Stormchaserchuck1

Good research Larry, like always, but this is not +PNA

I stand corrected saying the PNA has been positive all Winter yesterday. There is something wrong with the CPC's methodology of calculating.. this is a 1-month period of -PNA.. I don't care that the CPC says it was +pna. It's not going to actually be one of the most +PNA Winter's on record..

The pattern is ok... you guys aren't hearing me that, that's not a 50/50 low.. it's too far NE and actually a +NAO. Now +NAO has higher precip correlation, so when the Pacific pattern works you can get an overrunning storm.. that's probably what we'll get, but not a Miller A without south-of-Alaska low 500mb and sustained 50/50 low. Beyond there, I got weenied 10 times for saying this last night... but it's not an impressive cold pattern. The EPO looks to go positive for a few days. The next "threat" after the 20-22, probably right now looks like rain. @psuhoffman The AO pattern has its highest snow correlation when it's deeply negative.. not coming back to neutral or positive. The NAO is what you want to see go back to neutral because its negative phase is so dry... but we are missing a -5 AO here with 2 rainstorms. After that, when the AO goes back to neutral/positive, it's not a favorable pattern for MECS anymore! I know your research says lag, but besides the 20-22 storm, it's not looking like a favorable period, mostly because of lack of deep cold (because by that time it's not -AO)! The index regions do correlate the highest with US temps at Days 0 to +1.

My Christmas tree is still up! One year I left it up until July. Actually 2 years. but July is the record.

Uh oh.. 1st run showing it, and GFS ensembles have not been great lately, but Days 10-13 have a +WPO/+NAO pattern.. pretty strong. Going to flood the CONUS with warm air after the 20-22 storm if the run verifies verbatim. It does shift back to +PNA days 13+ though

Was there a 1001mb low in 1983?

No going back to what's behind us. that goes for all of, you

It has been a Weak Nina-like STJ

Nino's have correlated with +EPO lately. Actually, the NPH (North Pacific High) is its main correlated region.. last Winter it did pop a -NPH, which is typical of +ENSO El Nino's can be very warm, and La Nina's can be very cold.. but we can get big snowstorms in El Nino yeah West-based El Nino, focused near the dateline is the better potential scenario.

It was record breaking the last 7 years, especially in Feb-March, until this year. Big flip this year. Strongest non-Nino +PNA probably since 00-01. 2 weeks ago the GFS ensemble mean had a +300dm -PNA in the long range.. they didn't even come close to verifying.. it's still +pna

PNA hasn't gone below -0.1 a single day since Dec 1st.. and that looks to continue at least through March 1

The 90N block maxes out in the next 1-3 days, at +500dm. After then the AO loses its strength. It becomes about the Pacific moving into a more favorable pattern. The MJO is more about what H5 it's correlating with.. but this stuff at Day +0-3 is modeled well right now.. it's not something that is over the modeled 500mb pattern. It just sounds like you like +PNA over -AO... which is fine, but I think a Polar block maxing out and producing 2 rainstorms at its max without a -PNA pattern or anything like that is kind of disappointing. Like I said, AO is more about what it produces as it goes strong, not so much when it comes out of that max like the NAO.

With that south-based +NAO, I wouldn't be surprised if it trends wetter in the coming days. Also watch to see if that -AO holds strong with a -epo/+pna Pacific.. it might come a little north. AO is like -4 for the storm as modeled right now. Here is precip correlation to south-based +NAO in February https://postimg.cc/5H4Ty09s

1050mb High on the US/Canada border. +NAO's are wet, so it's not that big of a deal having the 50/50 displaced NE, you're just going to do more of an overrunning system vs a Miller A.

50/50 low really rolls north. Almost touching southern Greenland. and the +PNA trough in the N. Pacific weakens a little moving east.. We need that Pacific piece for the trough to dig.

Looks like a nice pattern actually. Not far from having a south-of-Alaska low (+PNA modeled) and 50/50 low. Then it's a matter of how wet the system is.

The 3-8" snow event with -AO at -3 wasn't part of the cold pattern? These next 2 rainstorms are frustrating. Supposingly, we are going to get well into the 50s both times. The Pacific pattern isn't bad for these storms. Gawx did research in the ENSO thread that showed, we have a chance at having the most DJF +PNA on record [CPC]. Out of non-Nino years, he says it will be the most +PNA DJF on record (going back to 1948). We all know how -PNA has been shutout pattern as of late, so it is a little concerning that DJF +PNA this year didn't produce more snow.. we aren't going to be so cold probably in future Winters.

AO sure is rising to positive pretty fast.. Maybe it's moving from -5 to 0 so fast that we will see a snowstorm around the 20th By the way, this pattern is in the N. Atlantic for the mean of the next 15 days.. When I rolled the February analogs ahead to March, they seemed to reverse.. notice the +AO/+NAO signal for March. Notice how the most +height anomalies in the N. Hemisphere are over the Azores.

Looks like about 1.5" here

Need it to hold when the storm moves east.. I still say the pattern is colder than average and above average precip, so snowstorm is probably high probability but a Gulf of Alaska low is not there, and 50/50 low is a little more progressive for when the storm arrives. There is more spacing between waves in the mid-latitudes, vs having it all slowed down. I don't think "coming out of -AO" produces the same snowstorm window as coming out of -NAO.. but I'm not 100% sure on that. I think -AO during the pattern favors snowstorms, but when you are rising up to neutral NAO from negative that has high major snowstorms correlation, especially with 50/50 low lingering.

Nice -5 AO rainstorm, 2 weeks from the coldest of the year, tomorrow. I still contest that 90N is too far north.. >95% of classic -AO cases were further south.

Here's 20 top analogs to the Atlantic/Arctic pattern

What do temps have to be for Kuchera to work? Looks like low 30s to me.. not even 1:10 probably.

They look +NAO to me. Just confirms that our best snowstorms happen with favorable Pacific and +NAO (that's why negative heading to neutral is so strong.. -NAO is actually a very dry pattern).

NAM has had the low near Detroit.. Gfs was much furth south. Still some spread, but fwiw the 0z Hrr looked like the 18z NAM.