usedtobe Posted December 2, 2012 Share Posted December 2, 2012 Although some are going hog wild for bitter cold for the second half of December, DT being one, until we see a clear sign of a west based NAO/Greenland block showing up in the ECMWF, I'm not sold on the idea even with a lot of frigid air in Canada to tap. Looking more like a broad trough and little amplitude in the upper flow...more zonal. Looks like getting a ridge to set up along the west coast is going to be tough also, making a west based -NAO all the more important. Mainly I'm talking about the Mid-Atlantic. Based upon the NAEFS, ECMWF, ECMWF Ensembles, GFS, GFS Ensembles, forecasting a very cold setup by mid and late December seems to be a fringe solution at this point. Hopefully I'm wrong. Until we gt a ridge farther east into the west coast, I'm also hesitant to go with a frigid scenario. Even by dec 15th the pattern still isn't where we need it in terms of the location of the pna ridge or the location of the high latitude positive anomalies. It's a better pattern than we have right now but still is not a typical snow pattern. That doesn't preclude a thread the needle weaker event but also argues for not getting excited yet. Link to comment Share on other sites More sharing options...
Deck Pic Posted December 2, 2012 Author Share Posted December 2, 2012 Until we gt a ridge farther east into the west coast, I'm also hesitant to go with a frigid scenario. Even by dec 15th the pattern still isn't where we need it in terms of the location of the pna ridge or the location of the high latitude positive anomalies. It's a better pattern than we have right now but still is not a typical snow pattern. That doesn't preclude a thread the needle weaker event but also argues for not getting excited yet. That ridge looks to be a pretty stable factor at least the next couple weeks. Not sure if it is PDO related. There is still a lot of warm water in the PDO region. Ideally I would think we want a trough off the west coast and ridging extending from the EPO region down to the PNA region and it looks like in the means we will have the opposite for a while. Maybe we can time something or the pAC gets better after the 15 th Link to comment Share on other sites More sharing options...
Bob Chill Posted December 2, 2012 Share Posted December 2, 2012 That ridge looks to be a pretty stable factor at least the next couple weeks. Not sure if it is PDO related. There is still a lot of warm water in the PDO region. Ideally I would think we want a trough off the west coast and ridging extending from the EPO region down to the PNA region and it looks like in the means we will have the opposite for a while. Maybe we can time something or the pAC gets better after the 15 th Euro and gfs both show some nice ridging in the vicinity of GL from day 8 on. Even with a less than ideal placement with pac ridge things look "good enough" to keep an eye on. Euro showing a low developing along the gulf coast @ day 8 isn't a bad thing either. Unless we have better blocking it's prob gonna be rain (assuming it happens of course). It is worth keeping an eye on. Euro and gfs also bring in some pretty cold stuff into the n plains after a week or so. It's kinda overdue too imo. Getting into mid dec without a cold outbreak in the n plains isn't all that common. Overall both models are showing an ok chance at getting some decent cold in here as we approach mid month. Until we get some cold canadian air in our back yard everything will require perfect timing and the dc area sucks at perfect timing. I'm not discouraged at all at this point. Things are looking ok at the very least once we get through the next week. Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2012 Share Posted December 3, 2012 A cluster of the gfs ens are taking the ao down to -4 to -5 range. Probably not gonna feel the impact because of the crappy pac but it is still statistically significant if it verifies. I went ahead and sorted the ao daily data and pulled all the days in Dec with an AO of -4.5 or lower since 1950. Some pretty good company if the ens verify and the AO drops below -4.5. With the exception of 1968, all the other years were on the -1.75 Dec AO list. Not sure if it means anything but if the ens were to verify this would be the earliest in the winter season that the ao has gone below -4.5 in the last 60 years. The lowest daily reading the the dataset is -7.433 and it occured on 1/15/77. The stretch from 1/14 - 1/16/77 was below -7. With reading like that it's no surprise that the winter of 76-77 was such an icebox. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted December 3, 2012 Share Posted December 3, 2012 A cluster of the gfs ens are taking the ao down to -4 to -5 range. Probably not gonna feel the impact because of the crappy pac but it is still statistically significant if it verifies. I went ahead and sorted the ao daily data and pulled all the days in Dec with an AO of -4.5 or lower since 1950. Some pretty good company if the ens verify and the AO drops below -4.5. With the exception of 1968, all the other years were on the -1.75 Dec AO list. Not sure if it means anything but if the ens were to verify this would be the earliest in the winter season that the ao has gone below -4.5 in the last 60 years. The lowest daily reading the the dataset is -7.433 and it occured on 1/15/77. The stretch from 1/14 - 1/16/77 was below -7. With reading like that it's no surprise that the winter of 76-77 was such an icebox. Seems like we have some good things going for us. Now if we can just get the pattern to come on around so that we can cash in. Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2012 Share Posted December 3, 2012 GFS said please hold for at least another 380 hours or so. Link to comment Share on other sites More sharing options...
aldie 22 Posted December 3, 2012 Share Posted December 3, 2012 GFS said please hold for at least another 380 hours or so. Dang...am I reading the 12z gfs right...looks like we are in the 60's into next week save a day or two? Gonna be real hard to erase that kind of positive departure....ugly Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2012 Share Posted December 3, 2012 Dang...am I reading the 12z gfs right...looks like we are in the 60's into next week save a day or two? Gonna be real hard to erase that kind of positive departure....ugly It's really bad in the lr too. Not a torch or anything but the pac jet rages across the entire basin and floods the US. eek. Link to comment Share on other sites More sharing options...
aldie 22 Posted December 3, 2012 Share Posted December 3, 2012 It's really bad in the lr too. Not a torch or anything but the pac jet rages across the entire basin and floods the US. eek. With the exception of Ct right? Link to comment Share on other sites More sharing options...
Ian Posted December 3, 2012 Share Posted December 3, 2012 December cancel. Oh well... not like it's usually any good anyway. Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2012 Share Posted December 3, 2012 With the exception of Ct right? Yea, sneaky cold always lurking around Tolland. It's a microclimate up there it seems. Link to comment Share on other sites More sharing options...
Yeoman Posted December 3, 2012 Share Posted December 3, 2012 I've seen this movie before.. the major pattern change that keeps getting pushed back each week.. and when it does happen it's a far cry from what's expected. I can't even rationalize it into a positive by being able to rake leaves or save on my heating bill.. I pay for neither. Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted December 3, 2012 Share Posted December 3, 2012 Not based on anything by anectodal memories, but I've always kind of believed that Dec was a precursor to winter. Bad december = bad winter. I guess it somewhat verfies with the research Bob and Wes have done regarding the AO index: big departures in Dec statistically verify with Jan and Feb anomolies. This year it appears that we have competing harbingers. We look to have a rather negative AO which should then average in the negative range for the rest of the winter, yet even in this -AO regime we are having a super-craptastic pattern and resulting weather. For gosh's sake we have a couple of +20s on tap for this week alone. It'll be interesting to see how the winter unfolds. Forgive me if it's been previously posted, but has anyone looked -AO winters to see if any of them had a crappy Dec and if so, did they turn colder? 76-77 is famous for the cold January and negative AO, what was Dec 76 like? Link to comment Share on other sites More sharing options...
midatlanticweather Posted December 3, 2012 Share Posted December 3, 2012 Euro - will it bring any hope? Link to comment Share on other sites More sharing options...
usedtobe Posted December 3, 2012 Share Posted December 3, 2012 Of Bob Chill's really strongly negative AO Decembers, 6 of the 18 were associated with a negative PNA. Of those, one was warm, two were normal and 3 were on the cold side of normal. Here's the warm one. Note that there is loads of flow into the west and that the negative AO is too far east while also keeping the heights above normal near Nova Scotia. The cold decembers with a negative AO had strong blocking farher west with a negative anomaly south of the strong positive over Greenland. So far in late November into right now, we've been dealing with the 1996 type pattern but that is forecast to change as a weak positive PNA develops. I haven't looked at the 12 positives PNA years yet. I suspect there will be a warm one with the ridge in the pac just a little too far west for us and a positive ao like the one in 1996. The good news is that if the AO holds on, we should eventually transition to cold. Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2012 Share Posted December 3, 2012 Thank's for posting that Wes. I was planning on getting around to NH 500 anoms to see what happened upstairs during those Decembers. It's ironic that we get the -ao (and looks like a really strong one) but the conus is still getting pummeled by pac air. It's not that big of a deal yet because we are just starting to get to our true snow climo window. I sure would like to see signs of the flow buckling and slowing down sometime soon. If you look at the npac 500 maps on the gfs it really shows the jet screaming across the ocean and into the us. And then it just continues right across the country with no amplification to speak of. I know eventually we'll see the flow slow down and make its usual bends. I have a feeling the first amped flow is going to be over the intermountain west and not over the ec. Hope I'm wrong. Link to comment Share on other sites More sharing options...
Deck Pic Posted December 3, 2012 Author Share Posted December 3, 2012 ENSO isn't just dead...all 3 important regions are now negative-neutral Link to comment Share on other sites More sharing options...
Deck Pic Posted December 3, 2012 Author Share Posted December 3, 2012 The Euro is vile...torch this weekend Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2012 Share Posted December 3, 2012 This is why I got a little discouraged when I saw the lr gfs. I know it's out there and not accurate but still, anything that resembles these 2 maps = no cold air to be found regardless of the AO. Link to comment Share on other sites More sharing options...
usedtobe Posted December 3, 2012 Share Posted December 3, 2012 The Euro is vile...torch this weekend If I was DT, I'd be worried about my pattern change. It may have changed some but still is not good. Link to comment Share on other sites More sharing options...
Deck Pic Posted December 3, 2012 Author Share Posted December 3, 2012 If I was DT, I'd be worried about my pattern change. It may have changed some but still is not good. have to take him with a grain of salt since he went for an epic winter and will find reasons to support it...often he will flip and cancel winter way too early when he gets frustrated...we'll see if that happens....haven't looked at the anomaly maps, but looks like we get cold in a week after a strong front based on a better positioned ridge but the NAO looks like it goes negative and we see a block form north of great britain...so typical pattern...cold then quickly warm Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2012 Share Posted December 3, 2012 This graph is the daily pna from June-Oct. The entire month of Nov is negative but the dailies won't be out for a couple weeks. PNA also looks to stay negative through mid-month. Quite an impressive stretch and definitely not our friend right now. Link to comment Share on other sites More sharing options...
usedtobe Posted December 3, 2012 Share Posted December 3, 2012 have to take him with a grain of salt since he went for an epic winter and will find reasons to support it...often he will flip and cancel winter way too early when he gets frustrated...we'll see if that happens....haven't looked at the anomaly maps, but looks like we get cold in a week after a strong front based on a better positioned ridge but the NAO looks like it goes negative and we see a block form north of great britain...so typical pattern...cold then quickly warm I think overall for the next 2 weeks we average above normal and could see the cold shot as an under performer if the GFS is right. Even last night's Euro wasn't that cold behind the front. DT may be better off than Weatherbell as their Dec forecast looks like it is in jeapardy even if the pattern shifts to cold around mid month. We're going to be stacking up degrees the next 10 days that will be hard to cancel out. Link to comment Share on other sites More sharing options...
GaWx Posted December 3, 2012 Share Posted December 3, 2012 ENSO isn't just dead...all 3 important regions are now negative-neutral Matt. Despite their drops, 3 and 3.4 are actually still hanging onto positive neutral at +0.2 and +0.3, respectively. Link to comment Share on other sites More sharing options...
Deck Pic Posted December 3, 2012 Author Share Posted December 3, 2012 Matt. Despite their drops, 3 and 3.4 are actually still hanging onto positive neutral at +0.2 and +0.3, respectively. not in the dailies Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2012 Share Posted December 3, 2012 Matt. Despite their drops, 3 and 3.4 are actually still hanging onto positive neutral at +0.2 and +0.3, respectively. Even so, those types of readings don't have enough influence to assert themselves in any predictable way. The pac is behaving a bit nina'ish. Neutrals after multi-year nina's typically have a bit of a hangover effect in the pac. Zwyts had a nice post about this last year I think. It's all but certain that +1.0 is totally off the table and that would be the minimum we need to get some sort of +pna and stj interaction. I don't know nearly as much as others on here about neutrals and the expected patterns in the pac but once I saw the nino fade a couple months ago I was worried about below avg qpf in the east and a bias towards the trough setting up in the west in between blasting pac zonal patterns. It's ok though. The mjo, snowcover index, and -ao will save us! Link to comment Share on other sites More sharing options...
Deck Pic Posted December 3, 2012 Author Share Posted December 3, 2012 Link to comment Share on other sites More sharing options...
Yeoman Posted December 3, 2012 Share Posted December 3, 2012 The Euro is vile...torch this weekend Per Bob - The first week of December 1998 had 3 record high temperatures in Washington Dec 4,6 and 7 Link to comment Share on other sites More sharing options...
usedtobe Posted December 3, 2012 Share Posted December 3, 2012 Matt, the op euro at least has a negative near 50 50, the ensemble mean gets rid of it and shows an even crappier look with the pac ridge too far west, lost of flow across the rockies and the nao too far east. That doesn't mean either of them is correct but isn't encouraging. Link to comment Share on other sites More sharing options...
Deck Pic Posted December 3, 2012 Author Share Posted December 3, 2012 Matt, the op euro at least has a negative near 50 50, the ensemble mean gets rid of it and shows an even crappier look with the pac ridge too far west, lost of flow across the rockies and the nao too far east. That doesn't mean either of them is correct but isn't encouraging. I'm guessing this look persists in the means for the next 6 weeks......-PNA/+EPO, weakly -NAO.....I'm glad I went warm..... Link to comment Share on other sites More sharing options...
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