2019 Autumn Discussion Thread (Northern Hemisphere)

Here is the NWS summary of the blizzard in North Dakota last week. Snow and wind reports, a video of radar, and a text discussion. alex992

Text discussion: This is the first paragraph, for the rest, and weather charts, see the Environment page on the link.

Through the day on October 9th meteorologist across the country were monitoring an upper level wave as it moved southeastward into the northwest United States (Figures 1 and 2). Ahead of this wave was was a pocket of unseasonably cold low-level air (Figures 4 and 5). As the upper level wave move over the Rocky mountains, west-to-east winds induced lee cyclogenesis over the Denver, CO region. Falling surface and low level pressure in Colorado induced northerly winds across the northern Plains that helped drag the cold low level air southward along the lee of the Rocky mountains.

Locally, this colder air moved southeastward through North Dakota behind a notable cold front. Although there was little precipitation as the cold front passed through, many locations reported thick cloud cover and fog as warmer air was lifted over the shallow layer of colder air pushed through. By Wednesday night, the cold front had stalled out from southeast North Dakota into north central Minnesota (this can be see early in the loop in Figure 6).


Pictures:

Snow totals. The highest recorded total was 29". Cavalier, the city with the webcam, saw 20". Webcam: www.earthcam.com/usa/northdakota/cavalier/?cam=cavalier


Maximum wind gusts. The highest recorded was 61mph. This storm had wet snow, so it didn't blow around as much as dry snow. Still, this is enough wind to make large drifts, see the pictures for some.



A car stuck in the ditch, under the water. It's fine...

Snow drifts. They need a bigger snow blower.





The area is mostly agricultural, so farmers are having issues with the rainfall and flooding. Some parts of the area have seen over 10"/250mm in the past month, and now there is snow on top of the mud, making it really hard to drive on the fields. The area near Grand Forks is very flat and has flooding issues in spring, this year it has flooding in the fall too.