A Severe Cold Air Will Impact Central and Eastern of North America

Affected by an upper-level cold vortex, it is expected that from November 15 to 18, a strong cold air mass will impact the central and eastern regions of North America from north to south (Figure 1). Average temperatures in southern Canada and the central and eastern United States will drop by 6 to 10°C, with localized cooling of 12 to 16°C (Figure 2). These areas will also experience winds of 5 to 6 on the Beaufort scale, with gusts of 7 to 8, and along the eastern coast of the United States, gusts could reach 9 to 10 (Figure 3). Parts of central and eastern Canada and northeastern United States will see heavy to severe snowfall (or sleet), with localized extreme snowfall events. Accumulated snowfall during this period is expected to reach 16 to 20 mm, with some areas exceeding 30 mm (Figure 4). New snow accumulation depths will range from 6 to 10 cm, with localized depths potentially exceeding 14 cm (Figure 5). Precautions should be taken against the adverse effects of the snowfall, strong winds, and cooling on local power transmission, shipping, and transportation.

Figure 1  500 hPa Geopotential Height (units: dagpm) and 850 hPa Wind Field (units: m/s) at 12:00 (UTC) on November 15

Figure 2  48-hour Temperature Change Forecast at 2 meters above ground level as of 12:00 (UTC) on November 17 (Unit: °C)

Figure 3  Maximum Gust Wind Speed (Unit: m/s) for 24 Hours as of 12:00 (UTC) on November 16

Figure 4  Accumulated Snowfall from 00:00 on November 15 to 12:00 on November 18 (UTC, Unit: mm)

Figure 5  24-hour Accumulated Snow Depth at 12:00 (UTC) on November 16 (Unit: cm)

                       Author: Yan Dachun                              Reviewer: Zhang Bo

                               English reviewer: Wang Yi                                                                       Issue approver: Dai Kan