NOAA预报G1级地磁暴持续到11月10日：美国北部地区今明两晚有机会看到极光
美国国家海洋和大气管理局（NOAA）空间天气预报中心11月8日发布的最新三日预报说，G1级（弱）地磁暴预计持续到11月10日，11月8日与9日还可能短暂升到G2级（中等）。地磁活动增强时，美国北部高纬度地区的居民今明两晚有机会看到极光。
预报说，过去24小时观测到的最大地磁指数 Kp 达到5，也就是 G1 级；11月8日至10日预计的最大 Kp 同样是5.00。这一轮地磁活动来自负极性冕洞高速流的影响，太阳风正吹向地球。
同一份预报还提到，过去24小时已经观测到 R1 级无线电中断，11月8日至10日出现 R1 到 R2 级无线电中断的概率约为60%。G1 级别属于地磁暴分级里最弱的一档，对日常生活的直接影响有限，常见的是高纬度地区电网的弱波动与卫星运行的轻微影响。
想看极光的读者，要等天黑之后、避开城市灯光、朝北面天空看。极光是否出现还取决于当晚的实际地磁活动与本地天气，预报中心会在空间天气变化时更新预报。
（来源：美国国家海洋和大气管理局）
NOAA Forecasts G1 Geomagnetic Storms Through Nov. 10, With Aurora Possible Across the Northern United States
The U.S. National Oceanic and Atmospheric Administration's Space Weather Prediction Center said in its latest three-day forecast, issued on November 8, that G1 (minor) geomagnetic storming is expected through November 10, with a chance of briefly reaching G2 (moderate) levels on November 8 and 9. When geomagnetic activity rises, residents across the northern United States may have a chance to see the aurora on the next two nights.
The forecast says the greatest observed Kp index over the past 24 hours was 5, which is G1 level, and the greatest expected Kp for November 8 to 10 is also 5.00. This round of activity comes from a negative-polarity coronal hole high-speed stream blowing past Earth.
The same forecast notes that R1 radio blackouts were observed over the past 24 hours, and puts the chance of R1 to R2 radio blackouts on November 8 to 10 at about 60 percent. G1 is the weakest category on the geomagnetic storm scale, with limited direct effects on daily life, mainly weak power-grid fluctuations at high latitudes and minor impacts on satellite operations.
Readers hoping to see the aurora should wait for full darkness, get away from city lights, and look toward the northern sky. Whether the aurora appears also depends on actual geomagnetic activity that night and local weather, and the prediction center updates its forecast as space weather changes.
(Source: National Oceanic and Atmospheric Administration)
来源：美国国家海洋和大气管理局
发布：GSM·美国（发布链接）
图片来源：图：极光（资料图）。CC0，经 Wikimedia Commons（Unsplash）。/ Photo: The aurora borealis (file photo). CC0, via Wikimedia Commons (Unsplash).
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