toronto blizzard Posted October 21, 2013 Share Posted October 21, 2013 That is kind of what happened in December 2007 when we had a cold and snowy December despite a solid +NAO. I'd rather not risk that, but its certainly a possibility if we end up with a +AO look going into winter. Do the models bring the AK vortex back in November and December? Link to comment Share on other sites More sharing options...
ORH_wxman Posted October 21, 2013 Share Posted October 21, 2013 Do the models bring the AK vortex back in November and December? http://www.americanwx.com/bb/index.php/topic/40158-the-early-speculation-on-winter-2013-14/?p=2439128 Link to comment Share on other sites More sharing options...
N. OF PIKE Posted October 21, 2013 Share Posted October 21, 2013 Do the models bring the AK vortex back in November and December?Well lets see how many recurving typhoons we can get to sustain the current pattern. There is a nice post in the general wx pattern thread that shows the wave propogation of teleconnectors (how recurving typhoon sets up aleutian low and western north american ridge and down stream eastern trough) More or less... it won't be quite as direct of an impact as the ET of Francisco which is driving the Rossby Wave Train amplification, but the poleward -PV advection from the outflow of Lekima should only further enhance the polar jet. Both the ECMWF and GFS as a result show a reloading of the cold in the day 5-7 period across the Midwest as the wave packet resulting from this jet streak amplification swings into North America. I've made a quick animation below that shows the propagation of this wave packet. If you notice, the energy doesn't move at the phase velocity (the speed of individual rossby waves). Instead the wave packet created by the jet amplification due to WPAC TCs travels at the group velocity (which is double the phase velocity), and this serves to amplify individual rossby waves along the waveguide. Thus, ET just off the coast of Japan tends to reinforce a pattern that favors trough amplification and surface cyclogenesis in the Aleutian islands, subsequent ridgebuilding over far western North America, and finally general troughing over the eastern US. Of course the magnitude of individual events varies, but you can see now how recurving Typhoons have a direct teleconnection to our weather downstream. Imo anything beyond 30 days is a guess wrt long range the vast majority of times, sure its a educated guess but i havent seen many accurate LR forecasts (in SNE) perhaps if EVERY single indicator is looking positive or negative. Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted October 21, 2013 Share Posted October 21, 2013 12z GGEM more defined than the GFS so verbatim would probably be some snow inland on it. Link to comment Share on other sites More sharing options...
ineedsnow Posted October 21, 2013 Share Posted October 21, 2013 meh for now though maybe a few flakes if people are lucky 12z GGEM more defined than the GFS so verbatim would probably be some snow inland on it. f60.gif Link to comment Share on other sites More sharing options...
weathafella Posted October 21, 2013 Share Posted October 21, 2013 Even with the stout stratospheric vortex ak hrs dont go low. Pacific is battling the Atlantic and ao. Link to comment Share on other sites More sharing options...
powderfreak Posted October 21, 2013 Share Posted October 21, 2013 12z GGEM more defined than the GFS so verbatim would probably be some snow inland on it. f60.gif You really think that would be cold enough for snow in the interior? It looks real marginal at best. I'd think we'd need -6C at 850 or lower...or insane rates like Oct 2011. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted October 21, 2013 Share Posted October 21, 2013 Pretty torched in the low levels, but it does cool at the end...maybe the hills end as some snow on the NAM. I don't really believe the model though at this point. Its more amplified than most guidance...and the fast compressed flow leads me to think the SE solutions are more correct. Yeah, I went over this NAM run a while ago and although it looks tasty from the 50,000 foot synoptic appeal, details have that the lower critical thickness as way too warm for snow in the lower elevations and the coastal plain. The front slips by and there is only very weak CAA in the low levels. Almost a calm fropa. Maybe in the distant interior ...Wachusett highlands/ridge lines for example ... there may be some wet flakes in the tail end of the NAM solution, and in fact there probably would be. But getting the NAM solution to verify is ..well, perhaps a challenge in its self. Link to comment Share on other sites More sharing options...
Tropopause_Fold Posted October 21, 2013 Share Posted October 21, 2013 euro not interested in giving any precip Wednesday. it's to the point now that it looks like the gfs from a few days ago. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted October 21, 2013 Share Posted October 21, 2013 Here comes Sandy's sister ... Link to comment Share on other sites More sharing options...
Tropopause_Fold Posted October 21, 2013 Share Posted October 21, 2013 euro is dropping the arctic down across the central canadian plains next week. -25C 850s dear lord. Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted October 21, 2013 Share Posted October 21, 2013 euro not interested in giving any precip Wednesday. it's to the point now that it looks like the gfs from a few days ago. I'd lean that way right now. I just think the flow is too fast/progressive to allow for much amplification. Link to comment Share on other sites More sharing options...
CoastalWx Posted October 21, 2013 Share Posted October 21, 2013 AT least it should be dry for the WS. Link to comment Share on other sites More sharing options...
CoastalWx Posted October 21, 2013 Share Posted October 21, 2013 Gonna be some nice diurnals coming up since the ground is chalk dust. Link to comment Share on other sites More sharing options...
OceanStWx Posted October 21, 2013 Share Posted October 21, 2013 Gonna be some nice diurnals coming up since the ground is chalk dust. Burned on that last night up here. Mid shift had 40s going for much of the areas just inland from the coast. Car thermometer was reading 32-34 for most of my drive up to the WFO. Link to comment Share on other sites More sharing options...
powderfreak Posted October 21, 2013 Share Posted October 21, 2013 Burned on that last night up here. Mid shift had 40s going for much of the areas just inland from the coast. Car thermometer was reading 32-34 for most of my drive up to the WFO.We were 49-50F at 11pm at MVL with wind and orographic clouds, and BTV forecast upper 30s. When I went to bed I was thinking we wouldn't hit those forecast mins.Then I woke up 7 hours later to 33F and frost. The bottom dropped out after midnight.hard forecast when temps are stagnant from 6-11pm. Link to comment Share on other sites More sharing options...
ORH_wxman Posted October 21, 2013 Share Posted October 21, 2013 Notice how as the pattern is trying to break down on the GEFS, all those El Nino years are disappearing from the analogs. (1976, 2002, 2009 all gone..still have 1972 at the bottom and 1965 is a new one in there) Link to comment Share on other sites More sharing options...
Typhoon Tip Posted October 21, 2013 Share Posted October 21, 2013 Notice how as the pattern is trying to break down on the GEFS, all those El Nino years are disappearing from the analogs. (1976, 2002, 2009 all gone..still have 1972 at the bottom and 1965 is a new one in there) Looks more +PNA/+EPO as opposed to the -PNA/-EPO Link to comment Share on other sites More sharing options...
HoarfrostHubb Posted October 21, 2013 Share Posted October 21, 2013 Gonna be some nice diurnals coming up since the ground is chalk dust.34 degree swing imby today Link to comment Share on other sites More sharing options...
dryslot Posted October 21, 2013 Share Posted October 21, 2013 Burned on that last night up here. Mid shift had 40s going for much of the areas just inland from the coast. Car thermometer was reading 32-34 for most of my drive up to the WFO. 30.6F for a low here this am Link to comment Share on other sites More sharing options...
dendrite Posted October 21, 2013 Share Posted October 21, 2013 18Z NAM weenie run for extreme NE CT and NW RI. Enjoy the flakage until 00Z. Link to comment Share on other sites More sharing options...
ctsnowstorm628 Posted October 21, 2013 Share Posted October 21, 2013 18Z NAM weenie run for extreme NE CT and NW RI. Enjoy the flakage until 00Z. NAM is complete nonsense. 500mb doesn't even come close to resembling that surface depiction. That sheared out s/w at h54 would probably spin something up farther offshore IMO. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted October 21, 2013 Share Posted October 21, 2013 NAM is complete nonsense. 500mb doesn't even come close to resembling that surface depiction. That sheared out s/w at h54 would probably spin something up farther offshore IMO. The NAM has a documented NW bias over the longer term verification. However, there are some unique situations where that bias helps. Case in point, Dec 2005. There are others, as well. Not sure if this is one of those situations, but I don't see really how the solutions of the day are at odds with the track of the v-max aloft. q- v forcing should be pretty good near the right entrance region of that jet core, and that's pretty close to collocated with where the NAM has it's closed circulation. The NAM is actually good when there are very compact horizontal thermal gradients and steep frontal slopes aloft ... inside of 48 hours. It also is parameterized with convective sequencing that is very good for initialization in the summer months (not relevant here). Otherwise, the model has a poor verification score beyond 36 to 48 hours. What stands out for me is what I was discussing with Will earlier in the day; if you look at the intervals leading up the "ana" -like blossoming, the actual llv CAA is weak. It leaves the lowest critical thickness pretty deep. On the FRH grid, BOS has moderate rain in roughly 43F, then cools back to about 36 as it's shutting down. Typically for that, it's snowing at 2,000 ft, and probably would be on these NAM solutions along the Wachusett highlands/extending up to the Monads. But the lower els and CP regions would be primarily cold rain with perhaps cat's paws in the last couple of hours. Of course, that is relative/relevant of the NAM's depiction ... getting them to succeed, well that's a different story. As an afterthought, I once spoke about this with Walter Drag a long time ago; typical rule of thumb is that a v-max translation 1.5 degree latitude S of the S Coast usually places a frontogenic sig through the mid levels near the Mass Pike. Combining that with total 500mb thickness crash into the upper 530dm, and the QPF layout, it may be an attempt to dynamically flip ORH-FIT-ASH-MHT. The CMC model is not too dissimilar to the NAM off the 12z run, fwiw - personally I think it would be a riot if the NAM won and spanked the Euro on this one. Link to comment Share on other sites More sharing options...
CoastalWx Posted October 21, 2013 Share Posted October 21, 2013 Not much change to the euro ensembles. Still very cold in Canada down towards Labrador. The flow in the Pacific flattens out pretty good but heights still sort of neutral with weak ridging in western Canada. The result is a near normal to perhaps a hair below in the 11-15 day. I definitely would like to see heights stay as they are....if those lower then we run the risk of furnacing. The weeklies still have a monster +NAO, but just enough ridging into the Aleutians to keep it near normal in week 4 here at the surface. Canada is frigid. Link to comment Share on other sites More sharing options...
toronto blizzard Posted October 21, 2013 Share Posted October 21, 2013 Not much change to the euro ensembles. Still very cold in Canada down towards Labrador. The flow in the Pacific flattens out pretty good but heights still sort of neutral with weak ridging in western Canada. The result is a near normal to perhaps a hair below in the 11-15 day. I definitely would like to see heights stay as they are....if those lower then we run the risk of furnacing. The weeklies still have a monster +NAO, but just enough ridging into the Aleutians to keep it near normal in week 4 here at the surface. Canada is frigid. That is is very encouraging! Link to comment Share on other sites More sharing options...
powderfreak Posted October 22, 2013 Share Posted October 22, 2013 Still waiting for that first below normal day this month at BTV. We've had one at MVL about ten days ago....but hopefully we can string a few in a row before it warms up. Last week on the models I was thinking that this past weekend and Monday might be below normal but it wasn't even close with +3 to +8 occurring. BTV saying normal to even above normal again by as early as next Sun/Mon. Before that though I bet we can enjoy a few -4 to -8 type days, which seems paltry compared to the +4 to +7.5 that most NE stations are so far this month...but it's the small battles and warning shots of colder air that'll make this week sweet. AFD.... "Below normal temperatures are expected Thursday through Saturday with highs mainly in the 40s with 30s in the mountains. Lows will generally range from the middle 20s to middle 30s. Temperatures warm to around or a bit above normal for Sunday and Monday. && " Link to comment Share on other sites More sharing options...
powderfreak Posted October 22, 2013 Share Posted October 22, 2013 Seems to be a little clipper type system on some progs for next weekend...18z GFS has it coming Saturday night. Although the temps are incredibly marginal (0C to -3C across pretty much all of New England at 850mb), and precip is very light, it is occurring at night so maybe that's a shot at some weenie flakes for the higher elevations? I wish the gradient with this cold shot was going to be steeper...there's one point at like 90 hours out where its -1C at H85 over Atlanta while NNE is only like -6C. That's waaaayyy below normal for the south but not nearly as much up north. In mid-winter when the 0C freezing line at H85 gets so far south to the Gulf Coast states, NNE will be like -20C, lol. Anyway, here's the clipper next weekend. May be close at the hill tops. Link to comment Share on other sites More sharing options...
dryslot Posted October 22, 2013 Share Posted October 22, 2013 Seems to be a little clipper type system on some progs for next weekend...18z GFS has it coming Saturday night. Although the temps are incredibly marginal (0C to -3C across pretty much all of New England at 850mb), and precip is very light, it is occurring at night so maybe that's a shot at some weenie flakes for the higher elevations? I wish the gradient with this cold shot was going to be steeper...there's one point at like 90 hours out where its -1C at H85 over Atlanta while NNE is only like -6C. That's waaaayyy below normal for the south but not nearly as much up north. In mid-winter when the 0C freezing line at H85 gets so far south to the Gulf Coast states, NNE will be like -20C, lol. Anyway, here's the clipper next weekend. May be close at the hill tops. image.jpg Been watching that on the models the last few days, Euro has it as well, Mtns would definitely see flakes i think with that Link to comment Share on other sites More sharing options...
CoastalWx Posted October 22, 2013 Share Posted October 22, 2013 Seems to be a little clipper type system on some progs for next weekend...18z GFS has it coming Saturday night. Although the temps are incredibly marginal (0C to -3C across pretty much all of New England at 850mb), and precip is very light, it is occurring at night so maybe that's a shot at some weenie flakes for the higher elevations? I wish the gradient with this cold shot was going to be steeper...there's one point at like 90 hours out where its -1C at H85 over Atlanta while NNE is only like -6C. That's waaaayyy below normal for the south but not nearly as much up north. In mid-winter when the 0C freezing line at H85 gets so far south to the Gulf Coast states, NNE will be like -20C, lol. Anyway, here's the clipper next weekend. May be close at the hill tops. image.jpg That can happen with deep troughs though. The cold plunges due south sometimes and then moderates a bit when it moves east. It's not rare for ATL to be colder than BOS sometimes. They also are at a thousand feet. Link to comment Share on other sites More sharing options...
dendrite Posted October 22, 2013 Share Posted October 22, 2013 Weenie cold shot at the end of last night's Euro...that's like 18C below normal 850s across CNE. Lots of spread on the ens past d7 though. Link to comment Share on other sites More sharing options...
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