Nice dose of snow coming late Monday but outlook takes a bad turn on storm late next week

Though we still have a dose of terrain enhanced snow to look forward to early in the upcoming week, the outlook has taken a bad turn today regarding what appears to be a sizable late week weather system. The Euro model showed signs of this subtropical phasing early Friday and other computer guidance has jumped on board. Often times "phasing" is a good thing but not this far south and this far west. More on that below.

In the meantime I would try and enjoy this upcoming dose of terrain enhanced snow. Precipitation Monday morning could remain a mix of rain and snow but the polar jet involvement will provide both the instability and cold air and shift everything to snow by afternoon which should occasionally be rather heavy. The snow would be rather fluffy thanks to the convective nature of the precipitation but the wind will be blowing rather fiercely which will compact some of what falls. Tuesday appears to be the best day to get out and enjoy it with snow showers continuing through at least part of the day and temperatures holding in the teens after falling into the 20's by Monday evening. Between late Monday and midday Tuesday, I am guessing the snow will total 4-8 inches but we could find ourselves in the lucky spot and score something even nicer. We deserve it because what's coming after isn't pretty.

Some clearing skies Tuesday night will bring temperatures back to the single numbers and Wednesday will feature a good bit of sunshine and afternoon temperatures of up around 30. Thursday will also be precipitation-free but will feature a bit more cloudiness and temperatures about 8 degrees warmer. We then get to our late week storm which appears to be an example of Nino delivering a large and very unwanted Christmas gift. Models hadn't really indicated too much activity in the southern branch of the jet but during El Nino winters, this activity is almost always underestimated and suddenly it's there and very ominous looking. The storm will begin to take shape along the gulf coast in the form of thunderstorms but the forming low pressure will phase with southeastward advancing clipper system and explode. Sometimes this is fantastic but we don't have the cold air and the phasing will simply occur way too early which allows the storm to suck very warm Atlantic Ocean air well inland, which it will do by late Friday all over New England from Cape Cod to Mt Washington. Rain will arrive early Friday and temperatures will continue to warm quite possibly making a run at 50 sometime Friday evening. We have to hope that the storm will simply occlude which will pinch off the northwestward advance of mild air and allow for a more modest thaw as opposed to a devastating one. If that happens, perhaps some of the most intense rain and mild air can confine itself to the coast and we can think of ourselves as lucky limit the rainfall to under a half an inch.

The high country will see a return to near freezing temperatures Saturday but the melt will continue across the low lying valleys. Snow showers will also return to areas above 2000 feet and we might see some accumulation as the storm proceeds into the Canadian Maritimes

The remaining issue for us is the continued presence of this positive EPO structure which is now indicated to persist through the Christmas holiday and probably through New Years as well. This does not appear to be a full fledged Evil Empire wrought with multiple rounds of Sir El Torchy, but we will need more help from our teleconnection friends to turn this weather pattern in the right direction and we could more high latitude blocking in the jet stream to send arctic air back in our direction. All of this said, since the EPO isn't overwhelmingly intense, both cold air and some snowfall will remain a possibility during the Xmas week though so does the possibility for another thaw. Lets give us some credit for surviving a pretty healthy chunk of this adverse MJO phase but we can't survive forever. When the MJO finally cycles through these phases, which it is doing slowly, we will slow the jet in the Pacific and get a pattern more conducive for cold and snowy conditions. I was hoping this might happen right around Christmas but unfortunately, we have to shift those expectations somewhat in light of what is being currently indicated.