To enhance the effectiveness of thunderstorm gale warning signals and achieve a scientific balance between accuracy and lead time, this study systematically evaluates the warning signals based on observation data from 245 automatic weather stations in Shanghai from 2016 to 2023 and warning signals issued by nine district meteorological stations, using the percentile method and synoptic classification. Results show that thunderstorm gales mainly occur from April to August, with the highest frequency in July; their diurnal variation is characterized by frequent occurrence from afternoon to nighttime; extremely strong gales are prone to appear in coastal and riverside areas; and the issuance of warning signals generally precedes the peak occurrence of gales by about 1 hour. The overall effectiveness score is 14.1 points (out of 100), and the average score for extremely strong thunderstorm gales is 28.2 points, with the warm shear type scoring the highest (49.2 points) and the stationary front shear type the lowest (12.1 points). During subtropical high-edge and stationary front shear processes, the western Pacific subtropical high tends to be stronger and displaced westward. Case studies indicate that extremely strong thunderstorm gales associated with the upper-level cold vortex under the influence of the northeast cold vortex achieve relatively higher scores. However, similar to other processes, when the wind force reaches beaufort scale force 12 or above, warnings are often issued later than the actual occurrence. Subtropical high-edge gales have a relatively wide impact range, and warnings are generally issued in a timely manner across districts, resulting in overall higher effectiveness scores.
