tomjnx wrote:
CFD means Computational Fluid Dynamics
Or alternately Color For Dollars 
Lucius wrote:
What is the advantage of Skew T? It is just based on the same computed weather models.
Skew T or “Temps” as we called them are actually normally plots of a baloon ascent, so real world data. Some people also make low level plots from stations in different altitudes.
You can actually take a lot out of a plot like that, some of it is explained in the video in this thread. I use them for convective stuff and for inversion warnings as well as of course windshears and winds aloft over a particular station. But there is a lot more which can be read from them.
Model plots have included so called prevision temps for decades, but now they become public domain which is great. Real world plots can be downloaded from the wyoming weather web.
Lucius wrote:
What is the advantage of Skew T?
Cloud layers, freezing level(s). Very, very useful stuff.
skew t is worth its money, become familiar with it
I don’t know if it works in Europe
here in use is extremely accurate for cloud bottoms, cloud tops, winds aloft, icing zones
I never fly without looking at it a better app is Scott Denastedt called weather spork worth every cent
you can plot your course and get a skew t chart along your route and expectations for ceilings, wings aloft and forecast very accurate
magyarflyer wrote:
extremely accurate for cloud bottoms, cloud tops
If it is extremely accurate, why do other products based off of the same computer models struggle with cloud tops, other than a stratus layer? For example, are Skew T diagrams automatically corrected by ingesting pilot report feeds, as other computer models do? If a non-meteorologist can derive meaningful conclusions from a Skew T diagram, so can every weather model codified in programming code, and display the resulting weather phenomena in a more user friendly manner, like the windy.com or aviationweather.gov do.
Mooney_Driver wrote:
Skew T or “Temps” as we called them are actually normally plots of a baloon ascent, so real world data.
I agree for balloon ascents. But these are spread far apart. The Skew T normally accessed through sites like Windy.com are based of off the same weather models and approximated to the closest grid location.
My main nag re windy.com is that the sounding diagram does not have the underlying lines for the dry and saturated adiabatic lapse rates, saturation mixing ratio etc to make it more usable. It is a highly sought after request in their support forums and I hope we can get that feature enhancement soon.
However, if you are generating skew-t diagrams from a computer model, you should get exactly the same 3D information out of it as if you generated a “gramet” (a wx profile along a specified route) from that computer model.
And since interpretation of the lapse rates etc in a skew-t (or the more “classic” tephigram) requires a lot more expertise than looking at a gramet, why bother with the skew-t?
The issue seems to be that the gramets produced by the Autorouter are largely fiction. I don’t know exactly why but they come from GFS and that splits up clouds (IMC) into Low Medium and High and presents these separately. This obviously was supposed to represent the real world of atmospheric physics in that you get different mechanisms producing these three types of cloud in very general terms, but we all know that this is a gross oversimplification much of the time. Often you get solid IMC from 200ft to 25000ft. The algorithms which plot the gramet make certain assumptions in deciding whether to throw in IMC and where, and they get this wrong a lot of the time. What I don’t know is whether ex-GFS skew-ts have the same problem (I think they must have) and whether ex-ECMWF (which from looking at windy.com seems to use the same three layer paradigm) is any better. I think ECMWF is better but this is just from general usage via windy.com.
are Skew T diagrams automatically corrected by ingesting pilot report feeds
PIREPs do not exist in Europe
In Windy, low clouds means less than 6000ft, medium clouds is where you can fly in a GA aircraft IFR en-route, top clouds is irrelevant unless you fly on CAT
They tend to have a nice forecast error on cloud % with those 3 fat layers, trying to predict exact tops of clouds or clouds bellow 2000ft is a different matter….
right now in texas my skew t log shows bases at about 3500 with tops at 6000
a pirep from united airlines a few minutes ago reported cloud bases at 3800 and tops at 5000 clear above
when the red and blue lines converge you have adequate conditions for clouds, as they separate you have certainly no moisture for clouds
the blue band is the icing chances, therefore in this situation you should not expect icing at any altitude due to the spread of the dew line and temps
