There must be serious error in weather forecast models. Today is a good example for that. Current GFS run 00z shows at 0600 minimum temperature of the place I live -2 deg. GFS T800 is 0 deg. Yesterday Met Office stated that today at 0600 will be -1 or -2 deg. Real temperature at 0600 was -5 deg. Met office update data to -5 at around 0300-0400. So if there is error of -3,-4 deg in T+6 so I don't know what sort of percentage confidence we can have in T+144 and more.