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Friday, July 28, 2017

WeatherTalk will be back August 11

WeatherTalk will not be published Friday, July 28 or August 4. Mark Seeley will send the next WeatherTalk on Friday, August 11.

Friday, July 21, 2017

Heavy Thunderstorms in Southern Minnesota

Heavy Thunderstorms in Southern Minnesota:

Fast moving heavy thunderstorms crossed portions of central and southern Minnesota over July 19-20 this week. These storms also brought strong winds, with many reports of wind gusts over 60 mph. Fortunately little hail was associated with these storms. The only area to report large hail was Windom (Cottonwood County) where hail stones up to 1.5 inches in diameter were observed.

The heaviest rains occurred in southeastern Minnesota counties and in western Wisconsin, where widespread street flooding, and even mudslides were reported. Many observers reported new daily record rainfalls, including:
5.11 inches at Minnesota City (Winona County)
5.03 inches at Wabasha (Wabasha County)
4.75 inches at La Crescent (Winona County)
4.55 inches at Red Wing Dam (Goodhue County)
4.50 inches at Winona Dam (Winona County)
3.89 inches at Hokah (Houston County)
6.37 inches at Alma Dam (Buffalo County, WI)
6.26 inches at La Crosse (La Crosse County, WI)
4.80 inches at Hillsboro (Vernon County, WI)

More information on these storms can be found at the Minnesota State Climatology office web site. Despite the recent rains, many parts of western Minnesota remain drier than normal for the month, with less than 1 inch of total rainfall so far.

Additional heavy rains were affecting southern Minnesota on Friday, July 21st as well, but total amounts were not yet available for this blog.

Topping 100 Degrees F:

Earlier this week on Monday July 17th the climate observer at Browns Valley (Traverse County) reported an afternoon temperature of 101 degrees F, the highest measured so far this year in Minnesota. Elsewhere Canby, Wheaton and Marshall all hit 98 degrees F that day.

The statistics for the past 40 years (my time as Extension Climatologist) show that 80 percent of the time (32 years), a temperature of 100 degrees F or higher is measured somewhere in the state. More often such readings come from western or southern Minnesota counties. For example, 19 of the 40 years the highest temperature in the state was measured in Traverse, Lyon, Lac Qui Parle, or Redwood Counties. These statistics conform to those of our state climate history all the way back to the second half of the 19th Century. Most of the all-time daily high temperature records for the state come from climate stations in Big Stone, Traverse, Lac Qui Parle, and Yellow Medicine Counties. On rare occasions the state's highest daily temperature for a given year may come from southeastern Minnesota, as was the case in 1985 when Theilman (Wabasha County) reported 103 degrees F on June 10th.

Interestingly enough, both the earliest and latest dates for measuring a temperature of 100 degrees F in state history are held by the same climate station. At Ada (Norman County), along Highway 9 in the Red River Valley, the temperature has reached 100 degrees F as early as April 21 (1980), and as late as September 23 (1936). So, if you like hot weather that is the place to choose. On the other hand, Ada has been as cold as -53 degrees F in the winter (Feb 15, 1936), so have some warm clothes for that season.

Only 1986, 1992, 1993, 1997, 2002, 2010,2014, and 2015 have produced no daily high temperatures of 100 degrees F or greater.

Special Conference at Macalester College this week:

"Transition US National Gathering: Growing a Movement for Resilient Communities" will take place at Macalester College over July 27-August 1. There will be workshops and presentation sessions related to planning and building more resilient communities, lowering carbon emissions, mitigating impacts of climate change, and building on social community strengths. Check out the web link for more information.

Weekly Weather Potpourri:

Earlier this month NOAA scientists announced that the Greenhouse Gas Index based on a global network of measurements of greenhouse gases in the atmosphere over oceans and land, has shown a rise of 40 percent since 1990. This is primarily based on a rise in carbon dioxide, although methane and nitrous oxide are some of the other important gases measured as well.

Also earlier this week NOAA scientists announced that the month of June 2017 on a global basis was the 3rd warmest of record going back to 1880. In addition the global average temperature for the first six months of 2017 was the 2nd highest ever for the same measured period (1880-20170, trailing only that of last year. You can read more at the NOAA News web site.

The United Kingdom Met Office had an interesting discussion online this week about common folklore wisdom related to weather. They dissected the accuracy of this folklore wisdom and found some of it to be valid, and some not so valid. One of the beliefs that proved to be highly invalid was that cows lie down before a rain storm.

A recent paper by Norwegian scientists in the journal Environmental Research Letters describes the disparities in the average carbon footprint among households across the European Union. It is interesting to note that the highest carbon footprints are from the United Kingdom and Greece.

MPR listener question:

It seems that we have had a real rollercoaster ride with temperatures around the state this month. Here in Ely half of the days have brought colder than normal temperatures, and half brought warmer than normal temperatures so far this month. Has Minnesota reported the either coldest or warmest temperature in the nations so far in July?


Indeed temperatures have been highly variable so far this month. We have not reported the nation's highest temperature on any day this month, and we rarely do. For example, earlier this week on July17th when Browns Valley reported a daytime high of 101 degrees F, hundreds of climate stations in western states were warmer than that, topped by 124 degrees F at Death Valley. On the cold side though, Crane Lake, MN did report the coldest temperature in the Nation on July 14th with a morning low of just 37 degrees F. That conforms to our national reputation.

MSP Local Records for July 21st:

MSP records for this date include: highest daily maximum temperature of 105 degrees F in 1934; lowest daily maximum temperature of 69 degrees F in 1927 and 1947; lowest daily minimum temperature of 49 degrees F in 1947; highest daily minimum temperature of 79 degrees F in 1983; record precipitation of 1.36 inches in 1951. No snowfall has occurred on this date.

Average dew point for July 21st is 61°F; the maximum dew point on this date is 78°F in 1983; and the minimum dew point on this date is 40°F in 1947.

All-time state records for July 21st:

The all-time state high temperature for today's date is 113 degrees F at Milan (Chippewa County) in 1934; the all-time state low for today's date is 34 degrees F at Angus (Polk County) in 1947. The all-time state record precipitation for this date is 7.83 inches at Chaska (Carver County) in 1987. No snow has fallen on this date.

Past Weather Features:

By far the warmest July 21st in state history was in 1934. Over 30 Minnesota communities reported an afternoon temperature of 100 degrees F or greater, topped by 113 degrees F at Milan (Chippewa County). The heat was compounded by widespread drought as well. Even the overnight temperature never fell below 80 degrees F at Beardsley, Montevideo, Albert Lea, and Zumbrota making for a very difficult night to sleep.

The coldest July 21st in state history was in 1947 when 15 Minnesota communities reported morning lows in the 30s F. Some mid-summer ground frost was reported from St Louis and Polk Counties in northern Minnesota. The afternoon high temperature at Two Harbors only reached 62 degrees F.

Severe thunderstorms dropped heavy rainfall across southeastern Minnesota on July 21, 1951. Many climate stations reported 3 to 6 inches of rainfall which washed out roads and flooded highways. Caledonia in Houston County reported a record 6.60 inches. Flooding of homes and businesses in the Rochester area was widespread, and the Zumbro River saw one of its highest every flood crests.


Partly cloudy with near normal temperatures for Saturday, and mostly dry conditions. Cooler with below normal temperatures for Sunday through Tuesday, and little chance for rain. Then warming for Wednesday and Thursday to near normal temperatures with a chance for showers and thunderstorms.

Friday, July 14, 2017

Great Variation in Rainfall this Month

Great Variation in Rainfall this Month:

So far this month the rains across the state have been very widely scattered and highly variable in amounts, including those of this week. This is especially true in western and southern counties. Across Otter Tail County total rainfall in July varies from less than a third of an inch to well over 2 inches; and across Blue Earth County rainfall for the month varies from less than a half inch to nearly 3.5 inches. Overall rainfall totals through the first 14 days of the month ranged from just trace amounts in portions of southwestern to nearly 3.5 inches in south-central Minnesota. Severe thunderstorms on Sunday, July 9th brought hail and high winds to many areas. Some very large hail (over 2 inch diameter) were reported, along with a tornado near Lake Crystal (Blue Earth County). Then another severe weather episode with dew points in the 70s F occurred across portions of central Minnesota over July 11-12, bringing hail and high winds to many areas. There was also a report of a tornado near Forest Lake. At one point, Xcel Energy reported over 56,000 customers without power because of high winds. The Minnesota State Climatology Office features more detailed descriptions of all of these storms so far this month.

Following the warm and sultry weather which produced the thunderstorms a cold front brought morning lows in the 40s and 50s F on July 13th. Crane Lake dropped all the way down to 37 degrees F on July 14th. This is a typical Minnesota rollercoaster pattern on the thermometer readings.

Weather Potpourri:

NOAA scientists announced this week, that after a number of years with little or no rise in global methane (a powerful greenhouse gas), there is now a rising trend in global methane that has been evident in the data every year since 2007. This trend had been predicted to resume by global climate models.

Hurricane Fernanda, located many hundreds of miles southwest of Baja California is expected to intensify and perhaps become a Saffir Simpson Category 4 storm (winds 130-150 mph) over the weekend and early next week. But it will remain well out to sea in the Eastern Pacific Ocean and no threat to land.

Earlier this week an iceberg the size of the state of Delaware broke away from the West Antarctica Ice Shelf (called Larson C) and is now floating. This 2200 square mile iceberg, estimated to weigh over a trillion tons, is expected to occasional get stuck on the bottom of the Wendell Sea over the next months and years. The weekly Earth & Space Science News from AGU provides more detail and perspective on this topic.

MPR listener question:

When I listen to the weather forecast I get confused by the rainfall predictions when meteorologists use the terms isolated showers, widely scattered showers, scattered showers, and widespread showers. Can you explain the differences?


This jargon issue has been written about over the years by many meteorologists, and there are certainly some geographic disparities in what these terms imply. For our region of the country they generally mean the following:

Isolated showers implies less than a 25 percent chance of occurrence anywhere in the forecast area.
Widely scattered showers implies a 30-40 percent chance.
Scattered showers implies a 40-60 percent chance.
Widespread showers implies over a 60 percent chance.
The bottom line is that when the terms isolated or widely are used, it is more likely to remain dry where you are located.

Twin Cities Almanac for July 14th:

The average MSP high temperature for this date is 84 degrees F (plus or minus 7 degrees F standard deviation), while the average low is 65 degrees F (plus or minus 6 degrees F standard deviation).

MSP Local Records for July 14th:

MSP records for this date include: highest daily maximum temperature of 108 degrees F in 1936; lowest daily maximum temperature of 65 degrees F in 2014; lowest daily minimum temperature of 50 degrees F in 1930; highest daily minimum temperature of 79 degrees F in 1980; record precipitation of 3.17 inches in 1915. No snowfall has occurred on this date.

Average dew point for July 14th is 60 degrees F; the maximum dew point on this date is 76F in 1995; and the minimum dew point on this date is 40F in 1930.

All-time state records for July 14th:

The all-time state high temperature for today's date is 111 degrees F at New Ulm (Brown County) in 1936; the all-time state low for today's date is 30 degrees F at Alborn (St Louis County) in 1930. The all-time state record precipitation for this date is 5.49 inches at Carlos (Douglas County) in 2011. No snow has fallen on this date.

Past Weather Features:

Perhaps the coldest July 14 in state history came in 1930. At least 15 climate stations reported a morning low in the 30s F, and a few northern communities reported frost. The air was especially dry with humidity reported between 20 and 30 percent. For some northeastern climate stations the afternoon temperatures remained in the 60s F.

July 14, 1936 was the hottest in history with 50 Minnesota communities reporting an afternoon high temperature of 100 degrees F or greater. Overnight lows never cooled off close to normal and remained between 74 and 78 degrees F in most places. Many people slept outside or on their porches.

Strong thunderstorms passed over northern Minnesota July 14-15, 1937 delivering hail along with 3 to 6 inches of rainfall to many areas, including Baudette. In Baudette ended up with 12.50 inches for the month, recording the wettest July in history there.

Eight consecutive days with rain showers saturated southern Minnesota over July 9-16, 2011. Many climate stations reported 5 to 8 inches of rain over that period and some corn and soybean fields showed standing water.


Warm and humid on Saturday, with a slight chance of thunderstorms. Cooler on Sunday with temperatures falling back closer to normal. Temperatures warming again Monday and Tuesday to slightly above normal, with chances for showers and thunderstorms much of next week.

Friday, July 7, 2017

July Temperatures Following Trend

July Temperatures Following Trend:

Though the first several days of the month were cooler than normal, with the recent heat, most observers are now reported mean monthly temperatures that are warmer than normal. This follows the pattern for many recent trends. Five of the most recent seven months of July have been warmer than normal in Minnesota, while 21 of the past 23 months have been warmer than normal in Minnesota as well. The highest temperature of the summer so far was observed at Browns Valley (Traverse County) on Wednesday (July 6) of this week with an afternoon reading of 98 degrees F. In addition at least 15 climate stations have reported overnight lows in the 70s F this week. That is about 6-10 degrees F above normal. National Weather Service outlooks continue to favor warmer than normal temperatures across the state through the third week of July. The outlooks also favor, for the first time in many months, drier than normal conditions for the remainder of the month. This means of course that watering will be important.

Watering Considerations:

Since the climate outlooks favoring a warm and dry pattern for the remainder of July, it is important to remember some water conservation tips from the U of MN Extension:

-water plants and gardens at night or very early in the morning to minimize evaporation losses.

-use a light coating of mulch around some plants to minimize water loss from the soil, and to suppress weed competition.

-adjust your lawn mower to a higher setting as the longer grass keeps root systems shaded. During a warm July, lawns will need 1-2 inches of water per week.

-direct downspouts and other runoff towards shrubs, hedges and trees that can utilize the water.

-try to water at a rate that matches the infiltration rate of your soil....perhaps with a soaker hose.

-for newly planted trees and shrubs (planted this spring or summer) water thoroughly at least once per week all summer.

Weekly Weather Potpourri:

NOAA recently announced intentions to upgrade the Tropical Pacific Observing System (buoy platforms with instrumentation) by 2020 in partnership with Australia, China, and Japan. This observing network transmits data by satellite routinely and these data are used to assess El Nino signals, as well as to help with tropical storm forecasting in the Pacific Ocean Basin.

This week brought a tropical storm and some unprecedented heavy rains to southwestern Japan, the island of Kyushu (reported by the Kydo News Service). At times rainfall rates reached 4 inches per hour. Some places reported rainfall totals over 20 inches. Many roads and bridges were washed out and over half a million people were evacuated because of threatening flash floods.

At the end of last week the United Kingdom Met Office put out a summary of June climate that showed the month to be very warm and wet. It was near record-setting wet in parts of Scotland and northern England, and also near record warm in eastern England.

Dr. Ben Santer of the Lawrence Livermore Laboratory in California wrote a very good piece on climate science and climate change for the Washington Post this week. It is well worth reading about the importance of staying engaged on this topic and finding ways for the USA to live up to the Paris Climate Agreement.

A recent paper in the Journal of Geophysical Research documents how the turbulence embedded in thunderstorms is linked to the lightning produced by such storms. It is the first of its kind to establish this link.

MPR listener question:

Now that we have the hottest part of the summer season upon us, we were wondering which part of the state has recorded the most 100 degree F days in history? Thought you might have the answer.


Indeed, using the climate records back to the 1880s, the clear winner is west-central Minnesota, near the junction of Traverse and Big Stone Counties. The combined Beardsley and Browns Valley records show that 287 days have reached 100 degrees F or warmer since 1880, the most recent date being July 3, 2012. Other long-term climate states with large numbers of 100 degrees F days include Canby (Yellow Medicine County) with 198 and Milan (Chippewa County) with 161. These climate stations far surpass even the Twin Cities "heat island" climate record for 100 degrees F days, which shows a total of 65 back to 1872.

There are many climate stations in Minnesota that have never recorded a 100 degrees F reading, including Gunflint Lake (Cook County), Crane Lake (St Louis County), Two Harbors (Lake County), and Waskish (Beltrami County).

Twin Cities Almanac for July 7th:

The average MSP high temperature for this date is 84 degrees F (plus or minus 8 degrees F standard deviation), while the average low is 64 degrees F (plus or minus 7 degrees F standard deviation).

MSP Local Records for July 7th:

MSP records for this date include: highest daily maximum temperature of 101 degrees F in 1936; lowest daily maximum temperature of 65 degrees F in 1918; lowest daily minimum temperature of 44 degrees F in 1891; highest daily minimum temperature of 80 degrees F in 1936; record precipitation of 3.00 inches in 1955. No snowfall has occurred on this date.

Average dew point for July 7th is 61°F; the maximum dew point on this date is 79°F in 1957; and the minimum dew point on this date is 38°F in 1934.

All-time state records for July 7th:

The all-time state high temperature for today's date is 108 degrees F at Browns Valley (Traverse County) in 1988; the all-time state low for today's date is 24 degrees F at Tower (St Louis County) in 1997. The all-time state record precipitation for this date is 5.00 inches at Elgin (Olmsted County) in 1990. No snow has fallen on this date.

Past Weather Features:

Temperatures fell into the upper 20s F to low 30s F across northern Minnesota on July 7, 1871. It was just 26 degrees F at Fort Ripley (Crow Wing County).

The hottest July 7th in state history occurred during the Heat Wave of 1936 (July 6-18). Over 50 communities reported daytime highs of 100 degrees F or greater. Some climate stations never saw the temperature drop below 80 degrees F even at night.

A strong thunderstorm gave birth to an EF-4 tornado (winds over 200 mph) on July 7, 1955. Between 4pm and 4:30 pm this storm moved 20 miles across portions of Lincoln and Lyon Counties in southwestern Minnesota. The tornado killed one person and damaged or destroyed 35 farms.

Strong thunderstorms brought heavy rains and hail to portions of northern Minnesota over July 7-8, 1962. Many observers reported 2-4 inches of rain, and nearly 4.5 inches fell at Fosston where crop fields were underwater for two days.

Frost occurred in parts of northeastern Minnesota on the morning of July 7, 1997. An all-time July low temperature of 24 degrees F occurred at Tower, bringing an end to a 23 day growing season there (last frost on June 14), one of the shortest in state history!


Near normal temperatures over the weekend under mostly sunny skies. Increasing cloudiness later on Sunday with a chance for widely scattered showers and thunderstorms, carrying over into Monday. Somewhat warmer for Tuesday through Thursday, with a chance for showers later on Wednesday and into Thursday.

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