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March 2023 General Discussion


Hoosier
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On 3/28/2023 at 7:22 PM, TheClimateChanger said:

Urban heat island effect can explain some of the local warming. But how can Urban Heat Island effect explain that Minneapolis had a colder average high in March from 1873-1900 [1900 population: 202,000] than International Falls [a town of 5800 on the Canadian border known as the "icebox of the nation] or Duluth, Minnesota [a city of 86,000 on the shores of Lake Superior]? Or that the average March high in Chicago [1900 population: 1.7M], Detroit [1900 population: 286,000], and Cleveland [1900 population: 382,000] in the same period is less than Green Bay's [pop: 107,000] high in the most recent 13 years?

Just some historical notes here. Duluth wx obs were downtown near the lakeshore up until the late 40's, when it moved to the current location 5 miles inland. Would be similar to Chicago. Different climos at those locations. Bigger swings in max/min temps at current site. The lake tends to soften the daily diurnal range than current obs site. MSP was downtown until the 30's, when it moved to it's current site. Both arpt sites went ASOS in the 90's, which put the readings more out around the tarmacs. Current instrument islands were set up during the 2000's I believe. This story is probably very similar to all current major airport set ups. The current set ups are ideal for airport ops, not necessarily for climate monitoring. CRN sites were set up for that, but very short records. 15 yrs worth right now. When all said, and done we try to gleam the best we can from all records that are biased to some degree. And yes, we base our records off the data we have because, well, that's all we have.

I've seen the UHI effect in small towns. One record I looked at moved from in town for most of its life to 1 mile outside into farmland. Avg temp cooled. It is what it is, and, again we do are best to gleam climo from that. 

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23 hours ago, Brian D said:

Looks like 3-5" forecast for the North Shore tonight, then a possible BOOM come next Wed. Records looking like they are going to fall. :)

 

1-2" only for the area. Dry air did the pac-man. Now another couple inches coming up but with lots of wind starting tonight into tomorrow. Up to 50+ mph possible.

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On 3/29/2023 at 3:44 PM, michsnowfreak said:

I called it cherry picking because Im not a fan of comparing apples to oranges. if you are going to do one 30-year period do another 30-year period. The avg March temp for Detroit's first 30 years of data (1874-1903) and the most recent 30 years (1993-2022) show a difference of 4.5° (33.0 to 37.5). A more compatible comparison than the high temp (which has warmed more than the low temp) of the first 27 years to the high temp to the small sample size of 13 years including record march 2012 heat.

 

I have so many documents on stats you wouldnt believe it. As said, I know Detroits climate like the back of my hand. Like I said I have no issue with stats. March is by far the month that has warmed the most since records began, and spring by far the season that has warmed the most. Locally, it is not even a contest. Spring/Summer have warmed much more than Winter/Autumn.  In fact, over the past 100 years, there has been NO warming in January or October. But March continues to be the most. 


It even shows in the snow record, as the 2000s-2010s were easily the snowiest 20-year stretch on record for Detroit, but March had the least amt of top 20 snowiest years since 2000.

Jan- 3 of top 20 since 2000

Feb- 10 of top 20 since 2000

Mar- 2 of top 20 since 2000, and 1 is this year

Apr- 5 of top 20 since 2000

Nov- 3 of top 20 since 2000

Dec- 6 of top 20 since 2000

Well, even the temperatures observed by the U.S. Army Signal Corps back in the 1850s and 1860s seem crazy by today's standards. The average annual mean temperature was observed to be 46F at Buffalo, 47F at Detroit, 47F at Erie, 48F at Chicago, 50F at Pittsburgh, and 52F at Philadelphia. What was considered to be the mean temperature in that era would be top ten coldest on record since 1870s at Detroit and Erie, top twenty coldest at Chicago and Buffalo, and  top five coldest at Philadelphia.

Not as bad at Pittsburgh, but still a couple degrees cooler than the modern mean observed at Pittsburgh Airport [51.8F], which is at 1200' elevation; whereas the 50F mean determined by the Signal Corps was observed at Fort Pitt, which is identified as 704' in elevation [or a full 500' lower in elevation]. For context, the average lapse rate is something on the order of 3.5-5.4F/1000 feet, and the calculated difference between the city office and the airport was 2.6F during the period of overlap [1952-1979], which would imply the city mean would be 54.4F today - or in line with the changes at the other sites.

image.thumb.png.06229bc0a677faeb08dad5c30033d87c.png

 

 

 

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Garden variety T-storm here on the southside of Chicago right now. Heavy rain and a few flashes of lightning.

 

looking forward to today, actually appreciate the uncertainty far more with severe storms than I do with winter storms 

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