Trying to Forecast High Altitude Relative Humidity

[Phil Bates]

I am trying to forecast thick and long lasting jet contour trails (it's unusual, I know). My guess is that I need to find forecasts for relative humidity between 30,000 and 45,000 ft (250 to 300mb?). I know the information is probably available on Unidata or COD, but navigating these sites is daunting for a newbee.

If anyone can help or point me in a better direction, I would appreciate it.

Thanks,
Phil

 

[Chris Foltz]

Phil,

Lots of different options here but Twister Data is a good one. Just click on the "Moisture" tab on the left then select the level you wish to view. You can switch between the various numerical models using the tabs across the top. Hope this is what you were looking for.

 

[Zach Young]

I know it's available on CoD.

1. Go to http://weather.cod.edu/forecast/
2. Select the model and region of your choice (only RUC, WRF, and GFS have this product)
3. You can find it in the sidebar where it says "250 RH".

I don't know if there are other better websites for this data off the top of my head though...

Edit: Oh yeah, twisterdata... That's a great site for things like that. The only drawbacks are that there's no way to animate the models and no way (as far as I know) to zoom in on more specific regions, but the sheer volume of data available there makes up for it.

 

[Phil Bates]

Thanks guys! So it looks like these sites provide forecast data up to 10 to 12 hours out, is that right? I am curious if there are models that predict further out, like 3 or 4 days (?).

Thanks again,
Phil

 

[Zach Young]

You must be looking at the RUC only. The RUC is run every hour, but only goes out 10-12 hours. To get longer range forecasts, you need to look at the WRF (aka NAM) which goes out 84 hours, or the GFS which goes out 240-384 hours depending on which site you're looking at.

 

[Phil Bates]

Thanks Zach, I'll explore those.

Phil