Friday, December 14, 2012

A Fast, Active Pattern Ahead

We can't say that the next week won't be "fun" from a forecasting standpoint!  What has been a generally quiet period of time going back to Hurricane Sandy's thrashing of the region will get replaced with a series of storm systems that will move through the region, pushed along thanks to a fast moving jet stream aloft.

It looks like we have 3 storm systems impacting us over the next week, bringing the potential for rain and snow to the East Coast.  The jet stream pushing these storm systems along is zipping at upwards of 150 mph, if not higher at times, over the next week, meaning plenty of fast-moving systems that have the potential to surprise...and disappoint snow lovers.  The fast movement of the jet means that computer modeling consistency will be a bit lower than usual so what you see in the model runs this morning may not be the same as what you'll see tonight.

Let's break down each system -- or try to -- as we go through the next week.

1) Sunday and Sunday night (GFS)

This wave of energy pushes through the region starting as early as Sunday morning...this could bring a brief shot of icy rain in the Poconos as temperatures drop below 32 at the surface although it will quickly warm above freezing aloft.  Modeling suggests a damp, chilled round of showers for most of the region on Sunday afternoon and evening as this wave of energy moves through.  The GFS is weaker with the energy, faster with it as well, pushing this in about 12 hours ahead of the Euro.  Also, the Euro develops the southwest energy slowly but turns it into a dominant feature on Monday night into Tuesday.  Instead of getting a Tuesday/Wednesday event (see below) in addition to the Sunday one above, the Euro slows the energy down into one longer-duration event on Monday and Tuesday which is rain that may end as snow in the Poconos.

2) Tuesday into Wednesday (GFS)

The Tuesday system on the GFS develops out in the Atlantic as the development is not rapid enough (again, blame fast moving flow) for bombing to take place to pull this close to the coast.  The GFS, with the separate events, allows for some colder air to work in and allows for snow showers to be in the offing on Tuesday evening and Wednesday but keeps the brunt of precipitation out in the Atlantic. The Euro (below) tries to bring this system through as a singular storm event on Monday into Tuesday instead of splitting the energy up into two waves...and the result is that the singular storm on the Euro is stronger, tracks overhead, and brings rain to everyone except an end as snow scenario in the Poconos.

Confused yet?  Yeah...there's a lot of factors on the table and with a 150 mph jet stream pushing everything along, we're going to have some pretty significant model waffling out there before this event reaches model consistency and consensus.  However, looking at the pattern, the fast moving nature of the jet, and the lack of cold air to work with at the onset of all of this taking place leads me to not be that terribly optimistic for the first half of the week.  We didn't dispute activity...but I can dispute a notable chance of significant snow potential through Wednesday.

3) Next Friday

After this first event or first two events, the potential for wintry fun may increase a bit for the end of next week.  Yet another system working through the Great Lakes late next week will transfer its energy to the coast, allowing for low pressure to fire in the Atlantic.  The chances for snow from this system look a bit more promising than they do from anything that develops in the first half of the week -- our temperatures will be colder to begin with.

The Euro is much more aggressive in bombing this wave out than the GFS but for the sake of posting realism and not the bullish scenario I have the GFS' map below for next Friday -- some snow, not a ton of it around, but the setup is similar atmospherically in energy getting transferred from the Lakes to the Atlantic. If it's going to snow, next Friday may be the best shot.