FOX44 - Burlington / Plattsburgh News, Weather & Sports02.16.12 Thoughts on Sunday Snow

02.16.12 Thoughts on Sunday Snow

On this Thursday morning I am crossing my fingers, but I'm also not getting too excited so I don't let myself down.

Since the morning of Valentine's Day (Tuesday) there have been hints at a possible coastal storm affecting a lot of the east coast with a 'potential' snow storm.  But when I look at a storm that is still 120 hours away, I will always have my doubts.  I've learned from my first several years of forecasting that my forecast for days one through four are accurate, but then accuracy really goes down in days five through seven.

Nonetheless we're nearing the end of the week as Sunday draws closer and closer in time.  More and more weather models are grasping onto a storm developing in the southern United States on Saturday, then differ on where to take it thereafter.

Here's one model run (as of 7 a.m. Thursday) that has been hinting at this idea for a day or two:

Here's what you're looking at.  An estimation of this weather model on temperatures, areas of low and high pressure, and accumulated precipitation.  This is the forecast for Sunday at 1 p.m. (Feb. 19).  It hints at the development of this low pressure area in the southeastern United States and takes it out just to our southeast.  High pressure over us also helps block the storm from heading too far north and west.

Here is a look at the higher-levels of the atmosphere, with what really drives the weather down here at the surface.  I love looking at the higher levels because it simulates where areas are spinning up storms.  You'll see here!

This is a simulation at about 15,000-20,000 feet.  Look for the yellow and orange areas.  THose promote spin and rotation in the atmosphere (vorticity).  This model (GFS) phases the polar jet and the subtropical jet a little better than the other model which I'm about to show you.  This phasing is very important to strengthen storms.  That big "u" shape across the eastern U.S. shows that "upper level low" if you've ever heard that on a weather report. When you see this, generally the storm center at the surface is east of it, so since this phasing is across the east coast, that may mean the storm development could be too far off the coast (into the Atlantic) to give the east some snow.

Now here's where we run into some discrepancies.  As we're moving into the timeframe of less than 84 hours away, more model runs include this storm.  One, called the NAM, keeps this storm much less 'phased.'

The areas of yellow are not really connected here. That means the shortwave north (top blue line) doesn't pick up and help out the one to the south.  This is at the same time as the GFS model above.  Without the phasing it makes the storm a little weaker, and also doesn't pull it up to the north as much.  As a result....

The low pressure is 'slower' being more west here than the GFS run.  Again this is 1 p.m. on Sunday, projection from the NAM.  The high pressure over us is a little more prominent, blocking the storm away even more.  Hopefully that can give you a sense of the 'uncertainty' in our forecasts. 

Personally here's what I think.  I am leaning toward the drier solution.  Many times this year the phasing has occurred over the Atlantic, with storms firing up way east of us.  I think this will happen again, maybe not as far east as other storms, but far enough away to leave us in the clear.  I personally give us a 15% chance of getting this storm.  So it's not out completely, but I think odds are against us.  HOWEVER, (and this is why I love weather) it is still days out as of Thursday. Things change, models change, even opinions change :)

In fact what I'm about to show you is a 'wishcast'.  Wishcasting is where you take a forecast that you wish would happen and make it what IS going to happen.  So if you see a sunny model run and you like sun, you say, "It's going to be sunny!." Or in this case, if one model run promotes a monster of a storm and you want that one big storm finally, wishcasting is "We're getting slammed Sunday!"

Here's the 7 p.m. update Wednesday, Feb 15 for the Sunday storm.  Notice the close track of this storm to the northeast coastline.  That would be awesome in my opinion, but I just have my doubts.

Of course you can stay updated to all of the latest weather discussion and forecasts here on our weather section.

OR, if you want to be a weather geek and look at these model runs yourself, go here to the Models and Guidance page from the National Weather Service.

-Meteorologist Steve Glazier

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