A Numerical Study of Cirrus Bands and Low Static-stability Layers associated with Tropical Cyclone Outflow

Abstract Prominent cirrus cloud banding occurred episodically within a northern canopy of Typhoon Talim (2017) during its recurvature. The generation mechanisms the bands and low static-stability layers that support are investigated using numerical simulation with Advanced Research Weather Forecasting Model. Inspection model output reveals thin near-neutral to weakly unstable static stability persistently present in upper lower parts upper-level outflow, shallow convection aligned along vertical shear vector is prevalent these layers. occurs as lowered outflow from weakening storm ascends slantwise over midlatitude baroclinic zone, updrafts preexisting part layer become saturated. It shown strong resulting violation gradient-wind balance core region, by itself, creates Analyses potential temperature budgets show created mainly differential radial advection thermal gradients on edges outflow. occur response outward air parcel acceleration region deceleration outer which, inducing compensating mass transport into out act tilt isentropes effects environmental flow radiative forcing also addressed.