Thursday, February 04, 2016

Why Long Range Forecasting Can Be Like Throwing Darts

Quick post about next week and why long range forecasting is very difficult and sometimes like throwing darts.  The first image is the operational GFS for its morning run on Saturday, January 30th valid for Tuesday, February 9th.  The blue line is the 540 line and a good indicator of the rain/snow line.  See that "U" shape it makes over the west and central portions of the country?  That's telling you there's a trough over that area and cold air is on the move south at the surface.  It develops a wave of low pressure along the boundary in the northern Gulf with precip overrunning to the north over Arkansas in the form of snow. 

Fast forward to the afternoon run of the GFS today (February 4th) valid for the same time period, February 8th.  It has the trough, but instead of it over the west and central portions of the country, it's over the central and east with the coldest air directed into the Great Lakes and Ohio River Valley.  Since we are now on the western side of the trough, it means a cold and mostly dry northerly flow aloft without any storm to deal with.  This post is also a reminder that what the models indicate 7-10 days from now are likely in la-la land.  

I thought it was interesting to show you how much a model can change over the course of a few days and why I don't like jumping on any particular solution.  You look for trends.  I will admit, I did think something would pop for us around Mardi Gras, but all we can hope for are a couple snow flurries or snow showers, especially over northern Arkansas.  This is still several days away and I have seen the models flip quickly in another direction.  But the data is hard to ignore at this point.  

Snow lovers, don't give up!  There's still plenty of winter left and I'm optimistic.  Can anyone calculate how many days until next winter? LOL


GFS run from Saturday morning January 30th valid for late Tuesday, February 8th

Afternoon run of the GFS Thursday valid at the same time, Tuesday February 8th.


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