http://www.meted.ucar.edu/metedbb/forums/show/4.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 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 http://www.meted.ucar.edu/metedbb/posts/preList/74/220.page http://www.meted.ucar.edu/metedbb/posts/preList/74/220.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
An example of this was from the 12 UTC 6/1/07 NAM which indicated the surface dewpoint temperatures at 18 UTC would be in the mid and upper 60s across the southern coalfields of West Virginia. The dewpoint temperatures were expected to increase to the lower and mid 70s by 21 UTC.

At 18 UTC, the surface dewpoint temperatures were actually in the mid to upper 50s.

Has anyone else noticed this problem?

Does anyone know if anything is being done to correct this?
]]> http://www.meted.ucar.edu/metedbb/posts/preList/62/199.page http://www.meted.ucar.edu/metedbb/posts/preList/62/199.page GMT
What is interesting is that the UKMET, NOGAPS and from what I can tell the ECMWF (looking back at some old day 3 forecasts) have this very impressive system.

CMC's GSM has missed Lane too. I was able to look at some of AFWA's MM5 runs - one of their runs (N. American 45km) missed the system, while their E. PAC MM5 run has it.

There must be some key data set that some have and others do not.

What are the NCEP analysis systems missing? I'm wondering if there is some source of satellite data missing?

Thanks - Jeff ]]> http://www.meted.ucar.edu/metedbb/posts/preList/53/185.page http://www.meted.ucar.edu/metedbb/posts/preList/53/185.page GMT
The changes increase vertical and horizontal mixing, which principally have the effect of eroding thin marine layers which have been advecting inland much too far in the Pacific northwest area. The changes will mix the boundary layer deeper in areas of complex terrain and dry climate with marine influence such as around the Great Salt Lake, and it reduces the frequency and intensity of grid-scale precipitation bombs, though there still are often swaths of very heavy precipitation in areas of strong synoptic or mesoscale forcing when precipitable water is high.

Also, the surface roughness is reduced, especially over high terrain, resulting in stronger 10-meter winds. The 10-meter winds over the west had a pronounced low bias and recent stats for the parallel runs show the bias is considerably improved but the RMS error stats are not improved. However, this is a short sample, we need to watch it over a longer period to see whether the RMS may improve from the bias improvement.

These changes may also affect sea and lake breezes and possibly hurricanes and any other phenomena with extremely sharp gradients. I suspect the model will be less likely to produce spurious hurricanes but may also be less effective at simulating the inner core of real hurricanes, however both of those await some examples to see if my expectations are correct or not.

Stephen]]> http://www.meted.ucar.edu/metedbb/posts/preList/52/180.page http://www.meted.ucar.edu/metedbb/posts/preList/52/180.page GMT http://www.meted.ucar.edu/metedbb/posts/preList/51/176.page http://www.meted.ucar.edu/metedbb/posts/preList/51/176.page GMT
I'll add this topic for the forum, even though the event took place the day before the NAM WRF NMM became operational.

I've attached some graphics as an example that came up in a discussion I had with some forecasters on Tuesday; how well did the NAM NMMWRF do compared to the NAM Eta with the flooding rains in Houston TX on 6/19. These are from the [url http://wwwt.emc.ncep.noaa.gov/mmb/ylin/pcpverif/daily/]Meso Modeling Branch precip verification webpage[/url]. Note that there really isn't much of a qualitative difference between the two, though it would appear that the NAM WRF-NMM had a little bit better intensity and placement. The Hi Res window versions of the WRF (with the NCAR/ARW/EM dynamics and the NCEP NMM dynamics) for the central region (not attached, but in the web page) produce prodigious amounts of precipitation; in fact, TOO much of it, but that would be a big heads up for the forecasters.

If you check out the webpage, you'll see that the GFS had the most precip. and the most consistent and accurate forecast as far out as 72 hours!

Bill]]> http://www.meted.ucar.edu/metedbb/posts/preList/48/170.page http://www.meted.ucar.edu/metedbb/posts/preList/48/170.page GMT in regards to relative humidity/dew point/temperature depiction
over the Great Salt Lake. This was noted in the parallel NAM testing as well.

An example included demonstates the nearly saturated layer that the
NAM-WRF displays over the GSL. Based on observations over the the lake
the NAM-WRF forecast is 50 to 70 percent too high for RH. This is also
affecting KSLC (Salt Lake City) BUFR data as depicted by the stable
marine layer in the attached sounding. We have had RH issues (too high)
before with the NAM-Eta but they were inconsistent and often in the
mountains. This appears to be tied to SST temperatures or other changes
to the GSI for the NAM-WRF. A local version of the WRF-NMM shows
considerable improvement. Perhaps it is possible to incorporate AVHRR for
the GSL or even climatology?

I will send another email with additional images.

Regarding convection, overall the test period was acceptable but we have
yet to see the NAM-WRF during a true monsoon. Recent examples during
"dry" westerly flow showed that the NAM-WRF produced unrealistic rainfall
over a small area when precipitable water was less than 0.40 inches. An
attached example was observed on several consecutive runs of the
NAM-WRF from June 23-24 2006. Though high based moist convection
was observed rainfall was minimal. NAM-WRF QPF was as high as 3 inches
over a small area. Runs of the local WRF-NMM using the KF scheme
predicted no precipitation. The behavior of the NAM-WRF in this situtation
looked similar to explicit convection results using the local model.

Any comments would be appreciated. Thanks!

Alex Tardy
WFO SLC]]> http://www.meted.ucar.edu/metedbb/posts/preList/47/171.page http://www.meted.ucar.edu/metedbb/posts/preList/47/171.page GMT
The webcast has a 40-minute short version focusing on the most practical information at
http://www.meted.ucar.edu/nwp/NAMWRF_short/
and a 65-minute full version that has more complete explanations at
http://www.meted.ucar.edu/nwp/NAMWRF/

However, for NOAA staff to obtain credit in the NOAA LMS, you should instead select the course through the LMS and take the quiz (same for both versions):
http://e-learning.doc.gov/noaa/
(short version is "The NCEP NAM-WRF Model (Short version)". full version is "The NCEP North American Mesoscale (NAM) Weather Research and Forecasting (WRF) Model".

Neither version has sufficient technical detail for someone wishing to conduct research experiments with WRF, though the full version may supply some useful introductory information about the operational model. Also, the webcast does not cover several new output parameters which are not available in AWIPS even in future AWIPS plans. The webcasts are oriented toward forecast application.

I am developing teletraining focusing on case examples. Probably this teletraining will begin delivery in early to mid July. We are also working on updating the COMET Operational Models Matrix
http://www.meted.ucar.edu/nwp/pcu2/
with information about NAM-WRF, but that will not be completed until later in the summer.

If you have any questions about the model not covered by currently available material, please do post your questions in this forum.

Stephen]]> http://www.meted.ucar.edu/metedbb/posts/preList/46/168.page http://www.meted.ucar.edu/metedbb/posts/preList/46/168.page GMT http://www.meted.ucar.edu/metedbb/posts/preList/45/166.page http://www.meted.ucar.edu/metedbb/posts/preList/45/166.page GMT
Here's a screen capture...
]]> http://www.meted.ucar.edu/metedbb/posts/preList/44/158.page http://www.meted.ucar.edu/metedbb/posts/preList/44/158.page GMT Subject: NMM (Parallel NAM) bullseye instance
Date: Fri, 12 May 2006 12:16:34 -0400
From: Peter Wolf

Was curious if the following had been observed by others presently
evaluating the NMM (ParallelNAM) version prior to implementation.
Overall, we're finding NMM doing better than the NAM. From today's 06z
run, however, I noted the following in Glynn County GA (coastal county
just north of FL border):

For 12z Sun (54hr fcst): Surface fields looked normal on the NMM. No QPF
forecast in the area. Broad southwest surface winds 10-15kts forecast.

For 15z Sun (57hr fcst): Minimum bullseye in surface temp and dewpoint
fields, with temps in the bullseye 10 degrees F cooler than well outside
of Glynn Co. GA (and 5 degrees cooler than at 12z). Surface winds
displayed divergent pattern...southwest winds across and north of
bullseye, northwest winds south of bullseye. QPF field showed a broad
band of 1/10" extending from bullseye area westward across southern
GA....there was no bullseye of either qpf or vertical motion in the
bullseye area.

For 18z Sun (60hr fcst): Fields return to normal, with no evidence of
bullseye, and southwest surface winds across the area.

Was unable to make images of case before it got replaced by later run.
The same run of the NAM showed no such bullseye in that timeframe. Any
thoughts on what could have caused this, and why it disappeared so
quickly thereafter? Will forward a message on Meted forum once
registration is complete. Was curious if anyone else evaluating the NMM
has seen this occur, and be so localized in nature.

Thanks...

Pete Wolf, SOO
NWS Jacksonville]]> http://www.meted.ucar.edu/metedbb/posts/preList/41/141.page http://www.meted.ucar.edu/metedbb/posts/preList/41/141.page GMT