Hot answers tagged

6

I'm no expert at this, I've just been working with a variety of gfs gribs for a while now. The only thing I know about them is what I've read and I'll cite them here. I don't know where you got those files. It looks like you're looking at the files that are sub areas, but in general the file format goes as shown more clearly on this website: data/nccf/...


5

The GFS is a model, and the model have a given time-step equal or smaller than the time-step of the output, that in this case is 3 hours. Different processes can be computed using different or even multiple time-steps. Some of the reported variables are instantaneous, others are cumulative, and others are time averaged. According to the documentation for ...


1

The coordinates defined in Global Forecast System (GFS -0.5º Degree) data defined somewhat unusual. In the GFS, longitudes and latitude contains 720 and 361 values respectively. Therefore to convert them to a common geographic coordinate system follow the procedure below: Suppose you are looking for index of coordinate pairs (36.5, -78.5) in the GFS data: ...


1

** All of the links given with times will need to be adjusted to current dates if reading this at later times or else will appear dead ** Once upon a time I dealt with such files, but not in quite a few years... and Google wasn't the best help at first in finding documentation on what the .ascii is exactly... but thanks to Kevin Goebbert's code here, I was ...


1

I would agree with your hypothesis, but I must point out that it will likely break down further and further as you approach the tropopause. Whether the ISA model is actually a average, I cannot say. However, the idea that the ISA model is a horizontal average is plausible.


1

This is not an explicit answer but might give you an idea. The US National Weather Service forecasters use a tool called GFE to create gridded forecasts, largely starting from raw model data. For most models, even those that have TCDC as an output field, the model sky cover grids are computed by GFE using RH at various levels. For a few of the high ...


1

You are right that upper air soundings are typically only done twice a day, and even at quite a coarse observation spacing. And that upper air data is definitely very important in models. I'd suggest that, firstly, it's important to note that even a broad, very hazy picture aloft really helps a great deal at the surface. That can be seen in the ...


1

Various processes affect the freezing point. Both CCN (cloud condensation nuclei) characteristics and drop size affect the freezing point.


Only top voted, non community-wiki answers of a minimum length are eligible