Another round of heavy rain

Another round of heavy rain:

Last week a slow-moving Hurricane Florence brought 20-30 inches of rainfall to portions of North and South Carolina. So in this context, our Minnesota rainfall recently is relatively minor. But Wet is Wet. This week, a slow moving, almost stalled warm front boundary along the Iowa-Minnesota border brought consistent and sometimes heavy doses of rainfall to the southern counties of the state. Many climate stations reported from 3 to 6 inches of rainfall over the Monday-Thursday period (September 17-20), with some stations setting new daily rainfall records. Minneapolis Crystal Airport reported over 7.5 inches of rain this week. For the month of September so far many parts of southern Minnesota have seen 6-9 inches of rainfall. In southeastern Minnesota both Winona and Elgin have reported over 9 inches of rain.

Some of the more recent new daily rainfall records set on Wednesday included:
2.37 inches at Lake Wilson
2.22 inches at Marshall
2.07 inches at Luverne

Thursday brought a great deal of heavy rainfall to the Twin Cities Metro Area, dramatically slowing and disrupting the evening commute. Many parts of the Metro Area saw from 3 to 4 inches of rain, while over 30 Cooperative Weather Observer climate stations reported record-setting rainfall amounts on Thursday as well, including:

3.28 inches at MSP
3.11 inches at the University of Minnesota (St Paul Campus)
2.56 inches at Jordan
2.16 inches at Hastings
2.25 inches at Elk River

Elsewhere on Thursday there were reports of tornadoes from Martin, Waseca, Rice, and Goodhue Counties, as well as many reports of damaging winds, some of which ranged from 50 to 70 mph. As a result of these storms many schools were delayed on Friday, and storm damage was being assessed by National Weather Service personnel.

Many southern Minnesota climate stations have reported over 35 inches of precipitation so far this year and there are still over 3 months left in 2018. Hokah, Lakefield, Caledonia, Mabel, and Harmony have already totaled over 40 inches of precipitation for the year so far. The expected climate trend for the rest of September and early October across Minnesota is expected to be cooler and wetter than normal.

Weekly Weather Potpourri:

Storm Ali hit Ireland, Scotland, and Northern England this week with high seas, strong winds, and heavy rainfall. A woman was killed when her caravan was blown off a cliff and into the sea in the Republic of Ireland. The storm disrupted flights and caused widespread power outages. Following Ali, Storm Bronagh swept across parts of Wales and England this week with heavy rain and strong winds, up to 78 mph. Trees were uprooted and travel disrupted.

In the Western Pacific Ocean, Tropical Storm Trami formed this week. It is expected to strengthen into a Typhoon over the weekend, but will remain out to sea for several days and watched more closely next week.

Using a combination of AI and weather forecasting can help scientists to predict the movements of millions of birds and support their conservation goals, according to new Oxford University research. More information on this study can be found at the Science Daily web site.

MPR listener question:

How far away can you see lightning discharged at night?

Answer:

Most of the time lightning discharges can be seen from less than 25 miles away. Under exceptional circumstances when the skies around you are completely clear and there is little moonlight, some lightning discharges have been visible from 100 to 150 miles away according to the American Meteorological Society.

Twin Cities Almanac for September 21st:

The average MSP high temperature for this date is 70 degrees F (plus or minus 10 degrees F standard deviation), while the average low is 50 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for September 21st:

MSP records for this date include: highest daily maximum temperature of 94 degrees F in 1937; lowest daily maximum temperature of 46 degree F in 1995; lowest daily minimum temperature of 32 degrees F in 1974 (though it was just 30 degrees F on this date in 1866 before the National Weather Service existed); highest daily minimum temperature of 66 degrees F in 1908; record precipitation of 2.07 inches in 1986. No snowfall has occurred on this date.

Average dew point for September 21st is 46°F; the maximum dew point on this date is 69°F in 1970; and the minimum dew point on this date is 22°F in 1974.

All-time state records for September 21st:

The state record high temperature for this date is 101 degrees F at Wheaton (Traverse County) in 1937. The state record low temperature for this date is 13 degrees F at Alborn (St Louis County) in 1934. The state record precipitation for this date is 3.95 inches at Lamberton (Redwood County) in 1968. Record snowfall for this date is 0.5 inches at International Falls (Koochiching County) and Walker (Cass County) in 1974 and at Park Rapids (Hubbard County) in 1995.

Past Weather Features:

This Saturday, September 22 (8:54 pm our time) brings the autumnal equinox as the
midday sun passes over the equator on its migration into the southern latitudes
for our winter season. Days will begin to grow shorter more rapidly, as much as
20-25 minutes each week.

In addition, Monday, September 24th marks the 119th anniversary of the famous
Morristown tornado in Rice County. Shortly after 5:00 pm that date in 1900 an
EF-2 tornado (winds 113-157 mph) formed over Rice County and sped eight miles
across the landscape at an estimated 60 mph toward Morristown. There were many
eye-witnesses to this storm as it was seen from some distance away. Many people
sought shelter in Gattske's Saloon, being one of the few brick buildings in
town. But the building walls were collapsed by the mighty wind and killed seven
people. In addition, a hog farmer north of town lost many of his stock to the
storm. This remains the worst tornado in history to hit Rice County.

September 21, of 1937 was the hottest in state history with over 30 communities reporting afternoon temperatures of 90 degrees F or higher. Yet, in the far north, both Roseau and Warroad reported frost that morning.

Outlook:

Relatively quiet, and dry weather early in the weekend, but much cooler than normal with possible frosts in northern areas. Warmer on Sunday and Monday with a chance of showers later on Monday and again Wednesday of next week. Temperatures will remain below normal for this time of year.