Tropical cyclone environments over the northeastern Pacific, including mid-level dry intrusion cases

Abstract

This study uses a 1°×1° lat/long dataset, extracted from ECMWF re-analyses for the 15-year period 1979–1993 (ERA-15), to diagnose the synoptic-scale kinematic, thermodynamic and moisture environments in the vicinity of named tropical cyclones (TCs) in the eastern North Pacific. Based on the NCDC best track dataset, TCs are partitioned into one of three categories: weak (W), strong (S) or intensifying (I). In total, 63 TCs are examined: 8 Ws and 20 Is at point A (maximum intensification) and 11 Ws, 13 Ss and 11 Is at point B (maximum frequency). Composite maps are compiled for all five groups, and six individual case studies are examined, four for extreme TC cases and two for cases involving dry air intrusions.