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Armando S

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  1. Absolutely ripping +SN and as @brooklynwx99 mentioned regarding cooling within the vertical; the rates increasing as a function of that mixing line maximizing ascent and therefore, cooling the column and keeping that line at "bay". We'll see how far north it makes it up, but then again, it also serves to really incite strong lift just poleward. Thank goodness for that Nova Scotia Sea Ice... or else we'd be absolutely screwed!
  2. Developing 850mb frontogenetical circulation and maturing rather quickly. This process via ageostrophic processes will establish your rapid cooling within the vertical column from surface up towards base of DGZ. Check out that robust LLJ gradient yielding speed convergence only helping to magnify this process as we head into this evening. Right on the “nose” of it. We’ll see some immense rates right within that “battle zone” and see sudden flips to snow.
  3. Check out the Nam’s 850/700 vorticity; certainly a shift in the depiction of 850mb vort as it essentially closes off further south thus allowing an advantage for stronger baroclinicity to occur and more dynamical cooling aloft via omega and upper level divergence via upper level jet streak. H7 verbatim has even shifted further south and west with a more cyclonic curvature indication. Insane low level f-gen circulation as well.
  4. Yes, @CCB! basically hit the nail right on the head. You have with what appears, to be a drastic and notable shift in not only thermodynamic structure, but kinematic "playing field". Below is the NAM wet bulb temps with a noticeable cyclonic circulation off the delmarva, and along this thermal boundary (dividing line), you have 1. DPVA and some mid-level deepening aiding in noticeable curvature offshore in a diffluent pattern 2. increasing theta-e gradient 3. ostensible vertical velocity (700mb) between ~ 6z - 9z Friday night/Sat... Going to catch people off-guard most certainly beginning with tomorrow morning's event...
  5. I believe this fully, and am not surprised by this trend if you look at the last several runs of the NAM 3km/12km with respect to the f-gen circulation intensity/magnitude. You can even see the responsive sinking via 700mb T. adv. Really no shortage of CVA either currently occurring in conjunction with robust QG-forcing (moisture/warm advection) streaming from South/Gulf area. So far, i'm liking what i'm seeing for the areas that have been shafted since Nov. I mean, look at this upper level jet with tons of ageostrophic flow and general embodiment of the south. It's this UPJ that will enhance your surface/ageostrophic flow, and looking at real-time obs, it's hard to not like what is unfolding.
  6. @Isotherm Thank you! To answer your question, no - here is the link. Indeed they're very useful! Enjoy http://ds.data.jma.go.jp/tcc/tcc/products/clisys/mjo/composite.html
  7. @Isotherm wonderful post as always! Going over just some data today being that guidance, especially 12z in the long range displayed with what'd be verbatim - an actually conducive h5 pattern - atypical of what we've seen thus far for a stretch. I began to check some of the "governing" facets that may or may not make those depictions true. Sure enough, it appears as you've already stated, that across the 30N belt, we're beginning to see a diminished depiction of net easterlies (sub-tropical highs - not what we want for NE cold/snow prospects) in conjunction with net westerlies (added momentum) seen at the 40-55N belt (impedes mid-latitude anticyclones from fully propagating poleward into subpolar/arctic domains, therefore, limiting any amplification and continuing the same theme). With apparent cross-equator rossby wave dispersion and interaction (MJO), favorably placed -VP, OLR, u850/200 current with lagging, it just makes sense to see something like what 12z NWP printed out today, post 25th. Even checking out the SOI index, we can see the net negative values accumulating in intervals and via this graph below shows its significance of a southward drop, relative to the timeframe seen as well (back to mid Jan). For one, i've seen some of the organic methods to a > -20 point drop, and there is some merit for sure, towards positioning the mean trough towards the East with an equator-ward adjusted STJ, therefore and hopefully, imparting net easterlies above 40N. Interestingly enough, if you take an EOF composite here that blends the going forecast (CFS) and real-time obs., of the zonal winds at 850/200mb and outgoing long wave radiation (also seen occurring presently), you get a 500mb composite of this below. I'd say early March offers quite something that we've failed to see come to fruition!
  8. This setup relative to the last two probably has the "best" favorable working kinematics going for it in terms of frozen precipitation (snow) vs. rain. Last 8 runs of the GFS shows a developing and more noticeable confluent flow and even the angular momentum (notice towards latter half of gif you see that kink in the isobars) is decompressing the flow downstream, which helps to keep the flow over Mid-Atlantic from buckling too much via WAA compelling the low levels. Even the ageostrophic component to this (i.e. - 250mb upper level jet) not only shows a pretty favorably placed right rear entrance region, but, note where the right LEFT exit region is superimposed.
  9. This is truly the first time this winter i've seen a highly desired and favorable harmonious conglomeration of hemispheric/synoptic forcings that many of us have been waiting to see work in motion together. I took a few different snippets of what i'm referring too and there is also the aspect of equator-ward rossby wave breaking into the Atlantic (saw this back in mid Nov) that is not shown in this, but adds to the excitement of finally(?) seeing everything that has been anticipated at a much earlier date, now manifesting. Biggest +AAM contributions in the tropics, +EAMT rebound incoming that helps incite a pacific jet extension and shift that GOA ridge eastward thus allowing the mean trough to nudge and shift east, and lastly a monstrous WWB/coherent wavenumber-1 type, MJO wave right over the dateline and is being enhanced via a rossby wave. We may even see this occur into phase 8 as well regarding amplifying the signal, but remains to be seen. Anyhow, it really aligns very nicely with the post 20th period and man i'm excited! While not necessarily a true +PNA pattern being shown in the medium and longer range, a +TNH pattern (below for visual purposes, except it's a composite for Jan, but remains similar and to get point across) appears to develop with a pumping STJ to add. -NAO signal still remains legit given this standpoint. Likely expect more corrections on NWP via synoptic pattern across N.A.
  10. Below is a signal i've truly yet to see all winter long; a stable constructive interference, intra-seasonal signal with what also looks like a dual-low frequency mode along and east of 180 degrees. This is the stability that many have been anticipating and expecting, but has yet to develop until about now. There is indeed an impressive Eq. Rossby wave that has allowed for some slowing and even causing chaos in those RMM phase diagrams (which be careful to use as they don't always tell the whole story). It's these depiction however, that kicks off with what looks to be our best conducive stretch of wintry prospects early-mid Feb into about late month. Sometimes, you just have to step back, and look at it from a wide view. Notice where the robust center of convection is and a coherent signal as well with some convection hanging back towards the MC. It's no coincidence that the EPS and GEFS are at odds with each other starting valid next week. It's here below, at this time stamp, that begins the divergence and this is attributed to the parameterization of there tropical forcing forecasts and initialization. I'm inclined to believe, based on what i've attached and been watching daily, that the EPS is correct in this poleward ridge into Alaska with a positive tilt, therefore, inducing lower heights downstream faster than its counterpart - the GEFS. Some similarities, but the difference is poleward amplification and it's stymied by its MJO progression. I'd expect a correction towards the EPS in time, but nonetheless, I do like the upcoming gradient pattern. Thereafter, it's interesting given +AAM in the tropics and a soon-to-be big +EAMT rebound and pacific waveguide shuffling that'll allow - bearing more curveballs, a +PNA depiction post ~ 20th with a potent window of actual Greenland blocking. i'm definitely intrigued by the cyclonic wave breaking that'll be occurring all the while this period happens and if we can get that retrograding signal to commence (0z/6z GEFS showed it as Geoff displayed). Despite the emotional rollercoaster, you have to just prevail against the "noise". Split flow, retrogression, and added westerly inertia.... not an easy thing for guidance. We'll see where it goes, but its hard not to like the period starting next week.
  11. In a general sense - the N.H. synoptic pattern and forcing mechanisms are finally changing and is evident through the waveguide around the mid-polar latitudes as a result from successful downwelling from the stratosphere. It's as @Isotherm put it; in a way, it has been a paradox because it was this event alone that has caused such disruption for the Mid-Atlantic and Northeast's sensible weather regarding snow and improper timing that has stemmed from such a decoupled state between the troposhere and stratosphere. Now we are truly beginning to see the long anticipated auspicious effects, properly couple with the troposphere -- therefore, rendering a highly receptive troposphere where it now will favor HLB and successful retrogression of polar positive geo. heights (likely to now dominate into Feb). That outline in yellow is basically looking at coupling and why we're now seeing more positive heights manifest into Greenland and Arctic. g this synoptic pattern below is a precursor for heights retrograding into Greenland and disseminating into the polar latitudes. This is the change that we've been waiting for and is bonafide. This is the feature (Europe High) that is favored from anticyclonic wave breaking across the Atlantic that changes in tilt, direction, and magnitude. Yes, this is a very good thing.
  12. "Main premise of this - available arctic air, confluence, not too shabby of an Atlantic domain, plenty of shortwaves rotating around a broadening and retrograding TPV with split flow, and now throw in a favorable coinciding MJO to boot with a -EPO (also some evidence of +PNA - ridge axis still questionable, but there). Also keep in mind that this is all happening amidst a retraction out in the pacific. We've seen time and time again poor timing of the TPV and its placement in conjunction with shortwaves. To see it first impart this weekend a sharp "nudging" and unfavorable orientation towards the Northeast to subsequently broaden and allocate back towards the west with diving shortwaves on the backside should have this group more stoked. Several opportunities heading into end of month and early February! Beware the volatility. " (my post Monday) There was discussion also today from reading pertaining to the TPV and shortwaves in the mix. Without a doubt, guidance is struggling with next week's synoptic mid level flow - and just to illustrate this concept, i've decided to show it through the illustrious GFS.... valid midweek next week, notice the profound difficulty in trying to decipher the positioning of the TPV, shortwave energy, and synoptic features such as the ridge out west. However, keep in mind as I show subsequent gifs of a similar thing in common - A long wave trough (via TPV injection) and its tilt. Also, that shortwave seen jumping around NewFoundland and Labrador and its implications(?) GEPS valid same time: Look at the allocation and tilt of the TPV (a clear retrogression) and that s/w south of Greenland and expanding heights across SE Canada as a result. Its surface translates to a better depiction for visual purposes; Look at the confluence zone back up into SE Canada (here is 1030mb high). This *could* have wintry implications and this may not be done trending since it's relevant on all NWP including EPS. GEFS - same thing and similar with the shortwave also in the aforementioned location and general vicinity. Also an inclination towards a negative tilt. There is a shortwave also that is rounding the bend of this entire long wave trough (won't take much to see this eject itself a bit more out ahead to make this interesting) GEFS surface - look at the common theme here and that confluence zone backing up also... Monitoring closely... then watch as this TPV shifts out and diving shortwave for next weekend... that is intriguing! We're headed in the right direction... this type of pattern is a "keep yourself on your toes".
  13. @Catacol I'm not Tom, but surely I can impart my knowledge to help. This right here is the best illustration for your question. When he discusses -VP in the Maritime Continent - which tends to resemble that of a La Nina walker cell circulation, you get something like this; (1st image) Using the 850mb zonal wind anomaly to further illustrate this concept - when you have a westerly wind burst (orange/yellows), you also must have compensation (like a vacuum) for that upper level divergence. In this case, sinking air is formed via surface convergence where that westerly wind burst meets easterlies - rises - allocates outwards, then sinks, then traverses westward towards convection and lowering of heights. Stronger the WWB, the more augmented net easterlies manifest. Note the enhanced easterlies region I circled - that in this case, is depositing net -AAM. In this case, you have destructive interference with the base state. However, if you take note of the 850mb Hovmöller, you'd note the forecast shows a continuation of that WWB eastward towards the Dateline and past it, but easterlies (blue) are present towards EPAC and Central America. A lot also depends on the MJO amplitude and wave itself, or envelope like a CCKW. I'm not sure If i misunderstood your question or interpreted incorrectly so let me know.
  14. 1. This Saturday, we see the tropospheric polar vortex once again stagnated and rotating around the Hudson Bay and Southern Canada in general. A ridge is seen off the west coast, which helps to keep shortwaves diving in from the Arctic while ushering in persistent areas of high pressure. There is also a clear sign of a split flow. Circled are 3 shortwaves – all beginning to gather themselves and enter into the CONUS. Valid Saturday, we see a somewhat distinguished piece of wind energy traversing our region (1stimage; right). This piece reinforces the pressing low level arctic air-mass. In the 0z 500mb EPS anomaly graph, you can also see it, but notice how many pieces of energy are shown (should give you a clue of how chaotic it’s for the modeling). Interestingly enough - this rex block configuration in the Atlantic is there verbatim for the next ~8 days. 2. Now, we turn our attention to the timeframe of Sunday night/Monday. The red circle that you see outlined in California from above, appears over the Gulf valid Sunday. The TPV still remains rotating and spinning, but there are tiny vortices that are seen to also be rotating in conjunction. In this same image, note the other 2 red circles indicative of yet MORE shortwaves diving in. The previous shot of cold air and tomorrow's frontal boundary help to establish a baroclinic zone. Fast forward Monday, we have to see if a polar disturbance transfers its energy to the coast, or if it traverses the area, or just remain separate. 3. Now we fast forward to Tuesday. This period has been the one many of us have been watching and why some earlier runs of the ensembles were showing robust tracks. From image 2, we see that whatever happens, shifts on towards Newfoundland and manifesting as a potential 50/50 low source. This also even helps to push heights poleward into Greenland more (0z EPS 500MB graph above). You have yet another piece of the PV digging *west* and *behind* the main southern stream. A southern stream system (circled from back from 1stimage that was in Cali.) now is off the SE Coast. Right here offers a potential phasing of the streams type solution, OR, just the polar trough axis guiding up the system (Can also just track harmlessly out to see and nothing but polar stream dominated). This is what we’ve been seeing over the past few days from earlier and why there were some robust runs. If you just stand back and observe this, one should see how explosive this type of pattern is for early next week. While verbatim it's just messy and chaotic, one should also be cognizant of how volatile this type of active pattern is and can easily revert back to something big along the coast. I decided to use the 0z ECMWF/EPS for this post also. 4. THEN, the next diving shortwave (circled above also - s/w in SW valid next Tues) for late next week traverses that established baroclinic zone (verbatim offshore - below image). Main premise of this - available arctic air, confluence, not too shabby of an Atlantic domain, plenty of shortwaves rotating around a broadening and retrograding TPV with split flow, and now throw in a favorable coinciding MJO to boot with a -EPO (also some evidence of +PNA - ridge axis still questionable, but there). Also keep in mind that this is all happening amidst a retraction out in the pacific. We've seen time and time again poor timing of the TPV and its placement in conjunction with shortwaves. To see it first impart this weekend a sharp "nudging" and unfavorable orientation towards the Northeast to subsequently broaden and allocate back towards the west with diving shortwaves on the backside should have this group more stoked. Several opportunities heading into end of month and early February! Beware the volatility.
  15. I decided to edit the CPC N.H z500mb pattern and their animated gif. It stems back from Dec 20th and finishes up to the 18th. I edited a few frames to guide the evolution. 1. You can’t argue that their is a clear as day, reshuffling of major synoptics features. 2. Look at the progression towards the latter half as the TPV descends down while in conjunction a retrogression out across the NEPAC occurs. As wavebreaking ensues, we’ll see the last of the “dominos” to fall in place across the Atlantic sector. This gif is clearly evolving to the operational 500mb runs 0z (yes, look at the *OP* guidance - Euro, Gfs, Cmc), ensembles as being discussed presently, and even the CPC’s 8-14 day analog composite. KU pattern certainly ahead, now lets see it (hopefully) produce.
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