You humored me yesterday by staring at the weather map I posted. I’ll press my luck again this time with four maps! This is a comparison of two different models, the NAM and the GFS, and how they depict rain versus snow.
These are the most commonly used weather models. They’re in agreement right now about as much as the Republicans and Democrats are!
Here’s the setup. Everything you see on the left map is rain. Everything on the right map is snow. An arrow on each map points to Connecticut.
Look closely and you’ll see the GFS favoring the left map over Connecticut. The NAM favors the right.
The exact numbers aren’t all that important now because I can guarantee they’re not accurate! Look instead at the colors. The hotter they are the more precipitation is predicted.
The GFS is forecasting a heavy rain event for nearly all of Connecticut. The NAM is much snowier with rain mixing in close to the shoreline.
Where they both agree is in accelerating the precipitation. It now looks like we’ll see the first of it (whatever it is) sometime Thursday afternoon. The NAM has everything ending around rush hour Friday. The GFS is a little slower and holds the rain into Friday afternoon.
Do you see why this stuff frustrates me so? Sure, we don’t miss them like ’78, but there’s still a lot of hemming and hawing on my part when I’d rather be firm.
Since we’re so much closer to the even my method of forecasting will change a little. I’ll start paying closer attention to how the models were initialized. That means I’ll check to see if that data fed into the computers as they started their work matches the real world conditions. Because of the methods used to create the initial conditions they don’t always!
I’ll keep you up-to-date.
It’s nice to be in the saddle again.