Strong Thunderstorms on September 2nd

Strong Thunderstorms on September 2nd:

On Labor Day a strong line of thunderstorms moved southeast across west-central Minnesota and into west-central Wisconsin during the evening. There were two tornado reports, one near Howard Lake in Wright County and another near Mound in Hennepin County. Both were rated EF-1 (max winds near 90 mph), with the Wright County storm on the ground for 1.1 miles and the Hennepin County storm on the ground for 3.5 miles. There was some structural damage to farm buildings and some tree damage as well. Seventeen other Minnesota Counties reported some strong thunderstorm winds with gusts over 50 mph and some tree damage as well. Some climate stations reported 1-2 inches of rainfall. Sandstone in Pine County reported over 2 inches. In addition, Pope, Stearns, Kandiyohi, Le Sueur and Rice Counties reported large hail. More detail is available from the National WeatherService.

Favorable Weather Leads to State Fair Attendance Record:

The 12-day run of the Minnesota State Fair produced a new attendance record this year with 2,126,551 people attending. There were new daily attendance records established on six days, with the lowest attendance falling on Monday, August 26 at 96,716, the day with the most rain (just under an inch).

Overall the weather was comfortable with an average daily high temperature of 75°F and an average daily low temperature of 59°F. The highest temperature during the Fair was 77°F on Friday August 23, and this marked the coolest maximum temperature during the State Fair since 1935. Only one day was consistently disrupted by rain (Monday August 26), while most days saw partly cloudy skies and comfortable dew points in the 40s and 50s F. Some days were breezy but that did not discourage the crowds.

Wet Year Continues in Places:

Although the amount of rainfall has slowed down a bit recently we still see that portions of Dodge, Olmsted, Steele, and Hennepin Counties have reported over 38 inches of precipitation for the year thus far. The extreme range in departure from normal is represented by Rochester (Olmsted County) which is over 14 inches above normal for the year so far and Orr (St Louis County) which is nearly 6 inches short of normal for the year so far.

Weekly Weather Potpourri:

The Science Education Resource Center (SERC) offers a timely online lesson plan this week to look at the effect of warming ocean temperatures on hurricanes. For school science teachers it is worth taking a look.

After devastating the Bahamas earlier in the week and bringing rains to portions of Florida, Hurricane Dorian continued to pummel SC and NC with heavy rains and strong winds on Thursday and Friday. Many areas had reported receiving 5-8 inches of rainfall. Wilmington, NC reported over 9 inches of rain. Fortunately the storm was weakening and turning more to the northeast and out to sea.

Elsewhere in the Western Pacific Ocean Tropical Storm Faxai was expected to strengthen into a typhoon as it heads for the east coast of Japan this weekend. It will likely bring winds over 80 mph, heavy rains on sea waves over 30 feet to areas around Kyoto.

Along the western edge of India, areas around Mumbai reported 16-20 inches of rainfall over 3 days this week. This caused widespread flooding and evacuation of some areas of the cities. Rainfall was expected to continue into the weekend there.

MPR listener question:

If I'm in my backyard and there's a thunderstorm approaching, can I get hailed on before rained on?

Answer:

Yes, this can happen. Though most hail falls from thunderstorm cells as they pass over the landscape below, some hail can be blown out of the cell by strong horizontal winds aloft and arrive as a swath of hail on the landscape where rain has not yet fallen. These are often smaller hail stones, while the largest ones are found more often under the core of the thunderstorm or supercell complex.

Twin Cities Almanac for September 6th:

The average MSP high temperature for this date is 76 degrees F (plus or minus 10 degrees F standard deviation), while the average low is 57 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for September 6th:

MSP weather records for this date include: highest daily maximum temperature of 98 degrees F in 1922: lowest daily maximum temperature of 55 degrees F in 1911; lowest daily minimum temperature is 35 degrees F in 1885; highest daily minimum temperature of 75 degrees F in 1913; record precipitation of 1.61 inches in 1881; and no snow has fallen on this date.

Average dew point for September 6ths 55 degrees F, with a maximum of 75 degrees F in 1970 and a minimum of 33 degrees F in 1956.

All-time state records for September 6th:

The state record high temperature for this date is 105 degrees F at New Ulm (Brown County) in 1922. The state record low temperature for this date is 23 degrees F at Park Rapids (Hubbard County) in 1885 and at Two Harbors (Lake County) in 2011. State record precipitation for this date is 8.44 inches at Cloquet (Carlton County) in 1990; and no snowfall has occurred on this date.

Past Weather Features:

September 6, 1922 was the warmest in state history with over 40 climate stations reporting afternoon highs of 90 degrees F or higher. Ten western communities hit 100 degrees F or greater. The nighttime minimum temperature at Winona fell no lower than 80 degrees F, a good night to sleep outside.

Strong thunderstorms brought heavy rains to northeastern Minnesota on September 6, 1990. Many climate stations reported 2 to 6 inches of rainfall, while Cloquet reported an all-time one-day rainfall record of 8.44 inches.

Many northern Minnesota communities reported frost on September 6, 2011. Many daytime high temperatures only made it into the mid50s to low 60s F.

Outlook:

Cloudy skies with cooler than normal temperatures for the upcoming Saturday through Monday period. There will be daily chances for showers and thunderstorms. Then warming up to near normal temperatures by next Tuesday through Thursday, but still chances for showers.