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high risk

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Everything posted by high risk

  1. high risk
    the front end thump for those of us in Howard/Montgomery isn't nearly as good on the NAM nest
  2. high risk
    100% true for this area. Well, ok, 90% true.
  3. high risk
    exactly. no one should ever post a 10:1 map when the precip type images clearly show a ton of sleet. The NCEP models tally snow and sleet together and put out a liquid total; a 10:1 ratio applied to that has no chance to be even in the ballpark.
  4. high risk
    You sure about that? Both the 12 and 3 km versions seems to have snow in your area by 2 or 3pm. (I'm commenting on the precip timing, as it does look like you will go sleet.)
  5. high risk
    Right. Those maps don't account for actual ability to build on surfaces. They just look for rain falling with a sfc temperature at or below 32. You're spot on that without it being very cold today/tonight (i.e. mid to upper 20s), rain falling at 31 or 32 isn't likely to be a major deal. I do, however, think that parts of this area will get a big 'ole sleet bomb out of this.
  6. high risk
    Ok, but the HRRR has been running stupidly cold for winter precip events at longer ranges. For today's cold rain, a couple of the longer range runs had 4-6" through the DC area.
  7. high risk
    appears to be a respectable front-end thump for those of us north of the DC Beltway Wednesday afternoon. Temperature profiles have no margin for error, but verbatim, it would be cranking here:
  8. high risk
    Fair enough. It could be wrong; I'm just reacting to the folks who said that the NAM showing an inland low track proved that it should be immediately euthanized.
  9. high risk
    Since it seems to be the afternoon for apologies on this board, perhaps one needs to be made to the NAM......
  10. high risk
    FWIW, and I am not saying that it's right, the CMC evolution/track is more similar to the 00z NAM than to the 00z GFS....
  11. high risk
    Chill out. The NAM was frozen with its 2017 upgrade (the 3 km component has been running for way, way longer) and is slated for retirement in the 2023-2024 time frame. It's also well known that the 3 km nest is a far superior model to its 12 km parent, although it too certainly has limitations.
  12. high risk
    12z CMC definitely disappoints after seeing the 12z GFS
  13. high risk
    Absolutely. I'm a huge fan of the positive snow depth change as an alternative to the 10:1 maps, but they absolutely are driven by soil type and especially soil temperature; they tend to be a bit underdone early or late in the season when the ground temps have been warm for a few days.
  14. high risk
    not really. Yes, the NAM (and other regional models) will be replaced by a system that is run hourly (like the HRRR), but the new system will be FV3-based. regarding the Monday event, the HRRR is the craziest for central MD and DC, but several other hi-res models show a change to snow on the backside of the system, at least across central MD.
  15. high risk
    I'm not sure about the EPS, but the GEFS members are run at 25 km resolution, while the ops GFS is 13 km. So yes, that could be making a difference.
  16. high risk
    Definitely much more dispersive than the previous version of the GEFS.
  17. high risk
    The previous version of the GEFS was extremely underdispersive, but the new GEFSv12 has way more spread. That was one of the strengths of GEFSv12 noted in the summary presentations on the evaluation web page: https://www.emc.ncep.noaa.gov/users/meg/gefsv12/ (It also helps that 10 additional members were added.) If most members agree something at day 5, that's a much bigger deal in the new version.
  18. high risk
    This is what happened on 11/15/18. The NAM was one of the coldest models for that event too and was largely dismissed, but it had the right idea of big rates overcoming a very marginal air mass.
  19. high risk
    The parallel GFS had statistically significant synoptic range improvement over the ops GFS in the medium range over the full course of the retrospective runs. But that certainly doesn't preclude it doing worse on any single event. I wish we were able to run it more than once per day right now.....
  20. high risk
    Honestly, those details haven't been sorted out yet. It's not an output in the RAP/HRRR (which have actual snow accumulation as an output), although their SLR methodology is documented. The plan is to carry over the RAP/HRRR products into the RRFS (replacing all of the regional models in 2023) and build it into the 2024 GFS/GEFS upgrade.
  21. high risk
    They do run tend to a bit low (especially when the ground is relatively "warm", but they're so much better than 10:1 maps in any event in marginal thermodynamic environment. I honestly don't blame WB or TT. The problem is that NCEP doesn't generate true snow accumulation output for any models except RAP and HRRR, so it's up to the user to assign and apply an SLR. This is going to be addressed going forward.
  22. high risk
    In these events with very marginal temperatures, the Tropical Tidbits accumulated positive snow depth change are the best maps to examine. They show what the model believes can actually accumulate on the ground.
  23. high risk
    Speak for yourself. It basically hits a wall at the Potomac.
  24. high risk
    00z NAM continues to show a deformation band of snow across the area Saturday.
  25. high risk
    a quick FYI for our severe friends that the HRRR is now run to 48 hours 4x per day, starting this morning.
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