The three-disc set Forecast: Tomorrow offers the entire scope of Weather Report’s career, from Joe Zawinul and Wayne Shorter’s early collaborations with Miles Davis and Cannonball Adderley to Weather Report’s 1985 swan song, Sportin’ Life. Zawinul and Shorter were the only constants in Weather Report’s DNA, and they continually promoted the idea that the group was based not on a certain team of musicians but an overarching idea of evolution. That’s why it’s so important, and even thrilling, to hear them morph from the acoustic jazz of “Unknown Soldier” into the hard funk of “125th Street Congress” and eventually the stratospheric musicality of “Havona” and “Palladium,” both of which are driven by the mystical intensity of bassist Jaco Pastorius. Though always challenging, Weather Report were never esoteric. Groovy hits like “Birdland” were as important to them as obtuse workouts like “Super Nova.” Even at the peak of their popularity, they never watered down their music; instead they tended to ramp up their density solely for the sake of challenging themselves and their audience.