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About scottd

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    : Charlotte, NC
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    Weather, writing, flying

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  1. That's correct Mike, I retrieved it from my app...sorry for my poor ain't too good sometimes.
  2. Bob, I pulled the Skew-Ts out of my WeatherSpork app, but you can also get them from The NOAA site has been operational since about 1997 or so. The site you are using are satellite-based soundings from GOES.
  3. Jeff, Here's what I said... "Notice that the lapse rate beginning at 8K nearly follows the moist adiabatic lapse rate." That's the MALR, not DALR. Yes, when the atmosphere is saturated (as it is here) and the environmental lapse rate is moist adiabatic (follows parallel to the MALR), then it's the most unstable as it will get. Instability means there's a large change of temperature with height. Yes, the curved "brown" line is the MALR reference line (see below). In this case, the environmental lapse rate is at its greatest between 8K and about 10K. The more the line leans to the left, the more unstable the atmosphere. So there's a stable or nearly isothermal layer below this (below 8K). I've flown into an area like this before (through the Richmond, VA area) and it feels like you are driving a car fast over an endless road of speed humps.
  4. Alex, In my experience, unless you are doing your checkride for a glider rating, no, most DPEs don't even know about a Skew-T diagram. Now, if they ask you, "How do you determine the freezing level along your proposed route?" you could say, "I use a Skew-T diagram to help make that determination." Or if you are a WeatherSpork user, you could show the examiner the profile view that depicts the freezing level along your entire route (dotted blue line).
  5. Jeff, Instability is all about lapse rate. Large lapse rates means unstable air. Notice that the lapse rate beginning at 8K nearly follows the moist adiabatic lapse rate. That's the largest lapse rate Mother Nature can dish out in saturated conditions. You can find this article I wrote in IFR magazine many years ago that discusses lapse rates that should help.
  6. If you are not a Skew-T fanatic, you should be. Here's an excellent example of what the Skew-T can do for you. Take a look at this Skew-T analysis from 15Z in southeastern NC. Notice at about 6,500 ft MSL, the winds are from the southeast at 58 knots and then around 9,300 feet, they are from the southwest at 57 knots. This is an excellent example of directional shear in the wind aloft. The key though is the moist unstable layer that starts just below 8,000 feet that enables the air to mix. All of this coupled together is the reason this pilot reported extreme turbulence at 8,000 feet MSL. If you are not a Skew-T fanatic, make a New Year's resolution to become one!
  7. Looks like I got two out of the three precip types right. Not going to mix in snow because the warm nose turned out to be too warm. So, just -FZRAPL. This shows, however, that it is snowing aloft, but the snowflakes are partially melting and refreezing into little nuggets. Overall in the S. Charlotte area, this turned out to be a very cold rain for the most part. Got some moderate ice pellets overnight, but nothing really to write home about.
  8. You are very welcome. You'd really like the next live workshop I'm doing starting in the Spring. It'll be a one day program that will discuss inflight weather hazard avoidance. The workshops I've done in the past 15+ years have all been (for the most part) oriented around preflight weather analysis...this will be one that focuses on the actual flight hazards with a little preflight analysis thrown in.
  9. Actually the GFS MOS valid at 18Z says "Z" which means freezing precip or a mixture.
  10. All good instincts so far. The answer is that it's could be just about any precipitation type or mixture given this profile. The cloud top temperatures are still kind of warm, but cold enough to start to build ice crystals and snowflakes. The temps only climb a degree or two above freezing over a 3,000 ft layer. This isn't typically enough to melt snow completely. But if any melting does occur in that layer, you will likely see the drop maintain a slushy core and there's a pretty generous layer of cold air just above the surface to refreeze the slushy core into an ice pellet. Here's the tough issue. If complete melting occurs, you may get freezing rain at the surface - if the surface temperature happens to be below freezing (it's pretty close). If it's above freezing, it's just rain (although freezing rain aloft). If it freezes into an ice pellet, then it'll reach the surface as an ice pellet. If it doesn't melt much at all, then you will get snow and if it melts just a little you may get graupel or snow grains. And the final catch-all is that there could be a mixture of snow, freezing rain and ice pellets...that would be my forecast at this point. So something like -FZRAPLSN
  11. Can't get credit for the answer unless you give some details as to why.
  12. Based on the GFS forecast sounding shown here in the WeatherSpork app below, what precipitation type would you expect to see reaching the surface at the Charlotte Douglas Int'l Airport (KCLT) at 18Z on Sunday? And of course, credit for the correct answer involves also answering why.
  13. FYI - Effective Tuesday, December 4, 2018, at 1800 UTC, the NWS office in Tulsa, OK, will temporarily suspend TAF service for McAlester Regional Airport (KMLC) in McAlester, Oklahoma. Service is suspended due to the unavailability of surface observations due to construction.
  14. FYI - Effective Wednesday, January 30, 2019, at 1800Z, the NWS office in Paducah, KY, will begin TAF service for Mount Vernon Outland Airport in Illinois (KMVN).
  15. scottd

    Wedding news

    Congrats!!! I just walked my oldest daughter down the isle on Saturday. Amazing day and amazing weather!