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Carvers Gap

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  1. Carvers Gap
    And continuing to look forward, some things I have seen in modeling just to review or add to: 1. The MJO generally looks like it will traverse the cold phases at low amplitude. 2. The CFSv2 is not enthused w/ cold until later in the month on about every-other-run. 3. Ensembles are a buffet of PNA and/or HB blocks w/ generally BN heights over the SE and E by Jan 8-10. We lose the Greenland block for some time. There are hints it may return. 4. Be happy you live on this side of the Apps in regards to cold and snow. If indeed this is the start to winter(and not the totality of winter as seen in 89), last week was a great start. 5. The Euro Weeklies (difficult to know if bias is in play there), takes the trough back northwest during the fourth week of January, and never looks back. That is plausible and is even in my winter forecast which I put out in June. I am not overly confident the Weeklies are correct there, but they could be. I tend to think the same pattern (cold builds in the Mountain West and spreads eastward) is the base pattern w/ a standing SER in the SE during the interludes.
  2. Carvers Gap
    PNA DRIVER? Moving the conversation forward. Afternoon modeling points towards an easterly displaced PNA ridge(almost a Plains ridge at times) which at times may hook into the HB block. It is not a great position for the PNA - need it back west just a tad. That said, I don't think modeling has this totally nailed down yet. If we were wanting to play the Nino card...the BN weakness over east w/ the PNA hooked into HL blocking looks almost textbook in the d10-15 EPS run. Will it have a source region for cold? TBD...and an important question to be answered moving forward. Of importance, our climatology begins to favor snow. There is less working against us. And sometimes....it just snows where it wants to snow regardless of the pattern. I have seen snow during warm patterns. And as we noted over the summer, Nina set-ups tend to favor middle and west TN. Does the waning Nina begin to release that grip and allow E TN snow? TBD...or Does Nina hang on and send the trough back to the northwest? TBD. Again, I like the 10-11 analog. Let's see if it still works in January.
  3. Carvers Gap
    Yeah, we posted the 10-11 analogs back in mid November in the December thread - nearly those exact images.
  4. Carvers Gap
    Yeah, it is just off in the weeds rounding back on the same points.
  5. Carvers Gap
    I am very aware of 09-10 and it is an anomaly re: December snow. You are missing the point. My point is that NAO blocking is effective as you just effectively proved. We normally don't get great NAO's early in the season and that conflicts directly w/ December's climatology in the eastern valley. One might make the case that December's climatology is actually not favorable for snow as blocking often develops later in winter. That might be why we don't have many 09-10 examples in the past 50 years. Snow is often just luck of the draw in regards to timing. The STJ, if I remember correctly, was more active during the cold snap of 09-10. Heck, the actual snow were got was terribly forecasted as many were caught on the road during rush hour. We entered this December in a drought. That is a pretty big difference. If the STJ had been active this December...different result.
  6. Carvers Gap
    Not necessarily. We had and HB block a few years ago, and maritime air flooded the continent. They can be really good re: storm track, but we have to have help from the Pacific or temps wash out. We got great benefits from the NAO - two snow events and record low temps. We are just going to have to disagree on that. I really don't want to go round and round on that anymore. There really is no disputing its benefits this month. Again, it doesn't want to snow in the forum area during December no matter what the set-up. That is the last I will discuss that as it is just beating a dead horse. The NAO brought near record cold, winter storms, and a great event to track for much of the country from the Rockies to the Apps.
  7. Carvers Gap
    Just digging through MJO plots this morning. Most, not all, try to rotate the MJO at low amplitude through the colder phases. There are cold outliers and very few warm outliers. That said, the models w/ the worst rotation through the MJO is the colder - GEFS. IF the MJO plots are correct, one would think some significant corrections to colder are upcoming. That said, the HB block is a thorn right now in some modeling. I have beaten that horse for days. It creates zonal flow. So, it is possible the MJO is about to lose influence, and we are about to enter a Wild West pattern where multiple teleconnections hold sway and forecasting is difficult. Short story: We are reaching prime climatology. The MJO is good. There are flies in the ointment, but when isn't there?
  8. Carvers Gap
    We continue to track a potential winter storm between the 7th and 10th. The GFS continues to show a storm during that time range. Last night, it went full Miller A. Previously, it has been a ULL moving through after a big storm. It has been on the GEFS for several days now. Interestingly, the CMC and Euro have similar evolutions at 0z...but their pattern transition and storm window is 48 hours-ish later. Notably, the EPS has a storm signal sliding across the Deep South just after the GFS does. My guess is the GFS/GEFS is too fast. However, big storms can/do form along cold outbreaks during January. We are about to enter our best climatology during the second and third weeks of January. For now, the GFS seems to favor a cutter and then a second storm on its heels which is further east. My preliminary guess is that storm would again favor middle and western areas of the forum. As we saw yesterday w/ the clipper, the eastern valley does best when cold is already in place. But we will see, it is a LONG way out there, and we are going to likely see multiple scenarios on modeling. One thing I am noticing is that there is a cluster of runs w/ very weak ridging out west. That has to be watched as noted above as that produces not so much cold here. What is interesting is that there is split flow found in most solutions re: how tall that ridge is. Split flow during January is normally playing w/ house money. There is also a cluster of solutions w/ a very powerful PNA ridge out West, and produces deep cold here. My guess is that we continue the same pattern as November. A period of warmth followed by cold temps - wash, rinse, repeat.
  9. Carvers Gap
    Robert, from WxSouth, had an interesting post on FB just a few minutes ago.
  10. Carvers Gap
    This model waffling reminds me of early December. Modeling at 12z and 18z seemed to be a little more aggressive w/ both the timeline and intensity of the cold. I just posted above(must have been at almost the exact same time you post this), the transition that the Euro control (notably WARM bias) sees from early Jan to the end of Jan. What I am looking for is whether the eastern trough can begin establishing around the 5th w/ likely a cutter. If it can hold, the dam may break and the PNA pops...and we hold a cold pattern for a bit. If the ridge can hold around the 5th, then we may be kicking the can. Good signs today. We will see what tomorrow brings. With models swinging so wildly right now, I have to think more cold is on the way into the Lower 48. Part of me thinks this is just going to be one of those winters that finds a way to stay cold. Fingers crossed. If that pattern holds, you would very likely see multiple bouts of snow. Is it right? Time will tell.
  11. Carvers Gap
    Food for thought....
  12. Carvers Gap
    Clippers often over perform when they follow big cold snaps. It also looked to me like you all caught some sort of jet max/streak(don’t know the official term) over the Central Valley.
  13. Carvers Gap
    I told ya’ll to watch this clipper. LOL
  14. Carvers Gap
    Winter Wx Advisories are posted for Northern Alabama.
  15. Carvers Gap
    Well, December wasn't done with us yet. Today, a clipper which was typical of the 80s winter cold shots....slid across TN(and really all of the forum area including MS) w/ light amounts. It even made it over the Plateau. In Kingsport the south side of town is getting decent amounts of light to moderate snow. The roads are covered. Many places in E TN received more snow with this than they did with the cold front a few days ago.
  16. Carvers Gap
    Ditto @tnweathernut, no SPV split for me either! The 18z GFS speeds up the transition back to cold. Instead of transitioning to cold between the 5th and 10th, it just flips cold(enough) on the 5th. That is now within the 10 day window.
  17. Carvers Gap
    Roads in Colonial Heights are a mess!!!! Moderate snow there.
  18. Carvers Gap
    Very fine, light snow is falling in west Kingsport - remnants of the clipper.
  19. Carvers Gap
    The Euro Weeklies are a mixed bag. The ensemble shows a window from Jan10-24th before the trough backs into the West for the foreseeable future. Oddly, the Weeklies keep temps at normal or just below even after the trough digs into the west. That tells me there is some variability in the pattern - meaning cold fronts push eastward at times. Honestly, it is a classic La Niña progression - and I am glad to be seeing the last winter of that front loaded winter progression!
  20. Carvers Gap
    12z comparisons EPS, GEFS, and GEPS. Some big differences exist. Scoreboard is 2 HB blocks vs 1 PNA ridge. I lean EPS. A storm signal is present from Jan7th-10th.
  21. Carvers Gap
    Here is how fluid long range forecasting is. The image on the right is 6z of the CFSv2. The image on the left is 12z(most recent) of the same time frame. It is possible that things are swing wildly like this due to cold wx about to enter the pattern. Still, this is why things are far from certain. I think the image on the left is likely as it matches its own MJO progression....but that is no slam dunk when the image on the right is only from 6 hours earlier. Also, as you can see, the PNA is either absent or weak. The colder solution occurs w/ HL blocking over Greenland.
  22. Carvers Gap
    The 12z GEFS, GEPS, and 6z CFSv2 show the Hudson Bay block as the primary driver and NOT the PNA ridge. I don't see that ridge being of any significant influence on LR modeling on todays runs. That could easily change at this range, and probably will. The HB block will work provided that it does not bridge to lower latitudes and form a ridge in the Plains. The GEFS and GEPS do like they allow enough space for colder Canadian(not Arctic air) to get infected into the pattern. The CFSv2 is maritime only. The opportunities we do have will be somewhat thread the needle if LR modeling is correct. I do want to see the Euro Weeklies as noted above....but they may not have the 12z trend away from the PNA. The pain in the neck right now the GOA low and Nina climatology which doesn't want to go to phase 8 of the MJO.. Those are the roots of the problem. Those GOA lows can take weeks to dislodge, but we will see. We are going to need the Atlantic to do what it did during this month...NAO block
  23. Carvers Gap
    I managed to make it through December w/ a trace of snow, but severely cold temps. I am beginning to wonder if this PNA ridge does NOT materialize or is too weak to be of any service. Remember the comment above when I was saying that modeling was waffling between a PNA ridge and/or HB blocking? It looks like the trend on today's modeling is for the HB block to hold. The positive is that we see plenty of storms w/ a good track. The negative is maritime air enters/stays in the pattern. There is very little ridging showing up in the LR in the West. Weeklies this evening will be interesting and needed. The lack of a -NAO is going to be a problem
  24. Carvers Gap
    Lesson from this week...don't sleep on clippers. Models definitely favored west TN. From this point to close out December, warming temps and then to January.
  25. Carvers Gap
    Any returns reaching the ground in Knoxville? It looks like it should be just judging by radar.
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