Errata added May 18, 2023.
This article was intended to point out a limitation in the HRRR data provided by several sources in that the wind directions on the two US coasts could be off by 10 to 15º. Several sources corrected the output shortly after this observation was reported, but others took longer to correct. Now we can report that all sources we originally referred to have updated the data output. It appears now that the HRRR data from the various public sources are now identical to what we would get from a direct NOAA download. We have not confirmed this for the other models in grib 2 Lambert format shown below.
Our lead weather instructor, Dave Wilkinson, serves on the race committee boat for setting up the race courses based on local forecasts in Port Townsend, WA. He uses several regional models for this, but his workhorse has been NOAA's High Resolution Rapid Refresh model (HRRR). He obtains the forecasts and views the data by two independent methods: the LuckGrib app running in an iPad and the qtVlm app running on a PC laptop. LuckGrib provides the HRRR data directly from their server; qtVlm offers an internal method of getting the data from a third party server.
As races came and went, he noticed a consistent discrepancy in these two presentations of what we all thought was the identical forecast—double-checking that the area covered, and, more importantly, the computational time of the forecasts were the same. HRRR is updated every hour and extends out 18 hr.
qtVlm has a convenient way to make this comparison as we can load both grib files and show them overlaid with different wind barb colors, as shown below.
C:\Users\macdavid\Desktop\wgrib2>wgrib2 -var -vector_dir LG_HRRR.20220909.21.grb2
C:\Users\macdavid\Desktop\wgrib2>wgrib2 -var -vector_dir NM_NOMADS_direct_HRRR.grb2
C:\Users\macdavid\Desktop\wgrib2>wgrib2 -var -vector_dir S2_HRRR_09_09Sep22_224022.grb
This is the 3rd hr forecast computed on 9/17/2022 at 18z (valid at 21z 9/17) for the lat lon box shown. Change these inputs as needed and paste into a browser to get the grid referenced HRRR forecast.