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Wet Start to May for Some

Wet Start to May for Some

Strong thunderstorms crossed the state overnight from May 1st to 2nd producing numerous reports of heavy rainfall, hail, strong winds, and even tornadoes. NOAA Storm Prediction Center received reports of brief tornado touchdowns in Pope and Stearns Counties between 9:00 and 10:00 pm Tuesday night. No serious damage reports from tornadoes were evident. There were numerous reports of strong winds and large hail (1-2 inches in diameter) from many western and southern counties. Sauk Rapids reported wind gusts to 64 mph while Wabasha reported winds up to 74 mph. Many observers reported rainfall from 0.75 inches to 1.50 inches, and some reported new record rainfall amounts for May 2nd. Among the new record amounts were 2.20 inches at St Francis; 2.10 inches at Elk River; 2.05 inches at Rush City, Slayton, and Windom; and 1.63 inches at Rice. The campus of St Cloud State University reported a rainfall of 3.11 inches.

May 3rd brought more heavy thunderstorms, strong winds and hail to southern Minnesota counties, especially the southeast. Winds up to 70 mph were reported near Harmony. Lake City reported a record rainfall for May3rd with 1.68 inches, while Zumbrota received a record 2.21 inches and Wabasha received 2.21 inches as well (not a record there). An observer near Zumbrota reported nearly 4 inches of rainfall with a record dewpoint of 67 degrees F. The Cannon River and north branch of the Zumbro River rose dramatically flash flooding in some places. Many observers are well on their way to reporting above normal rainfall for the month of May. Over the first three days of the month Rice reports 3.30 inches, Zumbrota 2.89 inches, Wabasha 3.15 inches, Milaca 2.48 inches, and Elk River with 2.47 inches.


Announcement of the Minnehaha Creek Watershed Stormwater Adaptation Study Forum, May 15th

Speaking of heavy rainfalls, the Minnehaha Creek Watershed District in the Twin Cities Metro Area is hosting a Forum on Tuesday, May 15th from 6:30 pm to 8:45 pm at the St Louis Park Recreation Center. They will be presenting and discussing objectives associated with their stormwater adaptation study. This is in response to changing precipitation patterns across the area which have not only brought greater annual precipitation, but more frequent episodes of intense,thunderstorm produced extreme rainfall events which pose a serious flash flood threat. I will be presenting a climate perspective and many others will offer perspectives on vulnerability of infrastructure, risk management and community response, including options for storm water management and associated costs. Those interested in attending this meeting can contact Leslie Yetka with the Minnehaha Watershed District (email: or phone 952-641-4524. If you want to learn more, go here.

Wrap-up on April Precipitation

According to DNR-State Climatologist Greg Spoden in his HydroClim Newsletter, "April 2012 precipitation totals were above normal in portions of west central, north central, and northeast Minnesota. Elsewhere, monthly precipitation totals were near the historical average. It was only the second month since July 2011 where monthly precipitation totals were near to above average." Some of the larger precipitation totals for April included: 4.91 inches at Pipestone (7th wettest April in history); 4.67 inches at Sherburn; 4.66 inches at Caledonia; 4.22 inches at Grand Rapids; 4.13 inches at Spring Grove and Wadena; 4.11 inches at Browns Valley; 4.10 inches at Albert Lea and Wheaton; and 4.09 inches at Grand Meadow. These amounts and others helped bring some relief from prolonged dryness dating back to last summer. Graphics and maps related to April's climate signature can be found here.

New web resource for recent precipitation reports

Greg Spoden from the State Climatology Office has designed a new web page for viewing maps, graphics and text associated with recent rainfall events in Minnesota. He calls it the "Puddle Page." You can also find access there to stream flow levels on Minnesota watersheds (provided by USGS). To view the page go here.

Weekly Weather Potpourri

Stan Changnon of the University of Illinois and Illinois Water Survey passed away this week. He was one of the most respected and prolific atmospheric and climate scientists of his generation. He was perhaps the first to study urban climates (St Louis and Chicago) in detail, and to work with the insurance industry in assessing weather and climate risks. Stan was our first Kuehnast Endowment presenter at the University of Minnesota giving a lecture titled "Is Climate Still Important" back in 1993. His son David is a professor of climatology at Northern Illinois University. Stan will be greatly missed by all in the atmospheric and climate science community.

The United Kingdom Meteorological Office reported this week that April was the wettest ever across that country dating back to 1910. Many observers reported over double the normal rainfall for the month, with several reports of 5 inches or more. Liscombe in Somerset reported over 10.5 inches for April.

A recent study in the journal Nature Climate Change suggests that large wind turbines in west Texas used for power generation are causing a night-time warming of temperatures. Scientists from SUNY who published the study suggest that turbulence in the wake of the large turbine blades pulls down warmer air aloft towards the surface, disrupting development of an overnight inversion and keeping warm air near the surface of the ground. This is one of the first studies to document microclimatic effects of wind turbines in the natural environment. You can read more about it here.

For horse racing fans a climatology of the Kentucky Derby (all 137 years) has been made available by the National Weather Service Forecast Office in Louisville, KY. The 138th running of this race is scheduled for this Saturday (May 5th), and the forecast calls for temperatures in the mid 80s F with a chance for thunderstorms. The coldest temperature was 47 degrees F in 1957, and the warmest 94 degrees F in 1959. You can read more here.

MPR listener question

Any correlation between the full moon and overnight frost in Minnesota?

Answer: We have had this question before, but the answer is the same. There are no studies that document a significant correlation of the full moon dates with spring and fall frost dates in Minnesota. It does occasionally happen, but certainly with no consistency. This correlation has been examined by many from several geographic regions of the world and I honestly don't know if it is significant anywhere on Earth.

Twin Cities Almanac for May 4th

The average MSP high temperature for this date is 66 degrees F (plus or minus 11 degrees F standard deviation), while the average low is 44 degrees F (plus or minus 9 degrees F standard deviation).

MSP Local Records for May 4th

MSP weather records for this date include: highest daily maximum temperature of 91 degrees F in 1952; lowest daily maximum temperature of 40 degrees F in 1890; lowest daily minimum temperature of 22 F in 1967; highest daily minimum temperature of 65 F in 1934; record precipitation of 1.74 inches in 1944; 2.0 inches of snowfall in St Paul in 1890 and there was a trace of snow in 1907 and 1944.
Average dew point for May 4th is 40 degrees F, with a maximum of 73 degrees F in 1912 and a minimum of 13 degrees F in 1957.

All-time state records for May 4th

The state record high temperature for this date is 96 degrees F at Wheaton (Traverse County) and Montevideo (Chippewa County in 1949 and at Springfield (Brown County) in 1952; the state record low temperature for this date is 8 degrees F at Cloquet (Carlton County) in 1911. State record precipitation for this date is 4.00 inches at Blanchard Power Station (Morrison County) in 1949; and state record snowfall for this date is 5.0 inches at Mankato (Blue Earth County) in 1890.

Past Weather Features:

May 4-5, 1890 brought a rare late spring snowfall. Mankato reported 5 inches, Le Sueur 4 inches, Duluth 2.5 inches, and downtown St Paul 2.0 inches.

A hard freeze prevailed on May 4, 1907. Mora and Long Prairie reported morning lows of just 15 degrees F, while Hinckley had just 16 degrees F and New London 17 degrees F. As far south as Zumbrota was as cold as 19 degrees F.

Another hard freeze occurred in many places on May 4, 1911. Cloquet reported a low of 8 degrees F, while Littlefork measured 16 degrees F and Warroad 17 degrees F. It was as cold as 27 degrees F at St Peter.

May 4, 1926, a typical Minnesota spring day. The temperature rose from 32 degrees F in the morning to an afternoon high of 89 degrees F at Morris.

May 4-6, 1949 was a hot, sultry spell over central Minnesota bringing 90 degrees F to many cities. It also brought daily thunderstorms which deposited a month's worth of rain in many places, including 4.77 inches at Brainerd, 4.39 inches at Blanchard Power Station (Morrison County), 4.33 inches at Onamia, 4.29 inches at Aitkin, and 3.94 inches at Gull Lake.

The first five days of May in 1952 brought a Heat Wave with many temperatures in the 90s F. Finally on the 6th temperatures dropped back into the 60s F bringing some relief to farmers who were busy with corn planting that week.

May 1-7, 1954 was the snowiest week of May in Minnesota history. Temperatures hovered in the 20s and 30s F up north with daily snow showers and snow flurries. Snowfall totals for the week ranged from 4 inches at Crookston to 17.8 inches at Virginia, where the snow depth was 14 inches on May 4th! Snow was measured (1 inch) as far south as Austin.


Warm to start the weekend as many places should reach the 70s F. Chance for showers and thunderstorms later in the day on Saturday, then more showers and thunderstorms for Sunday with cooler temperatures. Better chance for showers in southern counties. Continued chance for showers Monday and again by Wednesday with near normal to below normal temperatures.
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