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Freedman reports: "It's quite possible that this March heat wave will be considered an unprecedented event in the US historical record, which extends back to the late 19th century, based on the margin by which records are being exceeded, the wide geographic scope of the heat wave, the duration of the event and the time of year when it is occurring."

March may become the warmest month ever in the United States. (photo: News One)
March may become the warmest month ever in the United States. (photo: News One)

Historic March Heat Wave Sets New Milestones

By Andrew Freedman, Climate Central

21 March 12


he March heat wave continues to shatter longstanding records from the Upper Midwest to the Northeast, with more than 2,200 warm temperature records set during the month so far. It’s quite possible that this March heat wave will be considered an unprecedented event in the U.S. historical record, which extends back to the late 19th century, based on the margin by which records are being exceeded, the wide geographic scope of the heat wave, the duration of the event and the time of year when it is occurring.

"This will be a March event that we’ll look back on as one of the big March events of modern history," said Deke Arndt, who leads the climate monitoring branch of the National Climatic Data Center in Asheville, N.C.. "If it’s not unprecedented, it’s definitely very impressive."

According to the HAMweather website, 1,192 record daytime highs were set in the U.S. from March 12-18, along with 708 high minimum temperature records. This compares to just 66 coldest maximum temperature records, and only eight records for the coldest overnight low temperature. More records are likely to be set today through the end of this week, when a cooler airmass finally moves eastward (as it does so, it may spark rounds of severe weather). This data may be missing some records set after March 15, since there have been some problems obtaining data from the National Climatic Data Center's website.

According to the CapitalClimate blog, so far this month warm weather records have been outpacing cold records by a lopsided ratio of 19-to-1. Since January 1, the ratio has been closer to 14-to-1.

Temperature departures from average on during the period of March 1-18. Credit: NOAA/Southern Regional Climate Center.


In a long-term trend that has been found to be inconsistent with natural variability alone, daily record-high temperatures have recently been outpacing daily record-lows by an average of 2-to-1, and this imbalance is expected to grow as the climate continues to warm. According to a 2009 study, if the climate were not warming, this ratio would be expected to be even. Other studies have shown that climate change increases the odds of extreme heat events.

The exceptional heat is especially evident when viewed location by location.

Take, for example, the case of International Falls, Minn. Known as the "icebox" of the nation, the city is famous for its frigid temperatures and late onset of spring. Yet on March 18, the temperature at International Falls reached 79°F, setting a record for the month of March — beating the record of 77 degrees that was set just the day before! Before this heat wave, the warmest temperature during the month of March was 73°F, set in 1960.

In Chicago, the National Weather Service described the heat wave as "historic and unprecedented." Chicago has recorded five days in a row in which temperatures reached or exceeded 80°F, shattering the previous record of two consecutive days. When Chicago hit 82°F on March 16, it was the earliest it had ever been so warm there — breaking the old record by more than a week.

U.S. temperature records set between March 12-19. Credit:


Prior to this year, there had been just 10 March 80-degree days in Chicago, which means on average in March there’s an 80-degree high once every 14 years or so. Average temperatures for the month are on track to exceed the record for the warmest such month on record in the windy city. "It is likely that Chicago and Rockford will not only break… but shatter their current record warmest Marches," the Weather Service stated.

Milwaukee, Wisc. is also on track to set a record for the warmest March, beating the old record by 3.5°F. Even with cooler temperatures in the forecast for late this week, it’s likely that Milwaukee and Madison will both set records for the warmest three months of the year.

Just as it was a feature of the 2011 summer heat wave, this event has also seen many overnight low-temperature records being set. In fact, in parts of the Upper Midwest, some of the overnight lows threatened daytime-high temperature records.

In Madison, the temperature only got down to 60°F on Saturday — an all-time March record-high minimum temperature. The average temperature in Madison that day was 70°F, which is the warmest average temperature of any March day on record there.

Average temperature in Chicago during the warmest Marches on record, showing how much warmer this month has been so far. Credit: National Weather Service.

In Minneapolis, Sunday’s record high of 79°F was 37 degrees above average for the date. The Twin Cities recorded seven record highs and five record warm nighttime lows since March 10, according to meteorologist Paul Douglas.

Minneapolis set records for the earliest 80-degree temperature on record (March 17), and the maximum low temperature for the month (59 degrees on March 17).

"Hyperbole aside, I honestly can't remember anything like this, even back in 1988, when Minneapolis-St. Paul experienced 44 days above 90. I'm afraid we've run out of red dots,"  Douglas wrote on his Minneapolis Star-Tribune weather blog, referring to the red dots signifying warm temperature records on weather maps.

Daily high temperature records have also been set in the Northeast, where Boston reached 74°F on March 18, for example. The warm weather is expected to continue through most of the week in this region.

The weather pattern resulting in this heat wave is remarkably similar to ones that lead to prolonged periods of extreme heat during the summertime, with a huge dome of high pressure blocking the eastward movement of storms and cooler air off the Pacific. Some meteorologists are studying whether global warming is leading to more such "blocking patterns," and there are some indications that this may be the case, although there is considerable uncertainty surrounding this question. your social media marketing partner


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+27 # Kayjay 2012-03-21 15:06
Hey...will somebody, tell Rick Santorum that these blocking patterns are most likely caused by global warming. Not that he nor his corporate buddies care. But they might want to supply him with a case of ban roll-on.
+13 # soularddave 2012-03-21 23:02
Ban roll on won't help, as it is his philosophy that stinks to high heaven.
+7 # PhilO 2012-03-22 10:34
"Global warming" is a misleading term -- we should use "climate change". Although global temperatures will rise on average, there will be wide variations as how that will be reflected in any one region. The same will be true for precipitation. Incidentally, a good description for the shifting climate patterns and weather swings is "global weirding".

And, a general comment: "data" is plural of "datum". So, although "this data set" is fine, "this data" is incorrect (it should be "these data").

Can you tell that I'm science faculty... and I find it impossible to take off that "hat". :-}
+21 # Billy Bob 2012-03-21 22:20
This has been a freakish Winter for sure. Where I live Spring has sprung and I don't think that's ever happened this early in anyone's memory. It's about 1 1/2 months early. I've noticed that the non-native plants are all in full bloom and most of the native species living in the woods are only slightly ahead of schedule. The native species seem a little less easily fooled. Even more weirdly, I'm seeing birds and insects doing things I don't recall seeing this early in the year since I spent a few years in the South.

Do any of you get the feeling we're slipping into an exponential curve?
+5 # BobboMax 2012-03-21 22:31
And where I live, in Orygun, we're having snow, 7" in Salem, a record for the first day of spring.
+1 # Nominae 2012-03-22 10:24
Quoting BobboMax:
And where I live, in Orygun, we're having snow, 7" in Salem, a record for the first day of spring.

@ BobboMax

WoW ! After living in the Portland area for about sixteen years, the idea of 7" of snow in Salem sounds like a record for the absolute dead of winter, much less for the first day of spring !

Snow west of the Cascades, and lower than the timberline on Mt. Hood is almost a magical event anytime of year !
+2 # Smiley 2012-03-21 23:36
I don't know. Here in the north west we're getting a series of late winter snow storms like we haven't seen for several decades.
+1 # Billy Bob 2012-03-22 09:48
But by storms, you mean snow, which is precipitation. As the climate warms up, there will be MUCH MORE snowfall in some areas due to the added moisture in the air.
+3 # Nominae 2012-03-22 10:36
Quoting Billy Bob:
But by storms, you mean snow, which is precipitation. As the climate warms up, there will be MUCH MORE snowfall in some areas due to the added moisture in the air.

@ Billy Bob

Absolutely accurate. And, as to gradual warming in general, one need not believe any numbers if one is a dyed-in-the-woo l skeptic, or simply a "visual learner".

Simply take a plane ride over Glacier National Park, or over Alaska, and compare the photos (available from the Park Service) of the number of glaciers that were there just fifty years ago to all of the rocks, bushes and trees that you yourself can see there now.

As Billy Bob points out, the more the globe warms, the more the oceans evaporate into the atmosphere, and thus the more precipitation falls on land areas, both in the form of rain (with consequent flooding) and increased snowfall.

Thus "global warming" is an unfortunate and inherently misleading name for what scientists are now more accurately calling "climate change". And looking at climate the world over, it is hard to find an area where climate has not already dramatically "changed".

It's time for the oil company hacks to give up the howling about hoaxing and just look at the observable facts.
+3 # terrison 2012-03-22 00:02
It is snowing here in Portland. The author said this is remarkably similar to last year. I hope that doesn't mean that summer skips Portland again this year.
+6 # 666 2012-03-22 05:28
This is god's message to the climate change deniers...
+5 # dick 2012-03-22 05:56
The Mayan Calendar was off by a few months. The Greater Great Lakes Ice Fishing Tournament had to be called off. DQs are out of blizzards. Ski resorts have run fire hoses over hilltops & the adventurous are waterboarding downhill. 4th of July Fireworks have been moved up to April 1. The heat is making even the Good Humor man crabby. The White Sox are refusing to exert themselves earlier than usual. Romney's dog is on the roof of the campaign bus enjoying the cool breeze. Ain't global warming grand?
+2 # ericlipps 2012-03-22 08:24
Personally, I rather prefer this winter's weather in New York to what we had last winter, when we were buried in snow. On the other hand, if summer turns out to be similarly overheated, I won't be happy.
+2 # b_niles57 2012-03-22 09:54
It drives me crazy... I watch a lot of political shows like "Morning Joe" for example. For the past year, the weather person has said almost daily something along the lines of "the freakishly warm/cold weather continues in____ while freak tornadoes hit ______. NOT ONCE do the commentators reflect on whether this has anything to do with Global Warming!! Does "Drill Baby Drill" mean stick our head in the sand so deep you might find oil? What is wrong wit the media not covering this??
+1 # Billy Bob 2012-03-22 17:42
political fear.

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