Isotherm

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About Isotherm

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    Veritas Vos Liberabit
  • Birthday 09/24/1990

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    http://www.lightinthestorm.com/

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    Colts Neck, NJ

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  1. The recent MJO, FT/MT mediated momentum surge and concomitant high-GWO orbit should at least mediate the semi-persistent AK-GOAK low height anomaly --> wave 1 induction --> convergence/pressure onto the SPV. So, the material weakening of the SPV in mid February is likely more genuine than many of the GEFS plots have depicted this winter heretofore. As the stratospheric status begins to improve mid February onward, I am monitoring the next cycle of tropical wave propagation toward the Central Pacific as we reach the last week of February. At which time, better tropical--->stratospheric receptivity could mediate a more favorable pattern than we've seen to date, from approximately late February into March. Speculative/a priori, but as stated, there are signs that end of winter could feature an "improved pattern." Until late Feb, yes, I think RNA-type structure after a very marginal window in early Feb. As mentioned in my update a week or so ago, the pattern in Feb, while still favoring the interior (RNA structure) will probably offer more chances than Dec-Jan. Still watching late Feb-Mar [somewhat lower confidence speculation for now, but it's something to monitor].
  2. This is a very confused communication of statistics. In statistics, a normal distribution includes 68% of the observations falling within 1 standard deviation of the mean. However, Bluewave was specifically employing the term, "climate normal" which signifies an average over a given time frame. https://scied.ucar.edu/blog/what’s-new-climate-normal The average snowfall for the given time period in question was as he stated. So, I fail to see the issue with his post.
  3. @frd, I have read that research to which you refer, and believe it to hold value. There is a documented lagged-oceanic forcing, part of feedback cycle with the atmosphere. The interesting aspect about the NAO, as to why it is such a difficult 'beast' to forecast is its highly multifactorial nature. Unlike the PNA for example, which can be primarily forced by MJO or tropical Pacific disruptions, the NAO is forced by way of many disparate variables. That being said, there are propensities and correlations that can aid us in prognostication. Certainly, solar forcing is involved. As I believed I may have mentioned here before, there is a tendency for increased -NAO episodes immediately following the solar minimum point. Conversely, the years immediately preceding a solar minimum are often more +NAO slanted. This is not always the case but the tendency is quite noticeable. So, along those lines, yes, from a statistical and also physical forcing perspective, I think we will probably enter a period in which 2 or potentially 3 years out of the next 6 feature a -NAO in the means.
  4. In the spirit of self-reflection/verification, I simply wanted to inject my two-cents, in that the primary issue here, AAM/MJO wise, is the partitioning of momentum predominantly into the S Hemisphere. I cited and broached this issue on January 3rd, in reference to last year's distorted MJO-7-8 response in late winter. As it turned out, this year's response wasn't too dissimilar. So it was very much foreseeable from my standpoint. Note on the MJO u-div and also the convection cross-section, the preponderance of the momentum is directed southward. Additionally, the anomalous AAM spike is a function, partially of the MJO-tropical component, but also the intense frictional and mountain torque production. But note the partitioning of that torque activity; again, principally in the southern hemisphere. This is therefore insufficient as it pertains to the induction of material stratospheric - and by extension - tropospheric vortex deceleration/diminution. As such, the resultant z500 is a distorted conglomeration of Nino-esque and Nina-esque features in the northern hemisphere.
  5. And yes, I also agree with your point, @psuhoffman, regarding the altered base state, i.e., negative PDO structure, SSTA distortion in the WPAC, and this was certainly a variable in my winter outlook as well. When the waters are warmer in the macro-scale sense, the typical canonical weak Nino/neutral composites become much less meaningful. The jet flow is disrupted, hadley cells expand, among other things.
  6. Thanks for the kind words re: my forecast. And Frd, that is correct. The window of opportunity would probably arise later February forward. As said, no guarantees, but certain variables may ameliorate by then. Re, the NAO. It now appears almost a lock that the Dec-Jan-Feb mean NAO modality will average positive [in fact, per CPC data, I don't believe we have had more than 1-3 -NAO days since December 1st]. This will bring my formula to 90% exactly as far as the success/verification rate utilizing the years 1950-2019. As I've said prior, the formula is multifactorial. And yes, to PSU's note, the AAM periodicity/fluctuations is certainly involved in the formula, along with other variables. I had contemplated publishing a paper on the formula, but I'd like several more years of observing its performance.
  7. Unfortunately, the continental USA will be devoid of polar air during the time-frame of greatest PNA amplitude. So, even conducive storm tracks could imply rain rather than snow for the I-95 corridor. Due to the fact that we are at the climatological height of winter, marginal airmasses can potentially work for interior areas.
  8. Same: only 18.8F, which is fairly incredible when one considers my average lows are in the lower 20s. We've made it through 20 days of January and have not see an overnight low more than a couple degrees sub-normal.
  9. Yes, I agree with your post here and the others recently. Regarding the putative canonical Nino-look and seasonable temps in the South, that doesn't necessarily imply favorable pattern for snow in the Northeast I-95 corridor. Classical Ninos are typically seasonable temperature wise across the southern tier of the CONUS due to frequent clouds and precipitation. For example, see 97-98, which wasn't a torch for the southern half of the country, but it certainly wasn't snowy for our region. Similar look with 1982-83.
  10. Thanks, Chris. And great explanation above as well. Another factor supporting the notion of potentially a better window of opportunity late Feb-Mar is the wavelength alterations. The shorter wavelengths in late winter-March can often render than base state -PDO/-PNA less influential. I do not have the data in front of me, but I would wager to assert that a proportionally higher % of snow events in March featured a -PNA compared to Dec-Jan-Feb. @uncle W may have those statistics. Until late February, we may continue to battle this unpropitious base state.
  11. Likely because the skill scores are substantially lower. The EPS bias in our region was negligible in the recent 11-15, while conversely, the GEFS bias was significant.
  12. Well - it's something. 1.0" total here. IP/ZR now. 28F.
  13. I think we will probably diminish some of the warm anomalies (potentially materially) over the N Rockies and Upper Mid-west with a more genuine RNA structure in much of February. But we'll see how the rest of the winter progresses. I did have northern Arizona and most of New Mexico, including your area, near normal temperatures for the DJF departure. So that may verify.
  14. Surface southerly winds inland from the coast will be light through late afternoon: Temperatures rise during the evening on stronger southerlies:
  15. 23.2/2F here. This is a good resource for water temperatures. Readings presently around 46F near Sandy Hook, hence why light southerly winds are desired, and those on the immediate shoreline will have difficulty accumulating more than a trace to 0.5". http://www.fishtrack.com/fishing-charts/northeast-us_61130