Towards seamless prediction of extremes (TEX) (T02#)

天气预报界越来越有兴趣利用专门为极端事件设计的其他诊断工具来补充数值天气预报（NWP）模式的直接输出。在之前的SFB-Transregio“波到天气”（W2W）转移项目T1中，设计了一个策略来对意大利北部的极端降水进行分类。我们与区域气象服务机构ARPAE-SIMC合作，开发了诊断方法，以跟踪极端事件从预测中最早阶段到实际发生的跨尺度发展。在这一成功的基础上，我们现在提出一个新的转移项目T2“朝向极端天气的无缝预测”（TEX）。目标是将这种动态方法扩展和推广到欧洲其他地区，并进入分季节预报范围（10-30天），并在ECMWF和ARPAE-SIMC创建原型预报产品。TEX将为预报员提供极端事件展开的“叙述”，描述相关动态过程的可预测性。TEX将以重要的动力学理解来支持预测和预警链，而不是依赖于不完善模型的黑箱预测产品。为此，我们将开发一个真正无缝的诊断框架。随附的原型产品将演示动态思维和面向过程的预测器如何在所有预测范围内作为关键天气事件的“警钟”。作为第一个行动，TEX将把T1的洞察力转化为意大利北部（WP1）极端降水事件的新预报方法。接下来，我们将开发一个统一的、无缝的框架，系统地记录欧洲其他地区大规模极端流动及其动力驱动因素的联系（WP2）。这将由一个原型预测框架加以补充，该框架将现有的极端天气预报产品与描述极端天气动态前兆的指数层次计算的预测概率结合起来（WP3）。诊断框架和原型预报产品将与ECMWF和ARPAE-SIMC密切合作实施，用于极端降水和极端温度。专注于运动和过程的可预测尺度，我们提出的无缝方法将提供一种方法来增加对从中期到扩展预测范围（10-30天）的极端预测的准备，在这些范围内，经典的预测产品是不准确的。鉴于气候变暖中发生极端事件的可能性越来越大，而且在可预见的未来，数值模式仍然存在缺陷，因此对提前期的更好指导的需求变得更加迫切。最后，TEX将有助于实现WMO HIWeather项目的关键目标，即加强跨尺度的预警程序。

There is a growing interest in the weather forecast community to complement direct output from numerical weather prediction (NWP) models with other diagnostics tools designed specifically for extremes events. In a previous transfer project T1 of the SFB-Transregio “Waves to Weather” (W2W) a strategy was designed to classify precipitation extremes in N-Italy. Working in collaboration with the regional meteorological service ARPAE-SIMC, we developed diagnostics to follow the unfolding of the extreme event across scales from its earliest stage in the forecast, to its actual occurrence. Building on this success for a weather event in a particular region, we now propose a new transfer project T2 “Towards seamless prediction of EXtremes” (TEX). The goal is to expand and generalize this dynamical methodology to other regions of Europe and into the sub-seasonal forecast range (10-30 days), and to create prototype forecast products at ECMWF as well as at ARPAE-SIMC. TEX will provide the forecaster a “narrative” of the unfolding of an extreme event, which describes the predictability of the relevant dynamical processes. TEX will support the forecasting and warning chain with important dynamical understanding which goes beyond relying on black box forecast products from imperfect models. To this end we will develop a truly seamless diagnostic framework. The accompanying prototype products will demonstrate how dynamical thinking and process-oriented predictors can serve as a “warning bell” in critical weather events, at all forecast ranges. As a first action, TEX will transfer the insight of T1 into a novel forecasting method for extreme precipitation events in N-Italy (WP1). Next, we will develop a unified, seamless framework which systematically documents the linkage of the large-scale flow to extremes and their dynamical drivers for other European regions (WP2). This will be complemented by a prototype forecast framework which integrates existing forecast products for extremes with forecast probabilities computed for a hierarchy of indices describing the dynamical precursors of an extreme (WP3). The diagnostic framework and prototype forecast products will be implemented in close collaboration with ECMWF and ARPAE-SIMC and for both precipitation and temperature extremes. Focusing on the predictable scales of motion and processes, our proposed seamless approach will provide a way to increase preparedness for forecasting extremes from the medium to extended forecast ranges (10-30 days), ranges where classical forecast products are inaccurate. The need for better guidance across lead times is becoming even more substantial in view of the increasing likelihood of extreme events in a warming climate and remaining deficiencies in numerical models for the foreseeable future. Finally, TEX will contribute to the key goal of WMO’s HIWeather project to strengthen warning procedures across scales.