Severe drop in barometric pressure stirs up winds
A precipitous downward swoop in barometric pressure has set up a record-setting set of weather conditions in the area.
"This was a very, very strong low pressure system, and it's deepened," said Geoff Grochicinski, a meteorologist with the National Weather Service in Grand Forks, N.D.
Normal barometric pressure at sea level is about 30 inches, or 101 millibars. According to the National Weather Service website, the barometric pressure in Bemidji Tuesday afternoon was 28.33 inches or 959.3 millibars. Grochocinski said the unofficial record low pressure was set in the Orr, Minn., area Tuesday at 957.5 millibars or 28.2 inches.
(The lowest barometric pressure ever recorded was on Oct. 12, 1979, in the center of a Pacific Ocean typhoon at 25.6 inches. The highest barometric pressure ever recorded was 32.31 inches Dec. 31, 1968 in Siberia on a cold, clear minus-58-degree day.)
However, said Grochocinski, the biggest effect is the steep drop in barometric pressure called bombogenesis. "That is if it falls 24 millibars within 24 hours," he said. "It's creating pretty bad weather."
He said the weather isn't likely to be too severe in the Bemidji area, but high winds were picking up in the Red River Valley and points west. As with a hurricane, the strongest winds are some distance away from the low pressure center.
On Tuesday morning, areas of southern and western Minnesota were experiencing wind gusts of more than 40 mph, with a high of 59 mph recorded near the North Dakota border.
Grochocinski said he had never experienced a weather pattern like Tuesday's deepening low pressure system - bombogenesis
"At least not in my meteorologic career," he said. "This is the first one I've dealt with."
Here is the latest forecast for the Bemidji area:
Late Afternoon: Rain. Steady temperature around 50. Breezy, with a west wind around 25 mph, with gusts as high as 30 mph. Chance of precipitation is 90%. New rainfall amounts of less than a tenth of an inch possible.
Tonight: Rain before 1am, then rain and snow likely. Low around 37. Windy, with a west wind between 26 and 31 mph, with gusts as high as 44 mph. Chance of precipitation is 100%. Little or no snow accumulation expected.
Wednesday: Snow. High near 38. Windy, with a west northwest wind between 29 and 33 mph, with gusts as high as 50 mph. Chance of precipitation is 100%. New snow accumulation of 1 to 2 inches possible.
Wednesday Night: A 50 percent chance of snow, mainly before 1am. Cloudy, with a low around 27. Blustery, with a northwest wind between 26 and 29 mph, with gusts as high as 34 mph.
Thursday: Partly sunny, with a high near 37. Breezy, with a northwest wind between 20 and 25 mph, with gusts as high as 30 mph.
Thursday Night: Partly cloudy, with a low around 21.
Friday: Mostly sunny, with a high near 46.
Friday Night: Mostly cloudy, with a low around 29.
Saturday: Partly sunny, with a high near 45.
Saturday Night: Mostly cloudy, with a low around 29.
Sunday: Mostly sunny, with a high near 45.
Sunday Night: Partly cloudy, with a low around 30.
Monday: Mostly cloudy, with a high near 43.
Monday Night: Mostly cloudy, with a low around 32.
Tuesday: Mostly cloudy, with a high near 45.