Composite bow echo observed during BAMEX

Using a high density soundings and wind profiles taken around and within bow echoes during BAMEX, a composite bow echo has been produced. Both kinematic and thermodynamic quantities are directly observed and assimilated Into the composite. The mean CAPE of soundings ahead of the bow echo is 1581 J kg ^-1. A near-surface inversion is found in most soundings on the left side ahead of the bow echo, while the right side has predominantly well-mixed layers near the surface which is consistent with propagation along a low-level thermal boundary. There is strong storm-relative (20+ m s ^-1) low-level inflow. A deep cold pool is evident In the bow echo composite, with a negative temperature perturbation extending from the surface to 4 km AGL. The cold anomaly is strongest below 100 m AGL, with a secondary temperature minimum observed 2-3 km AGL. Wind shear normal to the leading convective line is about 15 m s ^-1, primarily below 3 km AGL. Moderate upper-level shear (5-10 km AGL) exists in the forward left quadrant ahead of the bow echo apex. The composite rear inflow jet starts out near the melting level around 5 km AGL, 200 km behind the line and descends to 2 km AGL. It is not clear how It interacts with surface flow just behind the convective line. It is important to note the composite is a mixture of several bow echoes and does not represent any particular event. Any particular event will have higher amplitude anomalies associated with it, since the averaging process will smooth out the peaks due to variation of storm structure among different events.