Development Conditions for Tropical Storms over the Western North Pacific Stratified by Large-Scale Flow Patterns

This study investigated the characteristics and environmental conditions of tropical cyclones (TCs) over the western North Pacific from 2009 to 2017 that dissipated before reaching tropical storm strength (TDs) under unfavorable environmental conditions; we compared TDs with TCs that reached tropical storm strength (TSs) in terms of modulations of relevant large-scale flow patterns. The flow patterns were categorized based on five factors: shear line, confluence region, monsoon gyre, easterly waves, and Rossby wave energy dispersion from a preexisting cyclone. Among 476 cases, 263 TDs were detected using best-track data and early stage Dvorak analysis. The TCs in the environments associated with the confluence region or Rossby wave energy dispersion (easterly waves) tended to reach tropical storm strength (remain weak) compared with the other factors. The average locations of TDs at the time of cyclogenesis in the confluence region, monsoon gyre, and easterly waves (Rossby wave energy dispersion) in the summer and autumn were farther to the west (east and north) than those of TSs that exhibited the same factors. The environments around TDs were less favorable for development than those around TSs, as there were significant differences in atmospheric (oceanic) environmental parameters between TDs and TSs in the factors of confluence region, easterly waves, and Rossby wave energy dispersion (shear line, monsoon gyre, and Rossby wave energy dispersion). The environmental conditions for reaching tropical storm strength over their developing stage, using five factors, can be summarized as follows: higher tropical cyclone heat potential in the shear line and monsoon gyre, weak vertical shear in the confluence region, wet conditions in the easterly waves, and higher sea surface temperatures and an intense preexisting cyclone in Rossby wave energy dispersion from a preexisting cyclone.</p

Urinary Retention Suggesting Aseptic Meningitis: Meningitis-Retention Syndrome Without Physical Signs of Meningeal Irritation

Meningitis-retention syndrome (MRS) is the combination of aseptic meningitis and acute urinary retention that occurs in the absence of other neurological diseases. The cause(s) of MRS remain unclear. A 57-year-old Japanese woman was referred to our hospital for the evaluation of persistent fever and headache. The fever’s cause was initially unclear, but the presence of urinary retention raised concern about possible aseptic meningitis despite no physical indications of meningeal irritation. Only typical cases of MRS have been reported thus far to our knowledge, and it is important that clinicians are aware of MRS when it presents in this atypical form