Skip to main content

Follow up on disparity of climate signals

Follow up on the disparity of climate signals:

Earlier this week there was a long article in the Washington Post by Chris Mooney and others about the extreme measures of climate change that are already occurring across the USA. Northern Minnesota is one area where the change in temperature has been most extreme, and highlighted in this article.

I wanted to point out however that there is some disparity in the net change of temperature across the state that has occurred over the past 100 years or so. Listed below (from NOAA-climate data) is the net change in mean annual temperature and mean winter temperature (Dec-Feb) over the past 100 years in Minnesota’s northern most counties compared to one of the southernmost counties (Fillmore). Numbers are rounded to nearest whole digit:

County                         Net Change in Mean Annual Temp         Net Change in Winter Temp
Cook                                        +3.0F                                                              +5.0F
Lake                                         +4.0F                                                              +6.0F
St  Louis                                  +5.0F                                                               +7.0F
Koochiching                            +5.0F                                                               +8.0F
Lake of the Woods                   +5.0F                                                              +9.0F
Roseau                                     +6.0F                                                             +10.0F
Kittson                                     +6.0F                                                             +10.0F
Fillmore                                   +3.0F                                                               +5.0F

The winter season has obviously warmed much more than the annual temperature, and certainly the northern counties have warmed more dramatically than the southern counties. Much of this has to do with the presence or absence of winter snow cover, which has become more intermittent in recent decades than it was ages ago. Also note that Cook and Lake Counties which are heavily influenced by Lake Superior show somewhat less total change in temperature.


Below is a similar data presentation for major cities in Minnesota:

City                         Net Change in Mean Annual Temp         Net Change in Winter Temp
International Falls                  +7.0F                                                           +11.0F
Duluth                                    +5.0F                                                              +8.0F
Rochester                               +3.0F                                                              +5.0F
Twin Cities                            +5.0F                                                              +6.0F



Some disparity in the precipitation signal change (most of which is upward-increased annual precipitation) across Minnesota also exists over the past hundred years, but it presents a more complicated geographical pattern.

A State Fair Weather Perspective:

This year our State Fair runs from August 22 to September 2. Over this interval, the date showing the fewest measurable rainfalls historically (since 1891) is September 1st, on which it has rained only 26 percent of the time. August 30th shows the most rainfalls over the same period of time at 36 percent
frequency.

How often is a sweater or light jacket appropriate during the Fair, other than occasionally in the early morning when the gates open? Not very often. When I looked at the frequency of afternoon temperatures that didn't reach 65 degrees F, I found that this only occurs less than 7 percent of the time (againsince 1891).

All-time extremes during the State Fair (according to National Weather Service MSP records since 1891) include: a high of 104 degrees F on the afternoon of September 10, 1931; a morning low of 33 degrees F on September 13, 1890; a Heat Index of 107°F followed by a sticky night with a 75 degree dew point and overnight low of 80 degrees F on August 22, 1968; a chilly afternoon with overcast skies, strong northwesterly wind and a high of only 58 degrees F on August 31,1958. Wettest run of the State Fair saw 9.48 inches of rain in 1977, while the driest run saw just 0.08” in 1968

One of the most unsettling evenings during the State Fair was probably, August 30, 1977, when one of the heaviest thunderstorms to ever hit the Twin Cities occurred, dropping 7.28 inches at the
airport between 8:30 pm and midnight. This obviously caused severe flooding, but primarily in the south Metro area. The State Fair Grounds actually recorded a mere 4.5 inches of rain. Still I wonder how many fairgoers brought their poncho and umbrella and I wonder who was playing in the Grand Stand that night.

If you will be at the State Fair this year on August 23 come on over to the MPR booth (corner of Judson and Nelson) for a broadcast of TPT-Almanac program starting at 11am. I will be on, along with storyteller Kevin Kling, some expert musicians, and a panel of political scientists. Or if you are at the State Fair on August 30, come over to Dan Patch Park at 10am for broadcast of the annul MPR Minnesota Weather Quiz. I will be there with host Tom Crann.

Weekly Weather Potpourri:

NOAA scientists reported this week that July of 2019 was the warmest month on record for the globe dating back to 1880. It has also been the 2nd warmest January-July period. Many European countries suffered through another Heat Wave in July, while Alaska reported its warmest July in history, setting many new daily temperature records (119 daily maximum temperature records set or tied).

Also NOAA announced the publication and release of the State of the ClimateReport for 2018. The year 2018 was the 4th warmest year in the global record and saw enormous rates of Arctic ice loss, as well as loss of glacial ice. Oceanic heat trends were especially noted.

The Weather Underground web site reported earlier this week that a recent hailstorm in eastern Colorado produced a new record size hail stone for Colorado. It measured nearly 5 inches in diameter.

The AGU-EOS newsletter features an interesting article this week about the distinction between weather and climate as perceived through a cultural and historical lens. It makes for an interesting discussion.

MPR listener question:

Want you to know that you have a lot of Morning Edition listeners in western Minnesota. Please settle an argument for us. At a recent farmer meeting I got into a debate with another farmer who lives near Crookston in the Red River Valley. He claimed that they typically have more days with 90 degrees F temperatures than we do here in Marshall. I said I thought he was wrong. Who is correct?

Answer:

You are correct in your historical interpretation of the climate. The climate history of Marshall shows an average of 18 days each year that reach 90 degrees F or greater, while Crookston’s climate history shows only 10 such days. In 2019 Marshall has reported 14 such days so far, while Crookston has reported only 4 days.

Twin Cities Almanac for August 16th:

The average MSP high temperature for this date is 81 degrees F (plus or minus 7 degrees F standard deviation), while the average low is 62 degrees F (plus or minus 6 degrees F standard deviation).

MSP Local Records for August 16th:

MSP weather records for this date include: highest daily maximum temperature of 99 degrees F in 1988: lowest daily maximum temperature of 64 degrees F in 1943; lowest daily minimum temperature is 47 degrees F in 1962; highest daily minimum temperature of 77 degrees F in 1988; record precipitation of 1.97 inches in 2002; and there was a trace of snowfall on this date in 1966.

Average dew point for August 16th is 59 degrees F, with a maximum of 76 degrees F in 1908 and a minimum of 40 degrees F in 1924.

All-time state records for August 16th:

The state record high temperature for this date is 107 degrees F Madison (Lac Qui Parle County) in 1988. The state record low temperature for this date is 27 degrees F at Tower (St Louis County) in 1976. State record precipitation for this date is 4.21 inches at Willmar (Traverse County) in 1920; and record snowfall is 6.0 inches at Pigeon River Bridge (Cook County) in 1927.

Past Weather Features:

Strong thunderstorms brought heavy rains to portions of northeastern Minnesota over August 16-17, 1972. Many climate stations reported 2-4 inches of rain and there were a number of state and county roads closed for a time.

In the drought year of 1976, August 16 brought frost to portions of St Louis and Carlton Counties in northeastern Minnesota, as morning temperatures fell into the upper 20s and low 30s F.

August 16, 1988 was the warmest in state history with over 40 climate stations reporting an afternoon high temperature of 100 degrees F or greater. It was a warm night too, as the overnight low temperature at Marshall and Winona never fell below 83 degrees F.

Outlook:

Slightly cooler than normal temperatures heading into the weekend with increasing cloudiness by Saturday night and a chance for showers and thunderstorms continuing into early Sunday. Brighter by Sunday afternoon. Slight chance for showers on Monday night, then mostly dry with a bit cooler than normal temperature prevailing for most of next week.
Print Friendly and PDF

Comments

Anonymous said…
Performers at the Minnesota State Fair in 1977 included Captain & Tennille, Kansas, Bill Cosby, Ed McMahon, Andy Gibb, King Family