Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) Forum
improved ceiling/vis fcst - operRUC change-8 Jan08
Posted By: Stan Benjamin
Date: 10-January-08 2036Z
A crisis change was made to the operational RUC on Tues 8 Jan 2008 (2 days ago) primarily to improve assimilation of METAR cloud and visibility observations. Some conditions in the RUC cloud analysis (merging background 1h fcst 3-d hydrometeors with GOES cloud-top data and METAR cloud (multiple levels) and visibility were found to be too stringent. FEW and SCT cloud obs were not being used properly.
With the new changes, the POD-yes and false-alarm fit for IFR, LIFR, and 1-mi vis to the METAR ceiling and vis obs in analyses and short-range forecasts are much improved. Thanks to Dave Rudack at NWS/MDL for help in identifying that there was a problem.
Two other small fixes were also made - fix to wind gust (thanks to Dave Novak - NWS-ER) and to precipitation rate (thanks to Ismail Gultepe at Environment Canada).
There is a nice 2-page write up on these changes with verification over the last 2 months available at http://ruc.noaa.gov/gif/ruc13/RUC-crisis-change-Jan08-summary.pdf
Questions are welcome.
Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) Forum is maintained by RR/RAP Forum Administrators with WebBBS 5.12.