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Armando S

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Armando S last won the day on October 11

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  1. Superb analysis @brooklynwx99 and posts today as one who is aware of the content he posts expects no less! Not much to further add, but finally having the time to take a look hemispherically (from a synoptic perspective), I find the upcoming subjective period (12-18 -- 12-23) being discussed a really interesting one; as exciting as it may appear given the tracking perspective, I find it just as interesting these "mini" periods amidst a "sea" of not as a "jackpot" , slam dunk, base-state regarding GLAAM (keep in mind Tom's and Tamara's posts), *BUT*, it doesn't mean you can't have certain periods of meridional patterns. Anyhow, its been discussed, but it's these transient waves emanating from the tropics/E.A. (function of dual-modes of competing tropical variability with large amounst of LHR), where these aforementioned waves can be "missed" in NWP. It's going to certainly be active, and you throw in these synoptic waves that result in rossby-wavebreaking (Anticyclonic wave break over the pacific in the ECM DT loop -- paper i've referenced earlier a while back shown were a consistency of a poleward displaced PJ with ACWB and is seen several days later having a CWB sequence --> -NAO), which can render these ephemeral anticyclones poleward into the higher latitudes. I've decided to show this very case with the ECM 500mb heights via a neat illustration (may not be as robust verbatim, but nonetheless, "just for fun" to show and has some merit); black circle = TPV, White pentagon shape = an interesting s/w that breaks off and actually breaks cyclonically downstream --> poleward ridge into Greenland, and the yellow square to illustrate the induced, poleward AC that actually cuts-off from the mean flow and propagates westward. You can even see how gorgeous of an illustration it's via DT loop (so sexy lol), but *IF* we can manage a setup as such verbatim (still lead-time for this to alter), the fact that this process of PAC ACWB --TPV descends into NA --> N. All CWB.... ooof.
  2. Thus far, my area has come away with probably just around 2-2.5" (no bonafide measurement, just local reports and eyeballing). Overall, not much has to be added given the catching up across this thread, but for those who ended up reaping the benefit of mesoscale banding, congrats. Others.... well, always next storm .... the one thing - and it's something i never take for granted, is the fact that with my present state of being a student in the field, I have the privilege to learn from storms such as these! Not just that, but being able to dissect, observe, and analyze the "what went wrong" aspect and/or other generic things like geography for example, has truly bolstered my knowledge and awareness so that it betters myself, and those on here as well! This forum goes without saying, but it's just one big happy digital family (with some exceptions of some posters... lol). Radar trends appear to finally fill in via mid-level H5 low finally allocating towards and within the vicinity of Delmarva. Few more hours of snow with lateral banding now easing in intensity, therefore, more snowfall can now reach the ground spatially.
  3. Over the next few hours, once the lower and mid-level lows allocate towards south of Mason-Dixon into Delmarva, that radar will quickly “light up”.
  4. Cross section using H7 VV. We'll see some sloping of frontogenesis with height as well. NAM 3KM showing plenty of lift below and into the DGZ. We'll see the DGZ grow especially under best dynamics. evolution from tomorrow morning into evening (added 0z tues frame so 7pm)
  5. Currently sleet mix with some rain here (NENJ). Check out the H9-H5 mesoscale banding from today’s 12z NAM. You’ll start to see it all of a suddenly manifest after ~16z tomorrow. There is even a bit of hinting at a doubled-structure F-gen circulation attempt if you look around 20-22z especially. Some CSI may even be released given forcing for ascent, saturation, and synoptic evolution of the mid-level low (look to the N and NW of the SLP). Mesoscale banding will surprise many where some overperform and we, vice-versa (aka “woah the sun is out over here”).
  6. Non wx nor storm related, but a sincere Happy Thanksgiving to you all! Pat and Geoff, i’m so grateful to you guys and appreciate what you’ve done for me and just so happy to be apart of this SENSATIONAL forum with WONDERFUL members!! Wx-related: NWP when looking at the dewpoints Sat. night, they’ve remained fairly consistent *prior* to WAA and isentropic uplift. Despite eroding of low level cold and downstream confluence, watch that frontogenesis-circulation suprise some (especially interior).
  7. So i've been watching the medium-long range, and i've taken into account the MJO biases and corrections. The GEFS (NCEP RMM) had it erroneously traverse back into phase 8-1, while the EMON/EMOM (EPS medium ensemble suite) has had the RMM phase diagrams propagate the forcing through the Indian Ocean, albeit low amplitude given the constructive interference with the antecedent low-frequency +IOD signal. Take a look at the last several runs of the GEFS. Since we know that NWP takes into account many physical components and fluid dynamics - including tropical convection diagnosis, it's no coincidence that we've seen a correction to a lower amplified, evinced suppressed NE Pac. anticyclone/EPO. In fact, the GEPS has even shifted towards a lower amplitude NE PAC rex block (which also can be coined as such). The EPS? It has remained rather consistent and I also included that last 3 runs just to make a point. Now, it's *not* to say this won't impart a downstream response of polar high's given the anticyclonic flow regardless upstream, it's just the discrepancy we see of how much of +GPH's manifests into the EPO domain. This does, however, make a difference in terms of timing with what appears to be a stormy/unsettled beginning to December, it's just the overall trend and mid-level flow isn't as propitious as what may it have looked last week (i.e. broader downstream trough) in conjunction with a transitioning NAO. Check out the split-flow on the GFS, which is focused on end of month into the first week of December. Few things to note; if timed (which the premise of this post is that the entire flow will be more of a synoptic progressive/semi-progressive pattern) right, this could render an interesting window (~5th-9th?), stronger Atlantic jet (indicative of -NAO diminution), and towards the end we see the Pacific flow influence; this is to likely render the moderation period and consistent with IO forcing/lag composites into ~week 3 (post early Dec). I think we have a legit shot for something early December, but it turns likely unfavorably for a bit thereafter, which appears to be collectively agreed upon.
  8. (Despite what may deem as negative; time the synoptic rossby-wave progression, you can still may things work in "tight windows"... we'll see )
  9. I'm mildly intrigued for the next storm window. In short, this is a classic case of an "in-situ" -NAO development with a precursor via the poleward shifted Pacific jet ("This calculation indicates that the Pacific storm track is shifted equatorward (poleward) prior to the onset of the positive (negative) NAO phase between 160°E–140°W. This result suggests that meridional fluctuations in the latitude of the Pacific storm track may play a role for triggering the NAO" - Franzke, C., S. Lee, and S.B. Feldstein, 2004). This is from a paper regarding wave breaking and developing -NAO's. However, what's most prominent in this case is this short sequential classic cyclonic wave break event right into Greenland just prior to this storm manifestation (also found consistent with that aforementioned paper). Also adding the evolution and eventual retraction of the state of the Pacific jet throughout the week leading up to it. Do we get enough net meridional component to the waveguide to allow this come together? This has a chance and well, some support via MJO.
  10. @brooklynwx99 awesome post! Speaking of next week, I'm mildly intrigued by the upstream processes and events on both synoptic and kinematic scale; The 18z GEFS below shown and annotated, is a gif of the last 6 runs. No need to post the EPS because it's very similar (to an extent, even the GEPS), but what the premise of this trend is to show is the net meridional component to the waveguide. Not only is the ridge more potent along the west coast, but its altered wavelength is that of a positively tilted anticyclone. The importance or rather significance of this verbatim, is that you increase anti-cyclogenesis, downstream you can lengthen the amplitude of the long wave trough; therefore, harboring vorticity and allowing a baroclinic zone to actually retrograde a bit west. It'd be counterintuitive to think the positively tilted trough = progressive synoptic pattern (true), but in this case you could theoretically allow an ana-frontal circumstance to manifest and usher in differential advection out ahead of the positively tilted trough (from that harboring of vorticity, therefore rendering DCVA downstream). Also, this event indeed does have "legs". Circled below is essentially, our coherent MJO wave and a robust one (almost nearly 2 SD's). It's no coincidence that NWP, such as the GEFS i'm showing, as corrected to an amplified synoptic permutation. Note even the negatively tilted trough located in the western Bering Sea, which diabatically "pumps" heights downstream over Alaska and into BC. . Prior to early next week, we also have a series of rossby wave breaking (CWB) with a gorgeous cyclonic wave break just before, and this we can thank a favorably timed MJO. Again, this supports potent ridging and inducing an "eye-opening" downstream evolution (with the baroclinc zone also established prior). We'll see where this goes, but nice to be posting about winter weather and it only being November.
  11. Source region = key for when we can get downstream propagation (e.g. building highs) via upstream processes I'd say it's a nice start to open up November with just a mere observation.
  12. It’s a topic still relatively “young”, but i’ll allow you and others interpret it plus, it’s also a relatively small sample size with a non-trivial correlation. @Analog96, yes 77-78.
  13. I’m surprised no one has posted Sam Lilo’s MQI phase (QBO averaged within the strat). Not only 95-96, but 78 and 02 as well heading into its Easterly phase and downwelling. However, regarding last year’s QBO structure heading into December; the premise behind why the SPV was weakening drastically and rendered unstable was because below ~45mb, easterlies were present. Above, the westerly +U was present and emerging while downwelling, therefore, the SPV became highly susceptible to wave activity flux and perturbations. So it was that transition that allowed a feedback to manifest, where we saw the stratosphere warm robustly -> Troposphere lapse rates increased/ambient environment cooled -> tropical forcing sustained in the “Nina” phases keeping the MJO and convection active with persistent net -AAM torques. This time around we have the actual opposite QBO structure and from an objective standpoint; it predisposes a more favorable “receptive” troposphere from analogs and research in conjunction with an interesting solar min aggregate study from Dr. Crawford coined “black sheep theory”. It pertains to the NAO and the influence solar min. years has, but more so the lag component. This winter, as some have mentioned has conflicting signals, should still turn out interesting given all that I’m seeing.
  14. Nicely done! If you know your r-value, do you mind sharing what it was (i.e. how strongly positive was it?). Just to add, the PMM along a normal distribution curve falls in the upper quartile (Q3 = >75%) translating to ~ >2 standard deviations above the mean in not only just for all SEPT. values, but also all monthly values dating back to 1950. That is a robust stat.
  15. The discussion regarding the IOD and the low frequency waves with constructive/destructive interference were fantastic and that got me doing some research. I wanted to see what the -VP in the upper height field this year from Jul1st to Oct 1st from last year, and this year (comes up short of Oct given the lag delay of data being added to NCEP reanalysis). I compared the SST's as well. What continues to stick out to me is the concentration and spatial orientation of the warm anomaly's; both surface and 150m depth, averaged 4-month progression (underneath). Notice that stripe of +SST's east of Asia, but longitudinally there is a smoothed anomaly, compared to that of this year with more of a "blob" depiction and confined. The striking aspect really, is the -VP field; there is a wavenumber 2 pattern evident with a max west of the dateline as well from last year. This persisted into the ensuing winter, a -AAM base-state followed, and a downwelling +QBO/transitioning phase situation manifested. This all led to an early SSWE in December, and that all rendered a feedback loop where the troposphere-stratospheric pathways resulted in an unfavorable synoptic-scale rossby wave train with a tenacious Nina tropical forcing paradigm from Dec into Feb. This year? Vastly different. Not only do we see more concentration of warmer Eq. SST's (thermocline as well via subsurface) towards the C.Pac, but that -VP field resembles more of a +ENSO/modoki-esque structure. As formidable the rising max is, note the sinking branch across the MC this year. Simply put, despite the -AAM/Nina GWO structure currently with sub-tropical ridges across the Mid-latitudes (remember we had this last year, but later in autumn and continued), the ocean's spatial pattern IMO at this stage, is propitious to establish a more favorable coupling. The other reason is the +IOD. (Note the differences in the subsurface between this and last year. More off-equator warmth and especially towards the W.Pac compared to this year - right). These are all the +IOD years since 1960 when reliable records began.To the left is the Pac. basin and to the right is a view of what the -VP was across the Asian continent and IO. Notice the similarities from this composite of years, to this year since July (which makes sense given what a typical +IOD VP field would look like) and also to add, we've hit now the 3rd strongest IOD event since 1981. Here is the difference, again to last year of the IO to support my statements. Why do I keep bringing up last year? It's because the disconnect of GSDM proxies seem similar, but different spatial circumstances regarding anomalies. Maintaining this +IOD and the SSTA composite across the Pacific right now - relative to last year is hard to not like in the very least. All the above implies keeping the tropical signal in the “favorable” phases, or actively consistent bearing any drastic change. If you throw in the QBO state and its negative downwelling combined with a very low solar MIN year (even lower than last year), preliminary speaking (also mere speculation from this point), I'll admit I like where we stand to setup the next several months.
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