jpeters3

Meteorologist
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Posts posted by jpeters3


  1. 1 hour ago, Windspeed said:
    7 hours ago, NJwx85 said:
    Honestly, who gives a damn what the seasonal ACE ends up being if most of the activity stays out to sea. I think the majority would agree that a category 2 hurricane making landfall in the US is a lot more interesting from a hobbyist standpoint than a category 4 hurricane re curving way out to sea.

     

    I mean part of an active season, especially hyperactive is your general September central Atlantic hurricanes. They usually produce a big chunk of ACE and most of the hyperactive years have them. I just enjoy tracking, attempting forecasts and observing the outcomes. Whether they are land threats or not matters little to me. Though I would prefer they avoid populated areas. A big CV hurricane is my favorite even if it threatens nothing but shipping. Aside from Dorian, Lorenzo was an incredible storm to track as well last year. Perhaps we'll get a few beasts over the next month.

    Yeah I'm with you.  I would rather see a monster cat 4 or 5 storm that remains out to see, than mayhem/destruction related to landfall.  This is why I find the east pac season fun to track.


  2. 13 hours ago, the ghost of leroy said:

    Lol

     

    13 hours ago, hlcater said:

    I still maintain that the amount of attenuation going on was negligible. This is especially true when in Laura's case, the southern part of the eyewall was weaker the entire day on both HGX and LCH and this is a weakness that was also evident on recon data. So while attenuation may be a convenient explanation, at least from what I can tell(and who knows maybe im wildly off the mark here) it doesn't seem to be the correct one.

    7cb06b621c414d64fef89036a306ad5a.jpg

     

    Then watch as the eyewall consolidated on LCH and HGX on final approach to the coast. My best guess is that frictional convergence played a role in this process but this consolidation was very much legitimate and not some radar enhanced artifact. There was almost certainly some attenuation going on from LCH (especially earlier in the day at higher beam heights) but in the hours before landfall, as @jpeters3 had explained, the amount of attenuation occurring was not enough to sufficiently explain such a weakness there on its own. 

    8c867291b82e99c7356b6075a66adf6c.jpg

     

    Appreciate the support ;)


    Certainly an interesting feature, and again seems to have occurred in past intense TCs (Harvey, Michael).  My suspicion is that it has to do with the modest southerly shear.


  3. Just now, JasonOH said:

    The good news is that there’s no datapoint for the surface on that sonde so we don’t know exactly how high that is. Sondes measure wind instantaneously so it may have caught a gust in a mesovort.

    This is probably what happened.  Seems like there is a reasonable case for 125 kt as the current intensity based on the most recent AF mission.


  4. Just now, Bostonseminole said:

    yeah, surprised still dropping.

    Sondes have been consistently showing higher pressures than extrapolations though.  Also, there hasn't been SFMR or a sonde that showed anything higher than 125 kts for a while.


  5. 1 minute ago, StormChaser4Life said:

    Looks like our rapid intensification finally stopped. 937mb at 150mph was our peak unless this strengthens again which looks unlikely. Most likely will maintain this intensity into landfall. God help those people 

    Looks like NHC went with 939 mb, but I agree that 937 was probably the low point.

    Interesting, I'm actually seeing outbound velocities in the western eyewall approach 160 mph per KLCH.  This is comparable to the eastern side, and the strongest winds I have seen there so far.  Seems to coincide with an apparent intensification of the western eyewall in the reflectivity.

    • Like 2

  6. 4 minutes ago, mattb65 said:

    Hwrf and HMON both show the southern part of the eye to be weaker during this time period and in particular the HMON shows some sight breaks but both show the ring becoming more symmetrical in the next few hours leading up to landfall.

    Probably a combination of weaker echoes and attenuation. I think completely discounting some attenuation contributing isn't correct.

    I am jealous that you live in Kailua.

    Latest radar scans show that *whatever* was happening with the southern eyewall may be abating.  New high DBZ returns have wrapped completely around the southeastern side.

     

    Image 8-26-20 at 7.38 PM.jpg

    • Sad 1

  7. 1 minute ago, Rjay said:

    I completely understand.  There's more important things to focus on right now though. 

    Agreed.  I am done (with that topic at least).


    New recon made a pass while we were arguing, FYI:

    145 kt FL winds in the western eyewall.
    recon_AF300-2513A-LAURA_timeseries.png

     


  8. Just now, Rjay said:

    People!  There has to be other things to talk about.  

    I agree, but every other poster tries to tell me I don't know what I'm talking about after I presented a clearly thought out argument, and it's fairly frustrating.

    • Weenie 1

  9. Just now, KPITSnow said:

    I think we understand that, but given that I showed examples of the same thing with both Michael and Harvey should we not consider the possibility that it is attenuation?

    I'm not arguing the souther eyewall isn't weaker....it seems in every one of these storms there is alway a dominant quadrant of the eyewall...but acting like it is an open eye seems rather absurd to my very untrained self.

    The southern eyewall is clearly weaker in this situation (or at least appears weaker) than in the case of Michael's southeastern eyewall.


  10. Just now, USCAPEWEATHERAF said:

    Because it is likely you have the same problem with both radar sites.  Each site you referenced is either from the NW or NNW or North.  They are trying to dissect a very intense band of northern eye wall convection/precipitation being produced.  The rain is falling so incredibly hard the beam cannot penetrate the band of convection enough to get a sample of the southern portion of the eye and eye wall.

    The second radar site was to the west.  Almost due west.  I can't believe we are still having this argument.  Nobody has even looked to see where KHGX is.

    • Like 1

  11. Just now, andyhb said:

    Here's a radical idea re: the southern eyewall. It's both a combination of attenuation (from KLCH) and partial degradation (via KHGX). There may be some slight attenuation from KHGX since the southern part of the eye is not perfectly east of it, but the southern eyewall is certainly weaker.

    It may not be open, it may not be fully closed, let recon handle that, but it is weaker.

    Jesus christ.

    No! there is no middle ground ;)

    • Haha 3

  12. Just now, MillvilleWx said:

    937.8mb at 40+kts  Yeesh

    The argument is somewhat moot, because my speculation that the strengthening would stop was clearly wrong.  

    In any case, mark my word, the last words I will utter on my death bed are "It was not attenuation!!!! I swear it!!!"

    • Like 2
    • Haha 3

  13. Just now, eduggs said:

    Where are the two radar sites located?  Are the images from exactly the same time.  Clearly the southern eyewall has lower intensity precipitation.  But depending on where the radars are located, there could also be some attenuation of the beams.  In one image, it looks like the radar is located almost due north.  In the other, it looks more like to the NNW.  I don't see how there wouldn't be some attenuation due to an intense hurricane eyewall.  But if one radar site is actually located far to the east or west, then maybe you are correct.

    second radar is KHGX, which is almost due west.


  14. Everyone is speculating, even Rick Knabb.  I'm having a conversation with another professor who is an expert in TCs, and he agrees with my explanation of the phenomena.  I also maintain that nobody has explained why the features shows up in the same spot from two different radars.  I guess we'll see if the VDM contains any remarks.

    • Thanks 1
    • Weenie 4

  15. Just now, WinterWolf said:

    Rick Nab on weather channel just said, it could be that the radar can’t see through the northern part of the eyewall very well, so that’s why the southern eyewall looks somewhat open.  If that’s what folks mean by attenuation..I apologize.  Just repeating what Dr Nab said. 
     

    He was the NHC Director after all...so??? 

    Explain this to me then.  How does "attenuation" show up in the same location from two completely different vantage points.  From KHGX, it should be on the eastern side, but it shows up on the south?

    • Like 1
    • Weenie 2

  16. 2 minutes ago, Windspeed said:
    6 minutes ago, jpeters3 said:
    There are clearly several regions on the south end where echoes drop below 20 dBz though.  So the intense eyewall convection is fairly degraded down there.  I'm not saying that recon will find this region completely devoid of convection and bright moonlight shining in, and these asymmetric eyewall structures are somewhat common in event intense hurricanes.  All i'm saying is that this may but a damper on continued strengthening.  But this seemed to have ignited a massive controversy.

     

    It is what it is. There are light echoes there for certain. But just look at the northern semicircle. This vorticity maximum isn't weakening anytime soon. It might have reached a steady-state. Good enough. Unfortunately the damage has already been cemented for landfall impacts.

    Yeah, I think the point of my original post was missed.  It seemed to have been interpreted as, "this has an open eyewall, it is going to weaken into an open wave before landfall."  In reality, i was just making an observation and speculating as to the influence of this observation on future strengthening.  To set the record straight:

    2 images from different radars at the same time.  Along the line I have drawn, which goes from the eye out into the open air outside the storm, there are no echoes > 15 dBz.

     

    RADAR.png

    RADAR2.png