Over the past week here in Rochester and our surrounding areas, we have seen a good amount of lake effect snow and light drizzle. With that, you have heard us say sometimes the radar can’t “see” the precipitation, whether that be the rain or snow, –but what exactly does that mean?

Well, when we say that the radar beam is too tall to see the precipitation, it means just that. The three main radar sites that we use to track and see precipitation are in Buffalo, Binghamton, and Montague, all in New York. Radar beams shoot straight at a slight angle up, which is contradictory because the Earth is NOT flat (hate to break it to you flat-earthers). With that said, as the radar beams from these three sites get further away they increase in altitude, or height above the surface. The closest radar site to our region, Buffalo, has a beam height of about 4,500 feet when it is overhead here in Rochester. This means that precipitation falling below that height will not send a return back to the radar site while precipitation above that height will.

This is the predicament that we have in our area when in comes to lake effect snow and even low level drizzle. For instance, the lake effect we had last weekend did just that. For areas Rochester eastward, the snow was hardly seen by the radar even though it was snowing in those areas while the snow was showing up the radar screen west of the city. This is not a new problem, as this is a reoccurring issue for other areas across the country — especially the Southeast during severe weather season — but something that us meteorologists need to understand to forecast correctly. Just because it’s not on the radar doesn’t mean it isn’t snowing or raining.