Weather It Is (The Threat Grows)

 Good Evening:

The threat of a major winter snowstorm has grown since our previous update.

However, there is still some disagreement among the global forecast models concerning the positioning of the trough of very cold air.

Based on the American GEFS, there should be heavy snow from late Tuesday into late Wednesday, possibly greater than 30 cm of snow (even in Jerusalem).  However, the European model and to some extent the Canadian global models are showing a shallower trough.  Their forecast solutions would lead to a slushy accumulations in Jerusalem with more snow in Gush Etzion.  Interestingly, the operational version of the Canadian model  (at higher resolution than its ensemble) is showing about 20 cm of snow, so that favors more the GEFS forecast.  

Differences in the model forecasts can be due differences in the grid spacing in the forecasts, data assimilation schemes, and model physics.  As we've noted before, the Siberian trough is originating from an area with less data coverage, making the forecast more difficult.  Regardless, we see a lot of potential for a snowstorm. 

Tomorrow morning, we should have more information to pass along. We'll then be able on Monday to offer our own snow forecast accumulations from our high resolution forecast model. 

Shavua Tov,

Barry Lynn