IWX discussion. Lol @ the first paragraph
The social media rumblings are gradually turning to a roar regarding
the snow potential Monday through perhaps Wednesday. This event is
far from a slam dunk. Regardless of the track of the surface low
that has everyone`s attention, there is also a notable lake effect
snow threat.
The previous three GFS runs (12z Today included) show a closed
low at 500 mb over southern Illinois (18z Monday), and a surface
low near Pittsburgh. The 12Z ECMWF upper-level pattern is a touch
farther east and less of a closed low at 500 mb. However, the
surface lows are in similar locations. Go back three runs and the
solutions are somewhat steady. However, add an additional 3-4
model runs and the solutions are erratic. I mention this because I
would like to see even more run to run consistency. Tracing the
northern stream 500-mb jet, this feature should arrive onshore of
British Columbia on Friday afternoon. This *should* improve the
modeling of this feature in subsequent runs, and therefore improve
the confidence in the forecast track.
Turning briefly to ensemble clusters (00z Thursday runs), the
overall shape of the 500- mb pattern for the eastern 2/3 of the
CONUS are similar. However, there continues to be a lot of noise
within these patterns. That is, while there may be a 500-mb low
located in our neighborhood, its placement amongst the members
varies notably. This decreases forecast confidence.