Carvers Gap

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.

MJO phases 1-2-3 centered on JFM are cold. The Weeklies yesterday were not warm. I have looked at them, and I looked at them again to be sure.

The 12z GEM sure makes the most sense given the cold which is incoming. Lots of small waves.

That is how I am rolling as well. Time of day does not help us with the first system.

That makes a lot of sense. I would suspect we may not know how strong that is until maybe even "go time." Tricky forecast w/ some upside as you note. We just don't want that to jog north at the last minute. Otherwise, that looks spot on.

I would suspect the event for the 17th-18th may well have some high ratios as BigBald noted. I actually like the 0z GEM-para look for that event IF that cold air is legit.

The 6z Euro has removed the 0z run Gulf event - weird run...plausible, but out of nowhere it came and back to nowhere it went.. It probably serves as a reminder that large scale, last minute changes are still possible as we get better NA data of those vortices(when they approach and make NA landfall). Looks like two minor events this week w/ "potentially" the coldest air of the season arriving the 19th-20th. Then we (maybe?) roll a ridge through, and the potential is there for another deepening of the eastern trough beginning sometime around or shortly after the 25th. I think we see a big dog before this winter is over....provided the cold air incursions continue. The tough thing w/ an EPO ridge patterns is that sometimes the ridge gets too tall like it did in 17-18(think that is the right year), gets very cold, but precip has trouble getting into the pattern. Ultimately, I think the main snow culprit is ongoing drought which is a thorn with La Nina patterns at times - and this is currently a textbook, QBO La Nina pattern. However, I think this winter is far from over at this point. The EPO ridge looks like it may well have some staying power. As we hit February, shortening wavelengths and a weakening La Nina should break the drought. Of note, Cosgrove notes the La Nina is moderate...and that is no bueno for eastern winters. SST anomalies depict La Nina for sure. The positive is that the Nina should rapidly weaken according to him and Webber. Good and bad -> One thing to watch w/ clippers and cold fronts. They can often strengthen a bit on modeling as we approach the event, and they will often lift north at the last second - buyer beware.

I don't trust the MJO plots right now. I quit using them about three weeks ago(roughly). I do think there are about to be some good things happen in the phase 8 region though, and that might be a legit signal - I hope. February in phase 8-1-2 would be crazy good. So far(fingers crossed) Feb looks like it is going to be a winter month this year....the Nina should begin to retreat to weaker levels by then. A weak Nina in February w/ a negative QBO is usually a great combo. I think what is driving the bus right now is the EPO (NAO component possible), and until it relents...going to assume blocking trumps the rest.

Even though that last storm is highly doubtful on the 18z GFS and because there is really a pause for a bit until the next models roll....that storm is a great example of a vortex coming into central or SoCal and causing a winter storm here, ie the Los Angeles rain rule. The GFS does seem intent on building a glacier in the Apps for sure. Prob isn't right, but lets see if the Euro AIFS has a hint of a storm around the 24-25th. Ensembles have keyed on that timeframe of late. Gonna be a fun clown map for the full run nonetheless.

And somehow, the GFS goes from that crazy northwest low to a SE winter storm...just like that. What a wild model. It is DGEX level right now after 150 on most runs.

It is everywhere right now, man. Hope you don't have it, but if you do...hope you feel better fast. Some great anti-virals out there right now - probably the only silver lining if you can call it that.

I think the thing to watch for is energy diving into the back of the trough around the 17th. The 500 Geopotential maps look ripe for mischief on the GEFS. I tossed the GFS as soon as it started to transfer energy from Calgary to Seattle - same deal where it tries to connect to energy 400 miles to the west and not realistic.