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Showing posts from December, 2018

Preliminary December Climate Summary and 2018 Climate Highlights

Preliminary December Climate Summary: December was a warmer than normal month with average monthly temperatures around the state running 6 to 9 degrees F above normal. In fact on a statewide basis this December will rank among the ten warmest historically dating back to 1895. Over 70 percent of all days brought warmer than normal temperatures. Extremes for the month ranged from 51 degrees F at Browns Valley (Traverse County) on the 16th to -17 degrees F at Seagull Lake (Cook County) on the 6th.

Thanks to the big winter storm over December 26-28 this week, most Minnesota climate stations reported above normal precipitation for the month. Storm total precipitation ranged from 0.5 inches to 1.50 inches in many places with some storm total snowfall amounts ranging from 8 to 24 inches. In fact some climate stations reported new daily precipitation and snowfall records from this storm. Some of these records included:

December 27th record daily precipitation reports (total of rain and…

2018 Climate Summary-New Statewide Precipitation Record

2018 Climate Summary-New Statewide Precipitation Record: As we near the end of the calendar year, a climate summary for the state statistically shows that both temperature (average annual) and precipitation (total annual) will rank among the 20 highest in state history back to 1895. The distribution of temperature patterns in the state was mixed with about half of the months warmer than normal and half colder than normal. Extremes of temperature for the year were 102°F at Madison (Lac Qui Parle County) and Amboy (Blue Earth County) on May 27th and -46°F at Embarrass (St Louis County) on January 14th.

The distribution of precipitation was mixed during the year with about half of the months drier than normal and half wetter than normal. At least 20 communities reported a one-day rainfall event of 5 inches or more. The wettest areas of the state in 2018 were the southern counties, where many climate stations reported the wettest year in their historical record. The driest area of …

Revisiting the AQI

Revisiting the AQI: With persistent Air Quality Alerts this week, I wanted to revisit this topic which we talked about last August when we had persistent air quality alerts due to smoke from Western USA and Canada wildfires. In fact we had 11 Air Quality Alerts last summer, a larger than normal number.

This week the Air Quality Alerts have been provoked due to high particulate matter trapped in the lower atmosphere by persistent inversions (warmer temperatures with height). The Air Quality Index (AQI) is calculated by the EPA as a mandate from the Clean Air Act (first passed by Congress in 1963 and amended several times since). The EPA meteorologists partner with the NOAA National Weather Service in issuing Air Quality Alerts. The EPA regularly monitors for five pollutants: ground-level ozone (O3); particulate matter (microscopic); carbon monoxide (CO); sulfur dioxide (SO2); and nitrogen dioxide (NO2). For each of these pollutants there are air quality standards (thresholds) us…

Significant Snowfall on December 1-2

Significant Snowfall on December 1-2: Many climate observers in southern Minnesota have reported at least a trace of snowfall on each of the first six days of the month (MSP, Rochester, and St Cloud included). The most significant snowfalls came over December 1-2, especially in the southern half of the state where many observers reported 6 to 11 inches. Several climate stations reported new daily snowfall records for December 2nd including:
Lakefield 11.0”
Windom 8.3”
Winnebago, Tracy, and Owatonna 8.0”
Caledonia 7.0”
Spring Valley 6.5”
Minneota, Austin, and Grand Meadow 6.0”
Hokah 5.0”

Much of the snow remains on the ground as temperature have generally stayed below the freezing mark around the state all week. Over 25 climate stations reported subzero overnight temperatures this week, led by -15°F at Warren (Marshall County). Also noteworthy is the fact that the weekly snow depth map from the Minnesota State Climatology Office shows an unusual pattern for Minnesota with both t…