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Isotherm

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  1. Re the insect discourse, Mosquito barrier works great, for both mosquito and tick control. It's entirely natural -- garlic water mixture. No environmental damage done. It's a deterrent to them. http://www.mosquitobarrier.com/?gclid=Cj0KCQjwuZDtBRDvARIsAPXFx3BUlDkEMSoFgAkNeSWNGnsVVKlrmTJH3JBPW00pM0usmv1muP9jpWMaAsqrEALw_wcB
  2. I was considering editing that into my commentary after I posted it, as one of the key variables that the 60s had superior to the past 20 years, was the frequency of white Christmas occurrences. So, I agree with that. The technical, numerical values re total snowfall can sometimes be deceptive. Certain winters seem snowy in the data, but the actual feel of the season was not wintry; I consider 17-18 to fit this bill. There's much more appeal to a mid Dec-mid Jan protracted cold period with snow on the ground and 30" total for the season than a year with 50" and much of that accumulating and melting in late winter.
  3. Although the 1960s were cold almost every winter, and snowy in the means, many [not you] often falsely refer to these putative 'old fashioned winters' in a nostalgic sense, indicating that they were snowier than present times. The past 20 years, since 2000 approximately, has featured the snowiest period probably since the last protracted solar minimum of the late 1800s-early 1900s. My decadal snowfall average for the 1960s [per the records] was 34.1", while my average for 2010-2020 thus far [per my records] is 38.7". Even if the upcoming winter is a complete non-event, this decade will finish even snowier than 2000-2010 for me, which was 33.8". Our long term snowfall averages have increased noticeably. It's likely due in part to increased water vapor via the background warming, and potentially altering storm tracks. So while it's generally been much milder the past 20 years versus the 1960s, it's actually been snowier. I can count on my one hand the number of truly sub normal winters since 2000 here --- last winter, 2011-12, 2007-08, 2006-07, 2001-02. There were many winters that I'd qualify as not very good, but managed to scrape our way to near normal snowfall over the past 20 years. It will be interesting to observe how and if the paradigm progresses heading into the new decade. I have my personal thoughts based upon various indicators, but will save that for another discussion.
  4. David @Bring Back 1962-63. Here's the global temperature anomaly map employing 1980-2010 as the base period -- as you noted, one can see significantly cooler anomalies. The warmer anomalies were located in the critical areas to force troughing in the E US and W Europe.
  5. Great discourse in this thread by all. In the spirit of continued constructive point/counter-point, I would simply like to add the following. Zac's [ @Snowy Hibbo ] proposition above, in his winter forecast; namely, for the genesis of predominate propensity for blocking under background conditions of low/suppressed AAM, is a supportable proposition as well. In the macro-scale, an overall deficit of angular momentum in the global system is not always an inimical factor, counter to induction of blocking action centers. Here are a couple of examples. See 1962-63, which featured quite suppressed AAM, proxy of which is this GWO plot. Seemingly paradoxically, the year featured one of the most negative NAO winters on record. NAO: 1962 0.61 0.55 -2.47 0.99 -0.10 0.16 -2.47 0.14 -0.37 0.41 -0.23 -1.32 1963 -2.12 -0.96 -0.43 -1.35 2.16 -0.43 -0.77 -0.64 1.79 0.94 -1.27 -1.92 2008-09: There are actually many other examples, too, of low AAM in the means, in the 1960s/early 70s in concert w/ blocking propensity. Exactly how the angular momentum is transported through the Earth system is pertinent; sometimes easterly momentum is deposited in auspicious spatial domains, suitable for blocking, and sometimes it isn't. Furthermore, often, there may be a superseding factor that countermands the block-mitigating effect of suppressed AAM. There are reasons why 1962-63 turned out the way it did, blocking wise. My only point is that each year must be investigated and examined in and of itself, in light of the totality of indicators. A low AAM background state might be destructive, but in certain cases, it may not be, depending upon other factors and how the momentum is transferred and deposited throughout the global system. Edit: Note that I don't disagree with the remarks made above by either Tams or James, but can also see an alternative interpretation.
  6. Yes, absolutely, Ray. Was implied but agree, definitely an important point to convey as well.
  7. I should clarify this so as not to confuse: what I'm referring to here is deep, tropical convective initiation. Convection can occur in the mid-latitudes with SSTs well under 28C, but in the tropics, for deep, tropical convection to develop, the type of convection that induces high altitude towers sufficient to mediate rossby wave dispersion, requires near 28C. The 28C temperature is also necessary to charge the boundary layer with moist static energy which can sustain deep convection. See the following: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1999GL900197
  8. It's b/c the ambient SST threshold for convective initiation is circa 28C, so alterations of +/- 1-2C will be very material as to the spatial and temporal distribution of convective forcing. Conversely, +3c or -3c SSTA anomalies in higher latitude zones don't have the same effect on convective forcing, since the ambient sea surface temperatures are lower. This is part in parcel for why I've always impugned others' assertions that warmer than normal water south of Greenland or south of Alaska can actually drive a pattern [edit: feedback on the pattern can occur though]. 49 degree water versus 42 degree water is thermodynamically immaterial. But 80 degree water versus 87 degree water is material.
  9. Tropical stratospheric temperatures [z30] continue to rise exponentially from their record lows. As a function of which, the intraseasonal-MJO signal disintegrates in the week 2-3 period. However, with continued well below normal tropical stratospheric temperatures, convection should remain prevalent in the tropical spatial domain, though, influenced in location by the +QBO. Momentum budget continues to be redolent of a paradigm felicitous for retrogressive features, through the medium term at least.
  10. The cool down is unimpressive, IMO. Only when juxtaposed with the recent week's heat does it seem more dramatic; however, average first frosts are nearing for most of NNJ in suburbia. As far as drought, my local area is still fine, due the excessive rains we received this past summer.
  11. To supplement Greg's answer above, it's a lot of trial and error. I've been doing this for 13 years, and over that time period, a significant amount of refinement occurred regarding the prioritization of indicators; identification of novel indicators; usage of analogs, etc. The only way one determines the relative importance of a particular indicator is by observing, season after season, the empirical data, and the resultant z500/surface evolution. It becomes an acquired skill, and I've found that there's a poor way and a good way to employ analogs. Like you mentioned, often times we have novel physical forcing permutations such that it's virtually impossible to find "excellent" level analogs. What to do then? Well, without revealing the secret sauce ( ), it takes some inference based upon anticipated physical drivers, i.e., "I expect that a mean z500 ridge will be positioned approximately here, given these factors." It's what makes long range forecasting so enjoyable: always difficult/challenging, and there is no unequivocal quantification for the weighting scheme. It really is part "Art" and tinkering with what seems to work best. That said, I do use a heavy quantification aspect in looking at the data, and developing formulas, but the end game of weighting is more variable/heterogeneous based upon the particular year.
  12. Station indicates a high of 93F for my area today. Today was the hottest October day I can ever remember. There have been memorable days in the mid-upper 80s, but they had a much more "summer in autumn" type feel. Today, to me, was indistinguishable from mid July, if I didn't have a calendar handy.
  13. Great analysis and write-up, @OHweather. Very nice discussion of the apposite factors.
  14. Very nice write-up, @Snowy Hibbo. I enjoyed the read. Good luck with verification. Is this a preliminary outlook or do you expect it's your final?
  15. Splendid analysis replete with salient points, @Bring Back 1962-63. I agree with your conclusions; hopefully a rapid refreeze occurs -- if not, another poor winter may set the stage for a grim outcome next summer.
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