tomatoes and cold snap sept. 2020

The cold snap Monday was a tomato wrecker for any vines not well-covered with heavy plastic or blankets. For those tomatoes that were, temperatures will be warming up starting Wednesday for a week or so.

Record lows were set this morning amid silent screams in the garden — the last gasp of uncovered tomatoes and squash caught naked in the sudden cold snap.

Temperatures reached 28 degrees in Williston and 27 in Sidney. That was abnormally cold — but not a record.

The new record for a North Dakota low on Sept. 8 was set in Alamo, which got to 18 degrees.

In northeastern Montana, meanwhile, record lows were set in Plentywood at 22 degrees, Terry at 29 degrees, and Saco at 28 degrees.

The temperature gradient drops the closer to the Canadian border you get, and that is in fact where all of this suddenly cold air came from.

You can thank that upper level pressure ridge that has parked itself across the Pacific Northwest. It’s causing heat and wildfires in California, and having an equal and opposite reaction here. That’s because the pressure ridge is pushing its way far up into that bucket of cold air Canada is already holding. And, much like a fist in a bucket full of cold water, the overflow had to go somewhere else.

Temperatures are forecast to drop to the low 20s and 30s overnight Tuesday, but should be warmer than overnight Monday. The wind is shifting a bit to come from the south, which should help a little.

After Tuesday, a gradual warming trend begins on Wednesday, with temperatures forecast to hit the mid 60s or so. That warming trend will more or less continue for at least another week, getting into the upper 80s and maybe even 90s by the weekend.

The good news for tomatoes and squash is, if you were able to cover them with heavy plastic or blankets overnight, they probably have at least another week of warm enough days to ripen — though they may need continued cover at night to avoid cat-facing. Tomatoes are tender and, while they may survive at temperatures between freezing and 54 degrees, they definitely do not like it.

You’ll have to bring the water to keep the tomatoes and squash happy — according to the forecast, little to no precipitation is expected through the week for the region from Williston to Sidney.

Precipitation is 3 to 4 inches under normal on average in the area. With that trend continuing, it will fuel some concern for fire hazards throughout the region.

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