Friday, November 23, 2012

Euro Fizzling Next Week's Storm System

A few days ago, there was pretty solid agreement that a storm system would impact the East Coast in the Tuesday-Wednesday time frame. As of this morning, that agreement couldn't be farther from reality. The two models and their ensemble variants are split quite a bit regarding the potential of a storm system next week, with two completely different solutions on the table for Tuesday and Wednesday depending on your preferred model.

The GFS has been relatively consistent in a track that brings precipitation to the region on Tuesday night and early Wednesday, mainly in the form of rain across the Delaware Valley as low pressure tracks through the Appalachians and intensifies as it lifts northeast.  The result would be a cold latter half of next week after a brief warmup ahead of this low.  The GFS has been relatively consistent in maintaining some form of a storm system and keeping the low track to our north and west.

The Euro, on the other hand, has suppressed the storm track for the past three runs.  In last night's run, the storm has pretty much fizzled into a weak clipper-like wave for Wednesday and Wednesday night as the southern energy is suppressed south and scoots out to sea before intensifying into low pressure overhead.  The result is a dry, chilled pattern that gets enhanced with additional chill in the second half of the week.

To make things more interesting for those of us who follow computer modeling a fair amount, the Euro and GFS were both discounted by the HPC in its discussion this morning, based on the pattern that's setting up aloft over the US for the next few days.  Part of the problem in the forecast over the next few days is the number of weaker, small systems that will be scooting through the country along a relatively fast-moving jet stream aloft.  There are a couple of weaker systems out there -- one that will try to dive into the Lakes on Sunday but will get sheared out by the fast jet aloft, a second that dives into the Plains on Sunday into Monday that may also get sheared out.  This second wave is allegedly the one that develops into a system for us early next week...but the weaker, sheared out scenario would likely result in a weak system that tracks to our south.

Given we're five days out and the Euro historically out-performs the GFS at this range, the Euro's trend towards a fizzled and flat storm is worth noting.  This system isn't quite on life support yet but the potential for a soaking rain of any variety is looking pretty unlikely.  Even if the GFS is right, the rains on that version of the storm are rather modest in substance.