It's another warm winter in Minnesota and, you might say, if it's gotten so much warmer here, it's likely to have gotten a lot warmer everywhere else too. Our Twin Cities climate now resembles what DesMoines or Chicago were like ten years ago. By the same token, DesMoines likely resembles what St. Louis was like and Chicago like Louisville, etc. As I have said before, you might debate what is causing climate change, but you can't debate what has happened over the last ten years.
I follow the weather blog of my friend Paul Douglas, who is the chief meteorologist both of the Minneapolis Star Tribune and WeatherNation TV, a new, national 24/7 weather channel with studios in Denver and Minneapolis (which Paul founded). I was looking at the long-range temperature models on his daily blog and noticed that the probability of deep cold has diminished substantially for the rest of January in the Twin Cities. I mentioned that to Paul in an e-mail and noted that if we don't have temperatures of -10(f) or colder in the next couple of weeks, we are going to have our first USDA Zone 6 winter in history in the Twin Cities. This conforms with the statistically valid trend line of my 50-year Extreme Minimum Temperature (EMT) graph that I prepared using Minnesota Climatology/NOAA data. That graph (below) indicates that, not only have we moved into USDA Zone 5, but that we are headed for USDA Zone 6 in several more years (or maybe sooner).
Paul wrote about our e-mail conversation in today's Star-Tribune and in his blog. Here is what he had to say, as well as the address of his blog:
"I asked Pete Boulay, at the Minnesota Climatology Working Group, for his perspective and here is an excerpt of what he wrote:
"We usually prefer a 7-year moving average to look at recent trends. Here is a graph of seasonal HDD (heating degree data) values for the Twin Cities from 1891-92 to 2011-12 (the last time we have a complete season). Yes, I believe we have saved a lot of money (heating our homes and businesses) in recent winters."
"Tracking The Trends. The graph above, from the Minnesota State Climatology Office and the MN DNR, shows heating degree days since 1891-92. To calculate the heating degree data for any given data determine the average temperature (high and low) and subtract from 65. So an average of 10 degrees F. would equate to 55 heating degree days, and then add them up over time. The black solid line above shows a smoothed trend line, showing a drop in HDD since the early 70s as Minnesota winters have warmed over time. It's hardly breaking news: our winters are trending milder over time."
"Coldest Nighttime Lows at MSP Since 1963. Here is another interesting way to look at the data, a graph showing the coldest nighttime low (for every winter) going back nearly 60 years. The black line is the trend line over time, showing the same gradual warming trend. It's not getting as cold, for as long, as it did back in the 60s and 70s. Again, if you've been paying attention, this hardly comes as breaking news. Thanks to Jack Falker, an accomplished rose grower from Edina, for passing this along. Jack has compelling evidence that the Twin Cities metro is already in USDA Zone #5 (warming from Zone #4 in recent years). He suspects we may be close to entering Climate Zone #6 before long. Jack Falker writes:
Twin Cities in USDA Zone 5
"With our very warm 2012, and much warmer than normal winter-to-date in 2013, it becomes more and more obvious to me as a rose gardener that the Twin Cities have moved firmly into USDA Zone 5, where the extreme minimum temperature (EMT) is expected to be between -10 and -20 degrees, rather than our previous EMT expectation in Zone 4 of -20 to -30 degrees.
Notice how the upward slope of the 50 year graph I developed using Minnesota Climatology (NOAA) statistics, takes us right out of USDA Zone 4 into Zone 5. And following that upward slope, it looks like we could be headed higher yet toward Zone 6 (EMT -0 to -10). Last fall and winter-to-date in 2013 certainly bear that out. Our EMT thus far in January was -5 on January 1st and, looking at the models in your weather blog on Thursday, January 10th, it looks like we might not get much colder than that, which would be our first zone 6 winter, with the highest EMT on my 50 year graph and perhaps in history."
So, we shall see what the next couple of weeks bring, but the models indicate that our low temperature for 2013 will probably be warmer than -10 (i.e. Zone 6).
Coffee Grounds in my Mulch Pile
It's 40 degrees here today and everything, including my big shredded oak leaf mulch pile, is thawing out (this is why you cover your roses so they don't thaw). So I went to my local Starbucks, ordered a cup of decaf, and asked for all their coffee grounds (my kind of stick-up). I left with a great decaf Pike Place pour-over and three big bags of fresh grounds totaling about 120 pounds. I brought them home and immediately worked them into my mulch pile, where they are beginning their good work, as I write.
I will elaborate on this in a future blog, but what's important to realize until then is that the pH of Starbucks grounds is 6.2, which is right in the range we’re shooting for in growing roses. And that’s not all. They’re also a slow-release fertilizer with 2.28% nitrogen, .06% phosphorus and .6% potassium.
So, that said, now is a perfect time to get on over to your local coffee shop and get some great coffee-ground "green manure" for your winter mulch pile!
January 11, 2013