Some notable changes occurred on the 06z GFS with respect to the storm Tuesday 11/25. The shortwave in southern Manitoba becomes more amplified early, and develops a negative tilt early.
00z 11/20 GFS (older run)
06z 11/20 GFS (newest run)
Secondary surface low pressure develops south of Long Island, and moves north and northwest into eastern New York causing 850mb temperatures to rise above freezing by Tuesday morning. Verbatim, precipitation would begin as snow after midnight Tuesday with light accumulations possible by 7am. Snow changes to rain, falling moderate to heavy through the afternoon, ending as snow as the low moves to our north Tuesday evening. This is still in the 5+ day range, and things could change, but with the GFS and ECMWF now mostly in the same camp, calling for warmth and rain, I am confident in all rain at the coast, and interior SNE snow accumulation looks light. The 12z GFS is in my opinion very important, because of new data input and the fact that the 06z run is a relatively new solution coming from the GFS.
|posted by Sam Lillo @ 11/20/2008 09:24:00 AM
