气象冬天在北美呼啸而至

气象冬天在北美呼啸而至

It's December, which means it's "meteorological winter" for the Northern Hemisphere. And while there are still a few weeks until the winter solstice — which marks the official beginning of "astronomical winter" on Dec. 21 — the weather across much of North America is already leaving little doubt that winter has effectively arrived.

现在是12月，对北半球来说，这是一个“气象冬季”。尽管离冬至还有几周的时间——冬至标志着12月21日“天文冬季”的正式开始——但北美大部分地区的天气状况已经让人确信，冬季实际上已经到来。

Motorists navigate during a winter storm in Mason City, Iowa, on Nov. 27, 2019. (Photo: Scott Olson/Getty Images)

A dangerous winter storm swept east across the country during the weekend after Thanksgiving, and more severe weather is forecast along both the east and west coasts in coming days.

感恩节后的周末，一场危险的冬季风暴席卷了美国东部地区，预计未来几天美国东部和西部沿海地区将出现更恶劣的天气。

The snow and ice was often exacerbated by strong winds, which gusted as strong as a category 1 hurricane Saturday in Nederland, Colorado, reaching speeds up to 94 mph (151 kph). Winds also gusted at 59 mph (95 kph) in Nebraska, according to AccuWeather, which notes icicles froze sideways during high winds in the city of Kimbell.

大风经常使冰雪更加恶化，周六在科罗拉多州的尼德兰，强风达到了一级飓风的强度，最高时速达到94英里(151公里)。根据AccuWeather的数据，内布拉斯加州的风速也达到了每小时59英里(每小时95公里)。

More on the way

更多的还在路上

A trio digs out of the Green Mountain neighborhood ahead of Thanksgiving in Lakewood, Colorado. (Photo: Joe Mahoney/Getty Images)

After sweeping across the Central U.S. last week, the severe weather battered the Eastern U.S. on Monday, dumping several inches of snow and causing additional delays to air traffic. Parts of the Northeast may have up to a foot of snow by Wednesday, according to the National Weather Service. Forecasters warned of "disastrous" travel conditions in some major metro areas.

在上周横扫美国中部地区之后，恶劣天气周一又袭击了美国东部地区，带来了几英寸的降雪，导致空中交通进一步延误。据美国国家气象局说，到周三，美国东北部部分地区的降雪量可能达到一英尺。气象预报员警告说，一些大城市的交通状况将是“灾难性的”。

This round of severe weather should dwindle as the first week of December wears on, but more trouble may still be brewing farther west. By midweek, for instance, an atmospheric river will carry bring rain and high-country snow from the Pacific Ocean across Southern California and into the interior Southwest. While this precipitation may offer relief to areas plagued by wildfires in recent weeks, it could also lead to dangerous flooding in some places, AccuWeather warns.

随着12月的第一周逐渐过去，这一轮恶劣天气应该会有所缓解，但在更远的西部地区，更多的麻烦可能仍在酝酿之中。例如，到本周三，一条大气河流将从太平洋带来降雨和高海拔地区的降雪，跨越南加州，进入西南内陆地区。AccuWeather警告说，虽然这种降水可能缓解近几周野火肆虐的地区的灾情，但也可能导致一些地区发生危险的洪灾。

A "train" of West Coast storms is expected to continue into late this week, potentially expanding into the Pacific Northwest by this weekend, according to AccuWeather. While temperatures are expected to be below average this month for the Eastern U.S., the latter weeks of December may warm up slightly for much of the rest of the country, the Weather Channel reports.

据AccuWeather网站报道，一列西海岸风暴预计将持续到本周晚些时候，有可能在本周末扩大到太平洋西北部地区。据气象频道报道，虽然本月美国东部的气温预计将低于平均水平，但12月的最后几周，美国其他大部分地区可能会略有升温。

A woman and a boy build a snowman in California's San Bernardino National Forest on Nov. 29. (Photo: Apu Gomes/AFP/Getty Images)

This marks a busy beginning to meteorological winter, which spans the three coldest months of the year in the Northern Hemisphere. It begins on Dec. 1 and runs through the end of February, differentiating it from astronomical winter, which begins with the winter solstice on Dec. 21. Determined by Earth's axial tilt and the sun's alignment over the planet's equator, rather than actual weather conditions on the surface, astronomical winter continues until the spring equinox on March 19.

这标志着北半球一年中最冷的三个月迎来了一个繁忙的气象寒冬。它始于12月1日，一直持续到2月底，与冬至日(12月21日)形成鲜明对比。由地球的轴向倾斜和太阳在地球赤道上的排列决定，而不是地球表面的实际天气状况，天文上的冬季将持续到3月19日春分。