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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…

November Climate Summary

November Climate Summary:
Cold and dry are the words for November. It was the coldest November since 2014 with average monthly temperatures around the state ranging from 5 to 7 degrees F below normal. Approximately two-thirds of the days brought cooler than normal temperatures. Extremes for the month ranged from 61°F at Marshall on the 1st to -20°F at Cotton (St Louis County) on the 20th. Within the state climate network over 75 low minimum temperature records were set or tied during the month, while over 90 low daytime maximum temperature records were set or tied.

Precipitation was less than normal for the month in most places, ranging mostly from 0.50 to 1.50 inches. Some places received over 2 inches, topped by 2.70 inches at La Crescent and 3.11 inches at Grand Portage. Snowfall was variable, with many areas around the state reporting 3 to 6 inches, and higher amounts in the north. In the northeast many climate stations reported 10 to 19 inches for the month. Grand Porta…

Cold November Continues

Cold November Continues: Through the first three weeks of November observers around the state reported an average monthly temperature that ranges from 7 to 9 degrees F cooler than normal. Over 80 climate stations in Minnesota have reported at least one subzero temperature so far this month, topped by -20°F at Cotton (St Louis County) on November 20th. Though much of the state has been spared from a lot of snowfall, the northeastern area has received from 12 to 18 inches, topped by 18.5 inches at Grand Portage.

The Minnesota State Climatology Office posted a Thanksgiving Weather Retrospective o their web site. It provides a look back at all the weather in the Twin Cities history associated with the Thanksgiving Holiday.
Weekly Weather Potpourri: Authorities issued a public health alert for Sydney, Australia on Thursday as the 500km-wide (310 miles) dust band began to reach the city. One of the largest dust storms in recent history blanketed many parts of SE Australia and caused a…

Widespread subzerio temperatures this week

Widespread subzero temperatures this week:
Last week on MPR's Morning Edition we talked about the widespread snow cover around the state and up until that time only about a dozen climate stations had reported a subzero minimum temperature so far this autumn. Since then we have seen severe cold weather dominate the landscape, and subzero temperatures have become far more common. In fact over November 13-14 this week over 40 climate stations reported morning low temperatures that were subzero with readings of -10°F to -15° in portions of St Louis and Lake of the Woods Counties. In fact on November 13th (Tue) many Minnesota climate stations saw the daytime high temperature remain in the teens F.

The week of November 7-13 brought temperatures that ranged from 11 to 15 degrees F colder than normal. In fact for the Twin Cities it was the coldest such week in history (1872-present). Here is a ranking of the five coldest weeks of November 7-13 for the Twin Cities climate:

2018 mean …

Snow cover season begins

Snow cover season begins: Even though more than 100 climate stations reported some snow this autumn before November began, all of that snow melted as the ground was too warm for snow cover to persist. There have been 87 more reports of snow from the state climate network so far this month, ranging from a few tenths of an inch to over 4 inches. In the northwestern counties Detroit Lakes and Fertile have reported over 4 inches, while in the northeast Duluth and Two Harbors have reported over 4 inches. And further up along Lake Superior’s north shore Grand Portage has reported 13.5 inches this week. But now the ground temperatures are cold enough in some areas of the state for the snow cover to stick around. Air temperatures this month have been colder than normal, with many nights dropping into the teens F, and even daytime temperatures remaining in the 30s F. The high temperature on Thursday, November 8th in the Twin Cities was only 28 degrees F, while at Pokegama Dam (Itasca Co…

October 2018 Climate Summary

October 2018 Climate Summary: Cool and wet are the two appropriate descriptions of October of 2018. Cooler than normal temperatures prevailed on 65-70 percent of the days in the month, while a number of climate stations reported precipitation on 20 or more days. On a statewide basis October of 2018 was the 12th coldest in history back to 1895, and it was the 10th wettest in history.

Mean October temperature in 2018 ranged from 3 to 6 degrees F cooler than normal around the state. The highest reading was 89°F at Marshall (Lyon County) on the 3rd, and the coldest reading was 8°F at Hallock (Kittson County) on the 12th. Within the state climate network the following record daily values were reported:
6 reports of a record daily high maximum temperature
2 reports of a record daily high minimum temperature
10 reports of a record daily low minimum temperature
111 reports of a record daily low maximum temperature

Many climate stations reported monthly total precipitation ranging from 3…

Precipitation for 2018: Yet, another wet year for Minnesota

Precipitation for 2018: Yet, another wet year for Minnesota:
As we wrap up October we already know it has been a wetter than normal month. October is the 5th month of the year so far that has delivered above normal precipitation. For the first ten months of 2018 only the counties of northwestern Minnesota have been marginally drier than normal. The rest of the state has seen a precipitation surplus, and for some southern counties the precipitation surplus has been record setting. Many climate stations in those counties have reported total precipitation through the first ten months that is over 13 inches above normal.

A sample of precipitation for 2018 so far shows: Ada (Norman County) in the Red River Valley is just 20 inches, one of the few drier than normal spots in the state (2 inches less than average); both Caledonia (Houston County) and Harmony (Fillmore County) have reported nearly 53 inches (about 21 inches above normal), already ranking as the wettest year in their resp…

Wide swings in temperature

Wide swings in temperature:
This time of year the combination of clear skies, bright sun, and strong air mass advection (from either the north or south) can cause some very dramatic and large swings in temperature. That’s is what we experienced back on October 3-4 when many parts of the state saw afternoon temperatures in the 70s and 80s F drop overnight into the 20s and 30s F. The complete reversal of that pattern took place this Thursday, October 18th as morning lows in the 30s F were followed by bright sun, and mild southwest winds which caused temperatures to rise into the 70s F. Here are some temperature changes reported on October 18th:

MSP from a morning low of 33 degrees F to an afternoon high of 71 degrees F
Hallock from a morning low of 36 degrees F to an afternoon high of 75 degrees F
Baudette from a morning low of 30 degrees F to an afternoon high of 71 degrees F
Roseau from a morning low of 30 degrees F to an afternoon high of 72 degrees F
Alexandria from a morning low…

October behaving like November

October behaving like November: So far this month most of Minnesota’s climate observers report a monthly mean temperature that is from 5 to 10 degrees F colder than normal. Widespread frosts occurred on October 5-6 and again over October 11-12. Some climate stations set new low daytime maximum temperature records on those dates. At MSP the maximum temperature of 39 degrees F on October 11th tied for the coldest in history, matching that of 1959. In fact on the 11th a number of climate stations reported record cold daytime maximum temperatures in the 30s F. Also many climate stations reported their lowest Wind Chill readings of the fall season so far, with values ranging from the single digits to teens F on October 11th.

Persistent cloudiness and rain have prevailed and brought about an early onset of Seasonal Affective Disorder for some people. Most days have seen rain, or complete cloud cover prevail. Rochester and several other locations have reported at least a trace of ra…

Wet, cool, and cloudy start to October

Wet, cool, and cloudy start to October:
The month of October has begun with plenty of moisture, measured in terms of rainfall, cloudiness, humidity, and dew points.

Cloudiness has been persistent across much of the state just as it was in the beginning of October 2005. Most days have had complete or near-complete cloud cover, with relative humidity ranging from 70 to 95 percent.

The majority of climate stations in the state have reported rainfall on at least one day and for some on three days so far in October, with many places already seeing a total of over 1 inch (2 to 2.50 inches is the range of normal total precipitation for the month of October in Minnesota).

A strong cold front passage affected the state on Wednesday, October 3rd. The dew point in the Twin Cities hit a remarkable 70°F on that day, setting a record high for the date, and matching only three other years in Twin Cities’ history when the dew point has it 70 degrees F in October, those years being 1962, 2005,…

Preliminary Climate Summary for September 2018

Preliminary Climate Summary for September 2018:
September continued a trend of warmer than normal months. Most climate stations reported a mean monthly temperature from 1 to 3 degrees F warmer than normal. Over 60 climate stations reported at least one day with a 90 degrees F temperature or higher, while Marshall topped the state with a reading of 100 degrees F on the 15th. Many northern communities reported overnight lows in the 20s F the first and third weeks of the month. Brimson reported a low of 26 degrees F on the 22nd, but there may be colder readings yet for this coming weekend.

For the third year in a row Minnesota has seen abundant rainfall during the month of September. Furthermore, this time around it appears that September will be the wettest month on the calendar for many climate stations in the state during 2018. This is unusual, but not unprecedented. For south-central and southeastern counties September of 2018 will rank among the wettest five in history. …

Another round of heavy rain

Another round of heavy rain: Last week a slow-moving Hurricane Florence brought 20-30 inches of rainfall to portions of North and South Carolina. So in this context, our Minnesota rainfall recently is relatively minor. But Wet is Wet. This week, a slow moving, almost stalled warm front boundary along the Iowa-Minnesota border brought consistent and sometimes heavy doses of rainfall to the southern counties of the state. Many climate stations reported from 3 to 6 inches of rainfall over the Monday-Thursday period (September 17-20), with some stations setting new daily rainfall records. Minneapolis Crystal Airport reported over 7.5 inches of rain this week. For the month of September so far many parts of southern Minnesota have seen 6-9 inches of rainfall. In southeastern Minnesota both Winona and Elgin have reported over 9 inches of rain.

Some of the more recent new daily rainfall records set on Wednesday included:
2.37 inches at Lake Wilson
2.22 inches at Marshall
2.07 inches…