Off Hour Model Runs and the 4/10/2011 Setup

[Zack Hargrove]

I know this is a forecast thread, so my question can be deleted if necessary, but I feel it is relevant to the discussion. But balloon data is not ingested into these off hour NAM runs are they? Could this be a possible reason why the trend is not as positive as the last NAM run? Can we see the NAM revert back to a more solid setup?

*Edit, thank you for transferring this to the right forum.

 

[rdale]

Balloon data is ingested (although there isn't as much as flies during 00/12Z) and it also gets new surface data, satellite data, aircraft soundings, etc. I'm not sure what you mean by a "positive" trend?

 

[Zack Hargrove]

Sorry, I guess positive trend is a relative term. To me, the strong tornado threat from the 18 Z NAM seems to have died a good deal and looks to be turning into mainly a linear event. I am wondering how likely it is that the model trends back towards a more discrete/cellular type of solution.

 

[rdale]

I see what you're saying... In general I find the off-hour runs aren't adding a lot of value in 24+ hour timeframe. But that's a very flexible opinion. Usually when an 6/18Z run makes things look better, you'll find plenty of posts from people saying they're great runs

 

[Zack Hargrove]

Yah, more than anything, I just know that balloon launches only happen twice a day, so I was curious about that when it comes to off hour models. I know that there is a ton more input that go into models than just balloon data, but I feel like the balloon data is extremely important. Guess we'll see what the 00 Z models look like later. I don't have plans this weekend and I really want to go out to Iowa, but I am sick of chasing lines and will cancel if thats the case again. For a while there, I thought we may be looking at our first High Risk of the year this coming Sunday... now the latest 18 Z NAM has me doubting again.

 

[GPhillips]

This is extraordinarily general, and not necessarily applicable to forecasting severe weather for the U.S., but at least at 500 mb, 5 days out, in the Northern Hemisphere, the "off hour" runs, on average, seem to do a little better than their "on hour" previous run. You can see that the improvement from one run to the next of the GFS is higher going from 06Z to 12Z or 18Z to 00Z, than it is going from 12Z to 18Z, or 00Z to 06Z. But there is, on average, improvement even in the off hour runs over the previous run.

http://www.emc.ncep.noaa.gov/gmb/STATS/html4x/esd500x.ver.html

Of course, the ECMWF is still king, on average.

http://www.emc.ncep.noaa.gov/gmb/STATS/html4x/rmsz.html

It would be great to see graphs like this for shorter terms, and for output variables that are utilized in severe weather prediction.

 

[Zack Hargrove]

Good information. Thanks! I would like to see how the off hour runs do in the 2-5 day range. I still like what I'm seeing from the ECMWF, so hopefully we'll still have a chance for some nice strong tornadoes out in a field Sunday.