August trending warmer with highly variable rainfall

August trending warmer with highly variable rainfall:

Despite a somewhat cooler than normal start to the month and the fact that very few places have seen a 90°F day, most areas of the state are reporting mean monthly temperatures that are 1°F to 3°F above normal. Much of this is due to warmer than normal nights, as no frosts have been reported so far this month in northern areas of the state.

Most places are reporting below normal rainfall for the month so far, despite a few record-setting daily amounts from thunderstorms. Some of those climate stations reporting at least one day of record-setting rain are:
August 6th: 2.38” at Artichoke Lake (Big Stone County), 1.15” at Lamberton (Redwood County), and 1.02” at Luverne (Rock County)
August 9th: 1.91” at Floodwood (St Louis County) and 3.06” at Rochester Airport (Olmsted County)
August 10th: 1.63” at Lake City (Goodhue County) and 1.62” at Theilman (Wabasha County) 

There are currently no designated Drought Categories in Minnesota according to the U.S. Drought Monitor and soil moisture reserves for crops are mostly rated adequate to surplus.

Outlook models currently favor warmer than normal temperatures through August 22nd, then cooler than normal temperatures for the last week of the month. Rainfall tendencies for the balance of the month are mostly uncertain. There have been 8 days so far this month with Air Quality Alerts somewhere in the state because of smoke from wildfires in Canada. Air Quality Index Values have been over 150 on some days according to the MPCA. A more thorough description of the Air Quality Alerts this month can be found in Climate Journal section of the DNR-State Climatology Office web site. We may have yet more Air Quality Alerts before month’s end. 

The 29th Annual MPR State Fair Weather Quiz, Aug 25th at noon:

Question: We have names for various groups of animals, a pride of lions, a murder of crows, a gaggle of geese. But what do we call a group of meteorologists (a sham, an embarrassment, a tent of prophets).

Question: Historically, what is the windiest month of the year in Minnesota? (April)

Question: When was the latest Spring snowfall in Minnesota?
(June 4, 1935, 1.5 inches in Koochiching County)

Question: What's the difference between a meteorologist and a climatologist? (a meteorologist contends with the uncertainties today, tomorrow, and next week and predicts the weather,while a climatologist conveys the certainties of past climate conditions, and the probabilities of future climate conditions)

If these questions tweak your interest, be sure to catch the broadcast on August 25th, live from the Minnesota State Fair at noon. Cathy Wurzer and I will be doing the 29th Annual Minnesota Weather Quiz, with a live audience from the MPR stage, corner of Judson and Nelson in the fairgrounds. Many of the questions will come from our Friday Morning Edition chats over the past year. All those who participate from the live audience will be eligible for a prize. If you plan to visit the fair that day, come on over and have some fun with us.

Weekly Weather Potpourri:

The BBC reported this week on the glacial flooding of the Mendenhall River near Juneau, Alaska. A massive volume of runoff from the melting glacier caused the river to reach a record flood crest. Many residents were asked to evacuate. By late Wednesday and early Thursday (August 140 the river was receding. The Juneau area has recorded a large number of days with above normal temperatures so far this summer.

This week’s AGU-EOS Bulletin features an interesting article from North Carolina about how local scale monitoring and measuring systems related to flooding add great and varluable detail to studies of flood prone areas. Such local efforts can help in the assessment of flood potential as well as flood mitigation efforts.

The Weather Underground offered a preview of the fall weather outlook this week on their web site. The outlook for September through November favors above normal temperatures for Minnesota and below normal precipitation. 

MPR listener question:

Earlier in the spring we recall that you and Cathy were talking about what a windy year it was with a large number of days bringing wind gusts of 30 mph or greater to the Twin Cities. But in recent months this windy pattern seems to have died off. Can you verify this? 

Answer:

Yes, you are right. The first four months of the year (Jan-Apr) brought higher than average daily wind speeds, as well as 51 days with wind gusts over 30 mph. Since May 1st, the last three and a half months have brought average daily wind speeds generally less than normal and 38 days with wind gusts over 30 mph. Much of this may just be related to seasonal transition and the usual weaken low and high pressure systems of summer. But, I would not be surprised if we experienced more frequent high winds this fall season. 

Twin Cities Almanac for August 15th:

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 63 degrees F (plus or minus 6 degrees F standard deviation).

MSP Local Records for August 15th:

MSP records for this date: highest daily maximum temperature of 103 degrees F in 1936; lowest daily maximum temperature of 63 degrees F in 1897; lowest daily minimum temperature of 47 degrees F in 1960; highest daily minimum temperature of 76 degrees F in 1937; and record precipitation of 1.23 inches in 1966. There has not been any snowfall on this date.

Average dew point for August 15th is 59°F; the maximum dew point on this date is 75°F in 1987 and the minimum dew point on this date is 41 degrees F in 1976. 

All-time state records for August 15th:

The state record high temperature for this date is 108 degrees F at Beardsley (Big Stone County) in 1937. The state record low temperature for this date is 26 degrees F at Tower (St Louis County) in 1976. The state record precipitation for this date is 5.06 inches at Albert Lea (Freeborn County) in 1993. No snowfall has occurred on this date. 

Past Weather:

August 15 of 1937 brought a stressful Heat Wave as most of the state recorded afternoon temperatures in the 90s F. The temperature reached 100°F or greater in 8 southwestern counties.

A frosty morning greeted campers in northern Minnesota on August 15 of 1979. Eight northern counties reported frost with some temperatures in the upper 20s F. Afternoon high temperatures only reached the low 60s F in some areas.

Strong thunderstorms brought heavy rains and flash flooding to parts of southern Minnesota over August 14-15 of 1993. Many observers reported between 2 and 4 inches of rain. Portions of Lincoln, Freeborn, and Nicollet Counties received over 5 inches of rain with many farm fields flooded. 

Outlook:

Warmer than normal temperatures over the weekend and into Monday with a chance for showers and thunderstorms, especially in the southern half of the state. Cooler and drier for next Tuesday through Thursday.