Rain and warmth prevail this week

Rain and warmth prevail this week:

A dose of welcome rain came this week or April 7-8. It was nearly ideal, as the rainfall rates closely matched the infiltration rates of most Minnesota soils, so that the soils absorbed nearly all of the moisture. Total rainfall was generally less than an inch in many northern areas, but elsewhere many observers reported over 1 inch of rainfall. A few places reported between 1.25 and 1.50 inches. Milaca (Mille Lacs County) in central Minnesota reported a new daily record rainfall of 1.23 inches on April 8th.

Despite these beneficial rains, the state drought status remained about the same this week, with about 44 percent of the state landscape in either Moderate or Severe Drought (most of the counties are in north-central, extreme northwest, or southeast sections of the state). With soils drying out and warming up, farmers are expected to begin planting crops full throttle sometime next week, unless interrupted by the rains coming on Tuesday.

Following the rains of April 7th and 8th the weather warmed significantly with daily high temperatures in the 60s and 70s F. Twenty-three central and southern Minnesota counties saw temperatures top 70°F on Wednesday. Temperatures are expected to dip a few degrees cooler than normal next week for a few days, but no major cold snap is foreseen.

One of the features of the weather that has been rather constant is the wind, with many climate stations reporting several days that brought gusts of 30 mph or greater. Some examples:

Moorhead, Duluth, Mankato, and Redwood Falls report 6 days
Rochester reports 8 days
MSP reports 9 days.

Some have reported peak gusts between 45 and 55 mph. It will likely continue to be a windy month, as the climate pattern transitions towards summary and more severe weather threats materialize.

Weekly Weather Potpourri:

This week’s AGU-EOS Bulletin features a study of the annual carbon budget of the continent of Africa. A research team of scientists found that “between 2010 and 2019, Africa transitioned from being a slight net carbon sink to a slight net carbon source.” This is due to a variety of factors, including increased population, expansion of agriculture lands and livestock grazing, as well as increased fossil fuel use.

For those who need to review Severe Weather protocols and procedures, you can visit the NOAA National Weather Service Forecast Office (Chanhassen) web site and find useful information there related to tornadoes, flash floods, lightning, hail, and extreme heat. It is worth a read.

This week the Weather Underground provided a synopsis of the weakening El Nino episode and the expected development of La Nina later this summer and fall. This will likely have little effect on the coming summer climate for Minnesota but may affect the fall and winter later this year.

MPR listener question:

I believe the soil needs to be 50 degrees or warmer to plant grass seed. What air temperatures do we need to sustain and for how long before the soil is warm enough for seed?

Answer:

Good timing for this question to be asked, although I would remind this listener that the best time to seed new grass is historically August and September, so that it can become established during the cool down of the fall season. But if you need to seed in the spring, according to our soil temperature network of observers around Minnesota, including the University of Minnesota Outreach Centers, the 2- inch and 4-inch soil temperature daily maxima just surpassed 50°F this week. University of Minnesota Extension recommends that a 50°F soil temperature threshold is suitable to plant fescue and Kentucky bluegrass varieties. Further, this level of daily soil temperature will easily be maintained as long as daily air temperatures exceed 60°F, which they are expected to do in the coming days. There will be a few days next week that daily temperatures will probably only reach the 50s F, but then the balance of the month should bring many days of 60°F temperatures. Grass seed can lay dormant for several days until temperatures warm up as well, so I think it is probably safe to start your spring grass seeding soon. Once planted, remember to water lightly, but frequently until the grass establishes.

Twin Cities Almanac for April 12th:

The average MSP high temperature for this date is 56 degrees F (plus or minus 12 degrees F standard deviation), while the average low is 36 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for April 12th:

MSP records for this date: highest daily maximum temperature of 88 degrees F in 2023; lowest daily maximum temperature of 28 degrees F in 1950; lowest daily minimum temperature of 12 degrees F in 1962; highest daily minimum temperature of 60 degrees F in 1941, and record precipitation of 0.67 inches in 1983. There was a record 6.6 inches of snowfall in 1920.

Average dew point for April 12th is 31°F; the maximum dew point on this date is 61°F in 1941; and the minimum dew point on this date is -1 degrees F in 1950.

All-time state records for April 12th:

The state record high temperature for this date is 90 degrees F at Canby (Yellow Medicine County) and Beardsley (Big Stone County) in 1931 and again at Mankato (Blue Earth County), Winona (Winona County), and Austin (Mower County) in 2023. The state record low temperature for this date is -7 degrees F at Warroad (Roseau County) in 1924. The state record precipitation for this date is 3.74 inches at Grand Meadow (Mower County) in 2001. The state snowfall record is 17.6 inches also at Artichoke Lake (Big Stone County) in 2019.

Past Weather:

April 12 of 1950 brought a taste of mid-winter weather with morning lows ranging from the single digits to the teens in most locations. Eight northern Minnesota counties reported subzero morning low temperatures, and the afternoon high temperature at Red Lake Falls only reached 19°F.

A complex winter storm brought lightning, thunder, rain, freezing rain, sleet, and heavy snow to much of Minnesota over April 10-12 of 2019. High winds knocked out power to about 100,000 customers, and heavy snows over 12 inches occurred in the north. Blizzard warnings were issued for some western parts of the state.

The only two times in state history that 85°F to 90°F temperatures have occurred on April 12th in Minnesota were in 1931 and 2023 (last year). In 1931 it was so warm on this date that many communities saw overnight low temperatures remain in the mid to upper 50s F. The same pattern prevailed last year.

Outlook:

Sunny, breezy, and very warm over the weekend, with a slight chance for showers in the north later on Saturday. Continued warmer than normal on Monday, but with increasing cloudiness and a chance for rain late in the day. Chance for showers and thunderstorms on Tuesday and Wednesday, then much cooler for Thursday and Friday.