Rapid Update Cycle is going away...sort of...

For those that use the RUC model, it is being "semi-retired." The RUC will be replaced with the Rapid Refresh model on 24 January 2012 per this technical implementation notice. This will affect the RUC soundings tool ([rucsoundings.noaa.gov]) and the Current Icing Product and Forecast Icing Product that both use the RUC.

I know some pilots use the RUC soundings, however, I am not sure how the interface will change. For the moment, the RUC will still be run for the next six months, so things won't change until then. Right now, there is a RR1h option for the Rapid Refresh that has been on the data entry page for the RUC soundings. That should remain available. I'll post more as I find out some info from the developers.

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™



Edited 4 time(s). Last edit at 12/19/2011 06:35PM by Scott Dennstaedt.

Wow that's crazy. Keep us informed..

Due to the holidays and other issues that have occurred, the transition to the Rapid Refresh has been postponed until March 6.

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™



Edited 2 time(s). Last edit at 03/20/2012 05:57AM by Scott Dennstaedt.

From the good folks at NCAR:

Quote:

The latest estimate for RAP implementation is now 20 Mar 2012. The 30-day evaluation had to be restarted twice to allow fixes to a post-processing problem on the Rapid Refresh lateral boundary. Although this problem was not related to the model or assimilation, by the rules, it was still necessary to restart the schedule.

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™

Update:

Quote:

Although the RAP evaluation resulted last Monday in a recommendation at NCEP for implementation, some computer issues have arisen since then resulting in a delay in the RAP implementation until no earlier than Tuesday, 3 April 2012. As the new implementation date is hardened, that information will be posted.

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™

Here's the newest information on the transition to the RAP model....

Quote:

The new scheduled date for RAP implementation is now either 1 May or 8 May 2012. It was found that due to a script problem in the NCO version, the RAP had not been assimilating radar reflectivity data in 2012. Two other smaller issues were found also due to script issues: lack of GOES cloud-top data over full RAP domain, and issuing of 0h/analysis fields after the RAP digital filter initialization instead of before. The NCEP Centers will re-evaluate the RAP guidance now including these revisions for the next 30 days. Again, the planned implementation date is now set for 1 May or 8 May (both Tuesdays).

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™

Appears they've settled on a date of May 1, 2012.

Quote:

The Rapid Refresh (RAP) model will be implemented May 1st. The RAP will be used as the forecast model that provides the initial forecast conditions instead of the Rapid Update Cycle (RUC) for Automated Icing CIP, FIP and Turbulence GTG products. In conjunction with the upgrade of RAP model, GTG will be upgraded from 20KM to 13KM resolution. During the upgrade process some interruptions of data availability may be possible. Further guidance can be found in the TIN for the RAP and GTG TIN.

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™

This transition appears to have taken place as of 12Z on May 1, 2012 with some issues as indicated here.

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™

Wow, the data seems to be pulled very slowly for each RAP sounding set, vice the old RUC. Many, many seconds inbetween.

Also, what is the new DFI label, where I might expect to see A for analysis?

* Orest

Quote:

Orest Skrypuch
Wow, the data seems to be pulled very slowly for each RAP sounding set, vice the old RUC. Many, many seconds inbetween. Also, what is the new DFI label, where I might expect to see A for analysis?

Yes, any data inputs at the bottom (below the line) are going to be slow given the format of the files that are read. Op40 and Bak40 are read from an older format called GRIB(1). The files below the line such as RUC20 and RR1h are read from GRIB2 files. GRIB2 is the new NCEP standard, and is the format they plan to use for all products in the future. The GRIB2 files are smaller than GRIB(1) files, but slower to decompress and read. The resulting data are identical.

DFI is the analysis counterpart. It stands for Digital Filter Initialization.

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™



Edited 2 time(s). Last edit at 05/02/2012 04:20AM by Scott Dennstaedt.

Comparing the new RAP sounding plots, and the old RUC (using Bak40), "side by side" does demonstrate some significant differences in the outputs.

* Orest

Quote:

Orest Skrypuch
Comparing the new RAP sounding plots, and the old RUC (using Bak40), "side by side" does demonstrate some significant differences in the outputs.

Yes, they are two different models. I find that the RAP model does better with moist-unstable environments. Often the RUC model would produce saturated lapse rates greater than the moist adiabatic lapse rate in rather deep layers...you just don't see this kind of moist-unstable lapse rate in nature. The RUC model also had a tendency to produce many more false alarms for dense fog scenarios - especially beyond about 12 hours in the forecast. In these cases, the NAM or GFS would typically underestimate the potential for low clouds. So when the RUC was implying OVC001 and the NAM/GFS was suggesting OVC025, I would usually split the difference and go with OVC010 and be correct most of the time. Appears that the RAP model does a bit better in this area.

BTW, it appears you will still be able to use the Op40 and Bak40 input data source until they eventually stop running the model - projected to be near the end of the summer. Who knows, they could continue to run the model for several years.

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™



Edited 1 time(s). Last edit at 05/04/2012 05:08AM by Scott Dennstaedt.