Saturday, 19 January 2013

#1 - Top Ten Weather Events of 2012 in the Winnipeg Area

Windom, Minnesota Mar 16;by Sally to
''March Madness''

     The off the scale-type warmth experienced in mid March was one of the most extreme meteorological events in history across North America. It was extreme in basically every way; its length, its coverage and just how extreme temperatures were compared to normal. After an early end to Winter, Mother Nature fast-forwarded past Spring and went straight to Summer; in many cases, even before the first day of Spring arrived. Temperatures soaring into the twenties and in some cases the thirties shattered thousands and thousands of records basically anywhere east of the Rockies in both Canada and the United States. Remarkably, these record-obliterating hot temperatures lasted for more than a week. As a result, the record books for March got a complete facelift in a way not seen since the insane heat wave of July 1936.

     The length and extremeness of the heat was thanks to the jet stream. The jet stream had entered into a blocking pattern, something that happens periodically anyway, but not to the extent that it did in mid-March. In western North America, the jet stream took a nose dive deep into the southern US while it then took an almost direct south to north path straight up over the Rockies into Canada. This pattern remained more or less anchored for at least a week. The persistent trough off the western coast of North America brought BC, Washington and Oregon cold, wet and snowy weather. Meanwhile, a persistent southwesterly to southerly flow aloft brought extreme warmth, and remarkably even high humidity, east of the Rockies within the persistent ridge of high pressure. This dome of warmth rapidly melted any snow that was on the ground across southern Canada and the northern US negating its cooling effect, another factor in how warm temperatures got.

     Here in Manitoba, the mind-boggling warmth began on March 10 and lasted more or less through the rest of the month, but peaking between the 15th and 23rd. On top of the warmth however, thunderstorms and humidex values also made an unprecendentedly early appearance. As soon as the warmth began, people were flocking to ice cream shops and geese were seen flying over.

     Despite there still being snow on the ground, incredibly warm temperatures aloft allowed temperatures to rise to near-record values on March 10. The high of 6.5°C in Winnipeg was just shy of the old record of 8.3°C in 1902. However, highs of 10.8°C in Melita, 11.1°C in Pinawa, 11.6°C in Pilot Mound and 12.4°C in Portage all broke records. It was even warmer in North Dakota with highs of 18°C in Minot and Jamestown and 22°C in Bismarck! The 22°C in Bismarck broke the old record of 18°C in 2008. Winnipeg got its chance at breaking records the next day with a high of 12.8°C on the 11th, breaking the old record of 12.5°C in 1981. Other records in southern Manitoba included an incredible 15.8°C in Wasagaming, 14.8°C in Pinawa, 14.6°C in Melita and 14.3°C in Sprague. It also reached about 16 to 17°C in the Whiteshell east of Winnipeg, but the station there is not with Environment Canada.

      This warmth and sunshine made for a very rapid snow melt. In Winnipeg, a snow depth of 25 cm  early in the morning on March 10 melted down to nothing by the 14th with grassy patches showing up as early as the 12th. The snow melt was also aided by a very warm night leading to the 12th. The overnight low was 6°C before temperatures dropped in the morning with some rainfall. This is significant because the old record high for the day was 7.2°C in 1922. The rapid melt kept city crews busy clearing street drains deluged with water.

Snow melt progression in Winnipeg from March 10 to 14. Pic by myself

Golfing on Mar 18! Pic by Barb Johnson; sent to TWN
     Temperatures reached the mid double digits in southwestern Manitoba again on the 13th, but the most insane warmth in southern Manitoba began on the 15th. By then, golf courses were beginning to open up one by one, some opening the earliest they ever have. In a normal Spring, they don't usually open until April. Garden centres were also preparing as quickly as possible to be ready for any people itching to begin preparing their gardens. The warmup did come with consequences however. Soils were already beginning to dry up with the sunshine leading to fire bans in eastern and southeastern Manitoba. These fire bans are quite exceptional for that time of year considering we'd usually be worrying about flooding. Fires did spark up in the Winnipeg area and in the RM of Stuartburn on March 16 and 22 respectively. Farmers were beginning to worry about the early dryness leading to drought conditions later in the spring and summer.

     On March 15, temperatures soared into the mid teens across southern Manitoba breaking numerous records. The full list of records can be seen here. Perhaps the most remarkable of these records was in Portage which, with a high of 15.9°C, broke their 126-year old record by 4.8°C! Most records were broken by at least 3 degrees throughout southern Manitoba.

      The first 20°C readings of the warm spell in Manitoba were seen on March 16. On this day, records were not just broken, they were obliterated! Winnipeg just missed 20°C with a high of 19.9°C. However, that broke the record for warmest temperature for so early in the year, breaking the old record by 3.4 degrees (16.5°C on March 6, 2000)! Essentially, this means that this was the earliest in the year that Winnipeg has ever been warmer than 16.5°C. The 19.9°C reading was also 7.5°C warmer than the old record high! The most remarkable margin was in Gretna, which with a high of 19.8°C broke their old record by 12.3°C!! The full list of records can be seen here. It is extremely rare for a station with over 50 years of data to break records by several degrees. To give a perspective, breaking a record high by over 6 degrees in the summer would equate to highs in the 40's.

     Temperatures hit the twenties in a few communities once again on March 17 and about a dozen record highs were obliterated by several degrees. The biggest margin was in Pilot Mound, which with a high of 20.2°C broke their old record by 13 degrees! Many records that were obliterated were set in 2010. The full list can be seen here.

     Just when you thought it couldn't get warmer in March, it did! This time on March 18, the vast majority of southern Manitoba exceeded 20°C making it feel just like summer. Shorts, t-shirts and sandals were worn instead of the winter coats and boots that we would normally be wearing. People flocked to the patios as well. 5 communities (Pinawa, Melita, Gimli, Pilot Mound and Fisher Branch) all broke their old record by more than 10 degrees! Gimli took the title with a high of 21.4°C; 12.2 degrees warmer than the old record for the date! Most communities across southern Manitoba had already broken their record high for the day mid morning, which just goes to show how unusually warm it was.
Mar 17 in Wpg, dressing like it's summer. Pic by CBC MB

     Winnipeg's high of 20.9°C wasn't too shabby neither, breaking the old record by 6.5 degrees. That also makes it the earliest 20 degree reading in history for the city, and also the first 20 degree reading in March in 66 years. In addition, it also broke the record for the warmest temperature for so early in the year; the second time we broke that record in this March warmth. The entire list of records broken in southern Manitoba on March 18 can be seen here. Normal highs for that time of year are around zero, therefore we were over 20 degrees above normal!

     Street cleaning crews started their spring cleanup on March 18, which is about a month earlier than usual.

     Amazingly, humidity was also starting to build in on the 18th. Dewpoints rose into the mid teens, the highest ever in March, bringing a max humidex value of 24.9 in Winnipeg. This was the second time that the city broke the record for all-time March high humidex (we had first broken it on the 16th with a humidex value of 20.5). The old all-time high humidex for March was 18.8 on March 30, 1967.

     March 19, ''theoretically'' the last day of winter, easily took the cake. It turned out to be the most anomalous day ever in southern Manitoba and perhaps the first time air conditioning was needed in March!

     A strong southerly to southeasterly flow of air ahead of a cold front kept temperatures and humidity levels high through the night. The overnight low to start off March 19 in Winnipeg was an extraordinary 16°C; more than 15 degrees warmer than the normal high for the day!!! That was also just 3 degrees off of the record high of 18.9°C for the day. In comparison, an overnight low that much above normal would equate to an overnight low of 30°C in the summer. As Winnipeggers woke up for work or school early in the morning, it was already 17 to 18°C along with dewpoints in the mid teens and lots of sunshine. It felt like a nice July morning!

Map of March 19 showing the heat into Canada and risk of evening storms. Pic by A Weather Moment blog
     At 19°C by 10 AM, the old record high had already been broken for the day. The temperature then rose to an incredible 21°C at 11 AM, along with a humidex of 25. By mid afternoon, the mercury reached an inconceivable 23.7°C along with a humidex of 28.0! May I remind you this was March 19 in Winnipeg! That's the warmest temperature ever recorded in March in Winnipeg, breaking the old record of 23.3°C on March 27, 1946. The humidex of 28.0 was the highest humidex ever in March, breaking the old record of 24.9 set just the day before. It's unimaginable to think just how humid it would have been if there was evapotranspiration going on!

     This wasn't just a Winnipeg story of course. Temperatures reached the low to mid twenties through almost all of southern Manitoba. The hotspot was Gladstone at 25.1°C. 6 towns and cities broke their old record for the day by more than 10 degrees. The warmth reached far north as well with a high of 21.9°C in Berens River. That broke the old record for the day by 13.0 degrees! It was also the warmest March day ever in the town, breaking the old record by 7.5 degrees! This is quite astounding considering that weather records in Berens River go back to just over a century! The full list of daily high temperature records broken on March 19 can be seen here. The list of all-time March high temperature records is as follows:

     What also makes this so astonishing is the fact that these all-time March high temperature records were broken in the middle of the month instead of near the end of the month when it is climatologically warmer.

     By the way, the warmest temperature ever recorded in Manitoba in March was 28.3°C in Morden on March 23, 1910.

     As if the day was not summery enough, a cold front moving through the province in the evening colliding with the extraordinarily high humidity for that time of year sparked off thunderstorms!

     In the morning, the Storm Prediction Center south of the border had put a 2% tornado risk all the way up into North Dakota. A slight risk for severe thunderstorms was also posted all the way up to the Manitoba border. To think that a single lightning strike is highly unusual at that time of year, it's inconceivable to think that the potential for severe thunderstorms was actually in the forecast. The ingredients for the storms were definitely there; decent shear, a very strong low-level jet, surface based CAPE of 1000-1500 J/kg, LI's as low as -5 and surface dewpoints in the mid to high teens. Sounds like a summer setup! (And this was the last day of WINTER).

Lightning Mar 19 near Niverville; by Ryan Buhler to TWN
     In the end, the storms remained non-severe in southern Manitoba but were still quite strong. A long line of storms fired up near Carberry all the way down into North Dakota and Minnesota late in the afternoon and quickly intensified as they moved northwards. The storms had developped into a nice solid line by the time it reached the RRV and the Interlake. The storms entered Winnipeg by 7:45 PM and lasted for about 45 minutes or so, making it the earliest recorded thunderstorm in the city. On top of being the earliest, it was the strongest storm to hit the city in March. The nearly north to south orientation of the line combined with its NNE movement caused the storms to train on some parts of the city. Rain came down in torrents flooding some streets; never thought we'd see the day in March! Vehicles were moving at a crawl on the streets, and some traffic lights were out in parts of the city. A peak rainfall rate of 155.6 mm/hr was recorded at 8:33 PM in Transcona and 135 mm/hr at 8 PM in Charleswood. No hail was reported here in Winnipeg, but hail did fall south of Altona and may have been as large as dimes.

     Frequent and intense lightning was also associated with the line of storms; pretty ridiculous for that time of year. Some cloud-to-ground strikes were seen at times, and lightning flashed every few seconds at peak. This lightning created some issues at the Winnipeg airport. A red alert was issued there around 8 pm meaning ground crews had to stay indoors, causing flight delays. In addition, power was knocked out to 3,800 people in Fort Richmond. Lightning sparked a pole-top fire on Bison Drive. The outage lasted about an hour and a half. More outages were reported in St. James later in the evening and lasted until 1 AM. There were also power outages near Carman, and those lasted a few hours. Generally, winds weren't extreme in this thunderstorm event, but they were quite gusty at times locally. Gusts of 70 km/h were reported in some areas.

     Total rainfall amounts in the storms can be seen here. Also some video to prove that these thunderstorms did in fact occur in Winnipeg on March 19... Video 1 high-rise perspective, Video 2 view from the ground, Video 3 brief capture of a cloud-to-ground stroke.

     Remarkably, the storms reached all the way into the northern Interlake and northern Manitoba in the overnight hours. Thompson was one community to get in on the action with a couple-hours long freezing thunderstorm. This event was particularly exceptional in the city considering that there was still a deep snow pack on the ground and temperatures during the thunderstorm were well-below zero (around -3°C to -4°C). Heavy freezing rain, ice pellets and hail came down making roads especially slippery. A must see video of the thunderstorm in Thompson can be viewed here.

     The dewpoint temperature reached 17.2°C at 8 pm in Winnipeg as the thunderstorm hit, the highest dewpoint ever recorded in March in the city. This was the third day in this March warmth that we had broken this record. Prior to 2012, the highest dewpoint ever recorded in March was 10.6°C on March 30, 1967.

     As dewpoints remained high in the evening after the storm, the temperature only dropped to 13.3°C making that the low for the day. This low is truely astonishing considering it is more than 10 degrees warmer than the normal high and broke the old all-time March high daily minimum temperature by 5.5 degrees! This 13.3°C low for the day was also just under the record high for the next day (March 20) which was 13.9°C in 1878. It is also the earliest double digit daily minimum. The earliest we had a double digit daily minimum prior to 2012 was 11.5°C on April 14, 2010, almost a month later!

    Thanks to the all-time highest daily minimum AND maximum temperature for March, the mean temperature for the day was 18.5°C; more typical of late June. That makes the day 23.4 degrees above normal; the most above normal day in history for any day of the year. Only about a dozen days since 1872 have been more than 20 degrees above the 30 year normal, and we topped them all!

     After cooling down behind the cold front for a couple days (but still being a good 15 degrees above normal), the temperatures skyrocketed again on March 22 with highs in the low twenties; the third day of 20°C weather of the month in Winnipeg. This is truly exceptional considering prior to 2012, only 3 days in March since 1872 have been warmer than 20°C! In contrast to earlier in the week, humidity was low with no humidex values. The full list of records broken on March 22 can be seen here.

     It was a different story the next day, March 23, when dewpoints skyrocketed once again, reaching the mid teens. The minimum temperature of the day in Winnipeg was 8.7°C, the second warmest daily minimum temperature on record for March. Only the low of 13.3°C just 4 days earlier was warmer. However of note, this low of 8.7°C was achieved in the evening. The morning low was an astonishing 12°C. This moisture was ahead of a cold front which moved through early March 24. This front brought yet more thunderstorms to southwestern Manitoba. Temperature which hovered near freezing meant precipitation in Brandon fell as freezing rain during the thunderstorms. Some of the freezing rain was heavy at times making for incredibly treacherous roads.

     Temperatures on March 24 fell below freezing in Winnipeg for the first time since March 15. We had a stretch of 8 consecutive days with a daily minimum temperature above zero. The average minimum through this period was 5.4°C, a good 5 degrees warmer than the normal high for the period!

     Temperatures finally cooled down throughout southern Manitoba for the end of the month to values 15 to 20 degrees colder. However, temperatures were still a few degrees above normal, and on some days more than 5 degrees above normal. Even so, it felt very cold after the summer-like weather mid-month. This just proved how unusual and extreme the warmth mid-month was. You couldn't blame people for forgetting what normal was!

Wpg early March 27. By CanadaNatureShots
     But the unusual weather was still not over. A vigorous system moving from the United States on March 26 and 27 brought yet another bout of thunderstorms to Manitoba. Late on March 26, a large complex of thunderstorms formed in the northern Interlake along the warm front and moved into northern Manitoba. Here in southern Manitoba, it was more of an overnight story in the wee-hours of March 27. The storms were surprisingly decent, especially for that time of year. The thunderstorms rattled Winnipeg around 2:30 AM. Lightning was frequent and intense with flashes every few seconds at peak. The lightning even caused some brief power outages across the city. Hail also fell and was as large as dimes in some areas. In some parts it lasted a good 5 minutes which was enough for the hail to accumulate. Downpours were heavy with 6 to 12 mm of rain in total. It was also surprinsingly cold during the storm with temperatures just a couple degrees above the freezing mark.
     Brief video of the lightning in Winnipeg

Winnipeg hail early Mar 27. By Eric Toupin to TWN

     With 2 thunderstorms in Winnipeg in March, it was just as many thunderstorms as we had in July and August 2011 combined! Prior to 2012, only 3 thunderstorms have been recorded at the Winnipeg airport in March since 1953 (Mar 27, 2004, Mar 29, 1999 and Mar 28, 1960)

     One last day of super-warmth on March 31 was a fitting way to finalize the absurdly-warm month. Temperatures reached 18.8°C in Winnipeg, just 0.1°C off the old record of 18.9°C in 1963.

     With an average mean temperature of 2.2°C, March 2012 went down into the record books as the warmest March in history for Winnipeg. That's a ridiculous 8.0°C warmer than the 1981-2010 normal of -5.8°C!! Daily highs averaged 8.0°C, or 8.8°C above normal and also the warmest on record for March. That broke the old record by 0.8 degrees! In total, there was 43.5 mm of rainfall at the airport, making it the 3rd rainiest March on record. Normal rainfall for March is about 11 mm (1981-2010 normal).

     In total there were 5 days with temperatures warmer than 19.0°C, truly amazing when you consider that prior to 2012 there had only been 4 days of 19°C + since 1872. What had been accomplished in 140 years only took 1 year to beat. Another amazing statistic is the fact that all three 20°C days occured earlier in the month than any 20°C day before 2012.

     In addition, there was no acumulation of snowfall beyond March 8, exceptionally unusual.

     In total through the month of March, at least 35 records were broken in Winnipeg, truly astounding. To finish off the Manitoba part of this story, here's the entire list of records broken in Winnipeg during this unprecedented month.
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     The heat in March covered pretty much all of Canada east of Alberta at at least one point during the month. Thousands of records were broken across the country and in fact it was a record for the most records broken. Hundreds of cities and towns from Nova Scotia all the way to Manitoba experienced their warmest March on record including Halifax, Québec City, Montreal, Toronto, Ottawa, Charlottetown and Fredericton. At times northern Ontario and Québec were as warm as regions along the coast of the Gulf of Mexico. Ontario and Québec saw the warm temperatures last the longest. While Old Man Winter is usually still hanging on in mid March in those two provinces, in 2012 words such as humidex, tulips, green grass, patios, swimming pools and thunderstorms were used instead. The warmth, which had reached in far northern Ontario, rapidly melted all the snow that was on the ground. In Geraldton for instance, 31 cm of snow cover on March 18 had virtually all melted in just 2 days. In Abitibi-Témiscaming, Québec, more than two feet of snow cover melted down to nothing in as little as a week and a half. It was a similar story in northeastern Ontario with over two feet of snow melting in under 2 weeks.

March departure from normal. Pic by Agriculture and Agri-Food Canada

Peterborough flooding; pic by TWN
     The warmth began with a bang in southern Ontario on March 15. Severe thunderstorms, yes severe, rattled the province in both the morning and evening. Severe storms early in the morning dumped over 20 mm of rainfall over Peterborough, flooding streets. City crews worked for several hours to get the flooding under control. Frequent lightning strikes caused havoc as well. A person was struck by lightning in Cambridge just before 8 am. The victim was taken to hospital and recovered. Some structures in the area were damaged by lightning as well. In the evening, severe thunderstorms moving in from Michigan prompted Environment Canada to issue rare tornado watches for the Windsor area in the evening. Frequent lightning and hail were the main stories with this evening round, including areas as far north as Ottawa. Thunderstorms in Ontario this early in the year are quite rare, but not unheard of, and usually not as strong. (Video of lightning in Windsor)

     After that, the heat really began to turn on across central and eastern parts of the country. In southeastern Saskatchewan, temperatures reached the low twenties on March 16 with many records shattered. Estevan reached 23.0°C and Weyburn 22.2°C, both breaking their old records by 6 or 7 degrees. Estevan reached 23.4°C again on March 22. And then on March 30, most of southern Saskatchewan reached the twenties including 22.2°C in Regina.

     Some of the most impressive records occurred in Ontario however. The warmth reached well-northwards as well. All-time March high records were shattered day after day in many communites between March 18 and 22. Fort Frances in northwestern Ontario broke their old all-time March high of 19.0°C on March 29, 1986 3 times with highs of 21.2°C on the 16th, 24.8°C on the 17th and an unbelievable 26.4°C on the 18th (they reached 26.0°C again on the 19th)! The low temperature on the 19th was 15.1°C or 5 degrees warmer than the record high for the day! In total there was 5 or 6 days of 20°C through the month, which is incredible considering they had never hit 20°C in March before.

     Here's a list I created of highs recorded during the peak of heat spell between March 18 and 22 in Ontario and Québec. The values in bold were all-time March high records broken.

     Some of these are extremely impressive, especially in northern Ontario and in Québec where some areas broke their old all-time March high temperature record by as much as 8 degrees! It's also incredible how Windsor recorded highs warmer than 27°C for 3 consecutive days. In fact, Windsor recorded 10 consecutive days with highs above 20°C, a record for the city and probably all of Canada. The average mean temperature for the month in the city was 9.6°C; over 7 degrees above the March normal and astonishingly a full degree warmer than the April normal! The city also recorded a humidex of 32.3 on the 22nd which breaks the old all-time high March humidex of 29.9 on March 30, 1998 and could possibly be the highest humidex ever in Canada in March. Also of note, the city recorded 6 days with a minimum temperature warmer than 10°C.

     An average mean temperature of 6.7°C for the month in Toronto made it the warmest March ever in the city, breaking the old record by 1.5 degrees (old was 5.2°C in 1946)! That's pretty rare to break a monthly record by that large a margin.

     In Petawawa, Ontario, the mercury reached 28.8°C on March 21, almost 17 degrees warmer than the previous record of 12.2°C. It's also the second hottest temperature ever recorded in Ontario in March. Hottest was 29.4°C in Wallaceburg on Mar 26, 1921.

     The warmth also brought incredibly warm temperatures to the Maritimes on March 20, 21 and 22. Fredericton broke its old all-time March high temperature of 22.2°C on March 30, 1962 3 times. The mercury hit 23.9°C on the 20th, 27.1°C on the 21st and 27.2°C on the 22nd. In Saint John, a high of 25.4°C on the 21st not only broke the all-time record for March by 7.9°C (old record 17.5°C on March 28, 1999), but was warmer than April's all-time maximum of 22.8°C on April 20, 1976! In Nova Scotia, Halifax broke their all-time March high twice with highs of 25.8°C on the 21st and 27.2°C on the 22nd (old record 25.6°C on March 31, 1998). The 27.2°C on the 22nd was also 15.4°C warmer than the old daily record of 11.8°C in 1983. Western Head, Nova Scotia had a high of 29.2°C on the 22nd. That broke the old daily record by a mind-numbing 18.6°C (old record 10.6°C in 1969). Lake Major, NS was the nation's hotspot in March with a high of 30.0°C on March 22, one of the hottest temperatures, if not the hottest, ever recorded in Canada in March.

     There were disadvantages to the early major warmth. The maple sugar season in Ontario and Québec was cut short giving below-normal yields. Blooming trees and plants brought out an early start to the pollen season across the country as well. Flooding was issue in parts of Québec due to an incredibly rapid snow melt and in Perth-Andover, NB, the warmth triggered one of the biggest ice-jams in history. Fruit trees in eastern Canada were hard hit when a widespread freeze occurred in late April. Trees which had bloomed 5 weeks earlier than normal faced major damage. Strawberry yields were generally 50% less than normal, while apple growers were hardest hit. Total losses from the freezes in Ontario were estimated at over 100 million dollars.

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The remainder of this post contains information from Jeff Master's WunderBlog

     South of the border, it was the most extended period of extreme and record-breaking warm temperatures ever in March, going back to the late 1800's. Tens of thousands of records were broken, most of them daily high and low records, all-time March records and records for the warmest its been for so early in the year. And these records were being broken day after day after day. In fact there were so many records being broken that the extremes section of the NOAA National Climatic Data Center website was down for several days. The software could not handle both the large number of records being set, and the huge demand from people wanting to see the records.

Mar 19, Ypsilanti Township, MI; by gardner48197 to

     The warmth also caused flowers and trees to bloom in many states east of the Rockies, including Michigan and Missouri in mid March. This was at least a month earlier than normal. As a result, similar consequences as in Canada were faced. Large parts of Michigan, and along eastern Seaboard had a major freeze on March 27 causing major damage to flowered plants. Fruit growers had worked through the night to try to save their yields by running large fans and propane heaters to attempt to keep temperatures a little warmer. However, damage was still widespread. In addition, the early warmth dried up soils which raised concern for drought later in the season.

     There were a few advantages however. The warmth caused huge savings in heating and snow removal costs and much fewer vehicle accidents from icy conditions.

     In the end it was the warmest March ever in the country. The average temperature was 10.6°C; 4.8°C above normal. The previous warmest March was 1910 at 10.3°C. Of the more than 1400 months of record keeping in 1895, only January 2006 was more above normal. 25 states had their warmest March on record and another 15 had a top-ten warmest March.

     The month also ended up second place for the most daily high temperature records since records began more than 100 years ago. Only July 1936 had more. 11.3% of all daily high records in March are now held by 2012 for the 550 stations in NOAA's database that have more than 100 years of records. July 1936 holds 14.4% of all the daily high records for July.

     Among all the records in the country, 21 were cases where the low temperature for the day was warmer than the previous record high for the date. Examples include:
  • A low of 17°C in Rochester, Minnesota on March 18 was warmer than the previous record high of 16°C for the date.
  • In Marquette, a low of 11°C on March 21 was warmer than the previous record high of 9°C!
  • In International Falls, Minnesota, a low of  16°C (60°F) on March 18 tied the previous record high for the date.
Mar 8-15 departure from normal temp. Pic from A Weather Moment blog
      Many notable records included:
  • In Minneapolis, for the March 1 to 20 period, there had only been 9 days in that period since 1872 with a high above 21°C (70°F) prior to 2012. But remarkably, there were 5 such days during that period in 2012. The high of 27°C (80°F) on March 17 was the hottest temperature ever in this period, breaking the old record of 23°C (73°F) on March 7, 2000. The city also broke the record for the warmest its ever been for so early in the year 3 times (on Mar 14, 16 and 17). The monthly high of 27°C (80°F) on March 17 was also just shy of the all-time warmest temperature ever in March of 28°C (83°F) and was 22°C (39°F) above normal for the date. In total, 9 daily high temperature records were broken through the month. Lastly, there were 8 straight days with a daily low above 10°C (Mar 17-24), at least 3°C above the normal highs for the period. The warmest low was 16°C on both Mar 18 and 19, at least 10°C warmer than the normal highs for the dates.
  • Bismarck hit a remarkable 27°C (81°F) on March 16 which was 23°C (41°F) above normal for the date. It ties for warmest temperature ever in March, and the warmest it's been for so early in the year.
  • In International Falls, Minnesota, it hit 22°C (71°F) on March 16, their earliest 21°C + (70°F +) reading by 2 weeks. Previously, their earliest such reading was March 30, 1967. The town then soared to 25°C (77°F) the next day, 23°C above normal for the date. That was the hottest March day ever, beating the old record by 2°C (old record 23°C (73°F)). However, it also broke the old daily record by 12°C (22°F)!! Records for this town go back to 1895. The all-time March high record didn't stand for long. The next day (Mar 18), the town hit 26°C (79°F) rebreaking the record for warmest March temperature. They then hit 26°C (78°F) again the next day, making it the second warmest March high ever.
  • In Huron, South Dakota, it reached a balmy 31°C (88°F) on March 18; just over 24°C (44°F) warmer than the normal high for the date.
  • In Milwaukee, Wisconsin, it reached 26°C (78°F) on March 14, the warmest it's been for so early in the year going back to 1869 and 20°C above normal. Previous earliest was 25°C (77°F) on March 7 and 8, 2000. The city also broke their all-time highest March temperature with a high of 29°C (84°F) on March 21.
  • Madison, Wisconsin also reached 26°C (78°F) on March 14, the warmest it's been for so early in the year going back to 1869. Previous record was 25°C (77°F) on March 7, 2000. A high of 28°C (82°F) the next day was tied for the warmest March day ever (tied with Mar 29, 1986 and Mar 31, 1981). It is also the earliest 27°C + (80°F+) reading by 2 weeks. They then broke the all-time highest March high again on March 21 with a high of 28°C (83°F). Prior to 2012 there had only been 5 days in March with a high warmer than 27°C (80°F), but in March 2012 they had 5 such days. What had taken 143 years to accomplish was matched in 1 year.
  • Chicago broke the record for warmest it's been for so early in the year several times. The city saw 5 consecutive days above 27°C (80°F) from Mar 14 to 18. You have to go at least a month later to find such a streak of days. Prior to 2012, there had only been 10 days above 27°C (80°F) in Chicago in March since 1871. They had 8 such days in March 2012. The city hadn't had such a temperature in March in 22 years. 
  • Fort Wayne, Indiana reached  31°C (87°F) on March 21, the hottest temperature ever in March.
      Michigan was no stranger to this warm spell. The warmth raised Lake Michigan's water temperature to the warmest ever in March. The average temperature of the lake was more typical of June.

     For two consecutive days (March 20 and 21) the majority of the southern part of the state recorded their warmest temperatures ever recorded in March. A wide swath of the area was near 30°C on Mar 21. Flint's high of 30°C (86°F) was just 1°C (2°F) shy of the all-time warmest April day. On March 22, the temperature reached 32°C (90°F) in Lapeer, the hottest temperature ever recorded in Michigan in March. Ypsilanti and Dearborn both tied the previous record of 89°F. The previous record was 89°F in Lapeer in 1910. Here are some Michigan highlights:
  • Detroit had a string of 9 days with temperatures over 21°C (70°F) from the 14th to 22nd. This is the earliest ever to occur, one has to go back to April 16-24 1886 to find a streak that compares for so early in the year. 28°C (83°F) on both Mar 21 and 22 broke the all-time highest temperature in March. Old record was 82°F on March 30, 1986.
  • Houghton reached 24°C (76°F) on the 17th and 18th, the hottest temperature ever in March and 24°C (44°F) above normal.
  • Traverse City tied or broke their all-time highest March temperature 5 times.
  • Pellston's 29°C (85°F) reading on March 21 was a ridiculous 18°C (32°F) warmer than the previous record for the date and 27°C (48°F) above the normal high for the date. Prior to 2012, the town had never hit 27°C (80°F) in March. In 2012, they had 5 such days! The town also broke their all-time March high temperature 5-consecutive times.
Radar image of storm over Ann Arbor. From Jeff Master's blog
      Rare tornadoes made their appearance in Michigan in March 2012. On March 15, at least 3 tornadoes touched down in the state, making it the second largest tornado outbreak for so early in the year. The only larger one to be earlier in the year was on March 12, 1976 when 8 tornadoes touched down in the state. The strongest tornado on March 15 was an EF-3 that hit Dexter. That made it the earliest EF-3 or stronger tornado to hit the state, with records going back to 1950 (previous earliest was an F-3 tornado on March 20, 1976). Surprisingly, the ingredients weren't even that impressive for tornado-formation so the town of Dexter was extremely unlucky. The tornado had an 11.6 km path and a width of up to 700 m. 128 buildings were damaged or destroyed, but luckily there were no injuries or deaths. Prior to 2012, only 16 tornadoes have been recorded to have touched down in Michigan before March 16. The storms also dumped golf ball to baseball sized hail and 100-125 mm of rainfall on Ann Arbor causing lots of flooding.

     Surprisingly there were also tornadoes in South Dakota and Nebraska on the 18th. A strong EF-3 tornado hit North Platte, Nebraska injuring 4 people.

     Some communities in the US also broke or tied the record for the most consecutive days with record high temperatures including:
  • International Falls had 10 consecutive days where they broke or tied their record daily high. This beats the previous streak of 5 days between March 3 and 7, 2000.
  • Chicago had 9 consecutive record high days, tying the previous longest streak of 9 days between August 26 and September 3, 1953.
      The month featured, similar to Canada, much higher humidity than ever seen in March before for some parts of the US. According to the NWS in Minneapolis, humidity levels in Minnesota on March 18 and 19 were the highest ever experienced in the state for so early in the year.
Mar 21 Washington DC; by KEM to

     Lastly, the heat eventually did reach the Atlantic coast on the 20th and 21st. Here are some highlights from the area:
  • Burlington, Vermont's high of 27°C (80°F) on March 20 was the earliest such reading in history and 22°C above normal.
  • Concord, New Hampshire (27°C (81°F)) and Bangor, Maine (26°C (78°F)) also had their warmest temperatures for so early in the year on March 20. Caribou, Maine reached 23°C (73°F), the highest temperature ever in March and broke the old daily record by 13°C (23°F).
  • For the second consecutive day on March 21, many parts of the east had their warmest temperatures ever for so early in the year. This included Bangor, Maine (28°C (83°F)), Buffalo, New York (28°C (82°F)), Houlton, Maine (26°C (79°F)) and Caribou, Maine (24°C (75°F)).

This post contains information, photos or video from the following sources:

Jeff Master's WunderBlog
Rob's Blog
Environment Canada Weatheroffice and Top 10 weather events of 2012
Manitoba Agriculture
NOAA's National Climatic Data Center
Minnesota Climatology Working Group (University of Minnesota)
CBC Manitoba
The Weather Network
A Weather Moment blog
CTV Winnipeg
Agriculture and Agri-Food Canada

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