Welcome Rain

Welcome Rain:

After a spell of very windy and dry weather last week that produced several days of Red Flag Warnings and resulted in some significant wildfires in northeastern areas of Minnesota, some much needed widespread rains arrived over this past week. Over 350 observers reported from 1 to 2 inches of rainfall over the period from May 15 to May 21. Some areas in south-central and east-central Minnesota reported between 2 and 4 inches of rain. Mapleton in Blue Earth County reported over 4 inches, while Winnebago in Faribault County reported over 3.80 inches. More details on the rain distribution and impact can be found at the Minnesota State Climatology Office web site.

The rain was also welcomed by crop producers around the state, as nearly all the corn and soybeans have been planted and will benefit from the added soil moisture, and alfalfa producers were looking for a rain induced burst of growth before taking their first cuttings this year. With the rain and warming temperatures more vigorous crop growth will be seen around the state in the coming week, when farmers will give more attention to weed control, most likely using post emergence herbicides or rotary hoeing to take care of weeds early in their growth cycle.

Recent weather outlook models favor warmer than normal temperatures for the balance of May and first part of June. They also suggest that rainfall is uncertain whether it will be more or less than normal. The stored soil moisture from the wetter than normal April will likely help most crop stands develop normally as we head into June, which is on average the wettest month of the year.

Weekly Weather Potpourri:

This week’s AGU-EOS Bulletin features an article about flood forecasting and how even with machine learning approaches and use of AI models, experienced forecasters bring needed skill sets to better predictions. Among other assets that experienced forecasters use is their ability to recognize poor input data that lead to modeling errors.

The Weather Channel web site reported on the record-setting Heat Wave over May 17-20 that occurred over the Northeast. Over 70 new daily maximum temperature records were set from northern Georgia all the way up to Maine. Philadelphia reached 98°F on May 19th marking the warmest May temperature ever. Newark, NJ reached 99°F and Boston, MA reached 96°F. Fortunately dew points remained in the 60s F, so the Heat Index Values did not soar above 100°F.

A recent article from EGU Weather and Climate Dynamics documents changes in precipitation over Macquarie Island in the Southern Ocean. The increases observed in precipitation are likely related to changing dynamics in the Southern Ocean which affect the latent energy available over storm tracks that produce most of the rainfall. Researchers encourage more study of the Southern Ocean and how its temperature and circulation may be altered by climate change.

MPR listener question:

We heard your remarks last week about how windy it has been this May. Can you offer some historical comparison?

Answer:

I can offer an example. MSP has reported peak hourly wind gusts since 1997. According to the historical data, May of this year has produced over 40 hours with peak wind gusts of 30 mph or greater. The 30-year average for May is about 31 hours. With 10 days to go in the month, there will likely be a few more hours to add to this total. In this context, it is likely that this May will rank about 5th or 6th most hours with wind gusts of 30 mph or greater over the last 30 years. The highest frequency of such wind gusts during May was back in 2022 when measurements show 90 hours with wind gusts of 30 mph or greater.

Twin Cities Almanac for May 22nd:

The average MSP high temperature for this date is 71 degrees F (plus or minus 11 degrees F standard deviation), while the average low is.52 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for May 22nd:

MSP records for this date: highest daily maximum temperature of 99 degrees F in 1925; lowest daily maximum temperature of 42 degrees F in 1882; lowest daily minimum temperature of 32 degrees F in 1917; highest daily minimum temperature of 74 degrees F in 1921, and record precipitation of 1.20 inches in 1936. No snowfall has occurred on this date.

Average dew point for May 22nd is 46°F; the maximum dew point on this date is 73°F in 1991 and the minimum dew point on this date is 19 degrees F in 1924.

All-time statewide records for May 22nd:

The state record high temperature for this date is.10 degrees F at Fairmont (Martin County), New Ulm (Brown County), and Tracy (Lyon County) in 1925. The state record low temperature for this date is 15 degrees F at Remer (Cass County) in 1986. The statewide record for precipitation on this date is 5.84 inches at Collegeville (Stearns County) in 1962. A record 8.0 inches of snow fell at Mountain Iron (St Louis County) on this date in 1907.

Past Weather:

July-like temperatures prevailed across Minnesota on May 22 of 1921. Many areas recorded afternoon temperatures in the 90s, as far north as Red Lake Falls. Some thunderstorms developed in the late afternoon heat and brought 1 to 2 inch rains in northwestern counties. Grand Marais Harbor on Lake Superior only reached a high of 50°F.

On May 22 of 1924 a hard freeze occurred over portions of western and northern Minnesota with morning temperatures ranging from the low to mid 20s F. Frosts occurred as far south as Canby. The afternoon temperature at Itasca State Park only reached 43°F.

On May 22 of 2001, climate observers at Grand Rapids, Big Falls, Waskish, Roseau, Tower, Babbit, Ely, and Isabella reported snowfall. The 2.5 inches measure at Big Falls was a statewide record for the date. Elsewhere, many climate observers reported 1 to 2 inches of cold rain.

Outlook:

Warming up to near normal temperatures over the weekend and into Memorial Day. A chance for showers in the north early on Saturday. By late Monday there will be a chance for rain in far southern counties. Much warmer temperatures for Tuesday through Friday of next week with readings well above normal. Another chance for showers by late Wednesday and into Thursday.