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Isotherm

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Posts posted by Isotherm

  1. 88 and 89 the past two days here. My DVP2 is fan-aspirated and sunlit all day, but the very rural setting typically keeps my summer highs similar to Central Park.

    The 46-day ECMWF weekly mean temperature anomaly, which runs out through second week of August, is around +2. The pattern implied would be very warm overall with spasmodic cool-downs. Lower dew points in the means as expected this summer.

  2. 15 minutes ago, SACRUS said:

    Between the rain and cooler week days the weekends have been mostly very nice since Memorial Day and today is shaping up to be one of the nicest.

    Sunny an 80 here.

     

    Believe THu - Fri /Sat (6/27-29) finally offer a shot at widespread 90s and the first for many. 

     

    Models a bit more split now  on next weekend and fourth of July week so more to come as we progress through this week.  

     

     

    Concur. 850mb temperatures would be supportive of upper 80s/90F three or potentially four days in the coming week. The warmer spots will probably hit 90F.

  3. 1 hour ago, SnoSki14 said:

    Except that the blocking is more than residual, June may set another 500mb record for blocking at this rate. 

    Can things drastically change by July, definitely, but I've got a feeling this current pattern isn't going anywhere.

    And to be clear we're still technically AN right now, so the only thing that's being kept at bay is the high heat maxes.

     

    1. The definition of, "residual" is remaining; it's not a qualifier for the magnitude of the blocking that was anticipated. There can be residual, strong blocking.

    2. Ok. Possibly, but without meteorological reasoning it is difficult to entertain your conclusion and have a higher level discourse. 

    3. Yes. I realize this. My forecast was +1 June.

     

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  4. Extracted from my summer outlook; just as an FYI for anyone who thinks the present pattern is antithetical to some forecasters' expectations:

     

    The coolest of the three meteorological summer months relative to normal should be June...Residual high latitude blocking may persist for much of June, permitting more frequent trough amplification events in the northern tier of the United States."

     

    So, the overall hot summer idea is not in jeopardy with the present pattern. The spasmodic cool-shots in June were expected from my standpoint. 

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  5. On 5/26/2019 at 5:40 PM, CIK62 said:

    Isn't it taken for granted that any 3-month (seasonal forecast) will come in AN a disproportionate number of times, like weighted dice?      The average age of all Top Ten Coolest Summers [NYC] is about 120 years.     For all the Top Ten Warmest, the age is about 35 years!    I am guessing this extends all the way down/up  the line in both cases.

    It appears sagacious to say nothing, unless you really have evidence for BN.

    Did you consider the Stratospheric Warming which is affecting southern latitudes too, as of late?    Weaker  SE Ridge a possible outcome here.

    I am hoping for short-term heatwaves of three or fewer days duration.     Your 26, 90-degree days implies at least one 5/6+stretch, I would bet.

     

     

    The background state is certainly a not insignificant factor inculcated in the overall long range forecast equation, from my standpoint. 

  6. 5 hours ago, Roger Smith said:

    I came to very similar conclusions from a different research perspective (summary posted in whatever we call the main forum, I call it the Quiet Zone). 

    Would not be surprised if there is some exceptional heat at some point in July or August as you seem to be implying. 

    Good luck with your forecast, if you're right, I'm right. 

     

     

    Thanks, Roger, and I concur, [while the language was qualified somewhat due to long range precautions] I saw some distinct signals for potential major heat. Good luck with your forecast as well. 

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  7. 1 hour ago, Ji said:
    1 hour ago, frd said:
    in regards to the NAO 
    From Isotherm courtesy 33andrain  
    This is closer. On the 12z ECMWF, we see an equatorward cyclonic wave-breaking attempt which pumps heights northwestward toward Greenland. We'll see what the EPS depicts, but if the Euro continued past 240 hours, one would want to see this CWB progress farther east, thus detaching the Greenland height/action center from the Azores sub-tropical high. It's almost there. The sensible weather effects with PNA coupling wouldn't be until after the 25th.
     
    r92vz8.png&key=860140de07f9e8770666cb3fc37d7f3f1f909d2c853581a4716e0d673f4aaacd

    Isotherm is brilliant but he has been wrong on almost everything this year

     

     

    It's an observation, not a forecast. I'm merely analyzing what could happen, and delineating possibilities. I said what needs to occur in order for the pattern to improve, not that I necessarily believed it would definitively occur. There are multiple ways this can evolve, one of which is a continuation of blocking-fail.

  8. 1 hour ago, raindancewx said:

    I think what I said in November more or less held up pretty well. The Fall being completely opposite to 1963-64 held through winter. It was warmer than average in the NE/Plains/MW in December, February is cold in the West to date, and the east is warm to date. The December blend of 2009/2015 for the Plains/NE/MW with Nino 4 SSTs basically matched exactly. If 1963-64 was the guideline, you'd have had a cold NE in Dec and Feb, both look warm, and Feb looks very cold in the West actually, instead of warm like in 1964 (outside NM where it was much colder in 1964). 

    It's not that I assign much value to US Temps themselves, I just thought from the temperature differences that 1963-64 must have had a completely different MJO progression than this year. My thinking was that the MJO was in phases 3-4-5-6 at high amplitude in Oct/Nov in 1963 and that's how the US had near record heat, and then it moved into 7-8-1 in December, which is why it was so cold. We were mostly in 1-2-3 or null in Oct/Nov. 

     

    Can you provide a link to your nationwide winter forecast, with departures forecasted Dec, Jan, Feb? I don't recall seeing your formal winter forecast for the country. 

  9. 49 minutes ago, 40/70 Benchmark said:

    The last man standing has folded.

     

    Ray, while that is effectively my prepared post-mortem, I do think there's still a chance the last few weeks of winter produce a good pattern, but that will be contingent upon scouring out the -AAM in the sub-tropics [finally erasing the sub-tropical ridges], to allow the jet to cut underneath in the Atlantic, so a bonafide NAO develops. We should see some PNA improvements in the last week of this month.

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  10. 1 hour ago, nzucker said:

    Tom,

    Great thoughts. I also think a major factor in the lack of significant winter weather (aside from the polar vortex and 2F low in NYC) is the location of the +ENSO event. Many were expecting a west-based El Niño/Modoki look like 09-10 or 57-58 (just weaker). That didn't come to pass as the Niño was basin-wide. I think that had a major impact on the lack of Nor'easters and unfavorable MJO pattern as it's largely SSTAs that determine tropical convection cycles, along with AAM as you mentioned.

    As the warmth in Region 1.2 has evaporated and cooler SSTs have emerged to the south, we now have a more Modoki look. I wonder if that's the reason for the more favorable pattern showing up on the models.

     

    Thanks, Nate. I did see some warning signs in the autumn, but November reversed toward a more high AAM/Nino-esque forcing state, coupled w/ NAO ignition, which tended to countermand my earlier thoughts. Overall, November's ephemeral flux of Nino-esque conditions proved to be a bit of a pretense, and a Nina-esque type forcing regime entered the picture in December. 

     

    47 minutes ago, 40/70 Benchmark said:

    @Isotherm.....1979-80 is the season that you are referring to. I noted the similarity QBO wise, but dismissed it.

    I don't think 1969 was a bad analog, but the blocking just didn't materialize, which is what saved that winter in February.

    Thanks.

    @raindancewx had the best call that I have seen this season...I'd be interested in his thoughts on this on what you have laid out...

     

    Ray, was referring to 2001-02 and 1994-95, the only two years since the late 1970s in which we had a +QBO at the 30mb level and -QBO at the 50mb level. It's something, with the benefit of hindsight, that I did not believe would be deleterious pre-season, but I think it has; of course, among other factors as well, like the basin-wide Nino, the off-equator warmth in the west Pacific enhancing poor MJO phases, the SSW as well, etc. Fortunately, my last winter miss was a long time ago [early part of the decade] and hopefully the next miss won't occur for a long time. Significant lessons derived this year.

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  11. 5 minutes ago, psuhoffman said:

    Thanks... What do you think is the main cause of the SE ridge and inability to get a PNA ridge on guidance despite -soi and MJO phase 8?  Error or time to admit its just not happening this year, even if we finally get the pacific forcing right?

     

    The atmosphere is behaving much more akin to neutral ENSO rather than El Nino this winter, so I would discard the z500 composites for MJO/Ninos evincing the favorability in the p7-8 transition. However, once we're into the core of phase 8 in a couple of days, with strengthening near 8/1 threshold, that effect will manifest with the typical circa 7 day lag. So I expect guidance will finally trend more favorable with the PNA ridging after about February 22nd or so. The MJO wave is more slow-moving and amplified than usual as well, so the effects are enhanced as far as Western trough. Typical MJO progression is faster, but this has been the winter of interference from other tropical waves. Like I said, that post wasn't a total post mortem, and hopefully it will become abstract, especially for you all in the MA who are nearing normal already.

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  12. 4 minutes ago, frd said:

    Seems when you look at the QBO for this winter we have a rare occurence. First time I heard of this combination taking place. @Isotherm was talking about things this morning.

    He states there are several things at play in regards to why we have not seen the typical responses including the blocking.

    I  brought over this section from his detailed update over , since we had touched on the QBO earlier. 

    His entire post covers a lot more, and is over at 33andrain.   

     

    He states :  

    <<<

     

     Finally, this particular QBO permutation (similar to this year) has only occurred two times since the late 1970s, namely, a +QBO descending at 30mb while the easterly -QBO at 50mb maintained. Those two years were nina like, with amplified intra-seasonal signals. One of those winters was one of the worst winters on record snowfall wise in our local area. 

     

    >>>>

     

     

    Frd - my full post is over on my winter outlook thread on the main board here as well, if anyone is interested.

    Re: those specific years - yes, extremely rare permutation. The only two years like this one as far the QBO dichotomy since the late 70s were: 1994-95, and 2001-02. Both of which were quite appalling snowfall wise. Obviously, no year is like, but those similarities in Pacific systemic issues and failed propagation / high magnitude tropospheric blocking were there. Again, there's a chance for a late-game save, but enough has happened to warrant a re-analysis of the widespread miscalculations, in my view, by everyone. The Pacific was the principal problem (AO will finished slightly negative, NAO probably near neutral/slightly pos); stronger blocking could have countervailed. Reasons are expounded in my post on the main board thread.

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  13. Winter 2018-19: A Re-analysis

     

    Science is all about advancement, usually due to anomalies that emerge spontaneously in any given dataset. Most scientific advancement occurs not as a function of status quo, but because something atypical, aberrant has arisen in any given field, and the scientists who are independently minded (and financed) enough to pursue those anomalies, are generally the ones who pioneer and "break ground."

     

    Before I get into this, just as a disclaimer: it is still entirely possible that there's a "late-game comeback" with respect to this winter, but, it is apparent enough to me at this point, that the winter deserves/warrants a re-analysis post of sorts, regardless of how we finish over the next month, which may or may not ameliorate the widespread busts of this winter. 

     

    Over the past few weeks, I've used some time to investigate, and believe I have a cogent hypothesis regarding the failings of this winter. In retrospect, I am rather disappointed in myself, being one who tries to be as meticulous as possible in research, that I missed this; however, it's easier to say such in hindsight, and I may not have detected this, but for the miscalculations of this winter.

     

    We had quite a bit of +AAM in the atmosphere this winter, but I think to some extent, in not exactly the "right" places, to induce the necessary countervailing easterlies in the high latitudes. The lack of FT cooperation courtesy of the meager Nino forcing was a major factor, which would have produced more sub-tropical westerlies / +AAM, initiate the STJ, form sub-tropical TROUGHS, and thereby weaken the polar jet. We have had a lot of sub-tropical RIDGES this winter, more La Nina like. 

     

    I do strongly believe the issues with respect to this winter's failures goes even deeper. Retrospectively, the tropical forcing pattern during much of autumn 2018 more closely resembled a La Nina, w/ subsidence large-scale over the Pacific, and more uplift over the Indian Ocean. This did attempt to flip somewhat in November, which is partially what led me down the putative rabbit's hole, prior to reversing back toward a Nina-esque tropical forcing regime in December. This was an aberration year in which November's regime certainly did not augur the mean winter pattern.

     

    Additionally, the positive 30mb QBO hurt us and destructively interfered more than anyone thought in my opinion. We were expecting that the -50mb QBO, which has high correlation to SSW events (that truly helped!) would countervail. Unfortunately, yes, the negative 50mb QBO produced a SSW, but it also tends to intensify the MJO/intraseasonal signal.

     

    Along that vein, I actually think this winter was too UNSTABLE in a number of ways. The MJO simply did not cease: constant propagation from amplified phase to phase, obviating any stable PNA or cold pattern from becoming locked in, compared to winters in which we stabilize in the colder MJO Nino phases. The negative 50mb QBO and thereafter the massive SSW only aided further to augment the incessant MJO signal.

     

    Then, the 30mb QBO, which I now think is really more important than the 50mb QBO, aided in stabilizing the tropospheric polar vortex, and decreasing the very necessary tropospheric receptivity to blocking. The unpropitious 30mb QBO, the negative 50mb QBO induced intraseasonal amplification, unstable MJO, and Nina-esque forcing, precluding FT cooperation, sub-tropical +AAM, sub-tropical troughs, and polar easterlies -- were all the factors in my opinion.

     

    Furthermore, the negative 50mb QBO, coupled with the cooling tropical stratosphere as a function of the major SSW event (I have noted this before), and the abnormally warm off-equator SST's in the West Pacific, aided in expanded hadley cells, poleward / retraction of the northern stream, yielding a less amplified, more disconnected, Nina-esque type of paradigm. Further, the very cold tropical stratosphere led to a convective disarray, much like a low-cap T-storm day, wherein destructive interference from rossby waves, and MJO amplification in the warm phases was frequent. 

     

    The NAO has been trying to go negative this season, evincing pretty positive geopotential heights over Greenland, but the Azores/sub-tropical high never departed, which has kept the NAO calculation technically slightly positive thus far. I think that's Nina-forcing and QBO induced largely. Notice in the below composite, and you'll see even on model data going forward, we try to achieve the higher heights in Greenland, but it doesn't DISCONNECT and DETACH from the Azores sub-tropical high, thus, Europe remains mild, rather than the classic undercutting jet -NAO signal.

     

    f57k9x.jpg

     

     

    Regarding the AAM point; this is a highly unpropitious / unfavorable diagram right now, if you're looking for high latitude blocking of significance. +AAM in the wrong places. The belt of easterly/-AAM deposits in the sub-tropics tends to induce more nina-esque sub-tropical ridges, and indirectly, intensify the polar jet, tending to countermand sustained blocking.

     

    http://gsdmsolutions.com/~gsdm/clim/daily_total/glaam.sig.90day.gif

    nfjwcj.gif

     

    That needs to alter for any major blocking to occur.

     

    Finally, this particular QBO permutation (similar to this year) has only occurred two times since the late 1970s, namely, a +QBO descending at 30mb while the easterly -QBO at 50mb maintained. Those two years were nina like, with amplified intra-seasonal signals. One of those winters was one of the worst winters on record snowfall wise in our local area. 

     

    Now, with all that being said, these are hypotheses, and correlations, with arguably debatable causation chains, but evidence of causality in meteorology is quite difficult as it's nearly impossibly to control for confounders and isolate the pertinent variables. Nevertheless, I am satisfied with re-analyzing this winter, and I will certainly not make this particular mistake again.

     

    A short summary of the problems: The Pacific was the largest problem; stronger blocking would have countervailed, but that wasn't the principal issue. The AO will average slightly negative for the winter, and the NAO probably near neutral to slightly positive. It was the pacific - due to reasons expounded above, and secondarily, the lack of more effective blocking, intraseasonal amplification / hadley cell expansion, due to the SSW and QBO as well as SSTA profile.

     

    As far as the remainder of this winter: the WWB looks good, as does the MJO propagation, but will the atmosphere respond? Or will the Nina-esque tendencies w/ atypical AAM distribution, and dichotomous QBO keep the blocking muted? That seems to be what models are currently indicating.

     

    Like I said, there is a chance for a late-game "save," and then, hopefully, all of the above will simply be good, abstract discussion regarding my take-aways going forward. On the other hand, if there isn't a late game save, the above is effectively a post-mortem on the issues underpinning (in my opinion) this winter's miscalculations by virtually everyone if not everyone in the meteorological community this winter.

     

    Thanks for reading.

     

    Tom

     

    A short summary of the problems: The Pacific was the largest problem; stronger blocking would have countervailed, but that wasn't the principal issue. The AO will average slightly negative for the winter, and the NAO probably near neutral to slightly positive. It was the pacific - due to reasons expounded above, and secondarily, the lack of more effective blocking, intraseasonal amplification / hadley cell expansion, due to the SSW and QBO as well as SSTA profile.

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  14. 1 hour ago, frd said:

    he thinks we might be going into a new NAO era.. I can only hope. 

     

     

    We are, at least in the means. My NAO formula which has 87% success indicated pre-season this would be a transitional year with a weakly negative NAO. We should continue trending in a more negative direction [in the means] prospectively.

    Note: the variance you see model wise is entirely MJO related. Again, VPM / z200 VP is most instructive. 

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  15. 34 minutes ago, 40/70 Benchmark said:

    He said the GFS was dead wrong. Saving his outlook? Stop being an idiot and accusing him of bias. If you want to dispute it, fine...have at it. This crap brings nothing to the table.

     

    Thanks, Ray. This is precisely what drives good posters away from the board. My track record regarding numerous warm winter and cold winter hits should lend credence to my objectivity. Rather than merely sitting back and inputting little value to discourse  I commend those who actually take the time to critically analyze the pros and cons of a pattern. Re: the MJO, it's not as if this hasn't happened heretofore. The tropical wave contaminating effects on the GFS have been recurring; the euro more accurately detects the true MJO signal. If I think winter's over, I will say so unequivocally. It is unfortunate that virtually everywhere in the Midwest and East have scored save for the PHL to BOS corridor. Patterns much worse have produced. The transient windows of Pacific favorability have been the primary flaw. We'll see going forward. I've said enough. 

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