The focus of the presentation will be on the special environmental conditions that led to pre-TD14W, pre-TY Nuri, and pre-TY Hagupit. Upper-tropospheric atmospheric motion vectors from CIMMS reveal the radial outflows and the interaction with the impinging flow that sometimes constrains the outflow until the environment becomes more favorable for development. Comparison with 25 km resolution ECMWF analyses from the Year of the Tropical Convection archive reveal the three-dimensional structure of the synoptic environment of the mesoscale convective events.
The ECMWF analyses occasionally have point-source convective towers with strong outflow aloft in association with low-level circulation centers (e.g., with pre-Hagupit) or a reverse-oriented monsoon trough in the pre-14W case. However, these convective towers do not necessarily correspond with the locations and timing of the ring-like mesoscale convective blowout events until the environmental conditions have been modified by a previous convective event as in the case of pre-TY Nuri.
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