Think Snow, Tweet Snow !!!

Wednesday, March 11, 2015

Reports of Winter 2014-2015 demise have been greatly exaggerated

The nationwide thaw and in some locations, a heat wave, finally pushed the mountain above freezing and thus the stretch of sub-freezing temperatures officially lasted about 45 days. Sub-freezing temperatures return to the mountain by Thursday morning and our focus turns to a potentially sizable precipitation producer for the weekend. Got some questions and comments regarding this event and I know some folks have already started sizing up some of the model data for the weekend.

Let me preface all this by saying that the pattern through the weekend remains warm and though we will have some cold air to work with, it will be quite limited especially relative to most of the other events we have seen this winter stretching all the way back to November. I also want to advise caution when looking at those model precip-type maps. The Euro in particular can be extremely bad and can lead many forecasters astray, usually by incorrectly assigning any kind of heavy precipitation as snow. When it comes to precip type, I prefer to look at raw data and then account for model biases accordingly. With this particular event, the consensus of data tries to take the storm into the St Lawrence Valley at least initially. Ultimately however the storm is expected to deepen along the New England Coastline. Such a scenario is not an all snow event even though some recent runs of the American GFS are suggesting such. Precipitation would likely begin as rain or a mix on Saturday and then as the storm begins to deepen along the coast Saturday night, precipitation would become snow and this would continue in some fashion through a good part of Sunday. This is a tricky event with lots of moving parts and the end results could vary based on where one is on the mountain. Right now however, I don't like the idea of an all-snow event and think it could get a little wet Saturday followed by several inches of snow Saturday night into Sunday.

We may get one more semi-warm day next week before winter returns for another significant stretch of March. This is another classic looking PNA-anchored pattern much like many of its predecessors this year. Consistent with much of what we have seen this year, the pattern appears devoid of support from the the AO or NAO. Its been a pretty simple process of simply placing a big upper ridge in the right place across western North America and watch as the cold and snow impact the eastern U.S. persistently. I expect this will occur again and I further expect multiple rounds of big results for interior New England. Being that it is later in the season, I think interior New England could be the favored location for some big events later this month though they are tough to pinpoint as of now.

4 comments:

Nate Cohen said...

Hey Josh, thanks for the in depth report yesterday (Wednesday). Not to be too much of a pest, but if you wouldn't mind tweeting an update today and tomorrow (maybe a tweet today based on an up to the minute model run? followed by a longer update tomorrow or Saturday morning?) that would be great.

Thanks for all your efforts this winter. It has been an great one!

More Cowbells said...

That is why I'm a loyal reader...so possibly getting better by Sunday. As always, hope there is a little more cold air for this storm to work with! Cheers

Nate Cohen said...

Hey More Cowbells...do you really live in Cameroon?

Mike Salnick said...

Any chance on an update at some point today would be appreciated - trying to make a last minute call on heading up north or not....