Stormchaserchuck1

0z GEFS holds the -EPO, which is the colder solution.. https://ibb.co/Xy73Yf1

The Day 11-13 storm? Pacific is trending not as cold, a few days ago it was pretty different actually with strong -EPO/+PNA, now it's just a weak pattern on the models. A weaker pattern actually allows things to cut, but we could be looking at upper 20s snow vs 10s it was showing before. I think it will be an interesting bit of time here tracking it all.

This one has a perfect 50/50 low. Historical maps of our best snowfalls have the 50/50 low area almost as low of an anomaly as the actual storm (meaning it is super important)! I'd definitely watch NE of DC.

Really strong -NAO through Day 15 on todays 0z GFS.. The Pacific ridge is trying to retrograde at the end, but it looks like an active pattern under Polar ridging Usually -NAO's aren't so wet but they've acted differently for the last 11-12 years, with less suppression..

It's going to be hard for it to cut into a -NAO block. The Pacific isn't unfavorable.. I think the key is how cold it gets before hand. The pattern is still raging +NAO/+EPO right now so we'll have to see how this pattern change over the next few days goes. Worst case scenario, the -NAO is not as strong as currently projected.. Edit: We do already have -NAO today, I was a day or two ago. So the pattern change is already taking place.. gives more confidence to the solution. The H5 does let up a little during the storm, any trend towards a continuum is good, we have a good pattern on the front and back end.

I still like the Jan 6th storm. It has a ton of moisture in the Midwest, moving into a -NAO block and 50/50 low. Very unlikely it will split off in pieces like the GFS is showing, there will probably be at least a 1-2 day space between waves, or it may organize as the front end storm completely. In which case, it could be a decent thump of snow with the moisture Jan 5-6. Not really a strong -EPO pattern yet on Jan 5/6, which is usually associated with a lot of ice. 7-8 days to go. A lot will be worked out. I love snow that precedes colder periods. These have been more rare lately.

I had a lot of roll forward stuff that was showing a warm Winter. It was interesting when the Southern Hemisphere AAO hit -5 and had a record breaking streak of 3 weeks of -AAO from Aug-Sept. That S. Hemisphere factor rolled forward to a -AO Dec/Jan at a 0.35 correlation. Sometimes the methods just become too stale in a changing system.. after 8 years of the same, indexes like the PDO become a strong state, but all they are doing is reflecting the atmospheric conditions. They hit on consistency really hard, but when change comes something like all the roll forward N. Hemisphere indexes will miss it. They will be 7/7, until they are 7/8. That's why it's sometimes important to go beyond the very basic area of atmospheric circulation that is occurring in a closed system (northern hemisphere). Changes in the Sun this year could also possibly be a factor of why it went colder, I was talking earlier in the year about how we had a -H5 over Greenland 9 times this year, when we saw that pattern something like a total of 3 times in the last 4 years.

0z GFS ensembles further SW than the OP with Jan 6 storm threat. We have a good 50/50 low for this

I would say in the upper latitudes it's trending better for Jan 6th though on the GFS https://ibb.co/rpfk5jg

It has a big -NAO block over the top.

Usually ice storms occur in -EPO patterns. -EPO and +NAO. The pattern occurring is -NAO/+PNA dominate, which in January is usually snow or miss (at least DC north).

Week 3-4, the CPC went with below normal temps and above normal precip, getting near the coldest time of the year.

I like the pattern. GFS really went stronger -NAO this run. It's consistent - neg NAO over the top, +PNA, -EPO.. these are consistencies that aren't really going to change a lot between now and verification. The only thing to tweak is timing of waves, but for the 2nd day in row, it looks like an active jet during the cold time. It's not like the last few years where we have a -PNA or +EPO and medium/long range models just don't estimate the pattern correctly downstream (too cold). It has upper latitude support. I think the only question is if it will remain dry or become wet.

It looks like it's a legitimate cold pattern coming up. The state of the PNA really makes a big difference.

10/16 games Ravens have played so far have been against playoff teams. That is even after playing them, Ravens are 7-3 in those games. Cincy 2x not included. This is a good team.

The biggest snowstorms have a +PNA/Gulf of Alaska low pressure. But it is also an on-average drier pattern, so more variance.

That's kind of a small sample size though. We know that in +3-6 years we have twice as likely chance of El Nino vs La Nina, but the odds are a bit more even, if not slightly favoring cold ENSO, next year.

Medium range/long range models went much colder today. Big +PNA. Models like the Euro/GEM have been doing much better than the GFS.

Good post. I've been noticing how much subsurface anomalies have been dropping the past few weeks, we are back almost in Moderate Nina range. And the 30-day SOI recently hit +15, after not going above +6 all year. There are not many analogs of the SOI behaving like that. Could increase La Nina chances going into next year, should be interesting to see how it evolves. Events don't usually "start" in December like this.

I just can't believe how much the polar blocking weakened on 12z GFS ensembles, again today. That is a 3 days in a row. It's a weak signal now. In January, you can get some snow with many patterns, but we are talking like +150dm over the EPO and NAO regions. It's not a major cold signal, we only get a substantial trough in the east at 384hr, again.

Only 3 ensemble members show snow though. The mean average looks like that because the cold front passages skew it, when mixed with warm members. Compared to earlier today, the GEFS is not nearly as cold in the long range. Last night and this morning it had heavy troughs focused over the Northeast. Now it dives troughs into the West coast and progresses them into the Midwest. It's still not warm here, but I like that cold trough look much better. His panel is a snapshot, what we need is a sustained trough there. This was the case yesterday but not today lol

The 18z GFS is cutter after cutter. Polar blocking really weakened in the last 2 days, it's still there, but things are able to run underneath. It's starting to look like the longer range, after Jan 5th, is the better chance, maybe when the NAO is neutralizing after its bout to negative. Let's see if LR models (300+ hours) hold the -EPO in the next few days.

Polar blocking really lost steam on todays 12z GEFS. It's a weak signal in the long range. Last February the same thing happened, people were comparing to 95-96, but in those maps we have 200-300dm patterns, and what the long range models are showing is only 150-180dm right now. Allows other patterns to happen underneath of it. The NAO turning very negative right after the +EPO CONUS ridge now happens with a -PNA And although we still have -nao/-epo in the long range, this is a weak signal... oranges and light red. I would not be comparing to Jan 5th 1996, lol

brrr!

0z GFS ensembles still have it, but I'd watch for a trend away from Polar blocking tomorrow, as the GFS usually leads the way and that's the 2nd consecutive run showing it. 2 days from now we have a 4700sdm PV strengthening east of Greenland, and shortly after a strong +EPO, so when those patterns pass, long range modeling should be more reliable.