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November 20, 2008 Meeting Summary

Vijay Tallapragada presented an update on the status of HWRF T&E for the 2009 implementation. He mentioned that the runs for H047 (New GFS/GSI) are concluding. Morris Bender ran the GFDL using the new GFS/GSI at 00z and 12z cycles for most of the available storms. He saw similar results to what was observed with the HWRF, namely that the new GFS/GSI doesn't produce significant differences in track and intensity values. H044 (gravity wave drag) runs for Kiko and Henriette in the East Pacific have been completed. H044 showed no real improvement but no degradation for track statistics and slight degradation from about 12-24 hours for intensity. Some new experiments will be run using Fay, Gustav, Hanna, and Ike from 2008. One set of experiments will feature HWRF runs without the GSI to asses the impact of the GSI on the HWRF, and the other set will use ECM analysis and boundary conditions to asses the influence of initial boundary conditions on the HWRF. Preliminary results showing the HWRF minus the GSI for Fay show strong positive bias in intensity and a westward track bias.

Hyun-Sook Kim presented a status report on the NAOMIex benchmark cases and preliminary results. Mean values of forecasted intensity for Katrina and Rita show a larger negative bias for NAOMIex than H41A. Mean values of track forecasts show similar values for both NAOMIex and H41A. Compared to observations, HWRF-HYCOM exhibits much cooler SSTs than HWRF-POM. This could be due to HYCOM's sensitivity to the wind field and POM's production of a more "rigid" ocean than HYCOM. Hyun-Sook suggested a diagnostic group form to further investigate these cooler SSTs. Such a group would be comprised of Hyun-Sook, Carlos, and Bob Tuleya.

Yihua Wu gave a presentation on initial soil moisture and hurricane-related inland flooding forecasts. His work used an EMC routing scheme to compute the concentration time for runoff reaching the outlet of a grid box and the transport of water in the channel system. His experiment featured two types of experiments: the WET runs used initial soil moisture from GFS for the US while the DRY runs used a combination of GFS and NAM soil moisture for initial soil moisture. Looking at results for the case of Hurricane Katrina, the WET and DRY runs showed some of the largest differences for 12-hr subsurface runoff and 12-hr total runoff. Yihua mentioned that forecasted runoff and streamflow are very sensitive to initial soil moisture, and streamflow forecasted from the predicted runoff using the NAM soil moisture as the initial field is more realistic.

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