Advantage of 30‐s‐Updating Numerical Weather Prediction With a Phased‐Array Weather Radar Over Operational Nowcast for a Convective Precipitation System. Issue 11 (7th June 2022)

• Record Type: Journal Article
• Authors: Honda, T.; Amemiya, A.; Otsuka, S.; Taylor, J.; Maejima, Y.; Nishizawa, S.; Yamaura, T.; Sueki, K.; Tomita, H.; Miyoshi, T.
• Is Part Of: Geophysical research letters. Volume 49:Issue 11(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-07
• Subjects: numerical weather prediction -- data assimilation -- rapid update -- convective precipitation; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2021GL096927
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Convective precipitation systems in the summer often cause sudden heavy precipitation and largely affect various human activities, but the rapid evolution limits our predicting capability. Phased‐array weather radars (PAWRs) with a high spatiotemporal resolution are useful for observing such precipitation system. A recently developed numerical weather prediction (NWP) system assimilates PAWR observations with a 500‐m mesh NWP model. It initiates 30‐min extended forecasts every 30 s, much more frequently than the operational NWP and nowcasting systems. This study investigates the benefits of the 30‐s‐updating NWP system in a single but representative convective precipitation event in which a convective cloud developed within 10 min, and its evolution was not well predicted by operational precipitation nowcasting. The rapidly updating NWP system successfully predicts the evolution of the convective cloud. Assimilating the PAWR observations every 30 s continuously modifies the moisture and dynamical fields and improves the forecast accuracy consistently. Plain Language Summary: Convective precipitation systems in the summer have a large impact on human activities, but predicting their rapid evolution is a challenge. Next‐generation weather radars with a high spatiotemporal resolution observe the rapid development of such systems in detail and have recently been used for numerical weather prediction (NWP) using a physics‐based numerical model. A new NWP system aims to take full advantage of frequent observations from next‐generation weather radar and updates 30‐min forecasts every 30 s. This study investigates the performance of the new frequently updating NWP system in a typical convective precipitation event in which a convective cloud developed within 10 min. The new NWP system successfully predicts the convective cloud's rapid development, although a short‐range operational precipitation nowcast fails to predict it. The use of frequent observations from the new weather radar continuously improves the forecast accuracy and enables us to know the evolution of the convective cloud at an earlier stage. These results indicate the benefits of a frequently updating NWP system with a next‐generation weather radar for the prediction of convective precipitation systems. Key Points: A numerical weather prediction (NWP) system updated every 30 s with a phased‐array weather radar is evaluated in a representative event The rapid development of a convective cloud is well predicted by the NWP system, whereas operational nowcast has limited capability The forecast accuracy improves continuously every 30 s by data assimilation, indicating the benefits of the rapidly updating NWP