###### Abstract
From a meteorological point of view, precipitation could be divided into two types, large-scale precipitation (LSP) and cumulus precipitation (CP). The former is generally introduced by the steady uplift of warm air mass, e.g., slow-moving warm fronts with little chance of strong wind gusts (Figure 1a), but the latter develops and intensifies when the lower atmosphere level is quite unstable, e.g., in squall lines or fast-moving cold fronts (Figure 1b-d), possibly with strong wind gusts. The total precipitation is commonly applied because, in practice, it is hard to discriminate convective and non-convective precipitation from the surface rain-gauge-based reading. However, in specific Numerical Weather Prediction (NWP) models, these two rainfall components were calculated, delivered, and stored separately. In dynamic meteorology  
Figure 1: Different types of clouds and precipitations: (**a**) frontal clouds (Ci, Cs, As, and Ns) with large-scale precipitation; (**b**) fair weather cumulus; (**c**) cumulus congestus; (**d**) cumulonimbus with strong precipitation. Arrow represents air particle movement direction. theory, CP is a much more suitable representative for the intensity of convective weather. For the crew, any precipitation will result directly in limited visibility, which affects the navigation of the vessel. However, due to the poor anti-wind ability of cruise boats, strong wind gusts might be a much greater threat than navigation visibility. The reason is that nowadays, the conventional cabin has evolved from a dormitory-style canopy bed to an independent window-viewing bedroom, in order to meet the demands of the passengers' private space and sightseeing. For example, during two renovations in 1997 and 2008, the shipyard enlarged the \"Oriental Star\" space, lifted the center of gravity, and reduced the wind pressure stability criterion numeral from 1.36 to 1.02, i.e., worsen the ship's anti-wind ability [3]. The wind gusts have the characteristics of sudden intensification; large, instantaneous maximum wind speed; and great mutability directions. When the wind pressure tilting moment is greater than the minimum overturning moment, the ship would capsize due to water inflow [15]. This situation is particularly dangerous for inland and offshore cruise boats. Although the concomitant relationship between short-term torrential precipitation and strong wind gusts under deep-convective weather has been confirmed both by observations and in fine-grid (resolution < 5 km) model [13], it is very difficult to apply the latter to provide operational early warning service because in most cases, the precipitation and strong wind gusts occur simultaneously. The fine-grid regional model needs the output of large-scale global weather products as initial forcing, which is time-consuming and disabled for operational warning. A hypothesis was raised by [PERSON] et al. [16] that it is possible to invert the intensity of severe convective events by watching the CP variance in numerical weather products, thus indirectly leading to strong wind gust warnings for small-sized vessels, especially cruise boats. This work looks at the possibility that the global numerical product itself can act as an efficient tool to retrieve adverse convective events, though the events' spatial scales are much smaller than the model's grid distance (also called sub-grid), which are usually considered lacking in simulation capabilities. This paper was organized as follows: Section 2 lists the data source and format; Section 3 discusses the weather components' space-time performance during the \"Oriental Star\" shipwreck; Section 4 verifies the findings in Section 3 for two other cruise boat wrecks; Section 5 introduces an automatic gust warning system developed for marine application; and Section 6 draws the conclusion.