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  1. 18 points
    I'd say it's fairly incontrovertible that the Pacific structure will be ameliorating, finally, as a function of the ewd propagation tropical convection and realignment of W/C forcing in more canonical orientation. Phase 8/1 entrance in a few days + 7-8 day lag, should elicit vicissitudes in the PNA domain by the end of February. The more intriguing and challenging inquiry for me, is can we get the NAO to play ball, at all? We have discussed this heretofore, and it's something @Snowy Hibbo noted I believe; namely, that much of the positive angular momentum has been concentrated in the southern hemisphere. Further, I noted that the equator-pole distribution of the angular momentum has been "wrong" and antithetical to the genesis of sub-tropical troughs, which accelerate jet flow and tend to initiate decelerating polar jets immediately to the north. Those conditions remain unpropitious through the next 7-10 days; however, if the CFS is correct, there may be a window within which a legitimate NAO *could* develop and actually retrograde a bit toward Greenland. This window of opportunity is approximately March 1/2-March 10th +/- a couple days. Besides the phase 1 lagged effects, forecasted equator-pole zonal winds are suggestive of an alteration from this winter's base state in the March 1-10th period by the CFS. Now, we continue to have persistence and descending wly QBO modulation countervailing, but if other variables rearrange, that shouldn't totally obviate the chance for at least a transient blocking feature. We'll have to monitor it, but I like what I see on the CFS zonal wind proggs in the first 10 days of March. Momentum diminutions in the SHEM, and reorientation of +AAM in more conducive places. We'll see. But, the Pacific alone will make things colder for the first half of March. The question is, are we talking about a decent pattern (which would be much better than what we've had = ghastly, hideous, and diabolically impudent), or, could it be "better" than decent? That's contingent upon whether we can induce a transient blocking period. As said, there's a chance. But it also may not happen.
  2. 17 points
    Bro, you need to take a step back with this type of nonsense. There are too many professionals and other influential people using this community for legit weather forecasting purposes.
  3. 16 points
    There is a circa 7-day lag with MJO forcing, so the trough in the West this coming week is a phase 7-early phase 8 response. The phase 8/1 MJO initiates around the 19th which will manifest about a week later around the 25th w/ the trough translating toward the East. Furtado's MJO phase 7-8 hypothesis (from what I've heard) correlates a weak SPV status to atypical MJO 7-8 response w/ SE-ridging. If true, one issue is that the SPV has already normalized and will be stronger than normal over the coming week. I'm not sure if he noted any temporal lag, but the MJO P8 is concurrent w/ a normal status SPV right now. I tend to think the Western troughing is more related to expanded Hadley cells and poleward displaced northern stream due in part to the non-canonical SSTA structure in the West Pacific (and -50mb QBO) which tends to produce a -PDO type resultant flow with the jet buckling in the Western US. But the SSW post-humous effects could modulate as well - I'd just like to read his entire explanation first before concluding that it is valid. It's difficult to unequivocally prove causality in meteorology as variable isolation is nearly impossible, so the best we have is strong correlations with theoretical causality chains usually, which I think can be very effective. So I give him credit for pushing the science forward with novel ideas.
  4. 15 points
    Great surface high pressure positioning on the GFS. The northwest confluent flow helps us ahead of the systems arrival as well. Plenty of warm air advection-drive precipitation, but it does hit a breaking point where the fgen will die off in Southern New England as the northwest flow aloft works in. This is a very convoluted setup, but the potential is there for snow area-wide.
  5. 15 points
    Basin-wide neutral-warm ENSO conditions persist. The ENSO Region 1+2 anomaly was +0.30°C and the Region 3.4 anomaly was +0.40°C for the week centered around February 6. For the past five weeks, the ENSO Region 1+2 anomaly has averaged +0.73°C and the ENSO Region 3.4 anomaly has averaged +0.40°C. Basin-wide, neutral-warm ENSO conditions are not conducive for large snowstorms in northern Mid-Atlantic cities including New York and Philadelphia during February.   During March, as wave lengths shorten, there is an increased frequency of such events during neutral-warm ENSO conditions. However, approximately 75% of the monthly snowfall occurs March 15 or earlier. Essentially, winter typically concludes by mid-March when such ENSO conditions are present.   March 2007 is the exception with the bulk of its monthly snow occurring a few days later. March 2007 is the only case where temperatures rose to near record levels toward the end of March rather than evolved toward persistent milder weather that fell short of challenging records.   Such ENSO conditions will likely persist through February with some possible fluctuations to levels consistent with weak El Niño events. Under such a scenario, the probability of a significant snowfall (6" or more) will be well below climatology for the northern Mid-Atlantic region. The SOI was -19.64 today. That's the fourth consecutive day during which the SOI was -10.00 or below.   Today's preliminary value of the Arctic Oscillation (AO) was +2.437. The preliminary average for meteorological winter is -0.222.   Based on historic experience (1950-2018) when the AO reached +3.000 or above during the February 1-15 period, the AO will likely remain predominantly through most of the second half of February. The AO could head toward neutral or negative levels during the last week of the month.   For the fifth consecutive day, Australia's Bureau of Meteorology reported no MJO data. That outcome may be the result of technical issues in pulling OLR data from NOAA sources due to website issues. However, based on model initialization (which is subject to some degree of error), the MJO has now moved into Phase 8.   The MJO could spend an extended duration in Phase 8. As it remains in Phase 8, the AO should begin to decline.   The SOI remains at very negative levels. The SOI has a correlation to precipitation in the southern tier of the United States. As a result, precipitation will likely be above to much above normal in both the Southwestern United States (including California) and Southeastern United States.   There could be several opportunities for snowfall in the East. However, the probability of significant snowfall events (6" or more) is below climatology for the Middle Atlantic region. Central/Upstate New York across central and northern New England have a greater probability of significant snow events.
  6. 12 points
    Quick note on this system... Recall this area of frozen precipitation will be occurring as it collides with a 500mb ridge (this is not unimportant). The anti-cyclone aloft provides flow out of the west to WNW. It's what sets the stage for that W to E gradient of the heavier banding as the precip runs into the surface HP. Question is, how far N? In this unique setup, even where you have the best lift at 700mb, we'll need to bear in mind that the dendritic growth zone is in the realm of 18,000 feet up... At times, it may be a challenge to continually garner an environment for well formed snow flakes. Also, when this is achieved, there is a lot of lateral motion in the lower & mid-levels that the flake will need to endure on its journey. That introduces the possibility of riming. This isn't some show stopper per say, it just limits the ability for the best possible rations. Even still, rates should still be impressive on the periphery of the best banding. That's the portion of the forecast that's really difficult to pin down. It leaves the door open that areas like PHL or even points a bit further north into NNJ could be in for a surprise. Watching the SPC meso-analysis & radar trends will be... interesting tomorrow. For most posters here, the snow should come in like a wall. We tend to use the term "thump" a lot, but in this case, it should largely apply for most posters here. Good luck to all! PS: While we know the general feelings on snowmaps, if you're going to look at any of em to get a general idea of how the snowfall will be distributed (not anyone's backyard), the rime corrected maps are probably a better bet than your 10-1 or Kucheras in this setup. (this is the 6z 3k map)
  7. 12 points
    A lot of great analysis in this post, very much appreciated!
  8. 12 points
    Conditions in Norlisk, Russia yesterday after a few storms dumped white gold. Thought just seeing this might brighten mood in here ahead of the Euro
  9. 12 points
    I'd say it's fairly incontrovertible that the Pacific structure will be ameliorating, finally, as a function of the ewd propagation tropical convection and realignment of W/C forcing in more canonical orientation. Phase 8/1 entrance in a few days + 7-8 day lag, should elicit vicissitudes in the PNA domain by the end of February. The more intriguing and challenging inquiry for me, is can we get the NAO to play ball, at all? We have discussed this heretofore, and it's something @Snowy Hibbo noted I believe; namely, that much of the positive angular momentum has been concentrated in the southern hemisphere. Further, I noted that the equator-pole distribution of the angular momentum has been "wrong" and antithetical to the genesis of sub-tropical troughs, which accelerate jet flow and tend to initiate decelerating polar jets immediately to the north. Those conditions remain unpropitious through the next 7-10 days; however, if the CFS is correct, there may be a window within which a legitimate NAO *could* develop and actually retrograde a bit toward Greenland. This window of opportunity is approximately March 1/2-March 10th +/- a couple days. Besides the phase 1 lagged effects, forecasted equator-pole zonal winds are suggestive of an alteration from this winter's base state in the March 1-10th period by the CFS. Now, we continue to have persistence and descending wly QBO modulation countervailing, but if other variables rearrange, that shouldn't totally obviate the chance for at least a transient blocking feature. We'll have to monitor it, but I like what I see on the CFS zonal wind proggs in the first 10 days of March. Momentum diminutions in the SHEM, and reorientation of +AAM in more conducive places. We'll see. But, the Pacific alone will make things colder for the first half of March. The question is, are we talking about a decent pattern (which would be much better than what we've had = ghastly, hideous, and diabolically impudent), or, could it be "better" than decent? That's contingent upon whether we can induce a transient blocking period. As said, there's a chance. But it also may not happen. Right, James. The tropical forcing and extratropical progression, i.e., MJO, GWO, etc., would certainly augment the argument for a retrogressive HLB feature. But the -AAM in the sub-tropics needs to decrease to permit it.
  10. 12 points
    EPS goes wild from the 25th until the the end of the run. ++pna with mean trough over Chicago. Neg nao comes and goes but no true Greenland block. Active STJ to end February and to start are snowiest month lately
  11. 12 points
    These are my favorite storms, because the anecdotal weenie comments are gone, people are done trolling and @ 'ing me on twitter, and we can enjoy tracking a storm.
  12. 12 points
    06z eps is beautiful for Wednesday. Big time thump
  13. 12 points
    winter's dead. time to plant lettuce seeds
  14. 11 points
    Our lonely eyes turn to a potential impactful event On the Wednesday evening commute. Happy tracking everyone!
  15. 11 points
    The 30-year running average [1987-88-2017-18] is actually up to 30", 29.8" to be exact, for New Brunswick. You can check the various stations and choose time frames here: https://w2.weather.gov/climate/xmacis.php?wfo=phi Other 30-year running normals: NYC: 29.3" EWR: 31.1" LGA: 29.8" JFK: 25.7" So, to me, the true normals are now around 30" to 31" for most of ECNJ-NENJ-NYC. 30-year running here is up to an impressive 31.6". My annual average snowfall map (may need to be updated soon if we continue with frequent high-end years): http://www.lightinthestorm.com/nj-snowfall
  16. 11 points
    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.
  17. 10 points
    700hPa fgen should quickly become diffuse as it moves north of the Mason Dixon line, separating and arcing to the east once it reaches Central PA. Northwesterly flow aloft should help guide it eastward but it will weaken and very quickly become unimpressive. Dendritic growth will slow and dry air will work in quickly. I'll take the under on this one.
  18. 10 points
    Euro 2-4 inches from nyc to Phl. Including eastern Pa and northern nj. 1-2 for the lower Hudson valley
  19. 10 points
    @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!
  20. 10 points
    Nothing but pure wishcasting and alarmism.
  21. 10 points
  22. 9 points
  23. 9 points
    Can you perhaps elaborate a bit on exactly how snow water equivalent in North america as a whole impacts our winter weather potential over the next week?
  24. 8 points
    I unfortunately have to disagree here. The ECMWF & other guidance have also picked up on an amplified trend. The issue is in regard to the resultant venting aloft. The bias of any given model won't matter much if the surface HP is shunted well off the NE coast. You're feeding warmer ocean air into the system vs. cold air out of SE Quebec. The one hope would be a push of the h7 frontogenesis further north quicker than currently modeled. That would aid in a decent thump across the greater tri-state area with better vertical velocities before the inevitable flooding of mid-level warmth. The threat of an afternoon rush hour wintry mess is real. But expectations of significant snowfall should be tempered at the moment IMO.
  25. 8 points
    GEFS really go wild with the pattern after the 27th. Would be fitting after everyone has given up lol
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