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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…

A look at the climate for 2018 so far for Minnesota

A look at the climate of 2018 so far for Minnesota: On a statewide basis we just concluded the 12 warmest June-August period in state history. In addition it was the 24th wettest summer back to 1895, but with great disparity, notably surplus rainfall in the south and deficit rainfall in the northwest.

Also on a statewide basis the first 8 months of the year averaged only about 1°F above normal, but it was the 4th year in a row, and 15 out of the last 20 years that the first 8 months of the year have produced an above average statewide temperature. In addition the first 8 months of 2018 brought a statewide average precipitation about two-thirds of an inch above normal, the 9th consecutive year this has happened.

So, when we talk about Minnesota getting warmer and wetter with each passing decade, it appears that the year 2018 will follow that trend line.
Gusty winds: The month of September is not known as one of Minnesota’s windiest months, but the last three days have brought a go…

Wet start to September, followed by cool temperatures

Wet start to September, followed by cool temperatures: With measurable rainfall on four of the first five days of the month, suffice to say September started off wetter than normal for many parts of Minnesota. Most of the heavier rains followed the closing of the Minnesota State Fair, which set record attendance this year of well over 2 million people over the 12-day run.

For the first week of the month Winona (Winona County), Theilman (Wabasha County), and Owatonna (Steele County) all report 5 or more inches of rain so far. Most of the heavier doses of rain (1-3 inches) fell over portions of southern and central Minnesota and came on the 4th and 5th, fueled in part by dew points in the 70s F. Some of the rainfall set new daily records in places such as Rochester with 3.32 inches and Granite Falls with 2.43 inches on the 4th. Other places reported new daily record amounts for the 5th. Too numerous to list all of them, some of those with longer climate histories that set new dai…

Climate Summary for August

Climate Summary for August:
After a warm first half of the month when many climate stations reported record-setting warm overnight minimum temperatures, the climate moderated and most observers are reporting a mean monthly temperature that ranges from 1 to 2 degrees F warmer than normal. The extremes for the month were 99°F at Preston (Fillmore County) on the 14th, and 34°F at International Falls (Koochiching County) on the 2nd.

For August rainfall, most northern counties reported below normal totals for the month, while many central and southern counties reported above normal rainfall for the month. The heaviest rainfall events came near the beginning of the month, and then again near the end of the month. During the course of the month 28 new daily rainfall records were reported in the state climate observer network. Extreme rainfall totals for the month ranged from over 11 inches at Caledonia (Houston County) to just over 1 inch at Browns Valley (Traverse County).

The other…

Climate Signatures in 2018

Climate Signatures in 2018: A certain high degree of variability is evident in the Minnesota climate statistics so far this year. Some examples:

-For the January through August period, both average statewide temperature and precipitation are pretty close to the 30-yr averages.

-But for the May-August period this year ranks as the 2nd warmest historically, trailing only the growing season of 1988. And this is mostly thanks to very warm nights.

-Though the statewide May-August rainfall has been near normal, there is great disparity across the state. The southwestern counties have had the 2nd wettest May-August period in history with an average of nearly 23 inches (2nd only to 1993), while the south-central counties have reported the 8th wettest May-August period with an average of nearly 22 inches. Conversely, northwestern counties, which are in a moderate drought, have reported an average of less than 10 inches for the May-August period, ranking as the 12th driest in history back …

Warm May-July Confirmed

Warm May-July Confirmed: Earlier this month NOAA scientists confirmed that for the 48 contiguous states of the USA the three month period from May through July was the warmest in history, back to 1895, surpassing the previous record year for the 3-month period set way back in 1934.

Specifically for the same time period (May-July) how did Minnesota rank? On a statewide basis the May-July 2018 period was the 6th warmest back to 1895. The only warmer 3-month periods were in 1934, 1977, 1987, 1988, and 2012. However within our state boundaries there was some regional disparity. Here are the rankings by region of the state:

NW-4th warmest

NC-3rd warmest

NE-9th warmest

WC-6th warmest

C-10th warmest

EC-8th warmest

SW-7th warmest

SC-9th warmest

SE-5th warmest

This follows a warming trend which shows that since 2000 the May-July period has warmed by about 1.5 degrees F on a statewide basis. Speaking of warmth, through the first half of August Minnesota reports average temperatures that a…

August Starts Wet for Some

August Starts Wet for Some: The first five days of the month brought some heavy rains to many parts of the state as many climate stations reported over 1.5 inches. There were strong thunderstorms over portions of central Minnesota over August 3-4 with a weak tornado reported on the ground for 11 miles across portions of Kandiyohi and Meeker Counties (see State Climatology Office Summary).

Some portions of Stearns and Benton Counties reported over 3 inches of rain. Lake Wilson, Moose Lake, Brainerd, and Gull Lake all reported new daily rainfall records on the 4th with amounts ranging from 1.5 to 2.5 inches. Lake Wilson (Murray County) with 30.17 inches, Redwood Falls (Redwood County) with 30.26 inches, and St James (Watonwan County) with 31.63 inches since January 1 are reported some of their wettest values in history for the first 8 months of the year, surpassed only by the wet years of 1979 and 1993.

Conversely portions of Roseau and Lake of the Woods Counties remain in moderate dr…

July Climate Summary

July Climate Summary:
After beginning the month very warm, temperatures moderated for much of the second half of the month from below normal to near normal. Still most climate stations reported a warmer than normal July, with average monthly values ranging from 1 to 3 degrees above average. A few places in the state reported slightly below normal mean monthly temperatures. The extremes ranged from 97 degrees F at Theilman (Wabasha County) on the 13th to 37 degrees F at Goodridge (Marshall County) on the 27th.


During the first half of the month three daytime maximum temperature records were set or tied within the climate station network, while 36 warm nighttime low temperature records were set or tied. Numerous Heat Advisories and Excessive Heat Warnings were issued by the National Weather Service during the first half of July. In the second half of the month no temperature records were set.


Most climate observers reported above normal rainfall during July. The wettest areas of …

Change in weather pattern brings relief

Change in weather pattern brings relief:
Since last Sunday, many areas of Minnesota have welcomed below normal temperatures this week, bringing relief from what has been an exceptionally hot summer so far. Many of the temperatures around the state ranged from the upper 60s to low 70s F on July 19th, about 4 to 6 degrees F cooler. In northern areas this week overnight temperatures fell into the low to mid 40s F, with a low of 40 degrees F at Brimson (St Louis County).

Except for far western Minnesota (Browns Valley, Marshall, Pipestone) most of the state experienced a relatively dry week as well, bringing some relief from the heavy rains and flash flooding that occurred in many areas during the first half of July.

It is interesting that the pattern change in the weather noted for this week, cooler and drier, is also the expected pattern for the balance of the month across Minnesota according to many of the NOAA outlook models. Most of the daytime maximum temperatures for the rest o…

Near Historic Heat for the Growing Season

Near Historic Heat for the Growing Season:

Michelle Margraf of the NOAA-NWS Office in Chanhassen put me onto the near historically warm growing season we have been having in Minnesota so far in 2018. Since May 1st, often considered the beginning of the growing season we can look at temperature patterns since that date in 2018. May was nearly 6 degrees F warmer than normal on a statewide basis, while June was nearly 3 degrees F warmer than normal. So the combination of May-June in 2018 produced the 4th warmest start to the growing season in state history, averaging 4.5 degrees F warmer than normal. Only 1934, 1977, and 1988 were warmer.

Now so far for July the average temperature across the state is nearly 4 degrees F warmer than normal, with extremes of 96 degrees F at Gaylord and 41 degrees F at Brimson. Heat Index values (a measure of warmth which considers both temperature and dew point) have soared up to 105 to 120 degrees F around southern Minnesota already this month. If …

Wet Start to July Continues a Trend

Wet Start to July Continues a Trend: Through the first six days of July thunderstorms have brought 1 to 3 inches of rain to many parts of the state. On July 3-4 heavy thunderstorms occurred causing some flash flooding, road closures, and ponded crop fields, as well as cancellation or postpone of some 4th of July events. Southwestern Minnesota was especially hard hit with many observers reporting rainfall totals of 3 to 7 inches. A couple of places in Redwood County reported over 7 inches. For many southwestern counties all of this recent rain came on top of getting 8 to 12 inches just last month (June). As a consequence many rivers there are running above flood stage and some roads and bridges remain closed.

On July 3rd Marshall received a new record daily amount of rain with 4.71 inches, while Redwood Falls receive a new record amount of 5.25 inches. Renville also had a record 4.32 inches.

Many areas have also reported strong thunderstorm winds, ranging from 50 to 70 mph. Yo…