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Extension > Minnesota WeatherTalk > December 2017

Friday, December 29, 2017

Cold Conclusion to December

Cold Conclusion to December:


Cold weather dominated Minnesota and much of the nation for the last week of December. Minnesota reported the coldest temperature in the nation on 7 days during the month of December (so far). For the Twin Cities the week between Christmas Day and New Years Eve will be one of the coldest since 1886. On Christmas Day Wind Chill values at places like Orr, International Falls, and Warroad ranged from -40 to -45 degrees F. Both Kabetogama and Cotton set new record lows on December 28th with readings of -40°F and -42°F, respectively. International Falls reported a new record cold maximum temperature for December 26th with a reading of -12°F, while Embarrass and Pokegama Dam only "warmed up" to -18°F that day setting records for cold maximum temperatures. At International Falls a new record cold minimum for December 27th was set with a reading of -37°F. Even more cold temperature records may be reported over December 30-31 this weekend. Thankfully towards the end of the first week in January temperatures are expected to moderate back closer to normal values.

Preliminary Climate Summary for December:


Despite a near equal distribution of days with above normal and below normal temperatures, the month of December will end up colder than normal across the state, only the third month this year (along with May and August) with a mean monthly temperature that was cooler than normal. Most of the warmth came early in the month. Over the first four days of the month temperatures averaged 15 to 20 degrees F warmer than normal. During this time 19 new daily maximum temperature records and 12 new daily warm minimum temperature records were set within the state climate network. Conversely, the last week of the month, beginning with Christmas Day (25th) brought temperatures that ranged from 15 to 24 degrees F cooler than normal. In fact a few spots reported the coldest Christmas Day maximum temperature in their climate records, including -12°F at Park Rapids and -11°F at Hibbing and Ely. Over the period from December 25-28 at least 31 new record daily low minimum temperature records were set and over 40 new record cold daily maximum temperature records were set. Extremes for the month ranged from 61°F on the 4th at Minnesota City, Hastings, and Zumbrota to -42°F at Cotton on the 28th. Over 20 climate stations reported an extreme minimum temperature of -30 degrees F or colder.

Overall December precipitation was generally less than normal, with many places reporting less than half an inch. Snowfall was near normal in nothern parts of the state, typically ranging from 10 to 16 inches, while in the southern part of the state snowfall was less than normal. Portions of St Louis, Lake, and Cook counties in the northeast received over 19 inches for the month. Only the far northern counties had over 8 inches of snow depth.

Several days produced wind gusts over 30 mph, and on the 4th of the month a number of western climate stations reported wind gusts over 50 mph.

Looking Back at the Weather of 2017, Part Two:


Of all the months in 2017 February was the most anomalous. It was the 5th warmest February in state history (back to 1895). There were 285 new daily high maximum temperature records set and 148 new daily warm minimum temperature records set within the climate observer network. Minneapolis Crystal Airport hit 70 degrees F on February 19th, one of only a few times in Minnesota history that the thermometer has hit 70°F during the month of February.

The three tornadoes reported on March 6th (in Freeborn, Faribault, and Sherburne Counties) were the earliest on the calendar ever reported in Minnesota history. Fortunately they produced relatively modest damage.

June 11 brought one of the most damaging hail storms in years across portions of southern and central Minnesota. Many areas reported golf ball size hail stones.

The strongest convective thunderstorms of the year occurred over August 16-17 when Redwood Falls reported a new state record rainfall of 9.45 inches and 8 tornadoes were reported as well. Many climate stations reported rainfall amounts ranging from 3 to 6 inches with widespread street flooding.

It was an unusual growing season in terms of temperature pattern, showing below average number of days with 90 degrees F temperatures, and one of only nine years in Twin Cities history when there were no days in August with 90°F temperatures, but then they occurred a month later during September.

Of final note, the Minnesota State Climatology Office Facebook page is conducting a survey to vote on the top five Minnesota weather stories of 2017. If you wish to vote please go to the SCO Facebook page.

Weekly Weather Potpourri:


Continental snow cover maps are available from NOAA and can be viewed on-line for any calendar interval. Currently the snow cover across the continental USA is below normal for this time of year, with many states reporting below normal snow depths.


New research from the AGU suggests that algae growth on the Greenland ice sheet may be reducing its reflectivity significantly and affecting the rate of melting more than earlier thought. In fact, the algae growth on the ice may be contributing more to the melting that accumulation dust or black carbon.

While the Great Lakes Region has been experiencing colder than normal temperatures recently, Alaska has been recording an exceptionally warm month of December with daily temperatures averaging about 15 degrees F above normal. So far over 200 new daily maximum temperature records have been set this month within the Alaska climate network.


A recent study published in Geophysical Research Letters and highlighted by the AGU suggests that anthropogenic climate change may be impacting the frequency of summer droughts in the mid-latitudes.

MPR listener question:

This holiday season between Christmas Day and New Years Eve is the coldest I can remember in the Twin Cities. Has there ever been a year when the average temperature for this week was below zero degrees F in the Twin Cities?

Answer:

Indeed it appears that the week between Christmas Day and New Years Eve this year will deliver an average Twin Cities temperature that is below zero degrees F, perhaps on the order of -2 to -4 degrees F. This is rare territory in Twin Cities climate statistics. Only three years have brought temperature conditions that averaged below zero degrees F during the week between Christmas Day and New Years Eve in the Twin Cities. Those years were 1880 (-0.6°F), 1886 (-4.7°F), and 1924 (-1.8°F).

Twin Cities Almanac for December 29th:


The average MSP high temperature for this date is 24 degrees F (plus or minus 11 degrees F standard deviation), while the average low is 9 degrees F (plus or minus 13 degrees F standard deviation).

MSP Local Records for December 29th:

MSP records for this date include: highest daily maximum temperature of 53 degrees F in 1999; lowest daily maximum temperature of -4 degree F in 1909; lowest daily minimum temperature of -24 degrees F in 1917; highest daily minimum temperature of 34 degrees F in 2006; record precipitation of 0.80 inches in 1972. Record snowfall on this date is 4.4 inches in 1889.

Average dew point for December 29th is 7°F; the maximum dew point on this date is 40°F in 1936; and the minimum dew point on this date is -24°F in 1976.

All-time state records for December 29th:


The all-time state high temperature for today's date is 61 degrees F at Montevideo (Chippewa County) in 1999; the all-time state low for today's date is -47 degrees F at Itasca State Park (Clearwater County) in 1917. The all-time state record precipitation for this date is 1.55 inches at Farmington (Dakota County) in 1982. Record snowfall is 16.0 inches also at Farmington (Dakota County) in 1982.

Past Weather Conditions:


Bitter cold dominated the state on December 29, 1887. Northern and western Minnesota communities reported temperatures ranging from -35 to -40 degrees F, while as far south as Rochester the temperature was -29°F. The daytime high temperature at Moorhead was only -11 degrees F.

The coldest December 29 in state history occurred in 1917. Morning low temperatures of -30 degrees F or colder were reported from 50 communities across the state. The temperature never rose above -18 degrees F at Ada (Norman County), making for one of the coldest days in history there.

A large winter storm brought heavy snowfall to parts of southwestern and central Minnesota over December 27-29, 1982. Snowfall amounts ranged from 8 to 18 inches and many roads were closed for a time.

December 29, 1999 was the warmest in state history. Over 30 communities reported an afternoon high temperature of 50 degrees F or greater. Redwood Falls and Milan reached 60 degrees F, while Montevideo set a state record for the date with 61 degrees F. Some western Minnesota citizens enjoyed an outdoor lunch.


Outlook:


Generally dry, clear, and cold over New Year’s Weekend, with temperatures from 15 to 20 degrees below normal. It may be the coldest New Year's Eve since 1992. Some moderation in temperature is seen by Tuesday and Wednesday with daytime highs in the single digits and teens. There will be a gradual warming to near normal temperatures by next weekend.








Friday, December 22, 2017

Oscillating December Temperatures and 2017 Climate Review

Oscillating December Temperatures and 2017 Climate Review:


Through the first three weeks of this month most climate observers have reported average December temperatures that range from 3 to 7 degrees warmer than normal. With the projected colder than normal weather dominating the Christmas to New Year’s Day time period, it appears that by the end of the month most climate stations will find that December mean temperatures have balanced out close to normal. Minnesota has reported the coldest temperature in the nation only twice so far this month, but is likely to see this frequency increase over the last ten days of the month. This oscillating temperature pattern is what balanced out the month of November as well, expect the first half of the month was exceptionally cold and the second half of the month exceptionally warm.

January may continue this oscillating pattern as it starts out colder than normal, then moderates mid-month and may even warm to above normal during the second half of the month.

Looking Back at 2017:


With most of the year in the rear view mirror now perhaps a look backward would be appropriate. The year 2017 is likely to end up among the ten warmest in state history. Both Granite Falls and Browns Valley recorded temperatures of 100 degrees F (July 17). Overall, only the months of May and August were colder than normal. Within the statewide climate network over 600 new daily maximum temperature records were set, while over 600 new daily warm minimum temperature records were set during the year. Most of these records were in the months of January, February, and September. Relatively few new low temperature records were set during the year. Coldest temperatures reported during the year were in mid-January when Blackduck, Celina, Embarrass, and Cotton reported lows of -40 degrees F or colder. A reading of -46°F at Cotton (St Louis County) on January 14th was the coldest reading of the year.

Most climate stations reported a wetter than normal year in 2017, but not anything close to a record value. Geographically the northwestern and north-central portions of the state reported less than normal precipitation for the year, while the rest of the state, especially northeastern and southeastern counties were well above normal. Among the long term climate stations in the state only Minnesota City (Winona County) reported a new record wet year with a precipitation total over 49 inches. A few climate stations in northwestern Minnesota reported less than 20 inches for the year. Within the state climate network over 500 new daily precipitation records were set, with the most occurring in the month of October, so wet that it delayed the corn harvest. The heaviest thunderstorm of the year occurred on August 16 when several observers reported over 5 inches of rain, and Redwood Falls reported 8.12 inches, a new statewide record for the date.

Ice dominated the weather headlines during January and February, especially in the southern half of the state where there were hundreds of auto accidents as well as pedestrian injuries reported. During these months at least six days brought rain, instead of snow, but then the rain froze overnight, leaving a coating of ice for the morning commute.

According to Warning Coordination Meteorologist Todd Krause of the National Weather Service, Minnesota reported 61 tornadoes this year, a larger than normal number. This is preliminary as the final report for 2017 is not finished.

Despite a rainy first few days, the weather during the State Fair (Aug 24 to Sep 4) was very favorable with comfortable temperatures, low humidity, and light winds. As a result a new record attendance was set with 1,997,320 people spending time there.

More on the weather headlines of the year will be in next weeks WeatherTalk Blog.

Weekly Weather Potpourri:


Much of the state received snowfall on December 21 though a section in the middle of Minnesota only received a dusting. In the northern third of the state reports ranged from just an inch to over 8 inches in some parts of Hubbard, Cook, and Carlton Counties, while 2 to 5 inches of snow fell across some southern counties. Pipestone reported 5.3 inches.

Jake Crouch of NOAA offers an interesting glimpse at climate trends across the nation in a blog post this week. Minnesota happens to show some of the strongest upward trends in both temperature and precipitation among all the states in the USA.


In the Western Pacific Ocean Tropical Storm Tembin will bring large waves, strong winds, and heavy rains to portions of Vietnam and Thailand over the coming Christmas holiday. Winds are expected to 70 mph or greater and sea waves may exceed 20 feet with this storm.

MPR listener question:


We just moved to the Twin Cities from Florida this autumn and look forward to having our first White Christmas. But what is with these subzero overnight temperature forecasts between Christmas and New Years Eve? Is that the normal around here?"

Answer:


For the Twin Cities we usually get at least one subzero temperature reading between Christmas and New Year’s Day 75 percent of the time (back to 1872). It has been as cold as -39°F on Christmas Day (1879) and as cold as -30°F on New Years Day (1974). But since 2002 only 4 years have brought overnight subzero temperatures to the Twin Cities between Christmas Day and New Years Day, and in 2011 the day after Christmas reached a high of 52°F. So we have certainly been experiencing a trend toward milder temperatures during the holiday season. This year will obviously been different, as the forecast calls for several nights to drop below zero.

Twin Cities Almanac for December 22nd:


The average MSP high temperature for this date is 25 degrees F (plus or minus 13 degrees F standard deviation), while the average low is 10 degrees F (plus or minus 13 degrees F standard deviation).

MSP Local Records for December 22nd:

MSP records for this date include: highest daily maximum temperature of 53 degrees F in 1890; lowest daily maximum temperature of -12 degree F in 1983; lowest daily minimum temperature of -20 degrees F in 1983; highest daily minimum temperature of 45 degrees F in 1877; record precipitation of 0.52 inches in 1968. Record snowfall on this date is 7.6 inches in 1968.

Average dew point for December 22nd is 13°F; the maximum dew point on this date is 44°F in 1941; and the minimum dew point on this date is -32°F in 1983.

All-time state records for December 22nd:


The all-time state high temperature for today's date is 62 degrees F at Two Harbors (Lake County) in 1899; the all-time state low for today's date is -44 degrees F at Baudette (Lake of the Woods County) in 1963. The all-time state record precipitation for this date is 1.30 inches at Glencoe (McLeod County) in 1920. Record snowfall is 16.0 inches at Artichoke Lake (Big Stone County) in1968.

Word of the Week: Snowcreep


This word does not refer to the guy who just put a snowball down the back of your neck, nor is it the snowplow driver who just cleared the alley by pushing all the snow onto your driveway. It is a term used to describe the slow, continuous downhill movement of a snowfield or mass of snow on a slope. Most often associated with mountainous areas, this feature can also be observed on less topographic terrain as well, such as the ridges of the Lake Superior shoreline, or the Mississippi River Valley in southeastern Minnesota.

Past Weather Features:


Very warm weather occurred on December 22, 1877. Temperatures were in the 50s F across southern Minnesota and even the mid 40s F in Duluth. Later in the day rain fell across most of the state, making for a muddy Christmas season.

Another very warm December 22nd occurred in 1899 as over 25 climate stations reported daytime highs ranging from 45 to 55 degrees F. The temperature reached 62 degrees F at Two Harbors, an unusual day indeed.

The coldest December 22nd in state history occurred in 1963 when over a dozen climate stations reported morning lows of -30°F or colder. The afternoon high temperature at Hallock (Kittson County) in the Red River Valley only reached -10°F.

A strong winter storm brought heavy snow and blizzard conditions to the state over December 21-22, 1968. Many areas of the state received 8 to 16 inches of snow, and 40 mph winds created some huge drifts and road closures. Over 40 climate observers reported new snowfall records on the 22nd.

The week of December 17-24, 1983 was one of the coldest in Minnesota history. Many climate stations reported average weekly temperatures that were 30 to 35 degrees F colder than normal. The average temperature for the week in the Twin Cities was -14°F. Over 35 climate stations reported minimum temperatures of -40°F or colder, while Tower and Mora reported -52°F. Many wind chill readings were -60 degrees F or colder.

Outlook:


Generally dry over the Christmas weekend, but with temperatures well below normal. Monday and Tuesday will be the coldest days next week with many daytime high temperatures remaining below zero F. There will be some moderation in temperature towards the end of next week, but remaining colder than normal. Slight chance for snow on Wednesday and Thursday.






Friday, December 15, 2017

Mixed climate patterns in December

Mixed climate patterns in December:


After an extraordinary warm start, with scores of record high temperature values set on the 4th of the month, December has been tracking with alternating periods of below and above normal temperatures. Overall through the first half of the month most climate stations are showing average temperature values that range from 4 to 8 degrees F warmer than normal, a trend that is likely to make December the 10th month of 2017 with above normal temperatures. Over 60 climate stations so far have reported subzero low temperatures on at least one day this month, with a minimum of -19°F near Ely earlier this week on the 12th. Embarrass was -15°F on that date as well. Eveleth reported -9°F on December 8th, the coldest in the nation.

Most observers have so far reported anywhere from 5 to 7 days with measurable snowfalls, mostly light in amounts from a dusting up to 1 inch. Though most climate observers have reported a total of just 1 to 4 inches so far this month, some northern climate stations have reported over 10 inches, including Kabetogama, Ely, Isabella, and Baudette.

Nocturnal Character of Winter Storms:


Frequencies of hourly precipitation from the Twin Cities climate records show some interesting daily patterns with respect to the onset of winter storms. Patterns in the hourly frequencies of precipitation do vary by month. In the winter months, December through February, the afternoon hours from noon to 4:00 pm show the lowest relative frequency of measured precipitation. Overnight frequencies of hourly precipitation are relatively higher, especially from 1 am to 6 am. This could be due to the relationship between temperature and the saturation of the air. Low temperatures usually occur during these overnight and predawn hours and probably remain closer to the dew point temperature, preserving the structure and continuity of precipitation, whether droplets, sleet or snow crystals. The other feature of winter storm systems to remember is that they are usually large and take some time to move across the area. Precipitation may last for several hours and since most of our 24 hour calendar day is in darkness during the winter, we associate the storminess with the night.

Reminder of Mn/DOT's winter driving tips:


Call 511 or go to www.511mn.org before departing on a trip to get current road conditions
Drive with headlights on and seat belt fastened
Turn off cruise control
Drive at slower speeds, and keep greater distance between vehicles
Never drive into a snow cloud
Respect snowplows, and stay on the road behind them


Weekly Weather Potpourri:


In the Western Pacific Ocean, Tropical Storm Kai-Tak was spinning southeast of the Philippines and expected to bring rain, strong winds, and high seas to portions of that country by this coming Sunday. It was not expected to strengthen into a typhoon.

The BBC reported this week on a project to map the continent of Greenland and how it would appear without any ice cover. The animated map depictions shows river valleys and mountain ranges underneath the massive ice sheet, which represents a volume of ice that is calculated to be 2.9 million cubic km (about 700,000 cubic miles).

Scientists from Ohio State University have collaborated with scientists from China to extract the largest ice core ever from a non-polar region. They extracted a 1000 foot long ice core from the Tibetan mountains and hope to reconstruct temperature and climate behavior over the past 600,000 years. So far their early results suggest a rapid increase in temperature and precipitation over the past 50 years or so.

A recent paper from scientists at the University of Colorado suggests that climate change may dictate a shift in the geographic deployment of wind energy technologies. Their studies of model depicted climate change suggest that wind power resources (based on estimate changes in mean wind speeds) in the mid-latitudes of the Northern Hemisphere may decline over the next century or so, while wind power resources may increase in the Southern Hemisphere and the tropics.


There is an interesting article by NOAA’s Deke Arndt this week about the changing climate on the North Slope of Alaska. Climate change is much more accelerated and significant there according to recent measurements.

MPR listener question:


I am doing a Science Fair Project for school about snowfall and wanted to know how often December is the snowiest month of the snow season (Oct-Apr) for the Twin Cities? I am guessing that it is less than a third of the time.

Answer:


Since 1884 when the Twin Cities daily snowfall record began, December has been the snowiest month of the snow season (Oct-Apr) 31 times (23 percent). If you want the rest of the historical distribution it goes like this......

November 15 times (11 percent)
December 31 times (23 percent)
January 36 times (27 percent)
February 17 times (13 percent)
March 29 times (22 percent)
April 5 times (4 percent)

BTW from 2007 to 2011 December was the snowiest month every winter. You can read more about Twin Cities snowfall record at the Minnesota State Climatology Office web site.

Twin Cities Almanac for December 15th:


The average MSP high temperature for this date is 27 degrees F (plus or minus 13 degrees F standard deviation), while the average low is 12 degrees F (plus or minus 13 degrees F standard deviation).

MSP Local Records for December 15th:

MSP records for this date include: highest daily maximum temperature of 51 degrees F in 2014; lowest daily maximum temperature of -5 degree F in 1932; lowest daily minimum temperature of -21 degrees F in 1901; highest daily minimum temperature of 39 degrees F in 1928; record precipitation of 0.71 inches in 1902. Record snowfall on this date is 7.0 inches in 1902.

Average dew point for December 15th is 10°F; the maximum dew point on this date is 39°F in 1928; and the minimum dew point on this date is -22°F in 1963.

All-time state records for December 15th:


The all-time state high temperature for today's date is 60 degrees F at Marshall, Springfield, and Tracy in 1939 and again at Canby in 1998; the all-time state low for today's date is -47 degrees F at Pokegama Dam (Itasca County) in 1901. The all-time state record precipitation for this date is 2.25 inches at Grand Rapids (Itasca County) in 1893. Record snowfall is 14.6 inches at Rockford (Wright County) in 1996.

Past Weather Features:


We know from the Ft Snelling climate record that December of 1855 was no picnic. Well, actually maybe you could have had a picnic during the first days of the month as temperatures reached the mid 40s F. But following that mild spell a series of arctic fronts descended across the region bringing measurable snowfalls on nine days and an especially heavy snow at mid month. Friday and Saturday, December 15th and 16th brought snow "with flakes as big as a featherbed" totaling 8 to 12 inches around the St Paul area. Sleighing was said to be excellent as total snowfall amounted to 22 inches for the month. The fresh snow cover and arctic air produced one of the coldest Christmas Eves in Minnesota history with a reading of -33 degrees F at Ft Snelling, -36 degrees F at St Paul, and -38 degrees F elsewhere in southern portions of the state. So after a teasing, mild start what a bitter month it turned out to be.

A rare December rain occurred across southern Minnesota on December 15, 1894. With daytime temperatures in the 40s and low 50s F and no snow on the ground, rainfall amounts ranging from half an inch to 1.50 inches (at St Peter and New Ulm) were observed across the southern half of the state.

On December 15, 1901 an Arctic air mass brought record cold to the state. Over 20 climate stations reported minimum temperatures of -30°F or colder, while the daytime high at Pine River Dam only reached a reading of -12°F.

On December 15, 1919 another Arctic air mass brought record-setting cold temperatures to parts of Minnesota. Over 30 climate stations reported a minimum of -30 degrees F, including Rochester in southern Minnesota. The daytime high at Roseau and Hallock was just -15°F with 10 inches of snow on the ground.

A strong winter storm brought 6-15 inches of snow to many parts of Minnesota on December 15, 1996. Snowplows were kept busy into the night trying to keep roads and highways open. Many climate stations reported over 30 inches of snow that month, and Two Harbors received 49 inches.

By far the warmest December 15th on a statewide basis was in 1998. Over 60 climate stations reported a daytime high of 50 degrees F or greater. Even as far north as Gunflint Lake reached a high of 52°F. The temperature never dropped below 36°F at Winona and Minnesota City along the Mississippi River Bluff Country.

Outlook:


Temperatures a few degrees warmer than normal for the weekend and early next week, with some highs above the freezing mark on Monday and Tuesday. An increasing chance for snow later on Wednesday and into Thursday, followed by cooler than normal temperatures towards the end of the week.

Friday, December 8, 2017

Winter Returns

Winter Returns:


This week the Minnesota State Climatology Office posted the headline "Winter Returns" referring to the snow and cold front that dominated the state over December 4-5.

Prior to the passage of the cold front during the afternoon and evening of Monday, December 4th many climate stations reported new record high temperatures for the date, including: Rochester and Austin with 64°F; Albert Lea and Theilman with 63°F; Grand Meadow with 62°F; Minnesota City, Fairmont, Hastings, Caledonia, Winnebago, Waseca and Winona with 61°F, Amboy, Red Wing, and Preston with 60°F; Rosemount with 59°F; La Crescent with 58°F, MSP with 57°F, and a number of other places as well. In addition MSP reported a new record high dew point on December 4th of 55°F, and the 2nd highest dew point ever reported in the month of December (only a dew point of 57°F on December 5, 2001 was higher). With the high temperatures and high dew points during the afternoon a few thunderstorms developed across areas of southern Minnesota (Red Wing among others), and rainfall amounts of 0.20 to 0.40 inches were reported from some areas.

As the cold front advanced, precipitation turned over to snowfall and many areas reported from 2 to 4 inches of snowfall with this weather system, but the most outstanding features that got people's attention were the strong winds and the dramatic temperature drop. Most areas reported wind gusts over 40 mph and some areas reported winds as high as 50-55 mph. The temperature drops caught a number of citizens unprepared and rushing for their winter parkas. While the temperature dropped 30 degrees F in the Twin Cities with the passage of the cold front late in the day, many other areas saw greater temperature drop. For example at Winnebago the temperature dropped from 60°F to 15°F (45 degree drop), while at Grand Meadow, Owatonna, and Waseca the temperature dropped 47 degrees, and at Albert Lea and Austin it dropped 48 and 49 degrees, respectively.

With the fresh snow cover, high pressure, and clear skies temperatures remained well below normal most of the week. On the morning of December 7th (Thursday) Fosston reported -6°F and Cotton reported -4°F. At least a dozen other northern Minnesota communities reported subzero temperatures as well. Many southern and western Minnesota climate stations reported their coldest temperatures since last winter, including 5°F at Browns Valley, 4°F at Montevideo, Wheaton, Lakefield, and Kimball, 3°F at Otter Tail and Worthington, and just 2°F at Pipestone.

With the colder temperatures soils are starting to freeze up again as they did for a brief time last month. At the two-inch depth soil temperatures dipped into the upper 20s and low 30s F by Thursday of this week.

Weekly Weather Potpourri:


On Thursday of this week winter storm Caroline brought strong winds and large waves to portions of western and northern Scotland. Wind gusts from 70 to 90 mph and large sea waves closed coastal highways, as well as schools in areas of Scotland. There were a number of power outages and rail and ferry services were disrupted during the storm, one of the strongest to hit portions of the UK in recent months. Some snow and ice was expected for some areas on the back side of the storm as it moved east on Friday.

Wildfires burning in the hills surrounding Los Angeles, and scattered elsewhere along the California coast down towards San Diego made the headlines this week as there were widespread evacuations, and the loss of a number of homes and commercial properties. Downtown Los Angeles has only received 0.11 inches of rain since October 1st, the 11th driest start to the Water Year (Oct 1 to Sep 30) in history there. The National Weather Service was continuing to release Red Flag Warnings Wednesday and Thursday of this week as relative humidity values ranged from only 5 to 15 percent and Santa Ana winds were gusting to 30-40 mph in places. The Weather Underground was continuing to issue updates on these fires as well.


A winter storm was bringing snow to portions of Georgia, especially higher elevations on Friday (Dec 8), with forecasts of amounts up to 3 inches in some places. The Winter Storm Warning, somewhat rare for this time of year, was in effect for areas from Rome to Blairsville where travel was difficult on untreated roads. A rare snow was also reported in southern Texas this week.
A recent study by the USDA Forest Service shows that California has the lowest urban tree canopy cover per capita of any state. With the ecosystem services provided by tree canopies this is an area where urban settings could be improved a great deal. This study provides motivation for urban planners to consider ways to improve and diversify tree canopies in some of California's urban communities.

MPR listener question:


Earlier this week at Waseca we saw a 47 degree temperature drop in less than 24 hours. What is the record 24-hour temperature drop in Minnesota history?

Answer:


According to my book, Minnesota Weather Almanac, the largest drop in temperature over a 24-hour period occurred at Lamberton, MN on April 3, 1982 when following a daytime high of 78 degrees F, the temperature dropped to just 7 degrees F overnight, a decline of 71 degrees.

MPR listener question:


After hearing the piece about the impact road salt runoff has on ponds, lakes, and rivers, I began to wonder if the increased salinity of lakes and rivers causes a [later] freeze up time [date]. I have noticed that the pond behind our house takes longer to freeze than it did when we first moved here in 1998. I think some of the later freeze time is related to climate change...but does the increased salinity also add to the later freeze time?

Answer:


I am no expert on water chemistry, but according to the NOAA National Snow and Ice Data Center the freezing point of water drops by half a degree F for each increase in salinity of 5 ppt (parts per thousand). In the Arctic Ocean where the salinity content is about 35 ppt the water begins to freeze at 28.8 degrees F. It seems to me that for smaller bodies of water like your pond, increased salinity from runoff into the pond may be a factor in the later date of freeze up. But for lakes and rivers in our state I think climate change is the primary driver of later freeze up dates. Consider this, over the 20 years since 1998 (the year you moved into your home) 18 of those years have brought a warmer than normal autumn season (Sep-Nov), and 8 of those autumn seasons rank among the 10 warmest in state history back to 1895. On that evidence alone it is no wonder you have been observing later freeze up dates.

Twin Cities Almanac for December 8th:

The average MSP high temperature for this date is 29 degrees F (plus or minus 13 degrees F standard deviation), while the average low is 15 degrees F (plus or minus 13 degrees F standard deviation).

MSP Local Records for December 8th:

MSP records for this date include: highest daily maximum temperature of 50 degrees F in 1939 and 1990; lowest daily maximum temperature of -6 degree F in 1927; lowest daily minimum temperature of -22 degrees F in 1876; highest daily minimum temperature of 40 degrees F in 1907; record precipitation of 0.44 inches in 1963, 1987, and 1995. Record snowfall on this date is 7.1 inches in 1995.

Average dew point for December 8th is 13°F; the maximum dew point on this date is 46°F in 1946; and the minimum dew point on this date is -20°F in 1978.

All-time state records for December 8th:

The all-time state high temperature for today's date is 67 degrees F at Grand Marais (Cook County) in 1913; the all-time state low for today's date is -38 degrees F at Big Falls (Koochiching County) in 1932 and again at Brimson (St Louis County) in 2013. The all-time state record precipitation for this date is 2.02 inches at Babbitt (St Louis County) in 1924. Record snowfall is 14.0 inches at Isabella (Lake County) in 1969.

Past Weather Features:


A major winter storm brought widespread heavy snow to the state over December 7-9, 1969. Many climate stations reported 10-20 inches of snowfall and in some areas schools were closed or started late. Duluth reported 21 inches of snow on their way to 38.8 inches for the month. On a statewide basis it was one of the snowiest Decembers in history.

December 8, 1990 was arguably the warmest in history on a statewide basis as over 40 Minnesota communities reported a daytime high of 50 degrees F or greater. A few places in western Minnesota topped 60 degrees F, under bright sunny skies and a south wind.

The coldest December 8th in state history was just 4 years ago in 2013. Arctic high pressure gripped the state and except for a few isolated areas of southeastern Minnesota, all observers were reporting subzero temperature readings. Over 70 climate stations reported morning lows of -20 degrees F or colder. Even the daytime temperature rose no higher than -11°F at Detroit Lakes and Hallock.

Outlook:


Partly cloudy over the weekend with warming temperatures. Highs on Sunday will be warmer than normal. A chance for snow late on Sunday and into early Monday. Then cooler temperatures again for Monday through Thursday of next week, though temperatures will be near normal. Little chance for precipitation over that time period.

Friday, December 1, 2017

November climate summary

November climate summary:


Precipitation was generally below normal across Minnesota during the month of November, while the temperature pattern was mixed with average monthly temperatures that were cooler than normal in the north and slightly warmer than normal in much of the south. The other contrast was in cloudiness, which was dominant the first half of the month, then there were many long spells of sunshine during the second half of the month.

The first two weeks of the month were the coldest since November of 1995, but then temperatures moderated the rest of the month, with several days bringing daytime highs in the 50s and 60s F. The last week of the month was about 12°F warmer than average in most Minnesota communities. Extreme temperature values for the month were 65 degrees F at Marshall (Lyon County) on the 27th, and -17 degrees F at Camp Norris (Lake of the Woods county) on the 24th. Minnesota reported the coldest temperature in the nation four times during the month.

Well over 95 percent of all climate stations in Minnesota reported a drier than normal month. Many climate observers reported less than half an inch of precipitation for the month and some were close to a record low amount. For example Windom (Cottonwood County) reported just 0.04 inches of precipitation for the month, Worthington (Nobles County) just 0.01 inches, and Faribault (Rice county) just 0.09 inches, all of which represent their 2nd driest November in history. Amboy (Blue Earth County) reported its driest November ever with 0.03 inches of precipitation. The overall lack of precipitation helped farmers wrap up chores like a late corn harvesting season, soil testing, applying fall nitrogen, and spreading manure. A few northeastern Minnesota climate stations reported over 1.5 inches of precipitation for the month, still a very modest total.

The most significant snowfalls for the month occurred during the first week when several northern climate stations received over 6 inches. Places like Orr, Cook, Isabella, Gunflint Lake, Ely, and Thorhult received over a foot of snow. International Falls reported measurable snowfall on 7 days, totaling 11.9 inches.

One other climate feature of November worth noting - strong winds. Most observers reported at least 10 days with wind gusts over 30 mph. Both Moorhead and Mankato reported wind gusts over 50 mph on at least one day.

Weekly Weather Potpourri:


In a new study from the Minnesota Sea Grant scientists in Duluth they find that some clear and seemingly clean inland lakes are actually so loaded with agricultural nutrients that algae cannot grow in them, leaving the water looking clear, but of impaired water quality. The excessive nutrient levels in these lakes happen as a result of heavy rains, or snowmelt washing phosphorus and nitrogen from agricultural fields, feed lots, or urban centers into the drainage areas that feed some inland lakes.


NOAA scientists reported recently that the extent of autumn sea ice around Alaska is the lowest ever measured. This is part of an ongoing trend in the data since 2001, and is also suggested to be a sign of climate change in that region.


Recent research from the University of Western Ontario examined the use of high-altitude turbulence radar measurements to detect tornado signatures. They found evidence in their data that may allow forecasters to predict tornado formation up to 20 minutes earlier than with current forecasting techniques.


Tropical Cyclone Ockhi is churning in the Indian Ocean with wind gusts to 100 mph and sea waves over 20ft. It is expected to bring heavy rains to western parts of India near Mumbai by the end of the weekend and early next week.

MPR listener question:


I know that complete ice formation on Minnesota inland lakes is late this year (again). When do you think we will see a streak of weather that causes our lakes to ice-in enough for ice fishing?

Answer:


As is so often the case in recent years, you will have to be patient. Please use the MN-DNR web site to periodically check for ice cover on your favorite lakes and remember the recommendation for safe ice fishing on foot is thickness of at least 4 inches. It looks like we will have a spell of good "ice-making weather" starting next Wednesday and running into the following weekend, as daytime highs will track in the 20s F and nighttime lows in the single digits.

Twin Cities Almanac for December 1st:


The average MSP high temperature for this date is 32 degrees F (plus or minus 10 degrees F standard deviation), while the average low is 18 degrees F (plus or minus 11 degrees F standard deviation).

MSP Local Records for December 1st:

MSP records for this date include: highest daily maximum temperature of 68 degrees F in 1998; lowest daily maximum temperature of 1 degree F in 1919; lowest daily minimum temperature of -15 degrees F in 1893; highest daily minimum temperature of 43 degrees F in 1962; record precipitation of 0.83 inches in 1985. Record snowfall on this date is 8.4 inches in 1985.

Average dew point for December 1st is 18°F; the maximum dew point on this date is 49°F in 1982; and the minimum dew point on this date is -17°F in 1930.

All-time state records for December 1st:

The all-time state high temperature for today's date is 70 degrees F at Chaska (Carver County) in 1998; the all-time state low for today's date is -51 degrees F at Pokegama Dam (Itasca County) in 1896. The all-time state record precipitation for this date is 2.12 inches at Two Harbors (Lake County) in 1985. Record snowfall is 16.0 inches at Winona (Winona County) in 1985.

Past Weather Features:


Following a strong winter storm over Thanksgiving week in 1896, December of that year began under an Arctic high pressure system that brought record cold on the 1st. Ten northern climate stations began the day at -30°F or colder. The temperature never rose higher than -16°F at Crookston (Polk County) that day.

By far the warmest December 1st in state history was in 1998. Over 40 climate stations reported afternoon high temperatures of 60 degrees F or greater, topped by 70°F at Chaska. Though it was a Tuesday, a work day, many people played hooky to go golfing, as many southern Minnesota golf courses were open that day. Temperatures over the first three days of that December average over 20 degrees F above normal

A winter storm brought high winds and a mixture of precipitation to Eastern South Dakota and portions of southern Minnesota over November 30 to December 1, 1981. Many roads and highways, including portions of Interstate 90 were closed for a time. Observers across southern Minnesota reported 8 to 14 inches of snowfall. Blizzard conditions with winds as high as 50 mph were reported in many western areas.

Another major winter storm brought widespread blizzard conditions to Minnesota on December 1, 1985. Winds were consistently between 30 and 40 pm with gusts to 50 mph. Many roads and highways were closed, and several Sunday church services were cancelled that day. Many areas of the state reported 10 to 16 inches of snowfall.

Outlook:

Mostly sunny skies and warmer than normal temperatures into the weekend. Increasing cloudiness on Sunday, with a chance for rain and/or snow by Monday. Then, much cooler for Tuesday through Friday of next week with below normal temperatures, and generally a dry weather pattern.


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