A Modeling Study of the Along–front Precipitation Variability of a Pacific Narrow Cold Frontal Rainband

Observations of an intense Pacific narrow cold frontal rainband (NCFR) on February 19, 2001, during the Pacific Coastal Jets Experiment are examined and compared with a numerical simulation. The NCFR was sampled by the NOAA P-3 aircraft, the QuikScat Satellite, and the precipitation radar (PR) and microwave imager onboard the Tropical Rainfall Measurement Mission (TRMM) satellite. The TRMM observations reveal complex variations of the structures of precipitation along the cold front: 1) the PR reflectivity shows that the leading convective line tends to have a greater separation from the trailing stratiform precipitation in the southern part of the NCFR than its northern part, and 2) the TMI brightness temperatures suggests a greater amount of ice present in the middle of the observed portion of NCFR (where the front is bowed out) compared to the northern and southern ends of the rainband.

An PSU-NCAR MM5 model simulation is used to analyze the pre- and post-frontal conditions associated with the NCFR. Dynamical, thermodynamical, and cloud microphysical features will be analyzed to understand the structure and organization of the NCFR, especially the mechanisms for its along-front variations observed by the TRMM satellite.