Shortwaves
move from day-to-day and are ÒsteeredÓ by the longwaves. Upper-level
regions very supportive of cyclone development (red shading) Shortwave
troughs (1, 3) along jet axis, near base of longwave troughsÉ They contain
strong upper-level divergence that initiates cyclogenesis!
Longwaves and
Shortwaves
Ahrens
Fig. 8.23