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Leaves are Changing Color Early in the Twin Cities — how the Urban Heat Island effect is likely playing a role

Summer isn’t officially over in Minneapolis, yet this year’s Fall Color Finder is revealing tree leaves in the Twin Cities metro area are turning early. The report, which comes from the Minnesota Department of Natural Resources, cites a cool/wet spring/summer among the reasons.

“We used to always do apple picking in October, and now I feel like by October everything’s almost done,” said local resident Rachel Osband. “It just feels like everything is shifting forward a little bit.”

National Weather Service Meteorologist Brent Hewett says the recent drop in both temperature and rainfall is helping turn the leaves earlier: “When you have a lot of precipitation, the trees will stay green longer.”

Fall Color Finder map — dnr.state.mn.us/fall_colors

Hewett also has a theory as to why the Twin Cities is seeing the color change first while the rest of the state, for the time being at least, remains green:

“Since we do have that heat island during the summer, we are four-to-five-degrees warmer than the areas surrounding us,” Hewett explained. “Those cooler nights that we switched to about two weeks ago could have had a [bigger] impact on the plants causing them to prematurely change.”

There it is, a NWS meteorologist pointing out that towns and cities are warmer than the more rural, less built-up areas which surround them. I trust his words will convince all those pushing the “ever-warming-planet” narrative to bin the data accrued by weather stations located within concrete jungles, and instead use only that from satellites or rural ground stations — because those unadjusted data points, once plotted, paint a much less alarming picture.

As Roy Spencer Ph.D. recently wrote:

I am thoroughly convinced that the global thermometer record has exaggerated warming trends due to the Urban Heat Island (UHI) effect. When natural vegetation is replaced with buildings, pavement, and we add spurious heat sources like air conditioning units, cars, and ice cream trucks, the microclimate around thermometer sites changes.

Many of us experience this on a daily basis as we commute from more rural surroundings to our jobs in more urban settings.

For example, Miami International Airport recently set a new high temperature record of 98F for the month of May. The thermometer in question is at the west end of the south runway at the airport, at the center of the Miami-Ft. Lauderdale metroplex. Only 120 years ago, virtually no one lived in Miami; in 1896 it had a population of 300.

The UHI effect is so strong and pervasive that it is now included in the GFS weather forecast model, and in the case of Miami’s recent hot spell, we see the metroplex at midnight was nearly 10F warmer than the rural surroundings:

GFS surface temperature analysis for around midnight, 28 May 2019.

When a thermometer site has that kind of spurious warming at night, it’s going to produce spuriously warm temperatures during the day (and vice versa).

The most thorough analysis of the UHI effect on U.S. temperature was by Anthony Watts and co-authors, who analyzed the siting of hundreds of thermometers around the U.S. and showed that if only the best (most rural) sited thermometers are used, U.S. warming trends are roughly cut in half.

Curiously, they found that the official NOAA-adjusted temperature data (which uses both urban and rural data) has even more warming than if no UHI adjustments were made, leading many of us to conclude that the NOAA UHI adjustment procedure has made the rural data look like urban, rather than the other way around as it should be.

For more from Row Spencer Ph.D., click the article below:

The global thermometer record has clearly exaggerated the warming trend we’ve witnessed over the past few decades. Instead of blaming historically high solar output –which naturally heated the planet since the last mini-cooling of the 1970s– we’re instead hellbent on pushing callous, affordable-energy-sapping policies designed at limiting/redistributing wealth (probably…?).

The Urban Heat Island effect (UHI) is a well-known phenomenon but it’s one all-too-often swept under the carpet by those selling the warming agenda, and you have to ask yourself why that is?

Why is logic disregarded in climate debates?

Why are facts from the other-side labelled heresy?

For the forecast, and relying again on the facts, latest GFS runs show some anomalous Arctic cold will descend into the North-Central US over the coming days — temps are forecast to dip close to freezing overnight, which could mean the beginning of the end for the Twin Cities’ color show.


The cold times are returning, in line with historically low solar activity.


Grand Solar Minimum + Pole Shift

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