http://www.meted.ucar.edu/metedbb/recentTopics/list.page JForum - http://www.jforum.net
However, NCEP was sending the new data accidentally before this date, as per this October 23 notice from NCEP:

"From 28 September through 22 October, NCO was inadvertently disseminating short-range ensemble forecast (SREF) mean, spread, and probability products to AWIPS from both the production and parallel runs. The two SREF runs were sent out at almost the same time. So for any given cycle, users may have been receiving products from either run, or even a combination of the two runs. The SREF products are now being sent exclusively from production to AWIPS."

Since the SREF changes have demonstrated forecast improvement, hopefully this oversight only helped to improve the forecasts of WFOs utilizing the SREF, although it may have made for some confusing inconsistencies if the old and new were mixed together in the output received.

NCEP lists the following as the changes, but note that new output fields and times are not distributed over NOAAport, instead the existing suite of output parameters and times will be distributed from the revised ensemble:
1) Upgrade WRF_NMM version and increase horizontal resolution from 40km to 32km
2) Upgrade WRF_ARW (aka WRF-EM) version and increase horizontal resolution from 45km to 35km
3) Upgrade RSM version and increase horizontal resolution from 45km to 32km
4) Replace a pair of Eta_sat members with WRF_nmm members
5) Replace a pair of Eta_det members with WRF_arw members
6) Replace a pair of RSM_ZhaoCloud with RSM_FerrierCloud
7) Upgrade BUFR code for WRF_ARW members
8) Adjust IC perturbations by using global Ensemble Transform perturbations for NMM and ARW members
9) Breakout the big BUFR output (with all 1376 stations all together) into individual station time-series
10) Increase output frequency from 3hrly to hourly for the 1st 39hr on grid212
11) Add aviation fields into ensemble products
12) Add wind variance into ensemble products
13) Add Richardson-Number based PBL height to the output products.
14) Add simulated radar Composite Reflectivity and echo top to the SREF output products.
15) Adjust all related aspects of the SREF system such as ensemble product generator and bias correction

Stephen]]> http://www.meted.ucar.edu/metedbb/posts/preList/80/232.page http://www.meted.ucar.edu/metedbb/posts/preList/80/232.page GMT
Stephen]]> http://www.meted.ucar.edu/metedbb/posts/preList/79/231.page http://www.meted.ucar.edu/metedbb/posts/preList/79/231.page GMT In AWIPS, these are labeled NAMdng, where DNG stands for Downscaled NWP [Numerical Weather Prediction] Grids.
These products downscale the 12-km NAM forecast to a finer grid using the same terrain fields used for the RTMA and using the full set of model fields available at NCEP.

The NAM DNG products appear in AWIPS in both D2D and GFE and can be used to substitute for the "NAM12" GFE products which use downscaling algorithms limited to the vertical levels and parameters of data available in AWIPS.

Details and comparison between the GFE "NAM12" and DNG products are presented on the DNG pages of the COMET Operational Models Matrix at
http://www.meted.ucar.edu/nwp/pcu2/
scroll down around 80% toward the bottom of the page, to the row labeled Postprocessing/Products, and click on the NAM DNG link in the NAM column.
Today, I am still working on the discussion for temperature, dewpoint, and wind - these are coming shortly. However, all background and the discussions for PoP and sky cover are complete, and side-by-side comparisons for temperature, dewpoint, and wind are there already too. I highly recommend making sure that the Java installed in your web browser has sufficient memory to display the comparison loops. Instructions are provided on the web page containing the loops.

Stephen ]]> http://www.meted.ucar.edu/metedbb/posts/preList/78/229.page http://www.meted.ucar.edu/metedbb/posts/preList/78/229.page GMT http://www.meted.ucar.edu/nwp/pcu2/
in the "What's New!" section at the top of the page.

The most important change with a consistent positive forecast impact in the 2-3 day time range is "partial cycling". The NAM uses a data assimilation cycle that starts 12 hours before the forecast initial time, such as 00 UTC the previous night for the 12 UTC morning forecast cycle. At the 12-hours-prior time (for example, 00 UTC), an analysis is performed using a first guess plus observations valid around that time. It is this 12-hour-old first guess which has changed. Then a 3-hour "forecast" is run, serving as the first guess to an analysis using more observations at 9-hours-prior (for example, 3 UTC), and repeated in 3-hourly increments up to the time of the forecast cycle (for example, 12 UTC). Thus, in total, there are four 3-hour "forecasts", each serving as as the first guess to the next analysis, culminating in the initial analysis for the 84-hour NAM forecast. This allows the model to utilize late data from previous cycles and spin up a dynamically consistent field across the entire domain over the 12-hour pre-forecast time period. Previously, the initial guess at the 12-hour-prior time came from the previous NAM assimilation cycle, so the NAM was essentially cycling on itself. Now, the atmospheric fields (e.g., not soil moisture and other non-atmospheric conditions) are taken from the GFS, using the final GDAS cycle which includes late-arriving data. Thus, now, the NAM forecast has a direct link to the GFS analysis from 12 hours ago, though it has been modified by 12 hours of NAM assimilation cycling.

Example:
12 UTC 84-hour NAM forecast
----------------------------------
1. 00 UTC first guess from GFS final analysis (includes data arriving later than from 00 UTC GFS run)
2. observations + regional GSI --> NAM analysis valid 00 UTC
3. 3-hour NAM "forecast" 00-03 UTC --> first guess for 03 UTC analysis
4. observations + regional GSI --> NAM analysis valid 03 UTC
5. 3-hour NAM "forecast" 03-06 UTC --> first guess for 06 UTC analysis
6. observations + regional GSI --> NAM analysis valid 06 UTC
7. 3-hour NAM "forecast" 06-09 UTC --> first guess for 09 UTC analysis
8. observations + regional GSI --> NAM analysis valid 09 UTC
9. 3-hour NAM "forecast" 09-12 UTC --> first guess for 12 UTC analysis
10. observations + regional GSI --> NAM analysis valid 12 UTC
11. 84 hour NAM forecast from 12 UTC

Stephen]]> http://www.meted.ucar.edu/metedbb/posts/preList/77/228.page http://www.meted.ucar.edu/metedbb/posts/preList/77/228.page GMT Details and a case example illustrating the differences are presented on COMET web pages linked from the Operational Models Matrix. The differences are large and noteworthy - you will notice a significant improvement!
Go to http://www.meted.ucar.edu/nwp/pcu2 then scroll down to the Assimilation System section toward the bottom of the page and click on "Updates" under RTMA.

If you notice anything about the RTMA you would like to discuss, any examples of problems you have seen or something it handled very well, or any questions about the changes, please post here and, if you can, attach an image showing what you are talking about.

Stephen]]> http://www.meted.ucar.edu/metedbb/posts/preList/76/227.page http://www.meted.ucar.edu/metedbb/posts/preList/76/227.page GMT
I am still not happy with some of the RTMA data across our higher elevations. When I examined the RTMA Max Temperature information for 3/11/08, I noticed the MaxT for Snowshoe (highest point in our forecast area) on that date was portrayed as 44 degrees. However, the actual MaxT for that location was actually 37 degrees.

The RTMA MaxT information across the lowlands seemed reasonable.

Has anyone else seen these issues?

Jeffrey Hovis ]]> http://www.meted.ucar.edu/metedbb/posts/preList/75/221.page http://www.meted.ucar.edu/metedbb/posts/preList/75/221.page GMT http://www.meted.ucar.edu/metedbb/posts/preList/74/220.page http://www.meted.ucar.edu/metedbb/posts/preList/74/220.page GMT http://www.meted.ucar.edu/metedbb/posts/preList/73/218.page http://www.meted.ucar.edu/metedbb/posts/preList/73/218.page GMT
So, is it reasonable to along with looking for inversions at the normal levels (~600-700mb), it might be good to also check lower levels (i.e. 750 MB) in the model forecasts closer to the model terrain surfaces? I welcome any thoughts on this!

Either way, this brings up an important point for forecasters to always keep in mind how a particular model replicates terrain features and how those might affect the fields (and levels) you are looking at.
]]> http://www.meted.ucar.edu/metedbb/posts/preList/72/217.page http://www.meted.ucar.edu/metedbb/posts/preList/72/217.page GMT
Where the downscaled terrain is below the 13-km RUC terrain, the temperature is now allowed to be up to 10 deg C colder than the 13-km RUC 2-m temperature, based on multiplying the elevation difference by the low-level lapse rate, though it is still not allowed to be colder than the 13-km RUC 2-m dewpoint. Previously, the lapse rate was truncated at isothermal, preventing the downscaled temperature at lower elevation from being colder than the RUC 2-m temperature. However, the dewpoint is still not allowed to be less than the 13-km RUC 2-m dewpoint.

When the downscaled terrain is above the 13-km RUC terrain, the temperature is now allowed to be warmer than the 13-km RUC 2-m temperature, based on the colder of: 1) multiplying the elevation difference by the low-level lapse rate, or, 2) the free atmosphere temperature difference in the RUC between the downscaled terrain and the lowest RUC model layer. Previously, procedure (2) was used except the result was truncated to not allow a warmer temperature than the 13-km RUC 2-m temperature. Also, the dewpoint calculation was changed so that the downscaled dewpoint now uses the 2-meter mixing ratio from the 13-km RUC based on the pressure at the downscaled terrain height.

Stephen]]> http://www.meted.ucar.edu/metedbb/posts/preList/71/216.page http://www.meted.ucar.edu/metedbb/posts/preList/71/216.page GMT http://www.meted.ucar.edu/metedbb/posts/preList/70/214.page http://www.meted.ucar.edu/metedbb/posts/preList/70/214.page GMT
Hi,

We've noticed a significant reduction in the number of bullseyes in the GMOS during the past month. First of all thanks, second - what changes have been made ? It appears to be helping.

Thanks, Jonathan]]> http://www.meted.ucar.edu/metedbb/posts/preList/69/212.page http://www.meted.ucar.edu/metedbb/posts/preList/69/212.page GMT
Have since tested successfully an email from the jforum configuration interface and moved nwp testuer to nwp admins group.]]> http://www.meted.ucar.edu/metedbb/posts/preList/68/211.page http://www.meted.ucar.edu/metedbb/posts/preList/68/211.page GMT http://www.meted.ucar.edu/metedbb/posts/preList/67/207.page http://www.meted.ucar.edu/metedbb/posts/preList/67/207.page GMT
What is the process to relay a systematically bad ob from the observation. Looks like we have a bad MADIS observation showing up over the Escambia County Florida/Baldwin County line. Can't recollect the ID number off hand.

Stephen Miller
Mobile AL]]> http://www.meted.ucar.edu/metedbb/posts/preList/66/205.page http://www.meted.ucar.edu/metedbb/posts/preList/66/205.page GMT