We always say that the GFS has a westerly bias and produces some very weird charts in Fantasy Island (FI). This is due to the fact that our normal pattern is a zonal westerly with depressions coming in from the Atlantic giving variable conditions on a day to day basis. When huge blocks occur, the models ALWAYS underestimate the power of them and try get us into a normal pattern regardless of the strength of the block. You know the way how early 1947 produced one of the most prolonged easterly spells in our country on record as a result of an unprecedented monster blocking area of high pressure up to the north? I can tell you if that were to occur in modern times, the models (especially the GFS) would push milder air up from the south with ease regardless of the block of high pressure.
We all say this without showing evidence of such generally but I'm going to give some historical examples from GFS 0z runs and compare with the actual charts for those dates to show you just how pointless GFS FI can be.
GFS 0z for Friday 22nd June on 10th June 2018.
Actual 22nd June 2018 chart.
-------------------------------------------------
GFS 0z for Sunday 24th June on 13th June 2018.
Actual 24th June 2018 chart.
---------------------------------------------------
GFS 0z for Wednesday 24th July on 12th July 2013.
Actual 24th July 2013 chart.
-------------------------------------------------
GFS 0z for Wednesday 25th June on 14th June 2014.
Actual 25th June 2014 chart.
Sometimes, you may be lucky in the GFS giving subtle hints or trends in the FI time frame but generally, it's pointless to take the GFS in FI seriously at all as you can see from the above examples.
Comentários