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In this paper, the sensitivity of precipitation associated with ordinary baroclinic continental winter storms to small variations in the synoptic-scale circulation is explored using ensembles of observed regional analogs. When seeking time-coherent analogs for periods of 1--2 days in length on the basis of anomaly correlation scores at both the surface and 500 hPa, the observed precipitation structures are strongly dependent on circulation details, reflecting subtle differences at both the synoptic scale and mesoscale. It has also been found that when seeking time-coherent regional analogs on the basis of the observed precipitation distributions, such analogs cannot be identified. However, coherent precipitation structures that are identified for shorter periods (order 1 day) are found to occur in association with highly dissimilar circulations. Thus, the sensible weather that results from a particular circulation is crucially dependent on the details of the flow. The authors believe that these findings provide some explanation for the relatively slow advance of precipitation forecast skill in the face of continuously improving forecasts of the large-scale circulation. The study of the evolution of the base case and its closest circulation analog is split into two successive 24-h periods. During the first 24 h, the substantial differences in the observed precipitation are linked to the complex interplay between precipitation events prior to the period of interest (which led to the generation of upwind sources of moisture) and synoptic-scale dynamics (primarily differences in the structure and intensity of the subtropical jet, which led to slight deviations in the low-level flow between the two cases and subsequent differences in moisture advection from the Gulf of Mexico and moisture convergence). [ABSTRACT FROM AUTHOR]

This paper is designed to be an annual summary of the Eastern Hemisphere tropical cyclones of 1995. The tropical cyclone statistics presented are those of the Joint Typhoon Warning Center, Guam. The text focuses primarily upon the tropical cyclones that occurred in the western North Pacific during 1995; however, since the area of responsibility of the Joint Typhoon Warning Center covers the entire Eastern Hemisphere, brief summaries of the tropical cyclone activity within the north Indian Ocean, south Indian Ocean, and the southwest Pacific are also presented. Overall, 1995 was a relatively quiet year in the Eastern Hemisphere: the 22 tropical cyclones of the Southern Hemisphere were only one shy of the record low of 21, and for the first time since 1988 the number of tropical storms and typhoons in the western North Pacific was below normal. In the western North Pacific, there was a marked shift to the west of the preferred region for the genesis and development of tropical cyclones. This is consistent with the end of persistent large-scale circulation anomalies characteristic of the warm phase of the El Nino--Southern Oscillation (ENSO) and the onset (during 1995) of weak ENSO cold-phase anomalies (i.e., La Nina conditions). [ABSTRACT FROM AUTHOR]

There is a growing use of multiparameter radars for observation of the atmosphere and, in particular, for remote sensing of rain. Radar systems have the undeniable advantage of being able to monitor very large areas with a single installation in real time. On the other hand, their measurements are often only qualitative; the conversion of the radar measurables into meteorological quantities (like rain rate) is not unique, depending on the model assumed for the target. In this context, the availability of sophisticated radar simulators can prove to be extremely useful to try and discriminate the effect of the different contributions on the received echoes. In this paper a physically based software radar simulator is presented; the synthetic radar signal is generated by adding up (in amplitude and phase) all the contributions coming from each single scatterer present into a virtual meteorological environment. The characteristics of the radar system are properly taken into account, as well as the effects of propagation and wave polarization. [ABSTRACT FROM AUTHOR]

The present study is devoted to a new analysis of wind measurements from dropsonding and/or radiosonding of Doppler information from multiple Doppler radar scanning and of other wind measurements (sodar, dynamical sensors on board aircraft, and instruments at ground) aimed at retrieving three-dimensional thermodynamical and dynamical fields both in clear air and in precipitating areas of mesoscale phenomena. This analysis, well suited to assimilate data from differing platforms specified at differing spatial/temporal resolutions, is based on the analytical and variational concept of the Multiple Analytical Doppler (MANDOP) analysis and thus is an extension of it. This new analysis presents many advantages, including the same as MANDOP and others well adapted for the verification or the initialization of a mesoscale cloud model. An application to simulated and to real data extracted from the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment database is presented in the paper. [ABSTRACT FROM AUTHOR]

Presents the reply of Haynes et al on the comment of Joseph Egger on their paper `On the `Downward Control' of Extratropical Diabatic Circulations by Eddy-induced Mean Zonal Forces'. Application of the downward control principle on time-dependent thought-experiments; Real atmosphere problems and its solution.

The article reflects the author's view on the paper presented by D. M. Schultz on the mechanisms for the formation of mammatus clouds. The author affirms the idea of Schultz that though the formation of mammatus cloud has less significance in the societal aspect, but it still deserves careful scientific study. He adds that any analysis of the possible importance of double-diffusive convection in the production of mammatus clouds would need the development of order-of-magnitude estimates.