From 19 to 21 July 2021, the central northern Henan province had experienced life and property losses caused by locally record-breaking extraordinary rainfall and waterlogging, with the severest disaster in Zhengzhou, the capital city of Henan province. The precipitation in the three days extended nearly 300 km in length from the first day 400.6 mm in Lushan to the second day 659.7 mm in Zhengzhou, and the last day 777.5 mm in Hebi. The hourly precipitation in a Zhengzhou station reached 201.9 mm from 16∶00 to 17∶00 BJT on 20 July. Identifying and forecasting the system that generates extreme rainfall is a prerequisite to reducing the loss of life and property. This paper did anomaly-based versus full-field-based weather analysis based on the daily atmospheric observations and the ECMWF (European Centre for Medium-Range Weather Forecasts) fine-grid model products on operational meteorological platforms. The results show that 1) the stable cloud cluster corresponding to the heavy rainfall in Henan is an easterly wave system formed on the south side when the northwest Pacific subtropical high is abnormally north in location and connected with a China mainland high; 2) On 20 July, Typhoon Chapaka near the coast of South China, Typhoon In-fa in the northwest Pacific, and the anomalous mesoscale low of strong ascending flow near Zhengzhou constituted three heavy precipitation systems that tied up nearby; 3) anomaly-based synoptic analysis was more effective in determining the location of extreme rainfall than full-field-based synoptic analysis of wind and specific humidity. The wind and specific humidity anomalies, and the moist vorticity anomalies (MVA) in the short-term forecast products of the ECMWF, have better guidance for operational extreme rainfall forecasts. Identifying the accuracy and stability of model products is essential to improve the skill of rainfall forecasting.