Abstract: Recent and Planned Changes to the NCEP Eta Analysis and Forecast System (18th Conference on Weather and Forecasting, 14th Conference on Numerical Weather Prediction, and Ninth Conference on Mesoscale Processes)

Monday, 30 July 2001: 9:50 AM

Recent and Planned Changes to the NCEP Eta Analysis and Forecast System

Eric Rogers, NOAA/NWS/NCEP, Camp Springs, MD; and T. Black, G. J. DiMego, Y. Lin, K. E. Mitchell, D. Parrish, M. B. Ek, and B. Ferrier

On 26 September 2000 several major changes were implemented into the NCEP operational Eta analysis / forecast system, including:

- Increase in resolution from 32 km / 45 levels to 22 km / 50 levels - Direct assimilation of GOES/TOVS radiances in the Eta 3-d variational (3DVAR) analysis

During the next 6-12 months EMC plans to implement several improvements to the operational Eta system. The first group of changes is planned for the spring of 2001 and should be completed at conference time:

- Modifications to the Eta 3DVAR analysis to improve mass-wind balance constraint - Assimilation of observed precipitation during the Eta Data Assimilation System (EDAS) - Modifications of the Eta model land-surface physics

The second group of changes is planned for November 2001:

- Increase resolution from 22 km / 50 levels to 12 km / 60 levels - Hourly assimilation of NEXRAD WSR88D radial velocity data in the EDAS - Assimilation of GOES cloud cover data - Upgrade to the Eta model prognostic cloud water scheme - Upgrade the shortwave radiation scheme

Results from real-time parallel testing of these changes will be presented, along with selected retrospective cases in which the operational Eta forecast was deficient (such as the 30-31 December 2000 East Coast snowstorm).

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