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Extension > Mark Seeley's WeatherTalk > September 2016

Thursday, September 29, 2016

Preliminary climate summary for September

Preliminary climate summary for September:

Like most months of 2016 September was warmer than normal. Most observers report a mean monthly temperature that is 2 to 4 degrees F warmer than normal. On a statewide basis September of 2016 will be among the 15 percent warmest in history back to 1895. This follows a trend towards warm Septembers, as last year produced the warmest September in state history, while 2004, 2005, 2009, and 2013 were among the warmest ten Septembers in history as well. Extreme values of temperature for the month were 94 degrees F at Amboy (Blue Earth County) on the 21st and just 29 degrees F at several locations in northern Minnesota on the 14th.

The month of September was moderately wetter than normal in the north and very much wetter than normal in southern Minnesota, where some observers reported rainfall that was 4X or 5X times normal. Most observers reported rainfall on at least half of the days of the month. Some of the rains came in heavy thunderstorms which produced well over 100 daily rainfall records in the Minnesota observation network during the month, including 7.64 inches at Waseca on the 22nd which was a new statewide record for the date.

Some observers reported their wettest September in history. Among these locations were:

Albert Lea 10.31 inches
Lanesboro 12.75 inches
Caledonia 13.13 inches
Spring Valley 10.44 inches
Hokah 11.54 inches
La Crescent 10.33 inches
Waseca 14.80 inches
Spring Grove 13.89 inches
Chatfield 12.55 inches

Overall on a statewide basis it was the 10th wettest September in history back to 1895. The heaviest rains over September 21-22 caused flash flooding in many areas, and an EF-1 tornado struck Camp Ripley on September 7th causing some damages to structures and cars (a somewhat rare event).
Climate Adaptation: Transforming Awareness Into Action:

Climate Adaptation Discussion:

I will be offering a one-night program on this topic through the University of Minnesota College of Continuing Education's LearningLife Program on October 5th at at 630 pm on the St Paul Campus. If you are interested about enrollment you can find out more at the LearningLife web site.

Weekly Weather Potpourri:

This week NOAA scientists offer an interesting look at the climatology of first seasonal snowfalls. Naturally the higher elevations in the western states are likely to have seen some this month, but many areas of the Northern Plains and Northern Great Lakes can see first snowfalls during the month of October.

The United Kingdom Met Office reported this week that September of 2016 will likely be the 2nd or 3rd warmest since countrywide record keeping began in 1910. The warmest day of the year occurred there (at Gravesend in Kent) when 94 degrees F was reported on September 13th.

Tropical Storm Chaba was churning in the Western Pacific Ocean and was expected to develop into a typhoon over the weekend. It will strengthen and heat for southern Japan next week, perhaps bringing high winds, large waves, and intense rainfall by the middle of next week.

MPR listener question:

You mentioned last week that Waseca is on a pace to set a new annual precipitation record for Minnesota. What other locations might set a new annual precipitation record during this extraordinary wet year of 2016?

Answer:

Using the year-to-date precipitation totals for 2016 so far, there are several communities that are within 6 inches of setting a new record for wettest year in history. Some of these are listed below with their year-to-date total precipitation in parenthesis:

Aitkin (35.79")
Brainerd (33.65")
Redwood Falls (38.06")
Faribault (39.57")
New Ulm (37.75")
St James (44.28")
St Peter (38.64")
Waseca (49.11")
Austin (37.79")
Harmony (43.22")
Preston (41.31")
Rochester (37.37")
Winona (38.51")
Zumbrota (38.92")

With three months left in 2016, climate statistics show that average precipitation for those months totals in the range of 4-6 inches for most locations in the state. With normal precipitation, most of these communities will set new annual precipitation records this year, and Waseca could be the first stations ever to report over 54 inches for a year.

Twin Cities Almanac for September 30th:

The average MSP high temperature for this date is 65 degrees F (plus or minus 10 degrees F standard deviation), while the average low is 46 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for September 30th:

MSP weather records for this date include: highest daily maximum temperature of 87 degrees F in 1897; lowest daily maximum temperature of 44 degrees F in 1985; lowest daily minimum temperature is 26 degrees F in 1939; highest daily minimum temperature of 68 degrees F in 1878; record precipitation of 1.06 inches in 2007; and a record 0.1 inches of snow fell on this date in 1961.

Average dew point for September 30th is 43 degrees F, with a maximum of 66 degrees F in 1971 and a minimum of 18 degrees F in 1974.

All-time state records for September 30th:

The state record high temperature for this date is 93 degrees F at Montevideo (Chippewa County) in 1897. The state record low temperature for this date is 10 degrees F at Big Falls (Koochiching County) in 1930. State record precipitation for this date is 5.00 inches at Cook (St Louis County) in 1995; and record snowfall is 3.0 inches at Isabella (Lake County) in 1985.

Past Weather Features:

The end of September and beginning of October brought a mini Heat Wave to Minnesota in 1897. Most communities saw daytime temperatures climb into the 80s F, while 20 climate stations set new temperature records with highs in the 90s F.

Thunderstorms brought heavy rains and flash flooding over September 29-30, 1925. Many areas reported 2 to 4 inches of rain. Harvest delays lasted over a week.

Widespread frost was reported on September 30, 1930. Many observers reported morning lows in the 20s F, while sections of northern Minnesota fell into the teens F.

North-central and northeastern Minnesota communities recorded their first snowfall of the season over September 30 to October 1 of 1985. Observers there reported 2-8 inches of slushy snow. Thankfully it did not last for more than a day or two.

Outlook:

Mostly sunny with above normal temperatures over the weekend and into next week. A chance for showers by Wednesday, then a drop in temperatures and showery the rest of the week.

 

Friday, September 23, 2016

More heavy rain and flooding

More heavy rain and flooding:

Thunderstorms, some severe, brought heavy rainfall again to portions of central and southern Minnesota over September 21-22 (Wed-Thu) this week. Many observers reported from 1 to 2 inches, and several places reported new record daily amounts up to 5 to 8 inches. Dew points spiked in the low 70s F at a number of locations just ahead of the storm indicating that there was a very high water vapor content. Preliminary data suggest that a new statewide record daily rainfall occurred on September 22nd (old record 4.84 inches at Cambridge in 1968), but the final say on the new record will come from the Minnesota State Climatology Office. Many communities reported flash flooding, including washed out roads and culverts, and some flooded basements.

Some of the new record daily amounts of rainfall included:

7.64" at Waseca
5.15" at Wells
4.11" at Rochester
4.06" at Bricelyn
3.81" at Preston
3.74" at Spring Grove
3.70" at Zumbrota, Grand Meadow, and Spring Valley
3.09" at Winnebago
3.08" at Theilman
2.75" at La Crescent
2.15" at Stillwater
2.10" at Winona Dam
2.06" at Kimball

Many other communities with shorter climate records reported even greater amounts of rainfall, including 5.34" at Lanesboro, 5.11" at Eau Claire, WI; 4.65" at Champlin; 4.15" at Owatonna; 8.11" at Maple Grove; and 5.12" at Byron.

The added rainfall this week pushed the total for the month of September to near record or new record values for a number of climate stations in southern Minnesota, including:
13.69" at Mabel (Fillmore County)
13.89" at Spring Grove (Houston County)
10.37" at Spring Valley (Fillmore County) 10.56” at Rushford (Fillmore County)
11.40" at Hokah (Houston County)
13.03" at Caledonia (Houston County)
14.56" at Waseca (Waseca County)

This wet September continues a trend toward above normal precipitation. Some climate stations in Minnesota have already received over 40 inches of precipitation for the year. Further at least ten climate stations are on a pace to set a new record wet year, including St James with 40.59 inches (2nd wettest year in history), and Waseca with 48.68 inches (2nd wettest year in history), and over three months to go in 2016! It is also likely that the all-time state record wettest single year, 53.52 inches at St Francis (Anoka County) in 1991 will be broken before the end of this year.

Weekly Weather Potpourri:

Earlier this week NOAA scientists reported that the Northwest Passage was ice-free again at the end of the summer, allowing for ship traffic to pass from the North Pacific to the North Atlantic passing through Arctic Canada. For the first time a luxury cruise ship, Crystal Serenity, was making the journey this autumn from Alaska to New York City via the Northwest Passage.




The U.S. Climate Resilience Toolkit, available online, now has a procedure to help communities assess their vulnerabilities to climate change, and select from optional strategies to make themselves more resilient. Even local schools and businesses might want to consider looking at this toolkit.

The United Kingdom Met Office announced this week that for the second consecutive year they will consult the public to name storms during the coming winter season. This will apply only to storms which bring a serious threat of precipitation or strong winds. They have found that weather warnings are better received by the public if the storms are given names.

The World Meteorological Organization published for the first time this week a study of lightning around the world. Two of the extreme events which they noted were the longest stroke of lightning every detected, nearly 200 miles across the sky of Oklahoma in 2007; and the longest continuous flash of lightning, 7.74 seconds which occurred over southern France in 2012.

MPR listener question:

It has certainly been a turbulent month of September. The tornado reported at Camp Ripley in central Minnesota on September 7th, made some of us wonder how often do tornadoes visit Minnesota during the month of September? It seems pretty rare.

Answer:

Indeed, historically less than 5 percent of our annual tornadoes in Minnesota occur during the month of September. In 1894 8 tornadoes were reported during September, and more recently in 2005 6 tornadoes were reported during September. In 2012 there were 4 tornadoes reported as late as November 10th, exceptionally rare for our climate. In Minnesota history there have been no tornadoes reported in the months of December, January, and February.

Twin Cities Almanac for September 23rd:

The average MSP high temperature for this date is 69 degrees F (plus or minus 10 degrees F standard deviation), while the average low is 49 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for September 23rd:

MSP weather records for this date include: highest daily maximum temperature of 90 degrees F in 1891 and 1937; lowest daily maximum temperature of 46 degrees F in 1965; lowest daily minimum temperature is 30 degrees F in 1983; highest daily minimum temperature of 71 degrees F in 1930; record precipitation of 1.98 inches in 2010; and a trace of snow fell on this date in 1928.

Average dew point for September 23rd is 43 degrees F, with a maximum of 73 degrees F in 1945 and a minimum of 20 degrees F in 1928.

All-time state records for September 23rd:

The state record high temperature for this date is 99 degrees F at Granite Falls (Chippewa County) in 1892. The state record low temperature for this date is 14 degrees F at Goodridge (Pennington County) in 2012. State record precipitation for this date is 9.48 inches at Amboy (Blue Earth County) in 2010; and record snowfall is 2.0 inches at Bigfork (Itasca County) in 1942.

Past Weather Features:

A short-lived Heat Wave brought temperatures of 90 degrees F or higher to many communities around the state on September 23, 1892. Two days later some areas reported frost.

Traces of snow were reported in northern Minnesota on this date in 1985.

Widespread freezing temperatures prevailed around Minnesota on September 23, 1995. Many observers reported morning lows in the 20s F. Tower fell as low as 16 degrees F. As far south as Preston it was 29 degrees F.

Thunderstorms brought widespread flash flooding to portions of southern Minnesota over September 22-23, 2010. Many observers reported all-time rainfall records in the range of 8 to 11 inches. There were widespread reports of flooded highways and basements. The Mississippi River rose above flood stage at St Paul a week later, and exceptionally rare occurrence for the month of September.

Outlook:

Warmer than normal with chance for showers and thunderstorms on Saturday. Continued chance for showers Sunday, but with cooler temperatures. Generally cooler than normal early next week with chances for scattered showers. Warmer by next Thursday and Friday.






Friday, September 16, 2016

A Taste of Autumn Weather the Second Full Week of September

A Taste of Autumn Weather the Second Full Week of September:

The first taste of autumn weather appeared this week with low relative humidity and overnight temperatures in the 30s and 40s F, especially over September 13-15. Many communities in western and northern Minnesota reported overnight lows in the 30s F and a number of places reported frosts, including:

31°F at Cass Lake (Cass County)
29°F at Brimson (St Louis County)
31°F at Cotton (St Louis County)
29°F at Embarrass (St Louis County)
32°F at Orr (St Louis County)
30°F at Hibbing (St Louis County)

It was 39°F as far south as Lake Wilson (Murray County).

Humidity exhibited a roller coaster pattern this week with readings from 70 to 90 percent earlier in the week, falling off to 20 to 30 percent during the middle of the week. The cooler and drier air was having its effects on native vegetation as the autumn color changes were beginning to appear more abundantly in northern and western counties. Remember you can track fall color changes to help schedule any leaf peeping trips you may plan by going to the MN-DNR Fall Color Finder Web Site.

More heavy doses of rain:

Thursday, September 15 brought some widespread rains to many parts of the state. Lighter amounts, less than half an inch fell in many northern areas, but a number of observers in central and southern Minnesota reported from half an inch to over 1 inch of rainfall. A few southern Minnesota communities reported over 2 inches, and some reported record rainfall amounts for the date, including, New Prague with 1.20 inches, Fairmont with 2.26 inches, and Luverne with 2.32 inches. Sioux Falls, SD reported a new record 3.61 inches for September 15th.

Climate Adaptation: Transforming Awareness Into Action:

I will be offering a one-night program on this topic through the University of Minnesota College of Continuing Education's LearningLife Program on October 5th at at 630 pm on the St Paul Campus. If you are interested about enrollment you can find out more at the LearningLife web site.

Weekly Weather Potpourri:

The National Snow and Ice Center reported this week that the Arctic Sea Ice reached its minimum extent for the season on September 10th, covering an area of only 1.6 million square miles, statistically tied with 2007 as the 2nd lowest of the satellite record. September 17, 2012 remains the lowest measured Arctic sea ice extent at 1.31 million square miles. You can read more about this at the Science Daily web site.

Earlier this week Super Typhoon Meranti caused widespread damage to Taiwan and brought heavy rains to portions of China. It was one of the largest and strongest typhoons ever measured with wind speeds up to 190 mph, rainfall measurements over 15 inches, and wave heights close to 50 feet. Central pressure dropped to 890 mb, or 26.28 inches. Following Meranti is Typhoon Malakas which is forecasted to pass over northern Taiwan this weekend, with wind speeds near 130 mph and wave heights of 35 to 40 feet.






NASA scientists say that a La Nina episode is now unlikely to develop in late 2016 and that Equatorial Pacific Ocean temperatures may hover around normal for the remainder of the year. This will have implications for the winter season outlook, slated to be released next month, covering the November through January period.

MPR listener question:

Someone mentioned the possible snow season in Minnesota starts on September 14th. How is that figured and which places have had snow that early?

Answer:

The start date of the possible snow season in Minnesota is based on the measurement of 0.3 inches at International Falls on September 14, 1964, the earliest date for measurable snow in the state climate data base. Also on that date communities in Kittson, Roseau, Lake of the Woods, St Louis, Cook, and Lake Counties reported traces of snowfall. A similar storm occurred on September 15, 1916 delivering 0.2 inches at Warroad and a trace amount in several other places, including the Twin Cities. In the Pioneer Era climate records the Twin Cities reported snowfall on September 18, 1863 (amount unknown) and September 23, 1868 (0.2"). So it is possible, but not of the current models show possibilities for snowfall anywhere in the state the rest of this month.

Twin Cities Almanac for September 16th:

The average MSP high temperature for this date is 72 degrees F (plus or minus 9 degrees F standard deviation), while the average low is 52 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for September 16th:

MSP weather records for this date include: highest daily maximum temperature of 94 degrees F in 1955; lowest daily maximum temperature of 50 degrees F in 1916; lowest daily minimum temperature is 38 degrees F in 1873; highest daily minimum temperature of 74 degrees F in 1955; record precipitation of 1.97 inches in 1900; and no snowfall has occurred on this date.

Average dew point for September 16th is 49 degrees F, with a maximum of 71 degrees F in 1997 and a minimum of 29 degrees F in 1959.

All-time state records for September 16th:

The state record high temperature for this date is 101 degrees F at Montevideo (Chippewa County) in 1891. The state record low temperature for this date is 17 degrees F at Karlstad (Kittson County) in 1973. State record precipitation for this date is 7.07 inches at Red Wing (Goodhue County) in 1992 and no measurable snowfall has occurred on this date.

Past Weather Features:

The hottest September 16th in western Minnesota occurred in 1891 when observers there reported daytime temperatures in the 90s F. It reached 101 degrees F at Montevideo (the state record). The mid-September heat wave lasted from the 16th to the 23rd, one of the longest ever for the month.

Another mid-September heat wave prevailed in 1955, lasting from the 16th to the 19th. Over 30 climate stations set daytime maximum temperature records with readings in the 90s F.
For some nighttime lows remained in the 70s F.

September 16-20, 1973 brought widespread frosts to many parts of the state. Low temperatures in the 20s F ended the gardening and growing season as far south as Wabasha County. Much of the corn was not yet mature and suffered damage.

September 16-18, 1992 brought heavy rains to many areas of the state, delaying the harvest season for corn. Portions of southeastern Minnesota reported over 6 inches of rain.
Ten years ago, September 16, 2006 a rapidly formed and relatively short-live tornado struck near Rogers, MN causing damage to many homes and killing a 10-year old girl.

Outlook:

Mostly sunny weekend, with a uptick in temperatures on Sunday and Monday. Increasing chance for showers late Tuesday through Thursday with temperatures near seasonal normals.



 


 

 




Friday, September 9, 2016

Wet Start to September

Wet Start to September:

After a wetter than normal July and August, September is following trend and beginning wetter than normal for many areas of the state thanks in large part to some strong thunderstorms that crossed the state over September 4-7. Several areas of the state have reported over 2 inches of rainfall so far this month. Many climate stations are already reporting rainfall totals which are near the monthly average for September, and some locations have already surpassed the monthly normal rainfall values. A partial list of these locations:

Mabel (Fillmore County) 5.54"
Caledonia (Houston County) 4.69"
Spring Valley (Fillmore County) 4.14"
Spring Grove (Houston County) 4.03"
Lanesboro (Fillmore County) 3.40"
Worthington (Nobles County) 2.86"
Wright (Carlton County) 3.93"
Brainerd (Crow Wing County) 2.90"
Ottertail (Otter Tail County) 2.52"
Eveleth (St Lous County) 3.20"
Pokegama Dam (Itasca County) 3.52"
Ada (Norman County) 2.97"
Roseau (Roseau County) 2.65"

Some of these thunderstorms produced new daily rainfall records for many observers. Some of these new record values included:
For September 5th: 1.03" at Amboy, 1.92" at Redwood Falls, 2.65" at Roseau, 1.41" at Floodwood, 2.02" at Argyle, 1.42" at Isabella, and 1.37" at Thief River Falls.
For September 6th: 2.78" at Pokegama Dam, 1.96" at Eveleth, and 0.89" at Grand Portage
For September 7th: 4.41" at Caledonia, 2.95" at Harmony, 3.35" at Spring Valley, 2.00" at Theilman, 1.47" at Grand Rapids, 1.27" at Zumbrota, 1.20" at Owatonna, 3.89" at Spring Grove, and 2.32" at Houston.

In addition, the thunderstorms on the evening of September 7th produced a tornado caused that caused some damage at Camp Ripley (Morrison County) The State Climatology Office wrote a report about this.

Thankfully the weather looks to be cooler and drier for much of next week.

Weather Associated with the Record State Fair Attendance:

The12-day run of the Minnesota State Fair (August 25-September 5) set a new attendance record this year with 1,943,719. Three dates brought record daily attendance: Friday, August 26; Friday, September 2nd; and Saturday, September 3rd (all-time daily attendance record set with 260,374). So what was the weather like and did it help promote this record attendance? Yes, likely. Here is the daily attendance and associated weather description for each day of the State Fair (* denotes record attendance for the day):
Thursday, August 25, 111,902, cooler than normal and breezy
Friday, August 26, 141,023*, cooler than normal, with low relative humidity
Saturday, August 27, 180,567, cloudy and humid day
Sunday, August 28, 177,906, warm and humid day, afternoon temperatures in the mid-80s F
Monday, August 29, 119,522, warm and humid with Heat Index near 90F, and rain at night
Tuesday, August 30, 126,354, early morning rain, cloudy
Wednesday, August 31, 118,042, near normal weather, partly cloudy
Thursday, September 1, 133,773, near normal weather
Friday, September 2, 182,926*, very sunny, with low relative humidity, pleasant temperatures
Saturday, September 3, 260,374*, sunny, breezy, and low relative humidity
Sunday, September 4, 233,303, cloudy and breezy
Monday, September 5, 158,027, early morning rain, very humid, warm and cloudy

Weekly Weather Potpourri:

As a follow up to the dialogue we had last week during the broadcast of the MPR State Fair Weather Quiz, I found reference to the two modern era Grandstand Shows that were washed out by wet weather. The first one was the concert by Mac Davis on August 30, 1977 when over 4 inches of rain fell at the Fairgrounds, the 2nd one was the evening of August 26, 1982 when a half inch of wind-whipped rain fell, getting all of the sound equipment wet and canceling the Willie Nelson concert. My wife Cindy vividly remembered that one as we had tickets to attend.

In a NOAA press release earlier this week scientists offered an assessment of the devastating floods in Louisiana during August. Over August 11-17 many areas around Baton Rouge reported over 20 inches of rainfall, setting records for the most rain ever. Widespread flooding resulted in over 60,000 homes being damaged, 30,000 people being evacuated, and the loss of 13 lives. The scientific assessment of this event concluded that climate change likely helped magnify the atmospheric conditions that produced such rainfalls.

NOAA also recently announced a new climate data search tool that simply uses your zip code. You can retrieve daily climate data for any historically measured time period by going to the Climate Data Online Search Page. Specific instructions for doing this can be found at the NOAA Climate web site.

The BBC reported this week on a new study of weather-related pain that is making use of a cell phone app. Over 9000 people have signed up for this study in the United Kingdom which will examine the correlations between pain and various weather conditions and patterns. They hope to learn more about what types of weather trigger different kinds of pain.

MPR listener question:

I am writing to you from rural Fillmore County where I have farmed since 1957. So far this month we have recorded about 5 inches of rain. Over coffee this morning we wondered what has been the wettest September in history for our area of the state, over 10 inches perhaps?

Answer:

The wettest September for Fillmore County was in 1965. Numerous heavy thunderstorms delivered over 10 inches of rain to many communities, including 13.43" at Harmony, 12.74" at Preston, and 10.87" at Lanesboro. The most recent wet September was in 2010 when Rushford received 10.42 inches. That same year the all-time state record wettest September was reported from Zumbrota (Goodhue County), where 14.57" of rain fell.

Twin Cities Almanac for September 9th:

The average MSP high temperature for this date is 75 degrees F (plus or minus 9 degrees F standard deviation), while the average low is 56 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for September 9th:

MSP weather records for this date include: highest daily maximum temperature of 95 degrees F in 1947; lowest daily maximum temperature of 55 degrees F in 1929; lowest daily minimum temperature is 38 degrees F in 1883; highest daily minimum temperature of 76 degrees F in 1931; record precipitation of 1.79 inches in 1900; and no snowfall has occurred on this date.

Average dew point for September 9th is 55 degrees F, with a maximum of 75 degrees F in 1964 and a minimum of 33 degrees F in 1976.

All-time state records for September 9th:

The state record high temperature for this date is 105 degrees F at Beardsley (Big Stone County) in 1931. The state record low temperature for this date is 19 degrees F at Embarrass (St Louis County) in 2006. State record precipitation for this date is 4.75 inches at Gunflint Lake (Cook County) in 1977 and no measurable snowfall has occurred on this date.

Past Weather Features:

Strong thunderstorms brought heavy rains and widespread flash flooding to many parts of the state over September 8-11, 1900. Many climate stations reported from 4 to 7 inches of rain, along with strong winds. Bird Island reported nearly 8 inches. Farmers could not resume harvesting crops for nearly two weeks.

A hard freeze ended the growing season for many parts of northwester Minnesota on September 9, 1917. Low temperatures ranged from 22F to 30F across many parts of the Red River Valley, setting record early dates for frost.

By far the warmest September 9th in state history was in 1931. Only Grand Marais Harbor and Two Harbors along the Lake Superior shoreline failed to reach the 90F temperature mark. Over 35 communities reported a daytime high of 100F or greater. Temperatures did not fall to near seasonal normals until September 15th that year.

Outlook:

Slightly cooler than normal temperatures throughout the weekend under mostly sunny skies. There will be a chance for showers later on Monday into early Tuesday. Cooler and drier the rest of next week.

Friday, September 2, 2016

Climate Summary for August 2016

Average temperatures for August from observers around the state were generally warmer than normal by 1 to 2 degrees F. The hottest periods during the month were over the first ten days, when daily Heat Index values soared above 100°F in several locations. Marshall (Lyon County) reported the highest temperature for the state on the 10th with a reading of 96°F. The lowest temperature for the month was just 37°F at International Falls on the 21st. For the first 8 months of 2016 temperatures have consistently been warmer than normal in Minnesota, placing this period as the 6th warmest in state history.

The monthly total rainfall was above normal for most places in the state, except for a few isolated pockets of dryness. Many climate observers reported total monthly rainfall that was 2-3 times normal, and on a statewide basis it was the 3rd wettest August in history and wettest since 1980. For many communities it was a near-record or record wet August. Some examples include:

11.85 inches at Red Wing
11.82 inches at Theilman (2nd wettest)
11.70 inches at Waseca (2nd wettest)
11.37 inches at Redwood Falls
9.70 inches at Chanhassen
8.96 inches at Twin Valley
8.74 inches at downtown St Paul
9.90 inches at University of Minnesota St Paul Campus
7.86 inches at Kabetogama
9.66 inches at Faribault (4th wettest)
10.21 inches at Milan (2nd wettest)
10.23 inches at Wabasha (2nd wettest)
8.36 inches at St Cloud (2nd wettest)
7.82 inches at MSP (6th wettest)

Severe weather plagued the state during the month on several occasions: Over August 10-11 severe thunderstorms moved across the west-central part of the state, bringing 4-7 inch rains to the Willmar-Olivia area, and later in the day to Wabasha County. Then over August 23-24 heavy rains fell across portions of southeastern Minnesota delivering 2-3 inch amounts, and nearly 8.5 inches south of the border in Decorah, Iowa. Then over August 27-28 heavy rains, strong winds, and some tornadoes were reported in Polk and Norman Counties of northwestern Minnesota. Some farm buildings were damaged in Norman County.

With the added rainfall from August, following a wet July, this summer season (June-August) now ranks as the 4th wettest in state history, as the average 3-month rainfall for the state was just shy of 16 inches. For the Twin Cities this has been the 8th wettest summer in history with a total rainfall of 17.40 inches.

Weekly Weather Potpourri:

I will be broadcasting the MPR State Fair Weather Quiz with Tom Weber from the Minnesota State Fair on Friday morning at 11am (Sept 2). This year I had help from Greg Spoden, Pete Boulay, and Kenny Blumenfeld of the DNR-State Climatology Office in crafting the questions for the quiz. If you cannot listen to the broadcast you can find the quiz and take it for yourself at the MPR web site.

Hurricane Hermine was expected to bring high winds and heavy rains to Florida and then up the Atlantic coast states over Friday through Saturday. In the western Pacific Ocean Typhoon Namtheun was expected to bring heavy rains to southern Japan this weekend, while in the Central Pacific Ocean Hurricane Lester was expected to bring heavy rains and strong winds to parts of Hawaii.

There is a fascinating article on the NPR web site by Christopher Joyce about how the frigatebird uses clouds and air currents to stay aloft above the world's oceans for weeks at a time. They also fly at unusually high altitudes, above 12,000 feet. You can read more at the NPR web site.

MPR listener question:

Normally by state fair time my ragweed allergies are quite bad. Usually they start up right around August 15 when the ragweed blooms. However, this year my allergies are quite mild and it is already September. Has the wet summer affected the ragweed in some way? or is the more frequent rain simply taking more pollen out of the air?

Answer:

I would guess that both the frequency of rain over the past month, as well as the higher dew points (more moisture in the air) have somewhat suppressed the ragweed pollen count which according to the Twin Cities monitoring samples has been in the low to moderate category most days. Atmospheric moisture in both liquid form and vapor form (relative humidity) has been shown to keep less ragweed pollen from becoming airborne.

Twin Cities Almanac for September 2nd:

The average MSP high temperature for this date is 77 degrees F (plus or minus 9 degrees F standard deviation), while the average low is 58 degrees F (plus or minus 7 degrees F standard deviation).

MSP Local Records for September 2nd:

MSP weather records for this date include: highest daily maximum temperature of 97 degrees F in 1937; lowest daily maximum temperature of 55 degrees F in 1952; lowest daily minimum temperature is 42 degrees F in 1974; highest daily minimum temperature of 76 degrees F in 1953; record precipitation of 1.97 inches in 2000; and no snowfall has occurred on this date.

Average dew point for September 2nd is 56 degrees F, with a maximum of 75 degrees F in 1997 and a minimum of 29 degrees F in 1974.

All-time state records for September 2nd:

The state record high temperature for this date is 103 degrees F at Beardsley (Big Stone County) in 1929. The state record low temperature for this date is 22 degrees F at Sawbill Camp (Cook County) in 1935. State record precipitation for this date is 5.91 inches at Halstad (Norman County) in 1957; and no measurable snowfall has occurred on this date.

Past Weather Features:

The hottest September 2nd in state history was in 1929. Over 50 Minnesota communities reported daytime highs in the 90s F, and in the west Wheaton, Montevideo, and Beardsley surpassed 100 degrees F.

September 1-2, 1937 brought heavy thunderstorms across northern Minnesota communities which reported from 3 to 5 inches of rain. There was widespread flooding in both the Duluth and Grand Rapids areas.

Outlook:

Generally pleasant with near normal temperatures to start the weekend. Warmer than normal with Increasing clouds later on Sunday and into Monday with a chance for showers and thunderstorms, heavy in places. Continued chance for showers and thunderstorms Tuesday and Wednesday, with temperatures dropping back to near normal for this time of year.

 
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