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eduggs

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Everything posted by eduggs

  1. eduggs
    ICON and RRFS are south of 12z
  2. eduggs
    Sleet and rain now. But the surface temperature continues to drop. 34.7 now down from a morning high of 37.4.
  3. eduggs
    It's a little unusual to see snow accumulation on trees, grass, and car tops in the middle of the day and snow fog/ low visibilities with surface temperatures between 35F and 37F. And outside of a few bursts, the intensity hasn't been all that great either. This is an overperforming airmass.
  4. eduggs
    Snowy morning at 500ft in Morris County. Nice surprise coating! The bigger surprise is that the temperature has dropped almost 2.5 degrees since 10am allowing the trees to become increasingly frosted. Feels very festive.
  5. eduggs
    Chicago has had 13 straight hours of snow and moderate snow for the last 5, with more to come and temperatures in the 20s. Jealous. For reference, Chicago averages about as much snow annually as the interior Lower Hudson valley.
  6. eduggs
    5 days ago there was barely the hint of a ripple of a shortwave across the central US... And a big trof along the west coast.
  7. eduggs
    There's more going on than whether it's amped or flat. There's the location and amplitude of the shortwave, location of vorticity advection, the tilt of the trof, and its evolution over time. Some runs over the past few days have been "amped" with a sharp shortwave and associated vortmax taking a northerly route near the Great Lakes into NYS (e.g., 0z 28th GFS) and others have been "ampled" but with the shortwave taking a more southerly track from AR through KY to VA (e.g., 06z 27th ECM). Other runs have been a little flat initially but amped up late (e.g., 0z 29th ECM) or initially amped only to quickly flatten (various CMC and UK runs). This combination of variables has led to a spectrum of outcomes that defy a simple binary description.
  8. eduggs
    Not a fan of 12z. Noticable shift towards the GFS-like emphasis of vorticity near the Great Lakes and less in the South. This leads to quick warming of the boundary layer. This was observed across all guidance except the GFS, which shifted a touch towards the consensus. The duration has also been shortening. This is now looking like a relatively quick hitting 6-8 hours of precipitation. A few days ago is was stretched out across as much as 18-24 hours.
  9. eduggs
    The GFS has mixing issues in areas that are north of the steady precip. shield on the ECM. Contrarily, the 12z EPS is west of the 18z GEFS with the precip. sheild. If you believe in the predictive value of ensembles you might think the GFS will shift south in future cycles. We're still 3.5 days out, so inter-model variability is expected. It will be interesting to see how this plays out.
  10. eduggs
    The ECM is a strange solution. Its precip. field is well southeast of the 12z EPS and the shortwave is less impressive than 12z, but it still rapidly deepens the SLP into the 970mbs near the benchmark. The ECM family and the GFS are not close. Much more overlap between the ensemble means.
  11. eduggs
    Everything looks relatively encouraging for I-95 NW except the GFS. It's insistent on a packet of vorticity and associated sharp shortwave tracking from MO through OH through northern NY. Most other guidance is AR through KY through PA or SNJ. If a shortwave tracks that far NW it will be very hard to keep snow anywhere along the coastal plain. From memory I feel like if any model sees this kind of shortwave tracking near the Lakes with a coastal SLP, it ends up verifying.
  12. eduggs
    ECM-AI is on board for some snow I-95 NW. Accumulations maybe just west of there with moderate snow accumulations inland. The ECM is similar. Pretty good consensus with the GFS warmest at the moment.
  13. eduggs
    Agreed. While it's possible the Newburgh waterfront on the Hudson is a slushy 33F vs. 32F and accumulating snow at Stewart airport, the model soundings say elevation along the transition zone might only matter in terms of rain vs. ZR.
  14. eduggs
    We don't know exactly how this event will play out yet. But even if it ends up an interior event, non-elevated NNJ through the lower Hudson Valley haven't had a decent snow event in a while. So this wouldn't really be a repeat scenario in that sense.
  15. eduggs
    The 12z is the 4th cycle in a row that the CMC has shifted south with the vortmax... it had been up in Ohio/Great Lakes more like the GFS. The two models show important differences at day 4 with the 6z ECM kind of a compromise.
  16. eduggs
    This is the kind of storm that I can imagine looking borderline for snow right down to the Bronx until the NAM sends the vortmax to Buffalo and torches 900mb to 8C... signaling the rest of guidance to rain to Albany. That said, synoptically, right now as modeled, it's pretty close for snow even in the City itself. The ICON and GFS have shifted slightly colder/south at 12z and 6z respectively, and ensembles (if you believe they are useful at this range) are south of their parent operational runs. The antecedent cold is marginally supportive. It wouldn't take a huge change in the shortwave structure aloft to lead to a snowier outcome further south. It's not what I would bet on, but there is still some reasonable chance... especially outside of concrete jungles.
  17. eduggs
    The 0z UKMET and 18Z ECM-AI squash the shortwave and yield very little precip. At 4.5 days out this possibility is still plausible.
  18. eduggs
    Just noticed that there are still pretty big differences between the CMC and GFS days 4-5 at 500mb. The CMC actually doesn't look too bad aloft... that's a borderline snowstorm to pretty close N&W. The GFS upper levels look like they would support more rain and less snow than depicted. I feel like the GFS will end up more right... hope I'm wrong.
  19. eduggs
    It's difficult to know how significant it is that the GFS op is significantly wetter and further west compared to the GEFS mean. The GEPS and EPS are also a bit southeast and drier. Obviously the averaging-effect decreases the mean precipitation the more you go out in forecast time. But the majority of the individual ensemble members are also well east of the GFS. The op also appears to be a bit faster than ensemble consensus... maybe in response to the sharp Great Lakes shortwave/vortmax that is at the leading edge of the trof. I suspect the op (maybe higher resolution?) is more accurately resolving the shortwave progression than the ensembles. I expect the ensembles to play catchup, and I don't think we're done trending yet.
  20. eduggs
    The surface features aren't driving this outcome. The position and strength of the surface highs and lows follow the upper levels. The trend over the past 2 days is for the shortwave to not "dig" as far south. The vortmax that passes through the Great Lakes is becoming increasingly prominent. The path of this shortwave and vorticity advection ends up tracking pretty similarly to Sunday's wave that precedes it. That leads to a stronger surface reflection (primary) near Western PA and southeasterly low level flow that quickly changes snow to rain along the coastal plain. The hope is that maybe guidance is keying on the wrong packet of vorticity and that the models will shift back towards a more favorable trof evolution. As of now this is transitioning towards a SWFE-type event that favors the interior, particularly New England. But it's still close to a wintry outcome... and highly trackable.
  21. eduggs
    I'd like to see a sharper trof like last night's GFS and UK. That allows more intense and widespread precipitation and it also anchors the surface high further west in Quebec due to the strongest upper level convergence staying further west. With a more positively tilted trof, the surface convergence shifts east and the surface high goes with it. (upper levels and surface are connected in the sense that converging air aloft tends to sink [surface high pressure] and diverging air aloft tends to rise [surface low pressure])
  22. eduggs
    The GFS lost the big western trof and sharpened a different shortwave in the central US in just a few cycles. This happened in the mid-range, not fantasy range. It just goes to show how variable model output can be in this range.
  23. eduggs
    GEFS, EPS, and GEPS members clustered where we'd want them I think, mostly offshore with the SLP. Hints of a weak primary up the Apps. The bulk of the precipitation along the coastal plain. Surface temperatures for low elevation coastal areas are marginal for snow and the real cold doesn't move in until the storm is departing. But that's a pretty good look overall for a 6 day forecast. The bar for me at this point of the season is a shovelable snowfall. I don't want to get carried away by 10:1 snow maps.
  24. eduggs
    0z GEFS is slightly drier/south compared to 18z. So the GFS and GEFS moved towards each other this run.
  25. eduggs
    The GFS retrogrades the CA ULL west into the Pacific. If that doesn't happen, the longwave flow across the US would be significantly altered. Our downstream weather is extremely sensitive to the modeled evolution of the western trof over this period. Could still end up balls cold or periodically torched days 6-15.
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