TWO Models - TWO Solutions

I hate going for exact amounts early on, because things can simply "change", it is best to "hone in on" the exact amounts of snow when you get closer to it. That way you aren't flip flopping every 12 hours. In TV land, they used to like exact accumulations 3 days in advance, if you do that, you will drive yourself and the viewers crazy... start broad then work in. However, I have a major problem this afternoon honing in.

What produces heavy snow here in New England is not really the storm, but the result of positive vorticity advection blowing across a warm advection field. (I know, sounds complicated). Let's see if I can show you graphically. Click upper left, and you will see the 850mb low pressure system offshore on the NAM computer model, clearly it shows the warm advection, or blowing of winds across the temperature field, offshore, teh heaviest would be on the Cape only! So that is why many forecasters will start playing things down a bit midday today. HOLD ON! Take a look at the Canadian forecast model to the left. Here I am highlighting not only the fact that this is a Sunday storm with plenty of warm air advection, but a great PVA field, or positive vorticity advection running through it, also highlighted in a separate chart (click on it). That would mean rain cape, heavy snow inland, mix... Boston!!! Not to mention a super-deep surface low hugging the coast! What a difference! I'm going to leave my forecast as is, in between for now.

To understand how to read all these public accessible internet charts, just get Weather Maps by Peter Chaston, the best book written on it. I am carrying it at this time.

Comments

[christine]

I love semi-technical discussion. I also know that it is hard to forecast exacts, and everyone gets pissed at the weatherman (or woman) if it doesn't happen exactly the way they say it will.

still, it's exciting to wait in anticipation for a category four kill storm !!! (to steal from Kent Brockman on the Simpsons).

Run out now everyone! Buy bread and milk because they will NEVER MAKE THAT STUFF AGAIN!!!!!

;^)