The four frames show the evolution of the squall line system reflectivity pattern from a linear to a bowed-out structure, most well defined at 2219-2234 UTC. The northern mesoscale vortex was at about 9.4 S 159.2 E at this time. The main transverse precipitation band, best defined at 2141-2147 UTC, lies along 9.7 S. The squall line was linear and growing when first encountered at 1950 UTC, and much weakened by the time the aircraft completed the low-level patterns at 0100 UTC 23 February. The figure is based on lower-fuselage data from the NOAA P3 research aircraft, supplied through courtesy of David Jorgensen (NOAA, NSSL-Mesoscale Research and Applications Division). Boundaries of islands within the Solomon Archipelago are outlined by bold solid contours. Arrows show the flight tracks.
