Tuesday, November 22, 2011

What Do I Mean By A Lack of Consistency?

In a post earlier this evening regarding the potential for a major cooldown and associated storm system this coming weekend, I mentioned several times about how the computer model guidance is still inconsistent in handling the system.


As an example of what I was talking about, take a look at how the GFS model diverges over time in handling the system.  The GFS is made up of an ensemble of 20 different computer model solutions that are merged together to reach a "consensus".  Each of the ensemble models is represented by a different colored squiggly line on the images below.  The lines represent what you would generally refer to as the subtropical (Southern) and polar (Northern) branches of jet stream wind flow across the U.S. at each given time period.


The ensembles start out in near unanimous agreement, as to the position of each branch of the jet stream, as shown on the image below (valid 6pm CST tomorrow, Wednesday, evening):






By 6pm CST Friday, the consensus is beginning to shift apart just a bit:



...and by 6pm CST Sunday, it's a big squiggly mess out there:


...and now you know why the Hair Club for Men (and the female version I'm sure) is a favorite among meteorologists at this time of the year...


Stay tuned, there's lots more hair pulling to come on this one...


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2 comments:

Anthill_Goddess said...

Our local people (Iowa) are going out on a limb and saying "no snow" on this one even though they have told us for the better part of a week that they weren't sure what this one was going to do. Of course, the last time they said "little to no snow, just in grassy areas and it will melt off quickly" we got 6 inches of super-wet snow and lost power for 2 days because of all the powerlines down. LOL

Rob In Texas said...

Anthill,

Based on the way things are trending right now, I would agree with that (as far as no snow for your area). This is looking like more of a Southern storm (see latest post) - but still not 100% locked down just yet. Should be more confident later today and tomorrow...