Snowfall Accumulation Probability

The latest European Ensemble shows probability of 6″ or more of snowfall accumulation increasing 70 to 80% across the northern and western suburbs.

Current probability of 3″ or more has increased 70 to 100% across the northern and western suburbs

The upper-level disturbance responsible for inducing cyclogenesis will reach the Puget Sound tomorrow during the late-afternoon hours which means that the operational models we look at should have a better handle on where the surface low develops and its most likely track.

The Classic Cape Hatteras to Cape Cod Track?

The disturbance over the Pacific Ocean that will be responsible for the eventual exact storm track of the Nor’easter early next week is currently forecast to reach the Puget Sound Saturday around 6PM EST.  At that time the operational forecast models will have the most accurate sampling data.  I would not be surprised to see Winter Storm Watches issued for portions of the Mid-Atlantic and New England Saturday afternoon or evening if the current trends continue.  

Watch how last nights run of the GFS (06z/1 am EST) models how this disturbance may interact with the deepening trough that is forecast to dive into the midwest before becoming vertically stacked and negatively tilted over the Northeastern corridor:

Historically the ideal track for Washington’s biggest snow storms is the “Cape Hatteras to Cape Cod track”.  Currently, the GFS and European ensembles are beginning to suggest this possibility.

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