GEFSv12 High- and Low-Skill Day-10 Tornado Forecasts
GEFSv12 High- and Low-Skill Day-10 Tornado Forecasts
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GEFSv12 高技能和低技能第 10 天龙卷风预报
DOI：
10.1175/waf-d-22-0122.1
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发表时间：
2023
影响因子：
2.9
通讯作者：
Gensini, Vittorio A.
中科院分区：
文献类型：
--
作者：
Miller, Douglas E.;Gensini, Vittorio A.
平均而言，现代数值天气预报对每日龙卷风频率的预测在第10天之后没有表现出任何技巧。然而，在这个扩展范围的领先窗口中，有一些特定的模型周期对龙卷风具有非常高的预测技能，因为它们能够正确地模拟未来的天气模式。在这里，模型的初始条件，产生了更熟练的预测龙卷风在美国被利用，同时也突出了潜在的原因，低技能的周期内的全球包围预测系统，第12版（GEFSv 12）。有88个高技能和91个低技能的预测，其中验证了第10天龙卷风条件的天气模式显示了美国西部的热槽和美国东部的热脊，这是龙卷风风暴发生的有利配置。高技能预报的初始条件往往表现出整个热带太平洋和墨西哥湾的海面温度较高，活跃的马登-朱利安振荡，以及地球相对大气角动量的显著调制。在拉尼娜现象和太平洋十年期振荡出现负值的情况下，往往开始进行低技能的预报。在俄罗斯东部的显着的大气阻塞，其中GEFSv 12高估了下游流量的持续时间和特征，是一个常见的物理过程与低技能的预测。这项工作有助于提高我们的理解的共同原因，高或低技能的扩展范围的龙卷风预报，并可以作为一个有用的工具业务forecasters.Significance StatementThis研究提供了一个框架，预测一个更（或更少）熟练的10天龙卷风预报业务数值天气预报系统。高技能预报与太平洋和墨西哥湾的大量热带对流和温暖的海面温度有关，而低技能预报的根本原因通常与俄罗斯东部的阻塞反气旋有关。这些发现是重要的，因为它们允许增加或减少的信心，在长期预测龙卷风发生的动力预测系统的基础上。
On average, modern numerical weather prediction forecasts for daily tornado frequency exhibit no skill beyond day 10. However, in this extended-range lead window, there are particular model cycles that have exceptionally high forecast skill for tornadoes because of their ability to correctly simulate the future synoptic pattern. Here, model initial conditions that produced a more skillful forecast for tornadoes over the United States were exploited while also highlighting potential causes for low-skill cycles within the Global Ensemble Forecasting System, version 12 (GEFSv12). There were 88 high-skill and 91 low-skill forecasts in which the verifying day-10 synoptic pattern for tornado conditions revealed a western U.S. thermal trough and an eastern U.S. thermal ridge, a favorable configuration for tornadic storm occurrence. Initial conditions for high skill forecasts tended to exhibit warmer sea surface temperatures throughout the tropical Pacific Ocean and Gulf of Mexico, an active Madden–Julian oscillation, and significant modulation of Earth-relative atmospheric angular momentum. Low-skill forecasts were often initialized during La Niña and negative Pacific decadal oscillation conditions. Significant atmospheric blocking over eastern Russia—in which the GEFSv12 overforecast the duration and characteristics of the downstream flow—was a common physical process associated with low-skill forecasts. This work helps to increase our understanding of the common causes of high- or low-skill extended-range tornado forecasts and could serve as a helpful tool for operational forecasters.Significance StatementThis research provides a framework for the anticipation of a more (or less) skillful 10-day tornado forecast in an operational numerical weather prediction system. High-skill forecasts were associated with substantial tropical convection and warm sea surface temperature throughout the Pacific Ocean and Gulf of Mexico, whereas the underlying cause of low-skill forecasts were typically associated with a blocking anticyclone over eastern Russia. These findings are important because they permit increased or decreased confidence in a long-range forecast of tornado occurrence based on a dynamical prediction system.