NCEP Model Evaluation Subscribers,
The Environmental Modeling Center (EMC) has proposed an upgrade to
the Short Range Ensemble Forecast system (SREF).
The model changes include: 1. Three of the four models used in the SREF
(NMM, ARW and RSM) will be upgraded in model version (NMM and ARW from
WRF V2.0 to WRF V2.2 and RSM from V2003 to V2008) and increased from
40/45 Km to 32/35Km in horizontal resolution. The upgrade and increased
resolution significantly improve the performance of each individual
member. For example; reducing the temperature bias for WRF members and
adding more spatial detail. As a result, better behaved probabilities
are also achieved by increasing forecast sharpness for the ensemble as a
whole. 2. Increase of WRF membership (NMM from 3 to 5 and ARW from 3 to
5) and reduction of ETA membership from 10 to 6 (members N3, N4, P3 and
P4 are removed) 3. More physics diversity by switching from Zhao Cloud
Scheme to Ferrier Cloud Scheme in 3 out of 5 RSM members. 4. Forecast
output, GRIB, frequency will increase from 3-hourly to hourly for the
first 39 hours. 5. Four new aviation products will be added to ensemble
products, mean and variability:
Icing Clear Air Turbulence Ceiling
Flight Restriction 6. Three new products will be added to the
individual member output for some members:
PBL Height, Richardson number = 0.25 Simulated
composite reflectivity Echo Top, =18.3DBZ 7. Each SREF member
BUFR output will be broken out into individual station time series.
*Near real time parallel data:* Beginning Monday, September 28, 2009, a
consistent parallel feed of data will be available at:
FTP: ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/sref/para
HTTP: http://www.ftp.ncep.noaa.gov/data/nccf/com/ofs/para
We will make the model output available for 15 days starting Monday, 28
September so that end-users of the SREF data can verify that no
unforeseen changes have been introduced.
Any comments on this proposed change will be appreciated. Any feedback
you wish to provide during the evaluation period should be emailed to
NCEP.List.ModelEvalFeedback@xxxxxxxx prior to 16 October, 2009.
The Environmental Modeling Center, EMC, has a publicly available website
which can provide users with more information concerning the SREF:
http://www.emc.ncep.noaa.gov/mmb/mesoscale.html
Thanks
Dan Starosta
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