-26 FEB 10 -- all of these events except for December 03 featured a ridge axis aligned no more than 200 miles either side of the classic Boise ID line, but the amplitude of the ridge generally only extended into SW Canada. The difference w/ the H5 progression here is we've got the PNA high heights extending well into central Canada and hooking up with the west based -NAO block. What this does is force the short wave rolling down the periphery of the ridge to dig/amplify, slow down, and increase the potential phasing of streams. It also yields a height rise along the east coast in advance of the short wave, adding to the slow-down process of the storm, and essentially allowing the nern stream energy to catch-up to complete the phase. Although its not in the classic N-S position near Boise ID, the ridge amplitude is so extreme that it congeals with the N-C Canadian block and thus forces the downstream s/w to be slower and more energized/amplified. Of course we could still see the phase occur a bit offshore if the timing of the nern stream involvment is less than ideal, but as it stands right now, I think we're looking pretty good, and considering this is a strong La Nina, I can't paint a much better picture than we have on this H5 map. Link to comment Share on other sites More sharing options...
earthlight Posted December 21, 2010 Author Share Posted December 21, 2010 I know that everyone has commented already on your post, but seriously, your writing skills are seriously second to none.. Your analysis is thorough as hell and extremely helpful to all of us novices.. In any event, seriously- what are your credentials?? Are you a pro meterologist? How old are you? etc etc.. Seriously, you don't have to tell me or reveal any of this, but again, I can't think of anyone who writes and/or explains weather patterns like you on this forum or anywhere else for that matter. Jeff Jeff, I can't say enough about your comments. Thanks a whole bunch dude. I'm a junior meteorology student at the moment, not a professional meteorologist. I'm only 20 still, so I still have a lot to learn. Thanks again. John Link to comment Share on other sites More sharing options...
eduggs Posted December 21, 2010 Share Posted December 21, 2010 this thing is going south. look at that confluence off the eastern seaboard. that is a big change since 18Z The center of lowest heights at 500mb is definitely much further south in the Atlantic on the 0z NAM than 18z and confluence is slightly further south as well. But the s/w and upstream ridge continue to support a good threat. Link to comment Share on other sites More sharing options...
earthlight Posted December 21, 2010 Author Share Posted December 21, 2010 John, Nice analysis of the upcoming potential. I was looking through some H5 maps prior/during our big storms since 2000, and wanted to share an interesting finding regarding the orientation of the PNA ridge out West (don't worry, it's good news). For 30 DEC 00, 05 DEC 03, 22-23 JAN 05, 11 FEB 06, 19 DEC 09, 25-26 FEB 10 -- all of these events except for December 03 featured a ridge axis aligned no more than 200 miles either side of the classic Boise ID line, but the amplitude of the ridge generally only extended into SW Canada. The difference w/ the H5 progression here is we've got the PNA high heights extending well into central Canada and hooking up with the west based -NAO block. What this does is force the short wave rolling down the periphery of the ridge to dig/amplify, slow down, and increase the potential phasing of streams. It also yields a height rise along the east coast in advance of the short wave, adding to the slow-down process of the storm, and essentially allowing the nern stream energy to catch-up to complete the phase. Although its not in the classic N-S position near Boise ID, the ridge amplitude is so extreme that it congeals with the N-C Canadian block and thus forces the downstream s/w to be slower and more energized/amplified. Of course we could still see the phase occur a bit offshore if the timing of the nern stream involvment is less than ideal, but as it stands right now, I think we're looking pretty good, and considering this is a strong La Nina, I can't paint a much better picture than we have on this H5 map. This is an awesome post. I pretty much agree with everything you're saying. The PNA ridge heights are definitely the kicker in the setup. I think the fact that it's being so well modeled is certainly alarming. It doesn't give the setup as much of a chance to escape east. Can it still happen? Yes..but it will take a missed or disjointed phase to make it happen. Link to comment Share on other sites More sharing options...
earthlight Posted December 21, 2010 Author Share Posted December 21, 2010 John, wonderful write-up and a happy holiday to you and your loved ones. I think that the ridge axis being a bit too far east may be less of a concern because of the strong connection between the developing +PNA and the high height field left behind near Baffin Island. The amplitude of this ridge argues for a very powerful trough underneath it, especially given that energy is being sucked down from the polar low on Greenland due to the ridge's tilt. Certainly a very unusual blocking pattern that could produce a large snowfall followed by very cold air. Thanks, and same to you and your family and loved ones as well. I agree with your points about the ridge axis and it's connection between it and the greenland blocking. I like what I am seeing at this range. We still have a whole lot of time to go. That being said, for some it may be less than you would think. The main players in the setup will be getting very close to the CONUS and/or good data ingestion areas within 36-48 hrs. Link to comment Share on other sites More sharing options...
gkrangers Posted December 21, 2010 Share Posted December 21, 2010 Come on GFS, don't **** it up, just this once. Link to comment Share on other sites More sharing options...
tornadojay Posted December 21, 2010 Share Posted December 21, 2010 where's tombo with the play by play... Link to comment Share on other sites More sharing options...
ARyan Posted December 21, 2010 Share Posted December 21, 2010 Thanks John and Isotherm for writing such great synopsizes on this event. You guys really nailed on how unusual these series of events are for a strong La Nina year. On a related note, I've noticed that a lot of friends on facebook have been posting how unusually warm it is in the Southern Plains. I think this lends credence to the strengthening on the western ridge. Link to comment Share on other sites More sharing options...
tombo82685 Posted December 21, 2010 Share Posted December 21, 2010 where's tombo with the play by play... lol only at hr 33, nothing there yet. Link to comment Share on other sites More sharing options...
Jefflaw77 Posted December 21, 2010 Share Posted December 21, 2010 Jeff, I can't say enough about your comments. Thanks a whole bunch dude. I'm a junior meteorology student at the moment, not a professional meteorologist. I'm only 20 still, so I still have a lot to learn. Thanks again. John All i can say is - wow.. Seriously, wherever you go to school, they should be thrilled that they have you has a student.. While I've always loved weather, math was not my forte and prevented me from going to school for meteorology.. All I have to offer is an extensive knowledge of past weather events.. jeff Link to comment Share on other sites More sharing options...
tombo82685 Posted December 21, 2010 Share Posted December 21, 2010 through 42 everything looks pretty much the same as 18z, the s/w coming onshore in the pacific looks to be a little stronger. Link to comment Share on other sites More sharing options...
tombo82685 Posted December 21, 2010 Share Posted December 21, 2010 s/w deff a little stronger, also looks like the confluence has lessoned up a little. Link to comment Share on other sites More sharing options...
RutgersWx92 Posted December 21, 2010 Share Posted December 21, 2010 Wow, really great post Earthlight. Thanks to you and others, this forum gives me such a great opportunity to learn and understand meteorology far more than I would have otherwise. I hope to be that knowledgeable someday. Link to comment Share on other sites More sharing options...
tombo82685 Posted December 21, 2010 Share Posted December 21, 2010 s/w closed off at hr 51, only big difference through 51, confluence again looks less, ridge out ahead of the storm looks to be about the same Link to comment Share on other sites More sharing options...
SBUWX23 Posted December 21, 2010 Share Posted December 21, 2010 Nice analysis John.. but I am going to be one who does not want it to be a paralyzing snow. I am trying to drive on I-95 south early on the 27th to be with family for a delayed Chanukah celebration. Link to comment Share on other sites More sharing options...
Jefflaw77 Posted December 21, 2010 Share Posted December 21, 2010 I know this is off topic for a second, but can anyone comment on the current storm that is destroying cape cod.. Did any model project the 7-14" that the cape is receiving right now.. This storm was 200 miles to far east.. would have loved that back building type of snow to have come into LI... (had the storm been further west) Just curios.. thanks Link to comment Share on other sites More sharing options...
tombo82685 Posted December 21, 2010 Share Posted December 21, 2010 hr 60 has the low closing off again in nw arz. Link to comment Share on other sites More sharing options...
Isotherm Posted December 21, 2010 Share Posted December 21, 2010 This is an awesome post. I pretty much agree with everything you're saying. The PNA ridge heights are definitely the kicker in the setup. I think the fact that it's being so well modeled is certainly alarming. It doesn't give the setup as much of a chance to escape east. Can it still happen? Yes..but it will take a missed or disjointed phase to make it happen. Thanks and yeah it's going to be a real interesting storm to follow. Considering the potential on the table here, we definitely have a shot at making history in a strong La Nina event. IIRC, there's never been a 10"+ snow event in NYC during the winter of a strong la nina. March 18th-19th 1956 was a KU but that happened in meteorological spring. Link to comment Share on other sites More sharing options...
earthlight Posted December 21, 2010 Author Share Posted December 21, 2010 Much sharper with the shortwave and the northern stream seems more involved. I would be surprised if this run didn't phase it and bring it near the coast. It's going to take a disjointed phase or a missed phase or some wacky GFS solution to let that happen. Link to comment Share on other sites More sharing options...
tombo82685 Posted December 21, 2010 Share Posted December 21, 2010 hr 75 has a sub 1012 in extreme sw ok on the tx border both ridges on the back side and front side are more robust. Link to comment Share on other sites More sharing options...
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