Mesoscale analysis of a concentrated heavy rain event using an adaptable mesonet during the landfall of Tropical Storm Ida (2009)

During the landfall of Tropical Storm Ida on 9-10 November 2009, a wide swath of heavy rain occurred from near the coastal landfall point southeast of Mobile east northeastward to the Carolinas. In particular, a local maximum of near 150 mm was recorded near the coast of the Alabama panhandle. A mesoscale analysis of this event is presented using data from three Doppler radars (KMOB, the UAH X-band dual polarization radar (MAX), and the FSU C-band Doppler radar), the UAH Mobile Integrated Profiling System (MIPS, including a 915 MHz wind profiler, 12-channel microwave profiling radiometer, ceilometer, disdrometer and surface meteorological measurements) located 15 km ESE of the MAX radar, 8 Sticknet stations deployed by Texas Tech, a fixed mesonet operated by the University of South Alabama. An extratropical transition appeared to be occurring during the landfall process. Rainfall over the experimental domain was significant, in the range 100-170 mm, around the landfall point where the adaptable mesonet platforms were deployed under multiple Doppler coverage, including the MIPS. The greatest rain amounts and rainfall rates within a 100 x 200 km mesoscale domain occurred in advance of a well-defined warm front that was first sampled by a buoy off shore and moved well inland over the mesonet. A multiple Doppler radar analysis, along with single Doppler data from the three radars and surface data is used to define the mesoscale flows around this front. Details of the front and associated mesoscale precipitation features, notably a low-level jet overriding the cool air north of the front, were well sampled by the MIPS wind profiler and surface data.