Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) Forum

Re: computation of VFR/IFR in RUC

Posted By: John Brown
Date: 24-August-07 1847Z

In Response To: computation of VFR/IFR in RUC (Douglas Swol)

VFR, IFR, etc are based on the RUC postprocessed ceiling and visibility. At each hour, a cloud and precipition hydrometeor analysis procedure is used to combine a 1-hour forecast with satellite cloud-top information, surface METARs, radar reflectivity, and other data to obtain initial conditions for each model forecast, including cloud and precipitation. During the forecast, cloud and precipitation are predicted. In the postprocessing of model forecasts (or of initial conditions), ceiling and visibility are derived from the model output variables, then the VFR, IFR, etc., ceiling and visibility criteria are applied to get the fields of flight rules. The procedures for obtaining ceiling and visibility from the model output variables are briefly described on the RUC web site, at the link http://ruc.noaa.gov/vartext.html. Hope this helps...

Messages In This Thread

computation of VFR/IFR in RUC -- Douglas Swol -- 23-August-07 1819Z

Re: computation of VFR/IFR in RUC -- John Brown -- 24-August-07 1847Z

Re: computation of VFR/IFR in RUC -- Douglas Swol -- 27-August-07 1532Z

Re: computation of VFR/IFR in RUC -- Bill Moninger -- 27-August-07 1658Z

Re: computation of VFR/IFR in RUC -- John Brown -- 27-August-07 2002Z

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