Cold Start to April, With Some Record Snows

Cold Start to April With Some Record Snows:

Through the first six days of the month temperatures are averaging 15 to 20 degrees F colder than normal around the state. At least 17 climate stations have reported subzero overnight temperatures so far this month, including -8 degrees F at Warren (Marshall County). Most other climate stations have been reporting high temperatures in the 20s and 30s with lows in the single digits and teen values.

Some new daily minimum temperature records have been set around the state so far. A sample listing includes:

3°F at Floodwood on April 1
19°F at Minnesota City on April 2
13°F at Hastings on April 3
-3°F at Park Rapids on April 4
0°F at Morris on April 4
2°F at Pipestone and Marshall on April 4
3°F at Milan and Madison on April 4
5°F at Austin and Albert Lea on April 4
-6°F at Embarrass and Long Prairie on April 5
-5°F at Kabetogama on April 5
-3°F at Redwood Falls on April 5
1°F at Browns Valley on April 5
3°F at Montevideo on April 5

Many other low minimum temperature and cold maximum temperature records were set within the Minnesota climate network as well.

In addition, the double dose of snow storms over April 2-4 this week brought some new record daily amounts. Some of those new record amounts for April 3 included:

8.1” at Chanhassen
7.5” at MSP airport
5.5” at Artichoke Lake
5.0” at Amboy
4.0” at Rosemount, Winnebago, and Owatonna

Records for April 4 included:

8.6” at Hokah
7.5” at Bricelyn
7.0” at La Crescent
6.5” at Spring Valley
6.2” at Caledonia
6.0” at Minnesota City and Lake City
5.6” at Preston

The outlook for April continues to favor cooler than normal temperatures and mixtures of rain and snow for much of the month. So patience will be required by gardeners and farmers for this spring.

Weekly Weather Potpourri:

Tropical Cyclone Iris was moving northwest off the coast of northeastern Australia this week, but it did not pose a threat to coastal communities there. It was expected to dissipate by early next week.

Though the weather for the first two days of the Masters Golf Championship in August, GA appears to be very favorable, Saturday will likely bring some gusty and variable winds, along with a chance for thunderstorms. So playing the third round in foul weather seems somewhat likely.

There is an interesting article this week in EOS about the climate proxy data used by scientists to interpret past climate fluctuations and patterns. Among the sources used are bat poop and whale earwax.

MPR listener question:

Why does the snow melt when the air temperature is below freezing (32 degrees F)? This is from our “Morning Edition” producer Jim Bickal.

Answer:

Especially this time of year with a higher sun elevation angle and longer days, the sun’s energy is more powerful than earlier months. The full spectrum radiation from the sun can be absorbed by the snow, thus causing the snow to melt, even when the air temperature stays below freezing. In addition the surfaces that surround the snow, pavement, buildings, roof shingles, trees, etc will more readily absorb the radiation from the sun, and emit long wave radiation (heat) in all directions, and this too can cause the snow to melt. In addition very dry air can cause the snow to diminish by a process called sublimation, where the snow immediately changes to water vapor without melting. All these processes are in play this April.

Twin Cities Almanac for April 6th:

The average MSP high temperature for this date is 53 degrees F (plus or minus 12 degrees F standard deviation), while the average low is 33 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for April 6th:

MSP records for this date include: highest daily maximum temperature of 86 degrees F in 1991; lowest daily maximum temperature of 26 degree F in 1939; lowest daily minimum temperature of 10 degrees F in 1979; highest daily minimum temperature of 54 degrees F in 1921; record precipitation of 2.58 inches in 2006. Record snowfall on this date is 6.0 inches in 1962.

Average dew point for April 6th is 28°F; the maximum dew point on this date is 59°F in 1921; and the minimum dew point on this date is -3°F in 1979.

All-time state records for April 6th:

The all-time state high temperature for today's date is 90 degrees F at Madison (Lac Qui Parle County) and Winona in 1991; the all-time state low for today's date is -22 degrees F at Karlstad (Kittson County) in 1979. The all-time state record precipitation for this date is 2.67 inches at Dawson (Lac Qui Parle County) in 1997. Record snowfall is 18.0 inches at Fosston (Polk County) in 1947.

Past Weather Features:

A late season winter storm brought heavy snowfall to many parts of northern Minnesota over April 4-6, 1947. Observers from Willmar north to Fosston reported 7 to 18 inches of snowfall, setting records for the first week of April.

The coldest April 6th in state history was in 1979 when over 50 Minnesota climate stations reported subzero morning low temperatures. In northwestern portions of the state the daily high temperature never rose above 10°F at Hawley or Fergus Falls.

By far the warmest April 6th in state history was in 1991 when over 60 climate stations reported an afternoon high temperature of 80 degrees F or higher, topped by 90 degrees F at both Madison and Winona. In fact the temperature never dipped below 65 degrees F at Winona that day.

During the famous 1997 flood-fight along the Red River of the North between North Dakota and Minnesota, a blizzard and heavy snow storm occurred over April 5-7 hampering sandbag operations and the building of temporary dykes. Visibility was near zero at times and snowfall amounts were near record-setting, ranging from 5 to 14 inches. The flood fight continued for the rest of the month.

Outlook:

Partly cloudy with cooler than normal temperatures over the weekend. Increasing clouds on Sunday with a chance for snow later in the day. A chance for rain and snow mix early on Monday of next week, then dry until late Wednesday. Temperatures will continue the trend of being cooler than normal. Chance for rain/snow mix again by Thursday.