Holston_River_Rambler

Maybe it counts anything right of the y axis as east, as if it was a compass. I would read it the same way you would, but honestly not sure.

EPS now looking a lot well at least better than the GEFS better in the +240 hour range.

Just noticed the GFS has been doing a weirdly regular flip flop, in 4/4 time Carvers, lol. I know, I know, its the GFS at long range, but interesting to see such a regular flip-flop in the same region every 6 hours. I know it shows different looks every time, but sometimes they can be wildly different. This is kind of a more regular flop. Seeing that here at 12z reminded me of a Masiello tweet: A lot depends on exactly where that TPV goes. But they're both cut offs, a cyclone and an anti-cyclone so there could be some more variability even on the EPS in the mid range. Looking at the 12z GFS (Sadly some skippage on this loop since Tropical Tidbits doesn't have all the frames): On the first 4 frames I've highlighted the cyclone and anticyclone Masiello is stalking about (if there are some people lurking/new) who are wondering what I'm talking about. It's like a pinball machine up there. If that main vorticity ends up being pushed somehow back to our side of the globe, the pattern looks a lot better. If not, not so much. Sometimes you see models explained like the Price is Right Plinko. This is like that, but with pin ball paddles added:

In the short term, this may be one of the best tracks for a nice storm for us in years, but alas, too warm: Good weekend for a fire now that the birds are out of my chimney, lol. Kuddos to a met in the SE forum, ILMRoss I think? Even as all the models were sending it out to sea, they warned that convective feedback was probably causing that and to wait until mesoscale range. But check out what the NAM is doing in central AL and MS at 850 mb: now 700mb: now 925 mb: I think there may be a few more surprises with this track as we get closer. Might amount to nothing more than a 37 degree rain vs a 40 degree rain, but I think this one will be fun to watch regardless. If we could get that low to track just right and come a bit further north, maybe some not so much higher elevations (maybe 2500' plus) in upper east TN, SW VA, and W NC might have some fun.

Agree 100% Just because NWP looks bad now, it may not in a few days. As Jeff has said "NWP can and does flip on a dime."

One thing that is interesting (and probably not good) that all ensembles are showing is the TPV almost exactly over the pole. Now, it is a smoothed ensemble mean, but not sure I can remember seeing that. Isn't it usually at least on one part of the N. Hemisphere or another? The above also seems to me to be the reason for the GEFS flop. It had been getting squeezed down toward Hudson's bay by Scandinavian ridging. That has totally evaporated in the GEFS, and I don't think the EPS ever had it. Looks like the evolution that is favored now is for the ridging at H5 above the bowling bowl we get to enjoy this weekend, is going into eastern Canada and never really leaves, even finally linking up with some Atlantic ridging and keeping the TPV at the pole. May have to root for a very +NAO for a time to break that ridge down to at least have the TPV a chance to come further south. That low over NE Asia really seems to want to help us with an EPO, but just can't with the main TPV right there. If this happens as the EPS suggests, it may be time to break the arks back out after last Feb. Doesn't look quite as bad as last Feb, but the jet is stuck nearby, extending into the Pacific, and it's January, so at least cooler air will be nearby too to create fronts. Lift from the jet and WCB thumps of moisture from 850mb jets = At least the EPS has a sense of humor about it, but its hard to tell with those dead soulless eyes:

I don't know, I felt like we did ok, earlier in the season when the convection was in the western Indian Ocean. Now the eastern IO has played not so nice, but if we're looking at the same thing, that convection looks west and to be moving more west. Wouldn't the western IO be phase 2? Still quite a bit over the Maritime Continent though: Another thought (apologies if I messing this up): is the western Indian Ocean also being impacted by the Rossby wave Jax was talking about a few days ago? If so, that flare up may be temporary as it moves westward. Agree that the GEFS has done a typical GEFS flop. Even the spaghetti plots from the18z don't see anything like the EPO from only 12 hours ago: I thought at first maybe it was seeing some new convection in the maritime continent: But the GEFS had about the same thing as above 24 hours ago when it was showing the better 500 mb look. EPS likes more western IO convection and then a gradual transition to western hemisphere convection. Trying to find the GEFS Hovmoller diagrams, but alas, I can't right now for a comparison to see if the way it sees the same variable has something to do with it's flop. Looking at the trend of the trend at 500 mb, looks like the GEFS has suddenly changed its mind on the NAO region as well, and that impacts the way it deals with the TPV in Canada, and that guides the flow over us:

It would be intersting to see a spaghetti plot for the EPS. Weathermodels has it for the tropical cyclones, but not like the GEFS ones for 500mb: I know most of you know what there are, but again, if you are new/ lurking, it shows three, 500 mb height levels as projected by each of the members of the GFS ensemble. You can see which members build that ridge and which ones don't. It's hard to tell which are which, but some have some cut offs rolling into the west coast. The mean also does like the idea of the Pac jet trying to undercut the ridge. Would be interesting on the EPS so you could see if even any members show that EPO ridge or not.

Some other folks quoted Eric Webb today in saying that the EPS has a hard time seeing EPO ridges. Maybe we split the difference, add a few days on to the GEFS, but end up with something like what the GEFS showed at 18z by early January: EPO, with a trough in the southwest slinging moisture at us, but also with a good cold air source?

Some rain/ snow mix here in Morgan County now.

FYI, this is partly me trying to work through things so there may be more explanation than many of y'all need or want. But I also did a little more since I remember reading this type of stuff as a lurker and having no idea what it all meant, so I wanted to try to give some of those folks some explanation too. Time to take a magical mystery tour of tropical convection: Western Hemisphere and Eastern Pacific: Western hemisphere looks quiet, but the eastern Pacific is The real action gets going across the western Pacific, the dreaded Maritime continent, and the eastern Indian Ocean to an extent: Western Indian Ocean (I was kinda liking the pattern when it was there), is looking rather anemic too: On the RMM plots* the above tropical convection state looks like this: *(I know many of you know what these are, but if you are new or lurking and wondering what an RMM plot means: "Wheeler and Hendon (2004) constructed the RMM index for monitoring the MJO. This index consists of the first two principal components (PCs) of OLR, 850-hPa zonal wind, and 200-hPa zonal wind averaged 15S-15N". -definition taken from https://ncics.org/portfolio/monitor/mjo/rmm/ ) Why does tropical convection matter for the TN Valley you might ask. Well, where that convection thrives, it helps shape the jet to the north of it. JMA website(https://ds.data.jma.go.jp/tcc/tcc/products/clisys/anim/anim_tp.html) has a nice way to visualize this: The above is the 30 day average. You can see most of the tropical forcing, indicated by the blue colors (less OLR), at least the average over the last 30 days, has been over the Indian Ocean Dipole (IOD). Those little magenta? arrows indicate where the air is moving at the jet level, 200 mb. Masiello had a good tweet illustrating this a while back: Experience last year tells me that Maritime Continent convection and uplift usually means a strong Pacific jet aimed at the west coast of North America. Sure enough, for now, The Euro (RMM plot forecast above) sees the jet being pretty strong over the mid latitudes of east Asia, just north of where it sees the convection. You can even see a little bulge in that jet as the convections pushes on it. North of the equator, there are a few spots that have warmer than normal SSTs: Still looks like there is something of an Indian Ocean Dipole (warmer in the west, cooler in the east), some warmish waters around the Maritime Continent, and the fabled Western Pacific Warm Pool (WPWP, took me forever to figure out that abbreviation). I'm guessing the warmer waters around Hawaii and in the Gulf of Alaska, are probably not triggering much convection. Those should be the favored areas for convection, at least over the ocean. One problem that we have in eastern N. America is that it is not always possible to get good convection in the same ways in more favorable areas, since S. America and Africa are landmasses and can't have sea surface anomalies. That doesn't mean they can't have convection, but I'm not sure you could get a standing IODish wave in the Amazon, since sea surface temps are always going to be more stable than land temps. I think this may be why those MJO correlation maps, are always much more sure about what a phase 7, for example, correlates to in the west than the eastern US (purples mean more confidence, source https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/Composites/Temperature/readme.shtml): There is much more confidence that a phase 6 = warm eastern US, than a phase 1 = cooler than normal eastern US. Another way to look at tropical convection is velocity potential (labelled chi) at 200 mb. Currently most of the above, is where you would expect: Source for the above: http://mikeventrice.weebly.com/tropical-waves.html But the Euro Control thinks we may have convection once again strengthen into the western Indian Ocean: But the above is only one half of the equation. Go back and look at the EPS's depiction of the jet towards the end of its run. Notice the ridge trying to build into the arctic north of Alaska. You can visualize that another way: At 500 mb in the North Pacific you can see the tropospheric PV in two parts here. One over Northern North America and the other over Siberia. The piece over Siberia acts like a wall and a pitcher. It acts like a wall in that it stops the progress of the energy and air the convection to its south is pushing north and also throws little bowling balls of energy at the west cast of North America. It's like you create a funnel that forces air to move more quickly and then spins off a few blobs of vorticity as ridging attacks it. You get a few attempts to build a ridge into Alaska, but the TPV that's over North America keeps them supressed while the TPV over Siberia twirls any that make it, back around it as the ridging is shredded by the two. If you travelled on this mystery tour further up into the atmosphere, you'd arrive at a the Stratospheric Polar Vortex (duh...duh....DUHHHHH) looking a little wobbly at the bottom, but stout higher up. But let's dissect it a bit more. A cross section reveals that the whole SPV is sort of titled to favor Eurasia with its presence. If I'm reading this map correctly, the purple core is the main SPV. But wait, there is also a core of cooler temps from the bottom up over North America. I think what we see here are the connections both 500mb PVs have to the much higher stratospheric PV. Below you can see how this looks on a more recognizable map. The reds are above average temp anomalies at 10 mb. You can also see those on the above image as the reds and yellows in the upper right, while the greens and blues below are in the negative numbers in that cone I outlined in purple. The little bit of yellow and red above is what's left of the energy transport that gave us the -NAO. Subtle changes are all we need to get something better and the EPS shows some of that this AM: Waaayyyy too much interaction now between the two TPVs I mentioned. Not only does it keep ridging out of Alaska and western North America, but it also helps reinforce the Pac jet. I do think it is interesting that there are still some attempts, anytime one of the two TPVs wobble, to shoot some ridging into Alaska. Maybe that is a base state we have seen so far this winter trying to take the reins? GEFS agrees that there will be some separation. The real question now for me though, is: are there any actual clues in any of the real time observations above, that this could happen? After all, I think we are all on the same page this winter regarding models, even ensembles beyond 5 days or so, lol. In the less than fantasy range GEFS likes the idea of more convection in the western Indian Ocean which could help change up the jet configuration: and the EPS likes it too: But even if those changes happen, you still have to jet them percolate downstream to us, so like Carvers has been saying, maybe 3 weeks at best, assuming things do change upstream. To me, after last year and for a pattern change if the Pac jet is bad, tropical convection is like the first lane of traffic if you are trying to turn into the second. You have to have it be clear there, before you can even think about turning across the highway. Now that doesn't guarantee that the other lane (N. Hemisphere blocking) will be clear, but you aren't going anywhere until that first lane clears. Hopefully some subtle shifts can pay dividends down the road. And we definitely have going for us that even when the convection gets over the Maritime Continent, it has never looked as robust as it did last year. I feel like I've laid out the status quo pretty well, but maybe not done so well on analysis and forecast. i also maybe just wanted to give us a bunch of disparate pictures that might help visualize the current pattern at several different levels, to maybe help see a way out. Please add any and all things you think would help what I have here.

The cell over my area right now means business. Loudest thunder, heaviest rain, and most lightning of the night. Headed your way John.

Nothing like what's happened further south, but some very vivid lightning on the plateau as I drove in from Knoxville.

I know, I know.... About half way through making that the notion did enter my head. Oh well, back to EPS drams...I mean dreams

Radar looks healthy over the south:

EPS a little more interested than of late in the 22nd's possibilities with that upper low. Blunderstorm and anyone in extreme NE TN might have a shot: I think it's probably a 0 sum game with this one. It'll either knock it out of the park, or nada. Hopefully a fun one, either way.

Do not watch the following gifs if you have a neurological condition that may be triggered by flashes ...... ...... ...... ..... ...... .... .... .... ..... ..... .... All may not be lost!! W must summon baby yoda to attack the stratosphere, but only at 50 mb: Then the great one will percolate down to the surface, yea yes and verily creating HL blocking on his way, and at length, he shall reign in Siberia: There he shall create snow cover and forsooth this snow cover shall create a great high that shall descend into China and shall even force a +MT event and extend the jet BUT....what about the MJO you might ask?? well baby yoda has ~1,000,000,000 midichlorians and can impact both the stratosphere and the tropics at the same time!!! Baby yoda is like last year's SSWe, but better All convection shall be forced into the dateline and coupled with the pac jet extension that must undercut the high latitude blocking, we shall reap the rewards DO OR DO NOT. THERE IS NO TRY.

Happy hour gives us not ONE but TWO rainy bowling balls from the price of one!!!! Can't beat it with a stick, lol.

This Dec. 22 possibility is interesting for eastern areas and esp. those at higher elevations there. Don't think any model has it nailed down yet of course, but everything now seems to like the idea of a big cutoff upper low. Could bring someone a Christmas surprise? For my location right now it looks like 35 and rain, lol, but even with that a big storm near Christmas would be fun to watch develop. Happy hour GFS gets the job done for TRI though. The EPS has the moisture, but is not nearly as enthused about frozen as the GFS or GEFS, for even a place like Holston Mountain: But to be fair to GOOFUSv3, the Euro is now conceding that there could at least be an upper low. Kinda almost reminds me of a spring-type cut off upper low.

Pretty good convection flare up in the 7/8 regions to go along with that in the Eastern Indian Ocean. Still some in over Indonesia, but definitely looking a lot more spread out there. SOI down to -11 and if the above trend continues, it may continue to drop. Davis Strait ridge in NAM range now! Will be interesting to see how or even if models adjust once that develops and if we can get that convection into the Western Hemisphere

Poking around the Mid Atlantic forum and found this from someone who works with the models, I think... "Version 15.1 of the GFS officially became operational on June 12th of this year. It has a 13 km horizontal resolution and 64 layers. Data are assimilated at a 25 km resolution. Version 14 was retired on September 30. A minor change was made to the GFS in early November. It is now assimilating additional data sets including information from GOES-17. Version 12 of the GEFS is scheduled to become operational in August 2020. It will have the same dynamical core as version 15 of the GFS and its resolution will increase from 40- to 25-km and will include 31 members as opposed to the current 21. The system will be run 4 times per day with the 00 UT run being 35 days in length and the other runs 16 days in length. Apparently, the ensemble system has skill out to 10.4 days versus 9.8 for the current system with 2-3 hours of the additional skill due to the additional ensemble members. The next version of the GFS (version 16) is scheduled to become operational in January 2021. It is in the pre-operational stage now but has been frozen. It should have 127 levels compared to the current 64 and has bias fixes including (hopefully) one for the lower tropospheric cold -bias. Not sure what the fix is. Version 13 of the GEFS is scheduled to become operational in FY2023. It should be a "fully" coupled system that includes an ocean model, a wave model, an aerosol model etc. "

Happy hour GFS shows how to do post frontal snow right:

It's got a 1062 high at the end of its 6z run!

Tropical convection around the globe definitely looks CODish this AM with slight emphasis in MJO regions 4/5/6. To be fair, I've not been checking it a ton since we've had a few tracking events, but there seem to have been a few periods where there was really only convection in one area. Every area has a bit this AM. GEFS really wants to take that tropical forcing to the Western Hemisphere in the long range: EPS supports the status quo: IOD, according to Eric Webb's post on wxtwiter is weakening: and he thinks this will open the door for more western Pacific tropical forcing as time goes on. I guess we'll see how it develops but like I said above, interesting to see convection everywhere for now. Some of you may remember NCHailstorm had a good record with the MJO last year. That person is posting in the SE Fall thread and has been pretty good so far too using the sun and solar wind to diagnose what tropical convections will be doing. Of course in the medium range as Masiello noted yesterday there is going to be a cyclonic wave break in the 50/50 location that is going to create a -NAO. I know many of you know what this means, but if you're new and are like "what the &^%$#%^& is he going on about" The storms break (I guess this means they gain as much latitude as they can without weakening??) and pull up higher heights toward the arctic. Look at the circle and arrows This leads to higher heights over the Davis Straights. Exactly where those higher heights, the "blocking," the -NAO, develop determines the storm track (as tnweathernut posted yesterday), it can force energy south of us, which is what we want if we want snow. Looks like the GFS is trying to bring a lobe or the tropospheric PV south of Hudson's Bay, but it is the GFS, so who knows, lol. I wish I had access to the Euro forecast trend maps, but I don't think weathermodels has those. One thing I'm really trying to figure out now is how all this works together. How does tropical forcing AND its results or independent processes in the N Hemisphere work together to create our patterns? Writing about it helps me think about it, so sorry if I don't have any more concrete predictions. I've got a ways to go on that, lol. I'm just happy there is no sign of last year's endless MJO clsuter%^$*

Check out the 500 mb heights anomaly flip on the Euro: above to below in a matter of days, not sure I've ever seen a flip like that