Previous blog posts and presentations have introduced the ability to diagnose plumes of blowing snow in GOES ABI imagery. In particular, the feature becomes apparent in the Day Snow-Fog RGB, primarily due to contrast of the plumes with surrounding environment in the Snow/Ice band and Fog Difference, and shadowing. Recent snowfall and strong winds resulted in a widespread blowing snow event across southern Saskatchewan/Manitoba into North Dakota on Jan 8. Surface observations and webcams reported considerable visibility reductions within the region of blowing snow as detected by ABI and VIIRS, including some areas to less than 1 mile. The blowing snow was pointed out by Carl Jones (NWS/FGF) on Twitter:
An experimental Blowing Snow RGB captured the blowing snow well across the region, as a shade of gold to dark yellow compared to the red snow-covered background and blue of clouds. Some plumes of blowing snow appear to develop into HCRs at times (as was documented in this paper), and have shadows associated with them in the imagery. Recall, this experimental RGB is similar to the Day Snow-Fog RGB available in AWIPS, but with the higher resolution 0.64 um band replacing the 0.87 um band, and with ranges tweaked to better highlight the blowing snow feature.
Compare the Blowing Snow RGB in Fig 1 with the Day-Snow-Fog RGB in Fig 2.
A similar experimental Blowing Snow RGB can be applied to VIIRS 375 m I band imagery, providing excellent spatial detail (Fig 3 and Fig 4). The individual plumes/HCRs of blowing snow can better be observed, as well as more subtle areas of blowing snow. Combining NOAA-20 and S-NPP, an animation of four VIIRS swaths can be created within a period of ~2.5 hours. Of course, ABI has the advantage in showing the longer evolution of blowing snow with time. Utilized together, one gains an ideal understanding of the feature and its evolution.
Bill Line, NESDIS and CIRA