So after posting the forecast for Tuesday and Wednesday I decided it would be prudent to post some of the snow accumulation maps floating around the internet right now. For my own forecast I tend to use the Weather Prediction Center’s tool which allows me to select ‘accumulation by percentile.’ There’s some statistical math behind which percentile to use. The 50th percentile map tends to be the most realistic in my opinion. Selecting a high percentile can lead to ‘optimistic’ snowfall total predictions, and less than 50 tends to under-estimate snow totals.
In addition to the WPC’s map, I also took the liberty of curating a few other forecast maps from other public weather forecasters:
As you can see, a lot of these broadcast weather forecasters are calling for much higher amounts than I am for the Poughkeepsie and Mid-Hudson area in general. The broadcast consensus seems to be around 9-12″. Even the NWS Forecast Office in Albany is calling for 10-14″ in Dutchess County! I personally think that number is a bit optimistic. Yes, I too calculated about 1.1″ liquid equivalent QPF (~11″ snow) using the 18Z GFS weather model, using the maximum QPF values for each 3-hour period. Conversely though, I also calculated only 0.5″ (~5″ snow) using the minimum QPF values. In my experience, calculating snowfall totals basis the maximum QPF values often leads to exaggerated forecasts which rarely verify.
So, we’re still over 24 hours away from the start of the event so I guess we will just have to wait and see how things develop.