cbmclean Posted January 9, 2021 Share Posted January 9, 2021 6 minutes ago, CAPE said: Thanks, but what makes this fun is everyone contributing and sharing info and getting different perspectives. It's a group effort. GEFS 850 MB temp anomalies still look to improve considerably after Jan 16, both for us and for our source region. 2m anomalies are disappointing though. Link to comment Share on other sites More sharing options...
CAPE Posted January 9, 2021 Share Posted January 9, 2021 8 minutes ago, psuhoffman said: It just depends. Not all blocking patterns are the same. But a -NAO split flow isn’t uncommon and usually a good thing. It’s not a cold pattern. Feb 2010 was one. The Polar jet was directed across Canada by the trough in the pac but the southern streak was splitting into the SW and coming across the gulf coast. But the pac jet wasn’t as intense and the profile in Canada wasn’t as awful to start. But it wasn’t warm. Actually north of us was very mild. And even here it would have been 45 that week had there not been snow. It’s a puck your poison thing. A split flow cuts off the polar air but normally in winter we can develop a just cold enough airmass under the flow to get snow with a good track. This year that didn’t work out. A -EPO -NAO non split flow is much colder but it can be a dryer pattern if storms dive in too far north to amplify under us and the STJ is cut off in just case. So there are pros and cons to both. FWIW the split flow option accounts for a lot of our HECS storms. Could be just bad luck/bad timing then, or an indication of some longer term changes. Given the HL look we have had, it seemed different to me. Maybe that is partly due to the ground truth here being exactly the same as last winter, despite the HL blocking lol. It will be interesting to see how things play out over the next 10 days or so, when it appears we will have some colder/drier air to work with, and blocking in place. Better luck if nothing else, hopefully. Link to comment Share on other sites More sharing options...
CAPE Posted January 9, 2021 Share Posted January 9, 2021 12 minutes ago, cbmclean said: GEFS 850 MB temp anomalies still look to improve considerably after Jan 16, both for us and for our source region. 2m anomalies are disappointing though. Yeah I wouldn't worry too much about the 2m temps as advertised. Just having somewhat colder, lower dp air available will make a big difference. With a -AO/NAO, we tend to have the highs and lows in the right places, and evaporational cooling can work its magic. Link to comment Share on other sites More sharing options...
chris21 Posted January 9, 2021 Share Posted January 9, 2021 11 minutes ago, cbmclean said: GEFS 850 MB temp anomalies still look to improve considerably after Jan 16, both for us and for our source region. 2m anomalies are disappointing though. While they could be right for the wrong reasons I would tend to just look at the 850 mb anomalies. The long range 2m temp anomalies are atrocious to say the least. Link to comment Share on other sites More sharing options...
dallen7908 Posted January 9, 2021 Share Posted January 9, 2021 As snowdreamer noted, the best chance of snow in MBY according to the EPS is on the 20th - could be fun to watch the ... REMINDER: NO ... While there is nothing through the medium-range, the 15 day mean of 2 - 2 1/2 inches is higher than its been in quite a while. The 20th is roughly when the PNA is forecast to go negative for a while. Link to comment Share on other sites More sharing options...
psuhoffman Posted January 9, 2021 Share Posted January 9, 2021 8 minutes ago, CAPE said: Could be just bad luck/bad timing then, or an indication of some longer term changes. Given the HL look we have had, it seemed different to me. Maybe that is partly due to the ground truth here being exactly the same as last winter, despite the HL blocking lol. It will be interesting to see how things play out over the next 10 days or so, when it appears we will have some colder/drier air to work with, and blocking in place. Better luck if nothing else, hopefully. I think, as wxusaf, that it’s a bit of both bad luck and the background stage becoming incrementally more hostile. In December we had a nice AO ridge but it was a bit north of perfect. That can work though if you get other things to line up and we almost did but that SW that dive in out west really screwed us by amplifying the trough more. But it’s hard to get a big snow in mid December. The first iteration of the -NAO this month ended up too extreme imo. That was part of the problem. I posted this from a couple days ago. That ridge is centered way too far south and extends too far SW. Not only did that suppress 3 waves but it prevents colder air from draining into the pattern to the west of the block. Center that further north without that extension into Quebec and we get a slightly colder profile and less suppressed systems and I bet one of them “works out”. This next flex of the blocking looks more ideal but now there are questions about what kind of PAC we get. Ideally I would have liked one more bite of the apple with the current pac and a better NAO. But I don’t have the magic crayon. And the look we see now is pretty darn good. And I’m biased by my location. If I were you I would definitely go with the colder but possibly dryer option. We have way different climo. 1 Link to comment Share on other sites More sharing options...
Siberian-Snowcover-Myth Posted January 9, 2021 Share Posted January 9, 2021 Nothing like a mild winter drought in the supposedly greatest hyped up pattern in decades. Link to comment Share on other sites More sharing options...
CAPE Posted January 9, 2021 Share Posted January 9, 2021 Just now, Siberian-Snowcover-Myth said: Nothing like a mild winter drought in the supposedly greatest hyped up pattern in decades. Best since 96! I wont lie, I have enjoyed this week of dryness. My driveway has solidified again. 3 Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted January 9, 2021 Share Posted January 9, 2021 1 hour ago, psuhoffman said: The mean SLP is screaming this kind of result imo! Only 360 more hours to go which takes us to the last week in January. Our patience is truly being tested! 1 Link to comment Share on other sites More sharing options...
cbmclean Posted January 9, 2021 Share Posted January 9, 2021 14 minutes ago, psuhoffman said: I think, as wxusaf, that it’s a bit of both bad luck and the background stage becoming incrementally more hostile Just curious how much impact you think the hostile November had. You have mentioned it a few times as a negative factor, but was it a MAJOR factor? Link to comment Share on other sites More sharing options...
stormtracker Posted January 9, 2021 Share Posted January 9, 2021 18z GFS gonna provide some action 200+ hr. But....200 hr + Link to comment Share on other sites More sharing options...
stormtracker Posted January 9, 2021 Share Posted January 9, 2021 If you like rain, man have I got something for you. Darth Lake's Low strikes again. Link to comment Share on other sites More sharing options...
JakkelWx Posted January 9, 2021 Share Posted January 9, 2021 Merry Christmas 2 Link to comment Share on other sites More sharing options...
wawarriors4 Posted January 9, 2021 Share Posted January 9, 2021 Just now, stormtracker said: If you like rain, man have I got something for you Looks like Christmas Eve looked, but thankfully 220+ hours Link to comment Share on other sites More sharing options...
MD Snow Posted January 9, 2021 Share Posted January 9, 2021 As others have mentioned, 18z GFS still pointing to January 18-20 as a threat window. That's all you should take from an op run past 200+ hrs. Link to comment Share on other sites More sharing options...
BristowWx Posted January 9, 2021 Share Posted January 9, 2021 1 minute ago, wawarriors4 said: Looks like Christmas Eve looked, but thankfully 220+ hours Plenty of time for a westward adjustment. And it wouldn’t take much actually. 1 Link to comment Share on other sites More sharing options...
Cobalt Posted January 9, 2021 Share Posted January 9, 2021 That 360hr look lol, primary up in Illinois and we’ve got blue over most of the sub forum.We seem to have flipped from the GFS showing anything but snow over us but of course it will change in just 6 hours . 2 Link to comment Share on other sites More sharing options...
BristowWx Posted January 9, 2021 Share Posted January 9, 2021 I wonder if a clean all snow event is even possible anymore. Snow to rain to snow is fine but all snow would be fun too. Link to comment Share on other sites More sharing options...
psuhoffman Posted January 9, 2021 Share Posted January 9, 2021 Just a little blocking when storms transfer from Indianapolis to Hatteras 1 Link to comment Share on other sites More sharing options...
BristowWx Posted January 9, 2021 Share Posted January 9, 2021 2 minutes ago, psuhoffman said: Just a little blocking when storms transfer from Indianapolis to Hatteras Have we ever seen an IN to NC transfer? Seems like we would remember that Link to comment Share on other sites More sharing options...
psuhoffman Posted January 9, 2021 Share Posted January 9, 2021 19 minutes ago, BristowWx said: Have we ever seen an IN to NC transfer? Seems like we would remember that Recently no. Are there examples of that in the past yes. It takes a blocking regime and a cold airmass. Link to comment Share on other sites More sharing options...
psuhoffman Posted January 10, 2021 Share Posted January 10, 2021 32 minutes ago, BristowWx said: Have we ever seen an IN to NC transfer? Seems like we would remember that A storm in 1972 transferred from the UP of MI to SC. That was probably the most extreme example. 5 Link to comment Share on other sites More sharing options...
cbmclean Posted January 10, 2021 Share Posted January 10, 2021 Just now, psuhoffman said: A storm in 1972 transferred from the UP of MI to SC. That was probably the most extreme example. If you are feeling didactic tonight, what exactly is a "transfer"? I only have the vaguest idea of storm dynamics. Link to comment Share on other sites More sharing options...
Chris78 Posted January 10, 2021 Share Posted January 10, 2021 56 minutes ago, psuhoffman said: Just a little blocking when storms transfer from Indianapolis to Hatteras It's been so long since we've had an actual block I think we forget what crazy storm tracks that can cause lol. That storm on the GFS at 300+ hours out looks like it's going to be Rainer but the block says nope your going south. If we can't score the last 10 days of January If this pattern comes to pass, I dont know what to say lol. Link to comment Share on other sites More sharing options...
Heisy Posted January 10, 2021 Share Posted January 10, 2021 1 hour ago, cbmclean said: If you are feeling didactic tonight, what exactly is a "transfer"? I only have the vaguest idea of storm dynamics. I’ll let others explain better, but basically when a low pressure hits a high pressure and a new low forms. Here is a random map I pulled off google showing the two lows. The secondary is the one forming near the coast. 1 Link to comment Share on other sites More sharing options...
psuhoffman Posted January 10, 2021 Share Posted January 10, 2021 3 hours ago, cbmclean said: If you are feeling didactic tonight, what exactly is a "transfer"? I only have the vaguest idea of storm dynamics. A low transfers when it meets resistance and can no longer progress and reforms somewhere else along the thermal boundary. This can happen because of the upper level support jumping or a surface feature blocking progress. Often the jump we want is a system moving northeast up the west of the Apps to jump to the coast. What typically causes this is when a cold high is blocked in to the north impeding the low, and CAD banked in against the mountains so the path of least resistance is to jump east to the baroclinic zone along the coast. The example from the 18z gfs is below. the primary in the Midwest has hit a brick wall of confluence. Note that system to its north hit the same wall and has actually done a loop and is retrograding west because it’s an arctic wave removed from any thermal gradient so it had nowhere to jump too. It simply put er in reverse lol. That primary in IN can’t go anywhere. So it’s going to transfer to the triple point along the front in the Carolinas. That’s common because there is often a lot of lift there that can promote pressure falls and an enhanced baroclinic boundary. It’s also along the warm front providing a path east under the block for the storm to progress so it transfers the energy there. 2 5 Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted January 10, 2021 Share Posted January 10, 2021 Its the ICON and its at range, so take with 2 grains salt, but like several other pieces of guidance, it is setting up something around the 18th-20th with a 50/50 developing underneath the NAO block and energy ejecting out of the Rockies. Definitely a period to watch. 3 Link to comment Share on other sites More sharing options...
cbmclean Posted January 10, 2021 Share Posted January 10, 2021 10 minutes ago, Ralph Wiggum said: and energy ejecting out of the Rockies On this plot what indicates "energy"? I am used to seeing people refer to "energy" when they are talking about areas of enhanced vorticity on vorticity maps, but I don't see what you are referring to on this map. Link to comment Share on other sites More sharing options...
psuhoffman Posted January 10, 2021 Share Posted January 10, 2021 6 minutes ago, cbmclean said: On this plot what indicates "energy"? I am used to seeing people refer to "energy" when they are talking about areas of enhanced vorticity on vorticity maps, but I don't see what you are referring to on this map. You can’t see it directly there but you can see the evidence because there is a 1004 surface low with h5 low ejecting so obviously it has an associated SW and vort. It’s just assumed from secondary evidence. 1 Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted January 10, 2021 Share Posted January 10, 2021 3 minutes ago, psuhoffman said: You can’t see it directly there but you can see the evidence because there is a 1004 surface low with h5 low ejecting so obviously it has an associated SW and vort. It’s just assumed from secondary evidence. GFS isn't far off from that look either. Liking this setup more than 18z. Little more separation between jets, less phasing in plains Link to comment Share on other sites More sharing options...
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