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Sunday, February 23, 2014

Polar Vortex bringing lots of cold over the coming week but it's also hurting our new snow potential

No more melting of our hard-earned snow until we are well into March i am happy to report. We still do need the powder though, as we would after any rain event. Instability remains in the lower troposphere through Monday but we are too dry for significant snow, just flurries and lighter snow showers. Meanwhile, it is portions of southern New England again that are the first to get re-whitened following the thaw.

The big story for the upcoming week in many places is Polar Vortex round ??? I think it is 5, but I might have lost count. I still can't get over how the term has become so ingrained in the American social consciousness, I thought such terms were reserved for special geeky enclaves such as the SCWB. But I digress, we know from our PV experiences that we get cold in these types of instances and we also know that the jet stream gets revved up and can both suppresses and overpower many of our would be storm systems. The southern branch of the jet stream is not entirely dead during the upcoming week but it will have to compete with energy from the PV, a challenging undertaking.


The first real piece of southern branch energy that is worth watching is an impulse that will track over the southern states Tuesday and advance up the Atlantic coast Wednesday. Incoming energy from the southward dropping PV and the relative warmth of the ocean will help fuel this storm, but it will be somewhat tough for this system to make that critical northward turn although it will try. Snow should be able to advance at least into southern New England and a well-timed clipper might help suck some of this moisture northward into interior New England for a period of light and fluffy snow Wednesday. On the heels of this system will come a quick moving clipper system rotating through the PV Thursday. This should keep the snow flying for a 2nd straight day but in both cases the snow is not expected to be too significant, amounting to 3-7 inches over the two days. The Tuesday to Friday stretch will be characterized more by the unusual late February cold as readings will mainly be in the teens during the day and below zero on Wednesday, Thursday and Friday mornings. This is typically the period in the season where any sunshine can boost temperatures close to the freezing mark or beyond, so relative to normal this upcoming period will be very cold.


The pattern still seems on track to produce more active weather thanks to the combination of split flow in the jet stream across western North American and the eastern Pacific along with the receding PV. The first byproduct of this pattern may come over the first weekend in March with the southern branch producing what could be a coastal system. At this point in time, the PV might be too close to allow such a storm to get too much traction before getting guided out over the ocean. Many of these storms in these instances are getting blown away by fast balls when they encounter jet energy associated with these PV's. The storm I had mentioned for the last two updates in the period between March 3-5 will arrive after the PV recedes somewhat and I still think it is this storm that has the best potential to yield results.


No sign of an extended period of warmer temperatures in early March. The pattern will relax somewhat toward the end of the first week in March but ensembles are showing another pattern amplification between the 8th and 10th of the month and this promises to bring more cold and snow potential to the mountain.

2 comments:

edd samson said...

I have a flight out of Burlington to Dulles (and from Dulles to Denver) Wednesday night, do you think that storm will impact it?

Kristen S. said...

"Polar vortex" is the new "El Nino" (remember 15 or so years ago when El Nino was the big trendy weather story?)