Carvers Gap

What a run of the 12z Euro just speaking from a 500 pattern perspective. If snow is on the ground, this is how record lows are broken. Below is a textbook, high latitude blocking pattern. As long as that cold air pool is sitting and spinning over Manitoba, Ontario, and Quebec....that trough will have a hard time being anywhere but the eastern half of North America. The trough will try to go west from Jan 22-24, but it "appears" there is a very strong Arctic air mass poised to descend well below the 49th parallel. IF THIS IS REAL, many boxes are check for a pattern which would support a winter storm(s) over eastern North America. Trough east of Hawaii, phase 8 MJO, EPO ridge, block over Alaska, -AO, -NAO, and western Europe trough. IF REAL, I would expect there would be a potential storm run an impressive temperature and pressure gradient between cold and warm air masses. That gradient would stretch southwest to northwest. That potential storm could could be a cutter, or over-running event(probable), or EC storm. But when you draw up a pattern for winter weather....this is it. I do NOT know if this will verify, but this look is present across modeling right now in some iteration or another. I pulled the apparent temperature map as this rolls through at 306. And you all know the rules at this range, especially when looking at detailed maps at range. But this is just wild and worth a share IMHO. Those real feel temps. One end of the state is 27 degrees AN, and the other end is 20 degrees BN. That would be an all timer in regards to cold fronts.

Great find. 6 inches of snow and 40mph winds. Wow! Not a good time to be above 5000'. Almost seems like a WSW is applicable at higher elevations for this one?

Yeah, man. Big ol' banana over the top in the medium and LR. EPO -> AO -> NAO.

And who knows if it is correct, but the 12z GFS does have some support from both ensembles and other deterministic runs...the 12z GFS does amplify the pattern after the 25th w/ very cold air getting trapped over NA...just look at the 500 heights. The 0z Euro just about went to the extreme. Big story for 240+(proceed at your own risk...) is the movement of very cold air into NA. Can it get to our latitude? I think it has a chance. Feel better, @John1122! Hopefully @Daniel Booneis on the mend. I haven't seen him post as much recently.

That 25th-28th timeframe does coincide w/ the MJO potentially trekking into phase 8. Yeah, I looked, but kind of felt like it might impact EC weather. With HL blocking in place, a phase 8-1-2-3 of the MJO circuit, and it being mid-winter....I have seen A LOT worse at this time of year from both teleconnections and modeling.

And the 12z GFS shows the risk around the 25th or just after. The 0z Euro was more of a cutter type of system...but both kind of slide across w/ very cold air just to the north. The 12z GEM likely got lost late in the run w/ the weird West Coast stuff that models have had all winter - and yes, the West Coast does get precip during winter, but maybe not quite like that. Models are going to struggle a little bit as very cold air is potentially going to get trapped around the 25th(see my recent posts on the matter). How far west that cold goes will depend on the strength of the SER in the East. If it drops into the central or eastern Plains, we likely would be in business.

The 25th on all models(since overnight) looks pretty ripe. Long gradient w/ multiple high pressures and no slp in the Great Lakes!

The 12z GEM deterministic looks even better IMHO. I think the GFS just looks suspiciously dry for the weekend and yes....the PAC connection. I am gonna have to see it to believe it. That said, there should be little disturbances moving along the polar jet. If we can get some interaction w/ the STJ, we would be in business. It won't take much. No idea if the 12z GEM is right, but you can see how quickly things can escalate if the front taps the Gulf.

Nice littler run by the 12z GEM on the 17th.

The 12z GFS w/ a nice look at 165, but......yep. We've seen that movie before.

The 0z Canadian Para is how I think this week unfolds. the 6z Euro does have a sneaky little system again along the Gulf for the weekend...if that were to back westward? I don't think it is overly realistic, but the GEM para has a second vortex, but it slides over the Tenn Valley. Multiple, light waves of snow in that cold air makes a lot of sense for the weekend.

That is what I called it for a long time...still do for this area.

I mean...you all realize that we are pulling off this cold shot while in phase 6 of the MJO according to the Bureau of Meteorology of Australia. And yes, as @GaWxnoted, there are phase 6 analogs which have cold. Pretty interesting forecast plot as well. But...see how tough it has been to model. It has been all over the place, and makes me wonder if modeling (which is too sensitive to the MJO) is struggling due to that? And yes, I finally broke down and used the actual Australian index. Haha!

The 18z AIFS Euro is just one cold wave after another for 360 hours. Again, my general premise is to get cold in place and let's roll. Next rule is to be willing to ride the gradient where cold and warm meet...there you will most likely find the storm track.

If we get the avocado, I think it snows.

What did they call it then? And yeah, awesome stuff right there. You walk out of the airport in Reno and can see the Sierra. We looped through Tahoe on the way to Mammoth this past summer. I cannot even imagine driving those passes in the snow.

I have already told my wife that I am gonna start chasing the atmospheric river in the Sierra Nevada or big storms in the East.

@Holston_River_Rambler and Co...I have a hard time believing this doesn't produce 1-2" of snow for anyone under that.

Kind of like ocean waves. Longer waves are kind of easy going. During the middle of winter the jet streams(polar and subtropical jet) have longer waves. As we get closer to spring, those waves tighten up and increase - amplitude and width between crests are closer. Like waves in a surfing set, there is less time from one set to another if the wavelengths tighten up, and it may even change the number in a set. Short wavelengths shake up the eroding winter pattern. Even during the worst of winters, short wavelengths can sometimes allow for winter storms. Those shorter wavelengths will often dislodge cold and produce unsettled, unstable weather. During February(sometimes end of January...might be seeing it even now), the wavelengths tighten up...I would guess the cause of that is due to warming temps and the slow retreat northward as days lengthen.

And we are still in a retrograding pattern at 500. Just watch the ridge. Every time a trough comes through, it pops back up further west. The EPO looks like it wants to hold, but when it gets pushed out....up goes the SER and then it retrogrades. Weeklies update for today....see the comment I just made. Seasonal to BN temps as base pattern but with warmth(some very warm days) embedded w/ those ridges. Retrograding ridges and troughs. I think we eventually see the TPV get trapped(have I said that prior?) under HL blocking. That is when the real fun and games might begin.

Just looking at the 12z EPS which can have a warm bias. First image is the d10-15 blend. NAO block, EPO ridge, AN heights over Alaska, trough east of Hawaii. That is a storm signal - Miller B or A or both. Below is the temp map for d10-15. Remember, if you want big winter storms, you have to be wiling to ride the boundary on an west to east gradient. Below is a single day snapshot so as not to wash out how cold it may get. This is January and below normal temps in January are cold. See the gradient? Single image at the end of the EPS. This is the 18z GFS at 288. This is generally what I think we are going to see occur. The pattern over the top supports it, and the MJO probably does as well. Blocking in the NAO, AO, and EPO/Alaska regions. This creates a gradient pattern, and that is my 1b "go to" pattern. 1a is an inland runner. I do think we see yet another ridge roll through after this....wash...rinse...repeat through February. But see how the cold descends into the Canadian Prairie. That is generally a good spot for us.

Cosgrove noted over the weekend that modeling is having a very difficult time w/ the MJO regions. In some cases, MJO region modeling is changing every 12 hours according to LC. I almost wonder if our wx models are too sensitive to that area now. I also wonder if there is an overall data or programming problem. It may well be that the severe cold seen in some areas of NA is also causing havoc. I wondered how cold western Canada had been. We have all seen the massively cold departures there. I read a report from a guy and his wife drove through through western Canada over Christmas on their way to the SE from Alaska. They were stuck for 3 days in a hotel while the cold and storms blew threw - froze the road solid. Their journey took 3 days longer than it usually did. So, I think cold like that really messes with modeling. Feedback on modeling this winter has been really bad. I am a huge believer in getting cold in place, and then let it rip. I do think we have cold opportunities upcoming after this week. As tnweathernut noted, that is far better than some years.

I don't want to jinx us too much, but yeah....far better than normal. The 12z ensembles are trying to pull off a really stellar pattern for later winter...EPO/PNA w/ blocking over the top. If that verifies, folks better hang on to their butts. It could get wild. I am still concerned (because I like my pipes) that it is very likely we trap a portion of the TPV and send it south. That mechanism is present on modeling for at least the next 16 days and another window in Feb.

I haven't even begun to read back through this thread - not sure I want to. Our washer is broken, so I have been at the laundromat. I would rather look at a phase 6 MJO all day than to have my washer out. Anyway, we can't be rookies in this forum. We know that sometime winter never comes, but we also know that sometimes it comes late. I think a lot of us have been conditioned to the idea that Feb is gonna be not so good due to recent Nina climatology. But....that isn't the case every year. In fact, most of us have had pretty decent winters of late, and don't make me pull out your climatology records to prove it! Haha. And trust me...you don't want to be the person who complains all winter about no snow only to be sitting on 5-10" of powder while others are watching it rain, and have had to read it all winter. So far, we have been awesome in that aspect. But go to the MA forum for references to that one. I thought the 500 pattern on the Weeklies was decent. I would have talked more about them yesterday, but didn't want to interfere w/ short term disco. There are good things happening in the LR IMHO. We also have to remember that models have been turning on a dime. Once that phase 8 potential gets ingested...could be a pretty drastic cold swing. Already, the ensembles are HONKING for more cold at 12z w/ no crazy, long-term chinooks in sight. I remain optimistic.

Ditto. The risk is that they jog north. I suspect they are under modeled. Besides, w/ phase 8 lurking after the 25th....I highly doubt this is our only window. I could make a pretty good case right now that we have a couple of really good windows in February.