Severe WX April 12-15th, 2018 Severe Potential

Discussion in 'General Weather Discussion' started by KoD, Apr 4, 2018.

  1. KoD

    KoD Member
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    The dates may change, but the Euro is focusing in on a potential severe threat in the long range. Since there's been some consistency and much discussion, we can keep it focused on this thread.

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  2. Xenesthis

    Xenesthis Member

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    I will be curious to see how the models resolve this over the next few days... some of the looks are downright scary!
     
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  3. akt1985

    akt1985 Member

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    I hope I don’t have to dodge tornadoes on my birthday, the 14th.
     
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  4. ARCC

    ARCC Member

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    One of those cases that if the Euro is right , despite the slp being farther north you still get southerly winds at the surface.

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  5. rolltide_130

    rolltide_130 Member

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    It has to do moreso with the EXTREME depth of the low (Sub 980) than its positioning. We regularly get tornado outbreaks with surface lows up into Nebraska, Iowa, and even Minnesota (11/29/16)
     
  6. tennessee storm chaser

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    Doesn’t matter with that setup there. Will produce great height falls ... 1974 outbreak had SLp eve. Little further north
     
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  7. ARCC

    ARCC Member

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    Exactly. This will probably not be a case where the winds veer at the surface. In fact if last night's Euro verifies, surface winds probably back more than modeled due to another lobe of low pressure that may form to the south of the main low pressure.

    Another notch toward a higher risk setup is the large pressure falls. The Euro puts a very large area under 1008mbs.
     
  8. Jpgood20

    Jpgood20 Member

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    So as we look ahead, would next weeks system seem to stay in the Central US, or would we expect the southeast to be affected as well?
     
  9. CSimonds

    CSimonds Member

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    All of the local (HSV) stations are forecasting next week’s highs to be below normal. If that is the case, there would have to be a setup with a rapid temperature and dew point increase. Is that expected?
     
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  10. tennessee storm chaser

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    That would cover a pretty large area... southern plains .... mid south.... parts Dixie. Lower Ohio valley least... course still a lot model watching to do ... table being set for something big... and perhaps a multi day event
     
  11. rolltide_130

    rolltide_130 Member

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    This is more than 7 days out. There's no way to make any sort of reliable temperature forecast at that range.
     
  12. CSimonds

    CSimonds Member

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    Channel 48 now has next Friday’s high at 79
     
  13. tennessee storm chaser

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    Forecast high for Memphis 77 next Friday. Thunderstorms
     
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  14. Tennie

    Tennie Member

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    I've been looking at those models that have run out to at least as far as Day 10. They all seem to agree that there will be a low pressure system somewhere in the central CONUS on Friday, but they disagree on the exact placement and intensity. Of all the models only the Euro ensemble comes close to the main Euro on both placement and intensity, and even then the low stays well above 980 mb. Nonetheless, it does still show a fairly tight pressure gradient over the eastern CONUS, so that should be something to watch out for.

    Interestingly, the Euro models suggest that there will be a decently strong low (dipping into around the 980-mb range) moving through the Northern Plains on Thursday, with the Friday low spinning off immediately behind. So that would be two back-to-back strong low pressure systems tracking across the Northern Plains/Great Lakes region near the end of next week!

    One could only imagine how things could play out if that does indeed verify...
     
  15. ARCC

    ARCC Member

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    Looking a little closer at the 12z Euro, at 500mb winds quickly become almost parallel with the dry line vs last night's run which was much more perpendicular. While this run is more powerful as a system, last night's run would probably be a bit worse for the deep south.

    Still lots to resolve concerning this possible event.
     
  16. Taylor Campbell

    PerryW Project Supporter

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    So many different ensemble ideas, and model differences. I imagine a severe threat will take place during this time frame, but how bad it gets, and where exactly is very much up in arms.
     
  17. ARCC

    ARCC Member

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    Latest model runs from last night through today is trending away from severe weather east of MS. Still a significant system for the Midwest, but not what it was yesterday or a few nights ago. In fact the Euro doesn't get the dry line east of Memphis and the GFS/CMC show the same vein of thought.

    One thing to watch is what may come next should the above scenario take place. Most of the major tornado outbreaks had a large "priming" system before them. By hr240 on the Euro you have 72 degree dew points sitting on the gulf coast.
     
    #17 ARCC, Apr 5, 2018
    Last edited: Apr 5, 2018
  18. rolltide_130

    rolltide_130 Member

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    This is actually a system with two shortwaves. The leading shortwave is the one that's becoming a bit less amplified and that's the "primer" wave you're talking about. There's a second one digging into the rockies at 192 which is going to be the big one. It's overamplified right now, but I actually see that as a plus as the trends this year have been to deamplify systems as we get closer.
     
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  19. ARCC

    ARCC Member

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    The problem with the second system is the trend is farther NW with the trough and strengthening of the SE ridge. Like I said earlier, the dry line never gets east of Memphis on this run. Here are the last three Euro runs. Looks like the lastest Euro also slowing the system as well. Still a significant system, but a good bit less a threat verbatim for the SE.

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  20. rolltide_130

    rolltide_130 Member

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    The Euro is notorious for overamplifying things at this range. I'm not particularly concerned about it at this juncture. If anything, it's a good thing because that means that things may not be underamped at verification.
     

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