tombo82685

Like @Allsnow mentioned I have sneaky feeling this will gain amplitude in 4-5-6

I will never post on this site again if that rmm verifies, this should come out into 3-4-5-6. Why would convection just rot when it has all the warm water around Australia

It's not as simple as saying, it comes west it snows. First off look back at nyc snowstorms, how many times did they not have any good HP to the north or cold air in place before a system? Heck NYC dew pts aren't even below freezing on saturday, so you can't even evapo cool down. Meaning you're solely relying on dynamics to bring cold air in. West doesn't mean you snow either. Track further west also means stronger easterly flow out ahead of system and stronger sw flow in the mid levels. Look aback at the 18z run of eps, you had 23 members show over .5 of qpf, yet only 7 member show anything over 2". Thats gotta tell you something right there odds are heavily not in your favor not even with a further west track.

This still looks like a long shot for the coast. Hudson Valley on north still in the game IMO

I think its a combo of mjo that produced a record +AAM event that causes the pac jet to go on roids. It doesn't help that you have th intense goa low that also tightens the pac jet. That doesn't allow the pna ridge out west to build. With that being flatter it prevents the northern stream s/w from digging further south. Also think bad strat alignment has cut off cold air supply. That will change after the 5th as the strat alignment is more favorable for -epo development.

I agree 100% @Allsnow temps are a huge issue. If this is solely southern stream driven, no help from northern stream odds are it's a rainstorm for coastal plain. The way that changes is if the low bombs out and dynamically cools. The HP that scoots offshore just prior to the storm flips the winds to the south and that rots the BL for the coastal plain. If the northern stream gets involved that would be better, but you need the right track of that as well. Has to swing south of this area to pull the cold air in for a snow event along coastal plain.

prior to the low coming up, the HP that is over the area slides to the east/southeast. With that positioning you get southerly flow at the surface which warms the BL temps and thus a rainy outcome despite an overall good track

Yup, it doesn't matter if it's in Siberia or not but has to be elongated north south. It's not a 100% correlation but some of our good cold outbreaks had that look with ridging either in AK or Scand or both. Here is the winter of 2014 here is thestrat look a few days prior to feb 14 2016 that sent NYC to -1 1994 cold outbreak then cold shot this november. Can see how most of those years had either a wave 1 strat ridge near AK or had wave 2 strat ridges near AK and into parts of europe that elongates the vortex north south. If we look at where we are now, it's the complete opposite of what we want for any strat induced cold shots as the ridging is in central Canada. But we then head to this at the end of the euro run which if the past dictates the future, we should see a good cold shot coming into the plains and east past day 10 as we have a strong wave 2 ridging from AK and Europe elongating the vortex

Also it was the control run of the weeklies not the standard euro weeklies

No I definitely agree, I would never make a forecast like Judah does solely basing off the PV as there are ways around it. You can have a strong pv and still have a cold winter. I do believe though, when you get disruptions to the strat pv that can down-well and cause favorable conditions for cold outbreaks. I enjoy the mjo stuff, I think it's neat how the tropics alter patterns. I think it was the fall of 2013 where the tropical pacific had a lot of re-curving typhoons and the wavebreaks from those re curves just kept reinforcing the -epo look. A good example of a strong standing wave was this fall with the standing wave over the IO. That sucker lasted for months and pretty much had a strangle hold over the tropics.

What would you say played a role in the 2015 feb pattern? To me it seemed like the strat played a role more so than the mjo. I think how the pv is aligned is more important than where it's at. It can be located in Siberia but if the alignment is right it still can bring cold air into the states. The MJO plots I have access to show the mjo mainly in cod then into 6-7 which don't scream the cold we got.

I thought the strat was pretty good in 2015 with a weak vortex IMO. The vortex in 2015 was disturbed from strong wave 1 hits in Jan and first part of February. Also can see the positioning of it at 10mb from jan1-mar 1 was more favorable for dumping cold into the US unlike right now. From what I have seen when we have strat ridging over AK or Scandinavia it seems to teleconnect better to colder dumps into the US.

Ctp has a 6” storm last nov

Exactly it. That data is from my work here in wayne which is at 500' in elev.

Huh? outside of this winter so far NYC has had a 6" storm every winter back to 13/14.

The map they posted is run to run change from model cycle. Since eps lost the epo it was warmer but the 850 temp anom was below normal

Roundy’s hovmoeller diagrams of unfiltered and projected anomalies are the best I’ve seen

False and false. There is a complete atmospheric journal on slow and fast mjo and also the lag each response has https://journals.ametsoc.org/doi/full/10.1175/MWR-D-16-0352.1 and here is the cpc website that shows composite lag of each https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/LaggedComposites/description.shtml

Agreed, I would take that 6z euro map and cut it in half maybe more with accumulations if we are taking the model at face value here. While it’s cold enough to snow on it, how much of that truly will stick with surface temps in the 35-37 range? That just smells like white rain and Piss ooor ratios. Plus, that euro run was a major outlier in the eps. Same thing happened to nyc back in early dec just couldn’t overcome poor BL despite decent precip. If things tick colder then I would start to buy into a better chance for accumulations in the city. North and west complete different story.

these are the 850 anoms off it

EPS show it too, they have a good cold shot in the jan 6-10 period before we go into a la nina pattern

Yea that could be very true. Just seems like roundy's OLR plot is focusing on building a wave in phase 5 that travels through 6 and 7 to start january off. The stratobserve site just updated but you could make a case here the cold it's showing to start new year is strat related. We had a strong wave 2 hit in nov that brought about a period of -NAM to troposphere. Then we had wave 1 displacement hit that was slower to propagate downward, that brought us this cold shot. Now we have another wave 2 hit starting now and you can see the building -NAM right around new years

It has to be strat related the cold. The rmm plots, which are not the best tool to look at for the mjo continue to back up towards the warm phases. Newest one has a little pass into phase 5 before gaining amplitude into 6. This matches closer to the OLR plots I posted this morning and closer to the euro. So it's in warm phases of mjo, yet still gets to that h5 look post day 10? Either it's picking up on strat related or you will continue to see can kick that never makes it past day 10 till we get WPAC forcing.

The thing that has me skeptical on the GEFS faster return is how it's handling the tropical forcing. It seems to me it's rushing the convection to fast into WPAC. If you look at roundy's OLR diagram it doesn't get tropical forcing into the WPAC till after first week of January. By New Year's the forcing is only in phase 5 or so. Granted this isn't super strong, so it's not like it's overwhelming everything, but it still tips the scale towards warmer. The current cold shot is actually a by product of the strong wave 1/displacement we had back in early Dec. You can see the slow ooze from the stratosphere into troposphere on the NAM. We do have the strong wave 2 hit you would think that would influence the pattern. The euro has the same wave 2 hit so it's not like one is seeing it and the other is not. My guess is one model sees it coupling with the trop, while the other doesn't? I think best approach is to see if the gefs can kick it or hold steady. If they start can kicking, then we have our answer, but my money is it's fast

They also picked up on the cold shot this week first. Not saying I think they will be right in the long term, but it's not like they have bowed down to the eps. They have won their fair share of battles.