Climate in Minnesota
The climate of the US state Minnesota is assigned to the continental climate . While it is determined by the warm and humid air from the south in the summer months, it is mainly polar air masses from the north in winter. There are also differences between the northeast, whose climate is influenced by Lake Superior , and the northern and southern regions of the state. According to the Köppen / Geiger climate classification , the southern part of the state falls into the humid continental climate with hot summers (Dfa), the northern two thirds are largely assigned to the humid continental climate with warm summers (Dfb).
description
The geographical location almost in the middle of the North American continent in the Upper Midwest (between about 43 and 49 degrees latitude ) causes pronounced fluctuations and large differences between the individual seasons . Natural barriers in the form of mountains do not exist in the immediate vicinity. The Upper Lake connects to the state in the northeast, but only has a regional influence on the climate near the shore. Minnesota winters are characterized by low temperatures and snowfall . Well-known weather systems in winter are the Alberta Clipper and the Panhandle Hook , which bring cold air masses and, under certain circumstances, heavy snowfalls. The transition from winter to spring is fluid. Snow storms are possible until March and April. With the rise in temperatures, the risk of tornado increases, which lasted from summer to autumn. The summers in southern Minnesota are hot and humid, while those in the north are less humid and more temperate. The first snow can fall around the middle and end of October and in November.
Precipitation
Located between the semi-arid regions of the Great Plains in the west and the semi-humid regions in the east of the United States, Minnesota is the driest state in the Midwest. In Minnesota itself there is a semi-arid climate in the west and a humid climate in the other parts. Almost half of the annual precipitation falls in the months of June to August . Much of it make the thunderstorms and severe weather , which fall on the state. In addition to rain, these thunderstorms also result in hail , arc echoes , derechoes and tornadoes . In the summer thunderstorm fronts, the dew point rises to up to 21 degrees, in rare cases even up to 27 degrees Celsius. On average, thunderstorms lead to flash floods three days a year . Only eight percent of the annual precipitation falls in the winter months. Although snow is the most common form of precipitation at this time, freezing rain , clear ice , sleet and rain can also be found. The average annual snowfall varies from about 210 centimeters in the hill country near the coast of Lake Superior to 90 centimeters in southern Minnesota.
The lowest annual precipitation in Minnesota was measured in 1976 in Ortonville with 161 millimeters, the highest value in 1991 with 1359 millimeters in St. Francis. In terms of average annual precipitation, there is a gradient between the north-west (around 480 millimeters) and the south-east (around 860 millimeters).
wind
The jet stream plays an important role and largely determines the wind currents. In summer, the polar front jet stream moves at an average latitude of around 65 degrees and thus north of Minnesota. During this period the wind comes from a south to south-east wind direction. By winter it had shifted to about 45 degrees latitude and mostly supplies Minnesota with dry cold and polar air from Canada. The prevailing wind direction has turned from north to northwest. The most windy periods are spring and autumn.
The average wind speed is around 14 to 18 kilometers per hour. The exception to this is the Coteau des Prairies , which stretches from South Dakota to southwest Minnesota and Iowa . Here the average wind speed is 27 kilometers per hour. For this reason, the area is also used to generate energy with wind turbines .
Temperatures
The average annual temperature in Minnesota ranges from three degrees Celsius in the northwest to ten degrees Celsius in the south. This variation is due to the weakening of cold air masses in winter moving south from the north and warm air masses from the south moving north. A regional peculiarity occurs on the shores of the Upper Lake, where it has a warming effect in winter and cooling in summer, similar to the lake climate . The average daily temperature in Minnesota in summer varies between 23 degrees Celsius in the south and 15 degrees Celsius in the north. The warmest region in summer is the west, as warm down winds from the Rocky Mountains additionally warm this region. The lowest temperature ever recorded is minus 59 degrees Celsius (1996 in Tower), the temperature record is plus 46 degrees Celsius (1917 in Beardsley and 1931 in Moorhead ).
Seasons
winter
The winter in Minnesota begins in November, long before the official start of winter. This time of year is determined by the cold and snowfall. The jet stream is now running further south again and increasingly carries air masses from north to north-west with it. This is how the high pressure areas come from Canada to the state and bring with them weak winds, cloudless skies and temperatures well below freezing point . Since Minnesota is not surrounded by natural barriers, this air can flow in unhindered. For example, International Falls is also known as the “Icebox of Nation” and, at 3.0 degrees Celsius, has one of the coldest average temperatures of all NWS weather stations in the 48 contiguous states of the USA. In Tower, the temperature drops below zero degrees Fahrenheit (around minus 17 degrees Celsius) on an average of 71 days a year. The Alberta Clippers take turns using the high pressure systems and bring blizzards with them.
Occasionally, Minnesota comes under the influence of zonal winds from the west when the jet stream is stronger than usual in a west-east direction. This is how warmer air from the Pacific Ocean enters the areas. This leads to a longer-lasting warm phase with temperatures well above freezing point. These winds usually hardly bring any precipitation.
Precipitation in winter occurs mainly in the form of snow. In addition, there is also freezing rain, ice, sleet and rain. Depression from the southwest, like Panhandle Hook, can cause large amounts of snow and blizzards.
Alberta Clippers
Alberta Clippers are fast moving gravure systems. They get their name from the Canadian province of Alberta , where they form and continue to move southeast. Similar gravure systems with other origins are the Saskatchewan Screamer or Manitoba Maulers. They arise over the northern Pacific and lose most of the humidity due to the orographic uplift in the Canadian Rockies. Minnesota they rarely bring more than six inches of snow. The Alberta Clippers are followed by strong winds and polar air. This is accompanied by a high wind chill factor.
Panhandle hooks
Panhandle Hooks represent the counterpart to the Alberta Clippers. These low pressure systems arise in the southwest of the United States and then move to the northeast. They carry a lot of humid air from the Gulf of Mexico with them to Minnesota and the Middle Beings. To the north-west of the low-pressure area - as long as there is enough cold air there - heavy snowfalls occur. Snowfalls of over 30 centimeters are not uncommon. Panhandle hooks leave low temperatures and winds behind. Many famous blizzards in the Midwest were created by a panhandle hook.
spring
As soon as winter draws to a close from around March and the sun reaches a higher level in the sky, temperatures also start to rise. Air masses move inland from the Pacific Ocean and meet the warm and humid air of the Gulf of Mexico. At the beginning of spring the temperatures are still too low for severe storms, so that Minnesota is only on the northern front of these storms and there is only rain or snowfall. In early March, the snow begins to melt in southern Minnesota. Cold air, which is still supplied from Canada, delays snowmelt in the north and causes snowstorms until the end of April at the latest. As spring progresses, the jet stream begins to carry the air masses further north, making storms and tornadoes more frequent in southern Minnesota. The average temperatures in spring are two to seven degrees Celsius.
summer
In summer , Minnesota is divided into two areas: in the south, the summers are hot and humid, while in the north they are more temperate and less humid. Stable weather conditions can prevail and lead to more constant temperatures and decreasing winds. The existing air currents mostly come from the south and bring warm and moist air with them. Nevertheless, cooler air masses from Canada can continue to break in. However, these are mostly quickly displaced by the warm, humid air masses from the Gulf of Mexico . A clash of these opposites causes thunderstorms , especially in July and August . This leads to an average of 30 to 40 thunderstorm days per year. In summer, however, there are also longer periods of heat that can last up to several weeks. July is the hottest month in Minnesota with average summer temperatures of 15 to 23 degrees Celsius.
autumn
|
|
|
Fall in Minnesota (recorded October 3rd and 13th, 2006) |
The fall in Minnesota is characterized by a strong drop in temperature and frequent storms and thunderstorms. The first blizzards can occur later . The average daily temperature falls by around 23 degrees Celsius from September to December. During this period, Minnesota comes under the influence of the jet stream again. The cold air increasingly flowing in from Canada, as well as the air masses still in the south, can lead to strong pressure differences and temperature fluctuations within a short time, and provide the basis for storms. As autumn progresses, the precipitation turns into snow. Snowfall can occur in the north as early as October, and further south until November.
The worst blizzards occurred in November 1940. From one day to the next the temperature fell from plus 16 to minus 12 degrees Celsius. At the same time, 69 centimeters of snow and gusts of wind fell at speeds of up to 100 kilometers per hour. 149 people died in this blizzard. During the Halloween blizzard of 1991, parts of Minnesota fell 60 centimeters of snow on October 31. The average temperatures in autumn are three to eight degrees Celsius.
Regional differences
Lake Superior
Lake Upper affects the climate in northeast Minnesota ( Arrowhead Region ). Similar to the sea climate, it cools the temperature in summer and has a warming effect in winter. However, this effect only extends slightly inland. The riverside city of Grand Marais, for example, has an average temperature of 21 degrees Celsius in July, while Virginia , 160 kilometers to the west, already has 25 degrees Celsius. In January this effect is reversed: While Grand Maris' average temperature is minus five degrees Celsius, it is minus nine degrees Celsius in Virginia. The prevailing northwest wind in winter also limits the influence of the lake. The Sawtooth Mountains lie a few kilometers from the shoreline . They represent a natural barrier for the maritime air masses and result in precipitation on the shore. So there are repeated heavy snowfalls in this area. On January 6, 1994, 91 centimeters of snow fell in Finland within 24 hours. Within three days, he fell 216 centimeters. The port city of Duluth has the highest snowfall per year with an average of 216 centimeters. Lake effect snow can occur in the shore area . However, this phenomenon plays a subordinate role due to its geographical nature. Fog often forms near the shore .
Weather extremes
Flood
Large parts of Minnesota are at risk of flooding. The snowmelt regularly leads to flooding of rivers and lakes in the spring. There were severe floods in 1965, 1969, 1997 and 2001. In particular, the Mississippi River floods in 1965 are among the worst in the state's history. In 1997, the Red River flooded with the snowmelt after a total of eleven blizzards the previous winter. In addition, Minnesota has rainy late spring and summer. If rains and snowmelt coincide, this puts an additional burden on the water level.
The heavy rains of the storms in spring and autumn can also cause flooding. In August 2007, the collision of Tropical Storm Erin with cool air from Canada in the Driftless Area led to severe flooding. Up to 432 millimeters of precipitation fell within 24 hours.
Droughts
In Minnesota, a traditionally agricultural state, droughts are wreaking havoc on the economy. The growing season varies between 90 days in the Iron Range and 160 days in the southeast. During this period, almost two thirds of the annual precipitation usually falls. The last major dry season was in Minnesota in 1988. The lack of rain, together with very high temperatures in the months of May to August, caused crop failures worth 1.2 billion US dollars. Further droughts occurred in 1976 and during the Dust Bowl in the 1930s. In addition to the agricultural damage, forest fires occur again and again as a result of longer dry seasons .
Tornadoes
The tornado season is in Minnesota from March to November. Months with the highest risk of tornado are June and July, followed by May and August. The southern part of the state is located on the northern edge of Tornado Alley . But tornadoes can also occasionally occur in the other regions. An average of 24 tornadoes rage in Minnesota each year.
Some of the worst tornadoes to hit Minnesota include:
- August 21, 1883: An F5 tornado over Rochester kills 37 people. This tornado led to the construction of a new hospital, which later became the Mayo Clinic .
- April 14, 1886: A tornado over Sauk Rapids kills 72 people.
- June 22, 1919: A tornado over Fergus Falls kills 59 people.
- May 6, 1965: Four F4 tornadoes sweep across the Twin Cities region . 14 people are killed.
- June 16, 1992: A total of 27 tornadoes hit Minnesota. An F5 tornado hits Chandler and kills one person.
- March 29, 1998: Two F4 and F3 tornadoes hit Comfrey and St. Peter . Two people are killed in the process.
- June 17, 2010: 48 tornadoes are counted over Minnesota that day. Three of them have the strength F4. Three people are killed.
Selected climate stations
International Falls
International Falls is a city in central northern Minnesota on the border with Canada .
|
Monthly average temperatures and rainfall for International Falls
Source: missing
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Minneapolis – St. Paul
The metropolitan area of Minneapolis-Saint Paul consists of the twin cities called Minneapolis and St. Paul , as well as the surrounding areas. With 3.18 million people, it is the most populous region of Minnesota. The measuring station is located at the common airport .
|
Average monthly temperatures and rainfall for Minneapolis-Saint Paul
Source: missing
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Winona
Winona is located in southeast Minnesota on the Mississippi River. The river is also the border with Wisconsin .
|
Average monthly temperatures and rainfall for Winona
Source: missing
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Additional information
literature
- Mark Seeley: Minnesota Weather Almanac . Minnesota Historical Society Press, 2006, ISBN 978-0873515542 .
- Richard A. Keen: Minnesota Weather . Two Bears Press, 1991, ISBN 978-1560370000 .
Individual evidence
- ↑ World Map of the Köppen-Geiger climate classification updated . Markus Kottek. Retrieved January 8, 2008.
- ↑ Climate's impact on water availability . Minnesota DNR. Retrieved November 18, 2007.
- ↑ a b Minnesota Climate Facts . Minnesota DNR. 2004. Retrieved November 18, 2007.
- ↑ Sean Potter: Icebox of the Nation . USA Today. August 10, 2006. Archived from the original on May 7, 2008. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 17, 2007.
- ↑ Frank Gianassca: Zonal winds tend to bring calm weather . USA Today. Retrieved November 17, 2007.
- ^ Armistice Day Storm . NOAA. Retrieved November 17, 2007.
- ^ Top 5 weather events of the 20th Century . Minnesota Climatology Office. Archived from the original on December 7, 2006. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 17, 2007.
- ↑ Lake Superior Uplands . Minnesota DNR. Retrieved November 17, 2007.
- ↑ a b Climate Summaries . Midwestern Regional Climate Center. Archived from the original on November 12, 2006. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 17, 2007.
- ↑ superior pursuit: facts about the greatest great lake . Minnesota Sea Grant. Retrieved November 17, 2007.
- ^ Flood information . Army Corps of Engineers. Archived from the original on September 15, 2001. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 17, 2007.
- ↑ 2007 Federal Disaster Declarations . FEMA. August 26, 2007. Retrieved November 17, 2007.
- ^ The Mississippi River Flood of 1965 . NOAA. November 8, 2005. Retrieved November 17, 2007.
- ↑ Famous Minnesota Winter Storms . Minnesota Climatology Office. December 10, 2001. Archived from the original on January 7, 2009. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 17, 2007.
- ↑ Heavy rains fall on southern Minnesota: August 18 - August 20 . Minnesota Climatology Office. August 22, 2007. Archived from the original on February 23, 2011. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 17, 2007.
- ^ Climate of Minnesota (PDF) NCDC. Archived from the original on May 28, 2008. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 17, 2007.
- ↑ Drought of 1988 (PDF; 2.1 MB) Minnesota DNR. January 1989. Archived from the original on December 11, 2006. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 17, 2007.
- ^ Minnesota Tornado History and Statistics . Minnesota Climatology Office. September 20, 2006. Archived from the original on August 11, 2007. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 17, 2007.
