3km Nam?

[Glen Heinz]

This was new to me, seeing this. I guess it's an upgrade? Anyone have any news on the new 3km NAM? Not finding much info on it or any. Please share with us. Thank you...

If this is in the wrong Forum please move and my apologies...

EDIT:
Just as I post this few minutes later. Look what pops up on my twitter feed? :facepalm:
https://twitter.com/NWS/status/844611751656280064
The PDF file to read up on:
http://www.weather.gov/media/nws/Public_release_notes_NAM.v4.0.pdf

Quote from PDF:
"In the future This is the final science upgrade planned for the NAM Forecast System"

 

[mikegeukes]

Also, the DGEX will be discontinued.
http://www.nws.noaa.gov/os/notification/tin16-41nam_updatesaab.htm

 

[Jeff Duda]

Quote from PDF:
"In the future This is the final science upgrade planned for the NAM Forecast System"

Yes, this upgrade to the convection-allowing CONUS nest of the NAM was operationally implemented recently. Perhaps the main feature is the grid spacing refinement from 4 km to 3 km (not much difference from a theoretical perspective...just makes model fields look a little more realistic).

The quote is right. Since the FV3 model core was chosen for NGGPS last year, and at least as part of a consolidation effort, the NAM as we know it will change dramatically once FV3 becomes operational, but that won't be until probably 2019. However, because of the huge switch to a new dynamical core, no further effort will be placed on improvement or development of the current dynamical core, the NMMB (which has served as the dynamical core for the NAM for several years now). Thus, the NAM is essentially "frozen" in development.

 

[Terry Tyler]

Can someone here please explain what the "NEST" stands for as in "NAM NEST 3K"?

 

[Jeff Duda]

Can someone here please explain what the "NEST" stands for as in "NAM NEST 3K"?

The "12 km NAM" still exists and runs regularly just like it always has (what you're familiar with when referring to "the NAM"). The 3 km nest is a domain nested within that 12 km domain. It's the exact same model, just scaled down to allow for explicit convection (rather than it being parameterized).

 

[Terry Tyler]

Hey Jeff,

Thanks for the response. I was actually referring to what the acronym N-E-S-T stands for.

- Terry

 

[rdale]

It's not an acronym Just means it is "nested" inside the larger domain.

 

[Kyle Brittain]

The new nested domain cut off Alberta, Canada's thunderstorm belt HRRR and NAM 3km only get into the dry, southernmost sections of the province. At least there's still the WRF-ARW and WRF-NMM in the old NAM 4km domain. We also have a 2.5km HRDPS product, but it has CP.
Why can't we have nice things??

 

[Terry Tyler]

It's not an acronym Just means it is "nested" inside the larger domain.

Thanks, rdale

What is the larger domain?

 

[rdale]

The 12km NAM.