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Abstract Forecasting and early warnings for summertime flash heavy rain events (FHREs) in the middle Yangtze River basin (MYRB) pose significant challenges. This study examined variations in lower tropospheric wind profiles hours before these FHREs using reanalysis data and wind profile radar observations. The findings highlight wind accelerations, directional shifts, and associated vertical shears preceding FHREs, providing valuable insight for severe weather warnings. During the summers of 2010–2019, FHREs occurred most frequently and contributed significantly to total precipitation during the Meiyu period, compared to before and after. Meiyu FHREs also exhibit longer durations and nocturnal peaks. Spatially, FHRE frequency increases from northwest to southeast, with higher frequencies in the topographic areas. The discernible moisture influx 4 hr before FHREs primarily comes from southwesterly and easterly winds below 700 hPa. Before FHRE, weaker easterly winds dominated western MYRB, while strong southerly winds prevailed in the east, influenced by mesoscale cyclonic shear and low‐level jets. Detailed wind changes below 4 km altitude show that over the southeastern MYRB, accelerated west‐southwest winds are observed 3–4 hr before FHREs, while southerly components near the boundary layer top intensified 2 hr earlier. Within 1 hr before FHREs, the wind speeds sharply increase to peak. East of the western mountains, southwesterly winds strengthen 5 hr prior, then weaken as they shift to northerlies just before FHREs, accompanied by reinforced northerlies near the surface. Over the western mountainous area, southeasterly components below 2 km altitude increase 4 hr before FHREs, although at lower speeds.

The bright band (BB) is an important symbol of the ice–water transition zone in stratiform precipitation, and the presence or absence of BB will lead to different microphysical processes. In this paper, the characteristics of BB and precipitation characteristics with and without BB in summer at Tibetan Plateau (TP) as well as Central-eastern China (CEC) are analyzed by using Global Precipitation Measurement (GPM) and the fifth generation ECMWF atmospheric reanalysis of the global climates (ERA5) datasets. The results show the freezing level height and BB height in TP are 0.5 km higher than those in CEC. With the increase in rain rate, the BB height decreases in TP but increases in CEC. The BB width becomes wider with the increase in maximum radar reflectivity. Secondly, the maximum reflectivity factor and particle diameter of stratiform precipitation with BB appear at 5 km, while the maximum reflectivity factor of stratiform precipitation without BB and convective precipitation appear near the ground. The particle diameter first decreases and then increases from the cloud top to the ground. Thirdly, the land surface temperature of convective precipitation is about 2.5 °C higher than stratiform precipitation with BB, indicating higher land surface temperatures are more likely to trigger convection. Lastly, BB can lead to a decrease in brightness temperature and an increase in polarized difference at 89 GHZ and 166 GHZ in CEC, likely due to the increasing ice particles in stratiform precipitation with BB.

2020 and 1998 are the strongest Meiyu years in recent decades. The characteristics of the super-strong Meiyu precipitation and water vapor sources in 2020 and 1998 were compared, and the atmospheric circulation anomalies and the forcing factor SST were examined. (1) In 2020, the Meiyu duration, accumulated precipitation, and number of rainstorm days were greater than in 1998, and the highest since 1961. The Meiyu period in 2020 experienced 11 rainstorm processes. In 1998, a typical “second Meiyu” phenomenon occurred, and the area of heavy rainfall in 1998 was located further southward than that in 2020 (2) The contribution of the Bay of Bengal-South China Sea (BOB-SCS) to the total supply of water vapor in 2020 and 1998 was 43.0% and 42.0%, respectively, i.e., much higher than that of the climatological mean (25.5%). In 2020, the sources that provide most water vapor were the BOB, SCS, and central Pacific Ocean, while in 1998 were the Arabian Sea, BOB, and the western Pacific Ocean. (3) During the Meiyu period in 2020 and 1998, the position of atmospheric circulation pattern “two ridges and one trough” are different. Analysis of the vertical structure revealed that the specific humidity intensity above the area of heavy rainfall in 1998 was weaker than that in 2020, and the low-level convergence zone was further south and not as strong as in 2020. The positions of the western Pacific subtropical high (WPSH) and the western North Pacific anticyclone (WNPAC) in 1998 were both further south than those in 2020, which resulted in the more southerly locations of the southwesterly jet stream and rain belt. It should be pointed out that, the important contributions of the SST anomalies in the equatorial central eastern Pacific and the tropical Indian Ocean to the anomalous WNPAC in 1998 and 2020, respectively.

Extreme precipitation occurred in northern Hubei,with the maximum precipitation of 518.5 mm in 24 hours and 117.9 mm in 1 hour,causing serious disasters from 20:00 BT on August 11 to 20:00 BT on August 12,2021. Based on conventional meteorological observation data and ERA5 reanalysis data,the characteristics and synoptic causes of extreme precipitation for the event are preliminarily analyzed using statistical methods and synoptic diagnostic analysis methods. The results are shown below. (1) Although the characteristics of rain are different in different regions,the extreme rainstorm has the characteristics of large accumulated rainfall,strong short-term rainfall,concentrated precipitation period,strong disaster possibility,and extreme rainfall. (2) The rapid development,long duration and slow eastward movement of β-Mesoscale Convective System (MβCS) are the main reasons for the extreme precipitation. (3) The main influence systems are the high level South Asia High (SAH),the upper jet,the middle level West Pacific Subtropical High (WPSH) and the low trough. The direct participants are the mid- low level wind shear,mesoscale vortex and easterly jet. (4) The abnormal strength and maintenance of 850-925 hPa mesoscale vortex and easterly jet lead to the formation of strong dynamic convergence center and strong water vapor convergence center in the lower layer,providing continuous vertical upward movement below 700 hPa. The jet also favors the strengthening of energy front and the establishment of high-energy region and low-level instability,which leads to the occurrence and development of convective heavy rain. (5) The precipitable water in the whole layer and the vorticity and the vertical velocity and specific humidity at 925-850 hPa show relatively abnormal extreme characteristics. In addition,its anomaly evolution trend is basically consistent with the evolution trend of rainfall intensity.

In 2021, the weather situations are complex,the climate anomaly is significant,and extreme events occur frequently in China. This paper briefly reviews the abnormal characteristics of the main flood season over China and Huaxi Autumn Rain,and makes a preliminary analysis of four high impact weather processes in Henan and Hubei. The results show that the mean precipitation over China from April to October 2021 was 7.8% more than its normal value,specifically 100% more than that in some areas such as Henan,Hebei and Shanxi Province. Under the influence of the external forcing factor "La Nina" abnormal SST,the water vapor in the periphery of the subtropical high and the cold air in the north were very active,the Huaxi Autumn Rain broke the historical record since 1961. The "21.7" rainstorm in Henan Province occurred under the background of typhoon,vortex,shear line and convergence line. A large amount of water vapor from the Northwest Pacific appeared in front of the mountain under the coupling of low-level jet and boundary layer jet,dynamic blocking uplift and thermal uplift of terrain. Under the favorable multi-scale circulation background,the interaction between the terrain and the convergence zone of low-level wind field triggered convection,maintained the precipitation in the narrow and long valley terrain,and triggered the "8.12" heavy precipitation in Suizhou Hubei Province. The merging and strengthening of meso-γ scale strong convective cells caused two convective gale events in Wuhan. The sudden enhanced horizontal wind in the middle layer triggered the sinking movement,and the falling created the local strong cold pool and the extreme gale on the ground.

This study analyzes the occurrence and early warning of rainstorm disasters in China. It also analyzes the ways of communication of meteorological early warning information in detail, especially about early warning information of rainstorm disaster. In addition, this study also proposes some strategies for social management. The results show that the frequency of rainstorm disasters in China keeps increasing in recent years, which have caused heavy casualties and economic losses in China. The effective ways to improve the accuracy of early warning information of rainstorm disaster are to strengthen the monitoring capability of rainstorm disaster, conduct more researches of rainstorm, and improve the operational prediction and early warning of rainstorm disaster. Weather situation is the most important meteorological information needed by the public, particularly for the next 3-day. Mobile app has become the most frequently used communication way of meteorological service for the public for the last decade. The public has also paid more attention to obtaining meteorological early warning information through various ways. The rapid release is the key strategy to improve the effective coverage of early warning information. In order to spread the early warning information to the managers at all levels and the public in the shortest time, we must make full use of some new technologies and build an integrated release platform of early warning information based on the "cloud + end" architecture. In this way, the "one click" release and multi-way dissemination of early warning information can be realized. In addition, the monitoring and management of the whole process of early warning can be achieved. Finally, we conclude that the management strategies of early warning information of rainstorm disaster must include information dissemination, timely feedback, and simultaneous emergency actions

The academic journals of meteorological science and technology of China take the solicitation of review meteorological scientific and technological paper (RMSTP) as an important way to improve their core competitiveness and bibliometric evaluation indicators. Therefore, high-quality RMSTPs are favored by journals, and many scientists are also stimulated to write RMSTP. In order to advise the authors to write a successful RMSTP, this paper first introduces the four principles of the topic for RMSTP, and divides RMSTP into two types: overview type and discussion type. It highlights the importance of writing motivation and the scopes of time, space, and topic for RMSTP, and provides the suggestion about how to express them properly in the paper. Meanwhile, taking three RMSTP's published in recent years as examples, this paper focuses on the problems that should be paid attention to in the text structure and its content expression, summary writing, and literature citation of RMSTP. Finally, it points out that writing a successful RMSTP requires the author to read large number of literatures and have rich scientific research and writing experiences. In addition, the authors needs to develop themselves to have the sensitivity and insights to the scientific frontiers and development trend of certain discipline or professional field, as well as the corresponding abilities of comprehensive analysis and reviewing.

The meso-and micro-scale characteristics of an early spring convective weather event in southwest of Hubei on February 14, 2020 is analyzed comprehensively by using multi-source detection data such as Doppler weather radar, wind profile radar, micro rain radar, two-dimensional video disdrometer and three-dimensional lightning monitoring network, and then the application of the classified severe convective weather identification and warning algorithm is discussed. The results show that: (1) Because of the blocking effect of the mountains in southwest of Hubei, the cold front moves southward slowly in the north of Yichang, and an unstable stratification of upper dry and lower wet, induced by the intersection of the low trough of North China, the warm shear line in the north of the 850 hPa vortex and the cold air infiltrating in front of the cold front, forms in southwest of Hubei. Due to the combination of the warm and humid air of the mid- and low-level southwesterly flow transported along the lower frontal zone, the 850 hPa low level shear line, the surface cold front and the warm inverted trough, the convection is triggered and intensified, and the strong hail occurs at the intersection of the cold front and the warm inverted trough. (2) The wind profile radar data indicate that the southwest of Hubei is located in the warm inverted trough in front of the surface cold front. The continuous enhancement of the middle-upper level southwesterly jet and the incessant infiltration of cold air in front of the cold front jointly stimulate the occurrence and development of strong convection. (3) Disdrometer results illustrate that the raindrop pattern captured the accompanying precipitation process, with the particle diameter mostly within 1 mm and the maximum diameter close to 6 mm. (4) According to the characteristics of raindrop vertical distribution detected by the micro rain radar, due to the low environmental humidity in the early stage of precipitation, remarkable evaporation is existing; but in heavy precipitation period, the effect of coalescence and growth of raindrops near the ground is obvious. (5) The lightning frequency obtained by three-dimensional lightning monitoring network is positively correlated with the intensity variation of hailstorms, and the initial ground flash of two hailstorms is about 30 min and 33 min in advance of hailstone falling, respectively. (6) Doppler radar detected typical hail echo characteristics such as bounded weak echo area and hook-like echo, while the existence of mesocyclone, middle radial convergence and upper divergence area indicates that strong updraft is maintained in convective clouds, which is conducive to the generation and growth of hailstones.

Abstract The summer precipitation over the southeastern Tibetan Plateau (SETP) exhibits significant diurnal variability, with a notable peak before midnight. This study investigates how thermally forced circulations regulate the diurnal precipitation over the SETP, using surface rain‐gauge observations and high‐resolution reanalysis data from June to August during 2015–2019. Water vapor supply and precipitation onset in the afternoon are associated with the upslope winds and upward motions of the mountain–plains solenoid (MPS) between the SETP and nearby lowlands (the Sichuan Basin and Yunnan–Guizhou Plateau). After sunset, the sustained easterly and stronger southerly winds below 500 hPa transport abundant moisture from the rainy lowlands to the SETP. The findings suggest that these winds are mainly due to the larger zonal continental‐scale thermally forced circulation combined with the meridional large‐scale MPS before midnight and the meridional small‐scale MPS after midnight.

Aiming at the rainstorm days (≥50 mm/d) in the middle and lower reaches of the Yangtze River during 2010–2020, the obliquely rotated principal component in T-mode (PCT) method is used to classify the daily mean 850 hPa geopotential height, including Type 1 (vortex/shear line), Type 2 (frontal surface), Type 3 (warm shear line), Type 4 (warm inverse trough line), Type 5 (typhoon-westerly trough), and Type 6 (easterly wave). We studied the weather system configurations of different synoptic circulation patterns, their long-term trends, and their impacts on diurnal variations of heavy precipitation and drew the following conclusions: Type 1, Type 2, or Type 3 shows balanced double-peak frequencies of the start time of heavy precipitation during 06:00–08:00 BT and around 17:00 BT, respectively. For Type 1, dynamical lifting and thermal lifting play balanced roles, while for Type 2 and Type 3, dynamical lifting plays a key role. The number of rainstorm stations for Type 1 shows a slight increasing trend, while that for Type 2 or Type 3 shows a significant increasing trend. Type 4, Type 5, or Type 6 show a significant single peak frequency of the start time during 15:00–16:00. Type 5 and Type 6 are mainly affected by dynamical lifting along with favorable cape values, which can trigger rainstorms. The number of rainstorm stations for Type 4 or Type 6 shows a decreasing trend (that for Type 4 is more significant), while that for Type 5 shows a slightly increasing trend.

Writing an analysis paper on the rainstorm event (APRE) is of great significance for the professional and technical personnel engaged in weather forecast research, operations and services to fully understand the multi-scale characteristics and causes of rainstorm events. At present, APRE papers have a large amount of submissions, low writing quality and low acceptance rate, and it is more and more difficult to publish them in the core periodicals of atmospheric science (meteorology). In view of the above situation and based on experiences of the APRE manuscript editing and publishing for Torrential Rain and Disasters in recent years, taking the several typical APREs in the core periodicals in the Chinese mainland as examples, we have conducted an analysis of some problems including the difficulties and key points for title, introduction, main body, and conclusion and discussion in the writing of an APRE article, and discuss the corresponding writing skills. We expect to provide reference for the forecasters in the basic meteorological stations and related researchers to grasp the APRE article writing methods and improve the APRE article writing quality and acceptance rate.

Using observational data, GFS reanalysis data and high spatial and temporal resolution FY satellite data, we analyzed the relationship between the heavy rains in northeast Hubei at 16:00 BT on 30 June 2016 and the cloud wave originated from southwest vortex center 400 km away from eastern of Hubei at 08:00 BT. It is found that two gravity waves near the southwest vortex precipitation propagate north and east, before the occurrence of heavy rain in eastern of Hubei. The north-transmitted cloud wave propagated southeastward after triggering strong precipitation in northwestern Hubei. The north-turning branch cloud wave was affected by the 500 hPa symmetry instability which caused cloud wave, but the 500 hPa water vapor was not good for precipitation formation. The south branch cloud wave is affected by conditional convective instability below 600 hPa, and appears weak inertial gravity wave propagation. After the intersection of the two north and south cloud waves in different heights, shallow convection turns to deep convection. Under sufficient moisture and unstable conditions, local heavy precipitation in eastern Hubei was triggered.

The short-range numerical weather prediction model has been developed as a tool to forecast the torrential rainfall since it has the capability to describe the dynamic convergence, fundamental physics and the real topography reasonably when the horizontal resolution is increased to a few tens of kilometers. The nearly fifty years of development in the meso-scale numerical prediction model for heavy rainfall has witnessed great changes in the dynamical core from hydrostatic to non-hydrostatic, the resolution from coarse to fine, the physical processes from simple to comprehensive, cloud and precipitation forecast from implicit to explicit and initialization from simple interpolation to complicated assimilation. In this paper, we mainly focus on dynamical frames, physical packages and initialization techniques of the meso-scale numerical heavy rainfall prediction model to analyze its important advances at home and abroad. Some future directions of the model development are also suggested. The review will be helpful to understand the current status and development trend of meso-scale model as an important tool to study and forecast heavy rainfall.

Meiyu front rainstorm is the main meteorological disaster over the Yangtze River basin during summer, which has always been a hot topic and difficult problem in meteorological research. Since the 1930s, Chinese meteorologists have paid attention to it and conducted many researches on Meiyu front rainstorm, including the concept, structure, large-scale circulation field, climatic characteristics, multi-scale features, thermal and dynamic formation mechanism of Meiyu front, and so on. These studies provided theoretical guidance and scientific understanding for routine forecast of Meiyu front rainstorm. This paper mainly introduced the concept of MeiYu front and its research history, which emphasized on the structure, properties and formation mechanism of an equivalent barotropic type Meiyu front rainstorm. Then, we summarized the classification, structural characteristics and environmental conditions of meso-scale convective systems that caused the Meiyu front rainstorm in recent years, and the influence mechanisms of terrain on MCS, and the dynamic excitation mechanism of MCS.

The Yarlung Zangbo River is the largest river in Tibetan Platau. During the second synergistic investigation of science for the Qinghai-Tibet Plateaus,analysis of the precipitation variation over the Yarlung Zangbo River basin is helpful for understanding the hydrological cycle and water resource evolution in the alpine region,which has an important significance for the rational development and utilization of water resources in this region. This study reviews and sumerizes the latest achievements in the research of the precipitation variation over the Yarlung Zangbo River basin,including the temporal and spatial distribution characteristics of precipitation,the vertical variation of water vapor density,the characteristics of water vapor channels,and the trend of precipitation change and future projection under global climate warming. The review of the above researches aims at obtaining deep understanding of the precipitation variation over the Yarlung Zangbo River basin and shtrengthening the study of it in this basin. At the same time,some problems in the current research on the precipitation variation over the Yarlung Zangbo River basin are pointed out,such as the sparsity of stations,observation difficulties and data shortage as caused by the complex terrain,which should be paid more attention in future scientific investigation.

Based on the hourly rainfall data from dense automatic weather stations over Henan between May and September from 2010 to 2015, we have analyzed temporal and spatial distribution characteristics of flash heavy rain (FHR) in this province during rainy season. Major results are as follows. FHR occurs most frequently in July, followed by August. According to regional difference of FHR in amount, contribution rate and frequency, there are four high value centers of FHR, i.e. the north of the Yellow River in the northern Henan, the Shangqiu in the eastern Henan, the piedmont region involved with the south and east of Funiu Mountains in the southwest Henan, and the basins along Hwai River and its south in the southern Henan. Terrain has a significant effect on the increase of precipitation, which is mainly achieved by increasing the frequency of FHR. The diurnal variation of FHR frequency shows obviously a double peak structure, and FHR occurs mostly in the period from nightfall to wee hours of the morning. The diurnal variation of FHR frequency differs among the four high value centers mentioned above. For example, in the north of the Yellow River, it shows a single peak characteristic and its amplitude is large, while in the basins along Hwai River and its south, it shows a persistent and active characteristic and its amplitude is small. Most of FHR events are accompanied by continuous precipitation whose durations are between 1 h and 8 h, and those lasting longer than 3 h occur more in the two high value centers related closely to terrain, i.e. the bell mouthed terrain in the east of Funiu Mountains and the basins along Hwai River and its south.

Polarimetric radar data (PRD) have potential to be used in numerical weather prediction (NWP) models to improve convective-scale weather forecasts. However, thus far only a few studies have been undertaken in this research direction. To assimilate PRD in NWP models, a forward operator, also called a PRD simulator, is needed to establish the relation between model physics parameters and polarimetric radar variables. Such a forward operator needs to be accurate enough to make quantitative comparisons between radar observations and model output feasible, and to be computationally efficient so that these observations can be easily incorporated into a data assimilation (DA) scheme. To address this concern, a set of parameterized PRD simulators for the horizontal reflectivity, differential reflectivity, specific differential phase, and cross-correlation coefficient were developed. In this study, we have tested the performance of these new operators in a variational DA system. Firstly, the tangent linear and adjoint (TL/AD) models for these PRD simulators have been developed and checked for the validity. Then, both the forward operator and its adjoint model have been built into the three-dimensional variational (3DVAR) system. Finally, some preliminary DA experiments have been performed with an idealized supercell storm. It is found that the assimilation of PRD, including differential reflectivity and specific differential phase, in addition to radar radial velocity and horizontal reflectivity, can enhance the accuracy of both initial conditions for model hydrometer state variables and ensuing model forecasts. The usefulness of the cross-correlation coefficient is very limited in terms of improving convective-scale data analysis and NWP.

Using the data of CloudSat satellite, FY series satellite, CMORPH hourly precipitation, and ERA-interim reanalysis products, this paper aims to reveal the cloud features of Tibetan Plateau Vortex (TPV) category cloud clusters over its eastward-moving regions. 107 cases of eastward-moving TPV category that occurred in the summer half-year (April to September) are picked out, and then the cloud features of them are further analyzed by statistics. The results show that the eastward-moving TPV category occurs mostly in May and June, but leastly in July and September. With consecutive enhancement of precipitation intensity and convection intensity, an increasing trend is found in the proportions of deep convection clouds and multiple layer clouds during the TPV category eastward movement. In order to reveal the inner connection among the precipitation intensity, the convection intensity, and the microphysical characteristics of TPV category cloud clusters, the TPV category cloud clusters are classified into different categories by the criteria of the precipitation intensity and the convection intensity separately. Consequently, the two different criteria share the commonality that the number concentration of both ice crystal and cloud droplets increases obviously with the enhancement of precipitation intensity or convection intensity. However, the discrepancy of conclusions also exists between the two classification criteria. A notable stretching upward trend is found in the number concentration distribution of the ice crystal and downward trend in the number concentration distribution of the cloud droplet. The same increasing trend is also discovered in the effective average radius of the ice crystal and cloud droplet. But the TPV category cloud clusters with severe convection do not present the similar variation trend both in the number concentration and the effective average radius. Hence, although the above findings confirm that the precipitation intensity, the convection intensity, and the distribution of cloud hydrometers are associated and interacting mutually, the closed function relationship among them cannot be established, and other meteorology factors related to the ambient conditions should also be taken into consideration as a complete cloud microphysical system.

There are continuous precipitation systems moving eastward from the Tibetan Plateau to the middle and lower reaches of the Yangtze-Huai River during the Mei-yu period. We selected 20 typical Mei-yu front precipitation cases from 2010 to 2015 based on observational and reanalysis data and studied the characteristics of their environmental fields. We quantitatively analyzed the transport and sources of water vapor in the rainstorms using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT_4.9) model. All 20 Mei-yu front precipitation cases occurred in a wide region from the Tibetan Plateau to the Yangtze-Huai River. The South Asian high and upper level jet stream both had strong intensities during the Mei-yu front rainstorm periods. Heavy rainfall mainly occurred in the divergence zone to the right of the high-level jet and in the convergence zone of the low-level jet, where strong vertical upward flows provided the dynamic conditions required for heavy rainfall. The water vapor mainly originated from the Indian Ocean, Bay of Bengal, and South China Sea. 52% of the air masses over the western Tibetan Plateau originated from Central Asia, which were rich in water vapor. The water vapor contribution at the initial position was only 41.5% due to the dry, cold air mass over Eurasia, but increased to 47.6% at the final position. Over the eastern Tibetan Plateau to the Sichuan Basin region, 40% of the air parcels came from the Indian Ocean, which was the main channel for water vapor transport. For the middle and lower reaches of the Yangtze River, 37% of the air parcels originated from the warm and humid Indian Ocean. The water vapor contribution at the initial position was 38.6%, but increased to 40.2% after long-distance transportation.

An improved approach to derive pseudo water vapor mass mixing ratio and in- cloud potential temperature was developed in this paper to better initialize numerical weather prediction (NWP) and build convective-scale predictions of severe weather events. The process included several steps. The first was to identify areas of deep moist convection, utilizing Vertically Integrated Liquid water (VIL) derived from a mosaicked 3D radar reflectivity field. Then, pseudo- water vapor and pseudo- in- cloud potential temperature observations were derived based on the VIL. For potential temperature, the latent heat initialization for stratiform cloud and moist adiabatic initialization for deep moist convection were used based on a cloud analysis method. The third step was to assimilate the derived pseudo- water vapor and potential temperature observations, together with radar radial velocity and reflectivity into a convective-scale NWP model during data assimilation cycles spanning several hours. Finally, 3-h forecasts were launched each hour during the data assimilation period. The effects of radar data and pseudo- observation assimilation on the prediction of rainfall associated with convective systems surrounding the Meiyu front in 2018 were explored using two real cases. Two sets of experiments, each including several experiments in each real case, were designed to compare the effects of assimilation radar and pseudo- observations on the ensuing forecasts. Relative to the control experiment without data assimilation and radar experiment, the analyses and forecasts of convections were found to be improved for the two Meiyu front cases after pseudo- water vapor and potential temperature information was assimilated.