jpeters3

Meteorologist
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Everything posted by jpeters3

  1. I generally agree with this - anywhere near, or slightly south of the boundary (and slightly south of the sounding I posted) is going to be prime. I do expect that some of the convection the model is blowing up north of this region is going to be elevated though. Might end up being elevated supercells with the very high low-level SRH, but elevated none the less.
  2. Shallow convection/clouds or warm front are sort of semantics. Shallow convection/clouds is common just north of a warm front. Regardless of what is causing the profile to look like this, the shallow statically stable layer shows up in pretty much every profile north of the KS/NE boarder, and has in several rounds of model runs. What the model shows as SBCIN is not based on the actual surface virtual temperature (you see, the lifted parcel path starts to the right of the surface virtual temperature in the sounding), so the actual SBCIN is probably higher than what is listed on there. You can easily get supercells within an environment like this, but it is very difficult to develop a tornado when surface parcels are convectively inhibited.
  3. I am still convinced that most of the profiles in southern NE are actually slightly north of the surface front, and any supercells that develop there will end up being elevated. Take a look at some profiles out of the high sigtor regions in S nebraska. They all look like this: http://climate.cod.edu/hanis/model/fsound/index.php?type=12|NAM|US|con|stp|36|*129,113*|ml|severe Shallow saturated stable layer.
  4. After looking at the 12Z NAM, I've got my eyes on the KS/NE boarder somewhere between Belleville and Phillipsburg KS. While the NAM goes crazy with sigtor in southern Nebraska, soundings from this area all show a shallow and very moist inversion, suggesting to me that they are north of the effective surface front and that surface parcels in this area will be somewhat convectively inhibited. I like the profiles I see in northern KS around 00Z.
  5. With all the focus on VBV here, I can't seem to find any peer reviewed articles that demonstrate its effect on supercell dynamics. Can someone point me to an article that addresses VBV? From what I gather from rather "hand-wavy" arguments, VBV implies that a supercell ingests the opposite sign of vorticity from its ambient environment at mid levels, which is detrimental to mesocyclone. The problem I have with this argument is that the primary "fuel source," or the effective inflow layer to a supercell is usually well below the layer where the back-veer portion of the profile is. So I'm not entirely convinced that the storm is ingesting the opposite-signed ambient horizontal vorticity at mid levels. I could be convinced that the changes to the storm-relative wind profile implied by VBV results in more precip falling within the storm's inflow region, and thus evaporative cooling contaminating the storms inflow and leading to outflow dominated storm modes. Any thoughts? I spend most of my time reading MCS papers, so I could have missed some recent articles that address this.
  6. You have me on this one. I should have stated 'To the best of our knowledge, Hurricane Patricia is the strongest tropical cyclone in the history of reliable observations'. My apologies for harping on you, and then turning around and making a statement like that.
  7. The assertions in this article are still speculative. You earlier saw with this storm how significantly ADT numbers can sometimes give poor estimations for observed winds. In this case, the observed winds were higher than ADT estimates; however, there is certainly an error margin on ADT, and 'concluding' that unobserved storms that had ADT numbers a few decimal points higher simply isn't good science.
  8. I wouldn't venture to conclude anything from unsubstantiated speculation. Also, the Dvorak estimates for this system were comparable to, or higher than any other numbers I am familiar with. Does anyone recall what the highest observed Dvorak numbers are?
  9. These are probably correct. Dean on the Yucatan in 2007 is another candidate (155 kt I believe).
  10. Just to alleviate any confusion: https://en.wikipedia.org/wiki/List_of_the_most_intense_tropical_cyclones
  11. Hurricane patricia IS the strongest tropical cyclone in history in terms of 1-min sustained winds. End of story. There is no 'sensationalizing' a TC that achieves a low central pressure of <=880 hPa and 200 mph 1 minute sustained winds for > 6 hours. This has never happened since reliable measurements have been taken. Don't try and under sensationalize this event.
  12. No, but I deff woke my girlfriend up like 3 times between 6 and 7am with overly excited and unsolicited updates :-)
  13. I rarely see the GFS initialize with the correct pressure (presumably due to resolution issues). Furthermore, a significant component of storm track and intensity is dictated by large scales... so don't throw in the towel on every run that doesn't get the exact pressure right.
  14. Warmer RFD = better tornado potential. http://journals.ametsoc.org/doi/pdf/10.1175/MWR3288.1
  15. Even if you combine modest helicity with massive w gradients in the vertical (with this much cape, your updrafts are going to be very strong), you'll get spin.
  16. It's not that the models are "tuned" incorrectly for these marginal events. The same dynamics and physics that govern marginal events govern outbreak events. Rather, the events are frequently sensitive to the the upscale influence of prior convection. For instance, the location of cold pools and their boundaries - meso-delta scale atmospheric circulations that contribute to convective initiation. These area all processes that are poorly emulated by, and initialized in models. Outbreak events, on the other hand, are more synoptically driven, and models are better at getting a good handle on the synoptic scale environment. The point being - there isn't an easy way to just "tune" the models to better understand these upscale convective feedbacks and nuances of convective initiation. These processes are inherently chaotic.
  17. Elmer - Tipton tornado assigned preliminary EF-2 rating
  18. With the HRRR hinting at a palmer divide initiation, and the denver cyclone setting up, I may consider driving southeast toward Greeley (or a little bit south) to catch any supercells moving NE off the high terrain.
  19. ? There will almost certainly be storm initiation near the triple point (which is right up against the high terrain). Looks like a pretty decent setup for SE WY / NW NE. Best way to alleviate questions about convective initiation is to plow convectively unstable flow into mountains
  20. Okay this is getting ridiculous. Not much evidence to support an "EXTREMELY DANGEROUS TORNADO".
  21. I suspect the RFD is a bit cooler than optimal. There is a pretty well-defined OFB that trails this storm, and supercells that produce well defined cold pools don't usually seem to be prolific tornado producers (again, due to the RFD/cold pool being too cool). Also, 0-1 km SRH isn't particularly high. Edit: the storm also appears to be moving just east of the region of highest effective SRH.