Saturday, January 14, 2012

Rebuilding Deep Alaskan PV May Return Warmth to East US

Here we have the latest analysis of the Northern Hemisphere at the 400k level to analyze Potential Vorticity (PV). Right now, we can see very little PV values over Alaska (to the up and a bit left of the white circle). This is helping to develop snowy weather over the Eastern United States.
Something we are worried about has, and is still, this PV rebuilding over Alaska. That is looking the case to happen-
This is the 10 day forecast from the ECMWF at the 400k level of potential vorticity. We now see high PV values over Alaska, indicating that the deep low has rebuilt and may lead to warm weather in the East. In case you don't know, higher levels of potential vorticity are associated with stronger low pressure systems.
This rebuilding PV will not help along the snowy weather at all- more of a step backwards, if anything. What is still somewhat reassuring is how we see a jab of low PV values jutting right into the higher PV values, just to the right of the white circle (North Pole). That indicates that a ridge will be in place, helping to keep the stick in the gears, so to say, to keep the polar vortex from completely reforming.
If you have any questions about potential vorticity, because it is a complicated topic, you can ask below and we will try to answer them the best we can, because even I am still learning about it.

8 comments:

rod mclane said...

SO THIS MEANS THAT COLDER TEMPS NORTHWEST //WARMER S/EAST AND THE JET STREAM OUT OF THE S/WEST THRU MIDWEST TO GREAT LAKES??? (MEANING iowa wis. ill. would be stormier more snow events or not??? severe weather to the s/east)

Andrew said...

That sounds possible. With the Alaskan PV rebuilding we will likely see more cutoff lows.

Joshua Steiner said...

What is potential vorticity? I know what relative vorticity is and absolute vorticity, but I don't think I have ever heard of potential vorticity.

msilva said...

yes ..no...up...down....i have been told that this is more of a winter in virgina then, it snowing every year. so this should be normal to people here! why some of them r having a hard time excepting that snow may not come here is crazy, its alaskas turn to get pounded, i would think as it should every year. it is alaska. u save on ur energy bill that should be an upside...:)

Andrew said...

Joshua: We are still learning it, but it is increased when there are low pressure systems in place.

msilva: Some forecasters are just confused with this whole fiasco. I am too. The Euro long range came out and says the warmth will continue.

Anonymous said...

wat dose this mean for nyc

Scrappy said...

My question is this: Is the Northeast going to see an early Spring, and how does this warmer than usual Winter play out in the long term?

Andrew said...

Anonymous: Potential storms.

Scrappy: The effects of this warm winter will lead to this winter being one of the warmest recorded. That's about it- this isn't related to global warming. The northeast will likely see a late spring.