Monday, March 17, 2008

Midweek storm to start as rain and will hopefully end as snow

Its time to focus on what looks to be a powerful midweek storm system. In this La Nina year we have at times been dealt very little in the way of cold air as the many storms have approached. This is yet another case where the cold weather will remain focused on the western flank of the storms center. Precipitation will arrive Wednesday and any remaining cold from the weekend will by then be quite stale and allow precipitation to be a mix of sleet and freezing rain by around first tracks time. After that it is likely we are going to have to brave a period of rain.

Some details
Fortunately we have the NAO and a strong block at the southern tip of Greenland to help us. There is still time in fact for the storm which is currently indicated to travel through New York and into Quebec to track further south and thus improve the outcome. If that fails the aforementioned block will allow our storm to intensify while it slows its eastward progress across the Canadian Maritimes. This provides an extended opportunity for terrain induced snow as cold and instability combine with the lingering plume of wrap-around moisture. This outcome if it does occur would have the rain turn to snow showers late on Thursday and persist into Friday. In summary, it is going to be hard to turn Wednesday into a powder day as this appears to be the wet period for us. Thursday into Friday are a different story and a subsequent update will detail amounts and timing.

A cold weekend with another storm to watch
We are still on target for a period of below normal temperatures through the upcoming weekend. This is in association with a large upper trough which will allow the cold to extend fairly deep into the south. Models have been back and forth regarding our chances for precipitation. Specifically, there is another system that bares watching as it tracks through dixie over the weekend and prepares to make some sort of left turn on Sunday. Its eventual interaction with the Atlantic Coast and movement thereafter will have, as you might be able to guess, a profound impact on the big snow potential as we head into the early part of next week. At the very least, it appears as if the colder weather will remain in place through the middle of next week with a modification to follow during the middle of the week.

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