ORH_wxman Posted January 25, 2012 Share Posted January 25, 2012 We do not have a thread for the longer range right now...we've been discussing this in various storm threat threads, so I thought I would start this for the February pattern. What we are seeing is a pretty strong move by ensembles (both GFS and ECMWF) toward a +PNA pattern...with potentially a -EPO as well but it may hang more near neutral. For those not familiar with what it means...here are the loading patterns for the positive phases of both the EPO and PNA.... +EPO pattern: +PNA The EPO pattern I posted is positive...but the forecasted pattern is more negative shifted a tad east. It also depends on which set of ensembles you use as to the nuances of the pattern. The ECMWF ensembles are a bit more -EPO while the GEFS are more neutral. Both however are a big +PNA pattern. The nuances in the PNA ridge and if it can produce a more -EPO will determine the temperature departures in the period in question...but I'm going to focus more on the snow potential. A +PNA means a very large ridge out west usually and that teleconnects well to a trough in the east which is of course how we are going to get storminess more often. Here is the GFS ensemble mean valid for 00z Feb 7 That is a big +PNA but the EPO is kind of neutral or even slightly negative there...however the Euro ensembles are like the image above except shifting the ridge a bit west and higher into AK which would be a bit of a colder pattern. Another notable difference on the Euro ensembles is they have a more distinct ridging signal into Greenland whereas the GFS ensmebles above clearly do not. Both of these difference would make the Euro ensembles more conductive to cold/snow chances versus the GEFS....but the GEFS isn't bad. It would likely still offer some storm chances with a ridge like that to the west, but the cold wouldn't be as impressive. There is going to be a shift going on over the next 10 days or so to really get this pattern into place (assuming it happens)...in those next 10 days, we should average out mild and the storm chances will probably be tougher to get. My best estimate for more chances would be in the period after Feb 5th...probably until the 15th or 20th if this winter is any indication on how the favorable PAC patterns break down after 10-14 days....but its possible it could stay longer. Its also possible that the ridging is being over modeled on the ensembles...however, given that it has become more and more impressive the closer we get, it leads to a bit more confidence that we should experience a period with a significantly positive PNA which in turn will hopefully lead to an active pattern for storm threats. The NAO and how far north the ridge pushes in the west will be X-factors on the temperature departures...and the NAO of course can always help with the synoptics of a storm threat too. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2012 Share Posted January 25, 2012 Nice....all aboard the winter 2011-'12 salvage train. (I realize that it doesn't need to be salvaged in W. Chesterfield, Pete) Link to comment Share on other sites More sharing options...
Typhoon Tip Posted January 25, 2012 Share Posted January 25, 2012 The +PNA's been flagged for days... We spoke about the 28th through the first 10 days of Feb in that other thread - at least I did, in earnest. BUT, I'm a little leery about "extending" - pun intended ... - any confidence in this based purely on seasonal trend for redemptionless Shawshanking as Scott and I joked last night. One thing I have noticed over the last month and a half or so is that when you see cyclones modeled out in time, you rarely see the deep QPF on the cold side of the isobaric layout among the given model runs, over the mean of that time span. Yet, almost in the same sentence we can admit to an odd pattern of not snowing even when things looked better. ...save for a couple of light events. I don't believe those two observations are disconnected. It more than seems to me that a big intregal problem in the pattern(s) has/have been the lack of mixing/transportation of theta-e into the cold thickness. We rain, it gets cold...the ground freezes, we warm up 2 days later such that even on the cold side of the systems you end up at 37F with rain. Perhaps with this +PNA ...provided that actually happens...we'll finally get opportunities to change the "character" of cyclogenesis. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2012 Author Share Posted January 25, 2012 Nice....all aboard the winter 2011-'12 salvage train. (I realize that it doesn't need to be salvaged in W. Chesterfield, Pete) We'll definitely be rooting more for the Euro ensembles here...there is a decent chance a period of warmth too right before this sets up, so there will surely be some bridge jumpers if that torch looks more menacing to start February. But hopefully this +PNA and potential -EPO/-NAO setup looks better as we get closer. Certainly no guarantee this pattern produces, but it can. Its actually pretty similar to the first half of Feb 1996. Also not too dissimilar to the period from late Jan to mid Feb 2000 when we saw some active winter wx. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 25, 2012 Share Posted January 25, 2012 I also see a +WPO as well. It's not the most coldest pro, but the +PNA may help.Anytime you have a ridge out west, you should be excited. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2012 Author Share Posted January 25, 2012 I also see a +WPO as well. It's not the most coldest pro, but the +PNA may help.Anytime you have a ridge out west, you should be excited. The WPO loading pattern there shows well where our coldest air would be coming from...from Hudson Bay on eastward....which was what the Euro ensembles do...they bring it over the huge ridge out west and down through Hudson Bay and into Quebec. The central plains of Canada would probably be mild...though the eastern edge might be cold...esp if the EPO/.WPO are battling eachother there. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 25, 2012 Share Posted January 25, 2012 The WPO loading pattern there shows well where our coldest air would be coming from...from Hudson Bay on eastward....which was what the Euro ensembles do...they bring it over the huge ridge out west and down through Hudson Bay and into Quebec. The central plains of Canada would probably be mild...though the eastern edge might be cold...esp if the EPO/.WPO are battling eachother there. Yeah I think a blend of a bit of +WPO and +PNA would fit here. Basically not an ice cold pattern, but anytime you have ridge out west...things can happen. Link to comment Share on other sites More sharing options...
Ginx snewx Posted January 25, 2012 Share Posted January 25, 2012 as an aside we have not seen any re curving Typhoons this winter, one of the missing ingredients IMHO Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2012 Author Share Posted January 25, 2012 Yeah I think a blend of a bit of +WPO and +PNA would fit here. Basically not an ice cold pattern, but anytime you have ridge out west...things can happen. As mentioned above..the NAO will be a big x-factor in the temperature departures...but regardless there should be some storm chances even if we don't up that cold. Feb 1996 shows this well...the ridging poking into Greenland drove the cold south and it was very cold in the east despite even a +EPO/WPO...we want that ridge to be a little west more like Euro ensembles I def wouldn't forecast that cold though...there was actually a little ridging in the far west Aleutians in that pattern. But it shows how things can be driven southward with a -NAO. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2012 Share Posted January 25, 2012 as an aside we have not seen any re curving Typhoons this winter, one of the missing ingredients IMHO Yea, the Atl stole them all Link to comment Share on other sites More sharing options...
CoastalWx Posted January 25, 2012 Share Posted January 25, 2012 Oh I agree. -NAO is the X-factor. But I think if....IF the models were correct, we could see a big sharp cold plunge into the ne US. MJO forecasts seem to agree too, which is the first I've seen all season. I'm somewhat intrigued for February, but also aware it could go into the toilet. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2012 Share Posted January 25, 2012 It's funny how the best patterns in the awful winters are analagous to some of the lulls in the prolific seasons. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2012 Share Posted January 25, 2012 Oh I agree. -NAO is the X-factor. But I think if....IF the models were correct, we could see a big sharp cold plunge into the ne US. MJO forecasts seem to agree too, which is the first I've seen all season. I'm somewhat intrigued for February, but also aware it could go into the toilet. Classic scooter...ballz to the wallz, everything on the line You always have a trap door at the end of your thoughts in order to provide an escape route from your optimism. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 25, 2012 Share Posted January 25, 2012 It's also possible Feb may have a 10-15 day window, but if the -NAO does form...all bets are off. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 25, 2012 Share Posted January 25, 2012 Classic scooter...ballz to the wallz, everything on the line You always have a trap door at the end of your thoughts in order to provide an escape route from your optimism. What I mean is that it may not least long. I think the ridging is for real, but it may not last more than 10-15 days before tanking again. Link to comment Share on other sites More sharing options...
Ginx snewx Posted January 25, 2012 Share Posted January 25, 2012 Just Will mentioning 96 is enough for me. I like the signals all around. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2012 Author Share Posted January 25, 2012 Oh I agree. -NAO is the X-factor. But I think if....IF the models were correct, we could see a big sharp cold plunge into the ne US. MJO forecasts seem to agree too, which is the first I've seen all season. I'm somewhat intrigued for February, but also aware it could go into the toilet. You can on the spaghetti plots in the first post on the GEFS how the OP run (in white) has the ridging into AK further north and it has some ridging in Greenland....so its no surprise that the OP has that huge cold outbreak. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted January 25, 2012 Share Posted January 25, 2012 Reminds me of the winter of 06-07 when we had a good 7-20 days in Feb where it snowed everyday along with a norlun. Then winter was over. March blows Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2012 Share Posted January 25, 2012 Reminds me of the winter of 06-07 when we had a good 7-20 days in Feb where it snowed everyday along with a norlun. Then winter was over. March blows March blows and December roc.....oh, wait... Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2012 Share Posted January 25, 2012 What I mean is that it may not least long. I think the ridging is for real, but it may not last more than 10-15 days before tanking again. I know.....just bustn'. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2012 Author Share Posted January 25, 2012 Reminds me of the winter of 06-07 when we had a good 7-20 days in Feb where it snowed everyday along with a norlun. Then winter was over. March blows My biggest snowstorm (and most others) in 2007 was in March in the St. Patty's day storm. Link to comment Share on other sites More sharing options...
weathafella Posted January 25, 2012 Share Posted January 25, 2012 Reminds me of the winter of 06-07 when we had a good 7-20 days in Feb where it snowed everyday along with a norlun. Then winter was over. March blows March was the snowiest month of that winter for me and damn cold. WTF are you smoking these days? Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 25, 2012 Share Posted January 25, 2012 Good stuff...if we get another period or two of good snows I'm thrilled. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2012 Share Posted January 25, 2012 My biggest snowstorm (and most others) in 2007 was in March in the St. Patty's day storm. March was the snowiest month of that winter for me and damn cold. WTF are you smoking these days? The best snowstorm of my lifetime by far occured at the end of March into April. Link to comment Share on other sites More sharing options...
Ginx snewx Posted January 25, 2012 Share Posted January 25, 2012 The best snowstorm of my lifetime by far occured at the end of March into April. not 97 2007 Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2012 Author Share Posted January 25, 2012 The period surrounding the Feb '06 storm was similar as well...that period really didn't get all that cold, but it was cold enough. You never predict actual storms this far out obviously, but it shows that when you get big ridging out west, that you'll have a shot...you still need the synoptics to work out. Getting some of that ridging (even if not that big) poking into Greenland will be a huge help too Link to comment Share on other sites More sharing options...
Damage In Tolland Posted January 25, 2012 Share Posted January 25, 2012 March was the snowiest month of that winter for me and damn cold. WTF are you smoking these days? What winter am I thinking of when BOS only had like 26 inches or something. I had 43 inches..Thought it was 06-07..but you know me and dates Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2012 Share Posted January 25, 2012 not 97 2007 I was speaking of March in general....do you honestly think that I didn't know that Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2012 Share Posted January 25, 2012 What winter am I thinking of when BOS only had like 26 inches or something. I had 43 inches..Thought it was 06-07..but you know me and dates You are thinking of 2007....but Boston had like 17" and you simply forgot about that St. Patty's event. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 25, 2012 Share Posted January 25, 2012 What I like seeing, is that tropical forcing agrees.....or is trying to agree. We have not have that all winter. Makes me think ridging out west is for real. Link to comment Share on other sites More sharing options...
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