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Friday, April 27, 2012

Perhaps the season's last snowfall

Perhaps the season's last snowfall

Earlier the week over April 21-22 a storm system crossed the state bringing snow to many northern Minnesota communities. Some received record-setting values of snowfall, including International Falls which reported 2.4 inches on the 22nd. Others reporting record amounts of snowfall for April 22nd included: Orr with 5.8 inches; Hibbing with 3.5 inches; Kabetogama with 3.0 inches; Northome with 2.7 inches; and Cook with 2.0 inches. The snowfalls at Orr and Kabetogama pushed their seasonal snowfall totals to 71.1 inches and 78.3 inches, respectively. There is a chance of snow overnight Friday and into Saturday morning to start this weekend, but after that the climate outlook favors above normal temperatures through early May, and it is likely this is the last measurable snowfall threat for our region.


Preliminary climate summary for April

Average temperatures for April have been about 2 to 4 degrees F warmer than normal for the most part. Every month since last October has been several degrees F warmer than normal. Temperature extremes for April ranged from 88 degrees F at Pipestone on the 2nd and 25th to just 3 degrees F at Grand Marais on April 17th. Minnesota reported the coldest temperature reading in the 48 contiguous states on five dates during the month. At International Falls the mean temperature value for April was barely above the mean temperature for March, the first time this has ever happened.

Many observers reported precipitation that was generally above normal. In some areas it was well above normal, with many reports of over 3 inches and some reports of over 4 inches. Both Wadena and Pipestone reported 4.13 inches as of April 26th. The monthly total rainfalls may be added to over the weekend with chances for showers each day. The most snowfall for the month was reported from Orr with 17.5 inches and Kabetogama with 13.7 inches. April was only the second month of the last July (a period of 9 months) to bring above normal precipitation amounts to the state, the other being February.

April also lived us to its reputation as the windiest month of the year, with many days bringing wind gusts of 30 mph or greater. Both Moorhead and Rochester saw 15 days with wind gusts of 30 mph or greater. The Twin Cities had two days when winds peaked over 40 mph, while Rochester had seven such days, including 51 mph on the 15th. In addition to the wind, April brought some thunderstorms, hail, and even tornado reports. Tornadoes were reported in McLeod and Lyon Counties on April 15th, and then on April 21st, between 5:30 pm and 9:40 pm tornadoes were reported from Clay, Wilkin, Otter Tail, Chippewa, Redwood, Douglas, and Swift Counties. Some agricultural structures were damaged by these tornadoes, but overall they were short-lived and did not inflict widespread damage.

Weekly Weather Potpourri

The NOAA-National Weather Service is seeking comments on its newly designed web site. The public comment period runs until May 18th. If you wish to provide comments to the National Weather Service on the new design and its contents, please go to the "preview" web site.

Earlier this week for Earth Day, students helped NOAA launch new ocean drifters, which are 44 pound buoys instrumented to transmit pressure, temperature, and other measurements via satellite as they drift with ocean currents. These measurements help NOAA scientists gather data from the oceans and better understand the interactions between the oceans and the atmosphere. You can read more here.

Earlier this month a team of scientists from the Mayo Clinic established a laboratory at the base of Mt Everest to study the effects of high altitude on human physiology. The team will monitor nine climbers who are attempting to scale Mt Everest. Scientists say that the stress of high altitude exertion puts climbers under the same conditions experienced by patients suffering from heart disease. The Mayo scientists brought 1500 pounds of medical equipment and set up base camp at an elevation of 17380 ft. Weather conditions in May are usually the most suitable for climbing the mountain.

A study published recently in Tree Physiology documents that certain tree species appear to grow better in urban heat islands produced by cities. Tree physiologist Kevin Griffin of Columbia University found that species like red oak grow much better in New York's Central Park then they do in cooler settings along the Hudson Valley. Generally the higher temperatures of the city appear to stimulate more robust growth in some tree species. You can read more about this study here.

MPR listener question

Are the clouds in winter different from the clouds in summer? They seem to me to be different but I am suspicious that my attitude is clouding (pun intended) my vision. In summer clouds appear to me to be beautiful but in winter they appear to be threatening.

Answer: The mixing depth of the atmosphere changes with the seasons and affects cloud formation significantly. During the winter, long nights/short days, we tend to see more layered cloud forms (stratiform), with low ceilings, and little light penetration. During spring, summer, and fall the mixing depth is greater and we see more vertical cloud forms, with a much wider array of shapes and cloud elevations. The sun angle is higher, days are longer and we get many different perspectives on the illumination of the cloud forms, making for magnificent viewing of the sky. Almost any kind of cloud form is possible to see in Minnesota during these seasons.

Clouds can be equally threatening in all seasons of the year. Certainly during the current season when we see wall clouds, squall lines, or massive cumulonimbus clouds we should feel threatened by severe weather. If you want to gain a broader perspective on all cloud forms, I would encourage you to visit the Cloud Appreciation Society web page.

Twin Cities Almanac for April 27th

The average MSP high temperature for this date is 62 degrees F (plus or minus 11 degrees F standard deviation), while the average low is 41 degrees F (plus or minus 9 degrees F standard deviation).

MSP Local Records for April 27th

MSP weather records for this date include: highest daily maximum temperature of 85 degrees F in 1977; lowest daily maximum temperature of 34 degrees F in 1950; lowest daily minimum temperature of 21 F in 1909; highest daily minimum temperature of 60 F in 1938 and 1974; record precipitation of 2.22 inches in 1975; and record snowfall of 8.5 inches in 1907. Snow depth was 8 inches on this date in 1907.
Average dew point for April 27th is 36 degrees F, with a maximum of 65 degrees F in 1986 and a minimum of 8 degrees F in 1934.

All-time state records for April 27th

The state record high temperature for this date is 96 degrees F at Hallock (Kittson County) in 1952; the state record low temperature for this date is 7 degrees F at Halstad (Norman County) in 1909 and at Brimson (St Louis County) in 1996. State record precipitation for this date is 3.76 inches at Cambridge (Isanti County) in 1975; and state record snowfall for this date is 13.0 inches at Lynd (Lyon County) in 1907.

Past Weather Features:

This week in 1826 a massive snow melt flood on the Mississippi River swept away Chief Little Crow's Sioux settlement along the river where South St Paul is now located.

A late spring snow storm brought significant snowfall to many areas of the state over April 27-28, 1907. The Twin Cities received 13 inches; Stillwater reported 11 inches; Farmington received 10 inches; New Ulm reported 8 inches, and Milaca and Park Rapids reported 6 inches of new snow.
April 27, 1909 brought very cold temperatures to the state with over 17 communities reporting overnight lows in the single digits F. It was as cold as 17 degrees F as far south as Pipestone as well. It remained cold and unsuitable for farm field work until a warm up occurred on May 3rd.

The very next year, 1910 brought a Heat Wave over April 27-28 as 80 F temperatures reached nearly all communities across the state. Records were set at Lynd and Winnebago (95 F); Albert Lea, Redwood Falls, and Windom (94 F); Moorhead and St Peter (92 F); Winona (91 F) and Montevideo (90 F).

Just after 3:00 pm on April 27, 1942 an F-3 tornado (winds 158-206 mph) touched down in western Minnesota and traveled 40 miles across Lac Qui Parle, Big Stone, and Traverse Counties. A school near Ortonville was completed destroyed, with only the steps remaining. Two students were killed. There were also reports of widespread farm damage along the path of the storm and seven other people were injured.

April 26 to May 4th of 1952 brought an extended spring Heat Wave to the state. At least 18 communities reached temperatures in the 90s F, with strong southerly winds. Most major rivers were in flood stage during this time, having seen rapid loss of abundant snow cover from the winter.

Rainfall nearly everyday brought a halt to field work around the state the last week of April 1975. From the 26th to the 30th it rained everyday bringing more than 3 inches to Stillwater, Faribault, and Elk River, and over 4 inches to Red Wing, Winona, Rosemount, Hastings, St Paul, and La Crescent.


Cooler than normal temperatures over the weekend with chances for showers and even a little snow early Saturday. More sun on Sunday. Warming trend starts on Monday, with increasing chances for showers and thunderstorms next Tuesday and Wednesday.

Friday, April 20, 2012

Wind as art

Wind as art

Members of the American Association of State Climatologists shared this web site recently. It depicts near real-time wind patterns across the continental USA, showing the animated streamlines (trajectory and velocity) in a manner that is quite artistic. You need the latest Chrome browser to view it. The data come from NOAA's National Digital Forecast Database. Give it a try.

Dew point records set, along with precipitation and snowfall records, April 15-16

Just ahead of the rain and thunderstorms over April 15th strong southeast winds brought in warm, moist air to southern Minnesota, setting new high dewpoint records for the date. MSP tied a record from 1976 with a late afternoon dewpoint of 61 degrees F, while preliminary data indicate a new dewpoint record of 63 degrees F at Fairmont and Mankato. In addition a new dewpoint record of 64 degrees F was set at New Ulm. These values occurred just ahead of the severe thunderstorms, hail, funnel clouds, tornadoes, and strong winds which were reported last Sunday.

Many observers reported heavy precipitation on April 15th and 16th, some record-setting. MSP reported a new record with 1.19 inches, while St Cloud reported a record 1.51 inches. Others reporting new daily precipitation records included: 2.22 inches at Browns Valley; 2.11 inches at Wheaton; 2.10 inches at Pelican Rapids; 2.02 inches at Duluth; 1.97 inches at Rothsay; 1.87 inches at Babbitt; 1.85 inches at Tower; 1.71 inches at Moose Lake; 1.71 inches at Pipestone; 1.59 inches at Park Rapids; 1.53 inches at Aitkin; 1.51 inches at Grand Rapids; 1.46 inches at Spring Grove; 1.36 inches at Hibbing; and 1.14 inches at Morris.

In the far north, strong winds (50-60 mph) and significant amounts of snow were reported, with many roads closed, power outages, and numerous accidents. Several observers reported new daily record snowfall amounts for April 16th, including: Babbitt with 5 inches; Tower with 6.3 inches; Cook, Hibbing, and Bigfork with 8.0 inches; Kabetogama had a record 9.4 inches; and Orr and Chisholm received a whooping record 11 inches.

Weekly Weather Potpourri

NOAA-Climate Prediction Center released new seasonal outlooks on Thursday this week. They show that for the May, June, and July period Minnesota has equal chances of being warmer or colder than normal, and equal chances of being wetter or drier than normal. The drought-stricken areas of southern and central Minnesota are expected to see some slight improvement through July 31st. You can read more here.

With Earth Day coming up this weekend (April 22) and many celebrations and events planned for next week, NOAA features a number of ways to acknowledge environmental stewardship and to get involved. You can find a number of features and programs at their web site. They show a map which depicts up to 75 Earth Day events going on across the nation.

Following a record-setting April last year (2011) when there were 758 tornado reports across the nation, the NOAA-Storm Prediction Center shows 159 tornado reports so far this month. The vast majority occurred on April 14th with 146 reports filed. So the rest of the month has been rather quiet so far. Hopefully it will remain that way. Nevertheless if you want to update yourself on severe weather safety please go to the NOAA-National Weather Service Chanhassen web site and view the materials there.

The United Kingdom Meteorological Office has chosen ShelterBox as its designated charity for the past three years. They have supported ShelterBox both with a financial commitment and a service commitment, providing forecasts specific to community recovery efforts following natural disasters around the world. The UK Met Office three-year commitment will end this summer, but ShelterBox certainly is a charity worth supporting. They deliver the essentials a family needs to survive in the immediate aftermath of a disaster. Each large, green ShelterBox delivered to a disaster site is tailored to primary needs of families, typically containing a disaster relief tent for an extended family, blankets, water storage and filtration equipment, cooking utensils, a stove, a basic tool kit, a children’s activity pack and other vital items. You can learn more about ShelterBox at their web site.

A recent study from the University of Zurich documents that Himalayan glaciers are not shrinking as rapidly as predicted by the IPCC. However, they do continue to shrink and produce more glacial lakes and create greater variability in the volume of some watersheds that are relied upon by various cultures that occupy low-lying regions. You can read more about this study here.

MPR listener question

With the significant snowfall amounts up north earlier this week, did any observers reported above normal amounts for the 2011-1012 snow season in Minnesota? It seems like everybody ended up short of average.

Answer: Only a few observers have reported modestly above average total snowfall for the 2011-2012 season. These observers are all in the northeastern part of the state and include: 86.8 inches at Isabella (Lake County); 75.3 inches at Kabetogama (St Louis County); 65.3 inches at Orr (St Louis County); and 64.3 inches at Two Harbors (Lake County).

Twin Cities Almanac for April 20th

The average MSP high temperature for this date is 55 degrees F (plus or minus 11 degrees F standard deviation), while the average low is 35 degrees F (plus or minus 9 degrees F standard deviation).

MSP Local Records for April 20th

MSP weather records for this date include: highest daily maximum temperature of 84 degrees F in 2006; lowest daily maximum temperature of 33 degrees F in 1893 and 1928; lowest daily minimum temperature of 2 F in 1962; highest daily minimum temperature of 61 F in 1941; record precipitation of 0.94 inches in 1991; and record snowfall of 8.5 inches in 1928. Snow depth was 5 inches on this date in 1962.
Average dew point for April 20th is 31 degrees F, with a maximum of 64 degrees F in 1941 and a minimum of -2 degrees F in 1950.

All-time state records for April 20th

The state record high temperature for this date is 96 degrees F at Georgetown (Clay County) in 1980; the state record low temperature for this date is 0 degrees F at Cloquet (Carlton County) in 1928. State record precipitation for this date is 3.08 inches at Collegeville (Stearns County) in 1893; and state record snowfall for this date is 18.0 inches at Fort Ripley (Crow Wing County) in 1893.

Past Weather Features

A strong spring storm hit the state on April 20, 1893 delivering record-setting precipitation and snowfall amounts to many cities. Some of the record precipitation/snowfall amounts included: 1.50 inches of precipitation and 16 inches of snowfall at Cambridge; 1.40 inches of precipitation and 14 inches of snowfall at Rochester; 1.63 inches of precipitation and 14 inches of snowfall in downtown St Paul; and 1.80 inches of precipitation and 18 inches of snowfall at Fort Ripley. Many observers reported 8 to 12 inches of snowfall from this storm, one of the heaviest ever in the month of April.

Following a fresh snowfall of several inches a record-setting Cold Wave prevailed on April 20, 1928. Many record-setting low temperatures were observed, including 0 degrees F at Cloquet; 2 degrees F at Grand Rapids; 5 degrees F at Lake Winnie; 6 degrees F at Leech Lake and Bemidji; and it was 19 degrees F as far south as New Ulm. Temperatures remained below freezing all day at a number of locations.

April 19-21, 1970 brought heavy snowfall to many parts of Minnesota, especially central and northern cities. Strong winds up to 60 mph combined with the heavy snow to bring down some power lines and telephone lines in northern Minnesota counties causing numerous outages. Some communities reported a foot or more of new snowfall, topped by 17 inches at Big Falls and 21 inches at Kelliher.

The warmest April Heat Wave ever started on the 20th in 1980 and lasted 3 days. Many western Minnesota observers reached the 90 F mark, and some even reached 100 degrees F, the earliest date for such a mark. Those reporting 100 degrees F included: Ada, Campbell, Georgetown, Montevideo, Moorhead, Hawley (101 F a state record for the month of April), Browns Valley, Argyle, and Hallock. Thankfully a strong cold front collapsed temperatures into the 60s F by the 23rd.

Starting about 8:15 pm on April 20, 1985 an F-3 tornado (winds 158-206 mph) made its way 8 miles across the landscape in Pipestone and Murray Counties, near Lake Wilson. It damage or destroyed 43 farms and injured two people. Several livestock were reportedly killed as well.

Word of the Week: "Storm Scammers"

This term is used to refer to contractors who rush into communities following natural disasters and approach those home and business owners who have suffered loss with high pressure sales tactics to get them to sign contracts for repair and restoration services, even before insurance adjusters have had time to visit. Some states have taken action against such practices. Provisions are allowed in many states for home and business owners to cancel contracts that were signed without proper disclosure or licensing. You can read more about this here.


Most cloudy with chances for rain early in the weekend, some chance for showers in the east continuing on Sunday, brighter and warmer on elsewhere. Even more sun and warmer on Monday. Warming trend continues into next week with some temperatures reaching the 70s F. Chances for showers return on Wednesday and Thursday.

Friday, April 13, 2012

Hard freeze this week

Hard freeze this week

Several areas of the state reported morning lows in the teens and twenties F this week, the coldest temperatures since March 9th for many communities. The early spring advancement in vegetative growth had many concerned for plant damage, notably to flowers, trees, and shrubs which had already budded out or bloomed. It remains to be seen how many of the state's apple orchards were adversely affected by the freezing temperatures. Growers are cautiously optimistic that damage to orchards won't be extreme. Some of the minimum temperature observations included: 16 degrees F at Wadena, Windom, and Itasca State Park; 15 degrees F at Babbitt; 14 degrees F at Bemidji, Hallock, and Embarrass; and 13 degrees F at Park Rapids, lowest in the 48 contiguous states on April 11th. You can read more about the low temperatures on our web site.


Mid-April and still soils are very dry

With field working season underway, and some of the state's 2012 crops already in the ground many Minnesota farmers are waiting for rain to replenish the dry soils that were a carryover from last year. The precipitation deficiency reported by some climate observers is very significant. There are many areas of the state that have reported precipitation totals since last August (a period of 8.5 months) that are more than 7 inches behind normal values for the period. Some of these locations are in the list below, showing how the deficiency for this 8.5 month period ranks historically.

Location; Precipitation Total; Departure from Normal; Historical Rank
(8/1/2011-4/11/2012); (8/1/2011-4/11/2012);

Lamberton; 5.35 inches; -7.51 inches; Driest of record
Winnebago; 8.03 inches; -7.17 inches; Driest of record
Marshall; 4.66 inches; -8.69 inches; 2nd Driest
Granite Falls; 4.89 inches; -7.82 inches; 3rd Driest
St James; 6.35 inches; -7.72 inches; 4th Driest
Canby; 3.97 inches; -8.70 inches; 5th Driest
Zumbrota; 8.96 inches; -7.54 inches; 7th Driest

So far in April, rainfall has been lacking or totally absent in many areas of the state. Rainfall normals for April range typically from 1.50 to 3.00 inches. MSP International Airport in the Twin Cities is one of the few places in the southern half of the state that has received over 0.50 inches so far this month (0.63 inches). In the north some areas have received more, for example 0.75 inches at Orr and 0.70 inches at Cook. Some significant showers are expected this weekend. In fact, on Friday morning some areas of southern Minnesota had already received a half to one inch of rainfall. But the outlook for the remainder of April does not favor abundant rainfall in the state with the possible exception of southeastern counties. So by the end of April we may see these precipitation deficits increase even more.

Weekly Weather Potpourri

The 10th Annual Larson/Allmaras Emerging Issues in Soil and Water Lecture will take place on the University of Minnesota St Paul Campus next week, April 19th. The lecture program runs from 2:00 to 4:30 pm in Rm 335 Borlaug Hall. Our keynote speaker is Dr. Ken Cassman from University of Nebraska who will speak about "How to guide agriculture towards sustainable food security." We will also hear remarks from Minnesota Department of Agriculture Commissioner Dave Frederickson. All are welcome to attend.

NOAA announced this week that Coors Field in Denver, CO has become the 4th Major League Baseball Park to be declared a StormReady facility. The other ball parks are Target Field (Twins), Great American Ballpark (Cincinnati Reds), and Busch Stadium (St Louis Cardinals). To be declared and certified as a StormReady facility there must be:
-a 24-hr warning point and emergency operations center
-more than one way to receive severe weather forecasts and warning updates
-a local system that monitors weather conditions continuously
-promotion efforts toward public readiness through community seminars
-a formal hazardous weather plan, utilizing weather spotters and training exercises

I think Target Field was the first MLB ball park to be certified in this program thanks to the Twins meteorologist Craig Edwards.

The National Weather Service announced this week that Anchorage, Alaska has set a new seasonal snowfall record with a total of 134.5 inches, surpassing the season of 1954-1955 (132.6 inches). City snow removal crews worked overtime filling the metro disposal sites to capacity. Many other, smaller communities in Alaska also reported their snowiest season ever.

NOAA-National Weather Service in Chanhassen, MN will promote Severe Weather Awareness Week next week (April 16-20) with daily information about severe weather threats, communication procedures for watches and warnings, recommendations to protect yourself, and a siren drill. It is a good time to check your NOAA Weather Radio and make sure it has fresh batteries.

For those visiting the Washington D.C. area close to Earth Day, NASA scientists will be in place at their tent on the National Mall over April 20-22 to share their Earth Science technologies and explorations. This is a great opportunity to learn more about satellite monitoring, climate modeling, and sample some "hands-on activities." You can learn more here.

MPR listener question

With all of the dry, cold air this week around the state, have we set any low dewpoint or humidity records?

Answer: Though the air has been consistently dry we have not seen dewpoints fall below 0 F this week, which would have been record-setting values. The lowest readings in the Twin Cities wee 13-14 degrees F, while dewpoints fell as low as 10 degrees F at Marshall. Some afternoon relative humidity readings have ranged from 16 to 19 percent, very desert-like.

Twin Cities Almanac for April 13th

The average MSP high temperature for this date is 55 degrees F (plus or minus 11 degrees F standard deviation), while the average low is 35 degrees F (plus or minus 9 degrees F standard deviation).

MSP Local Records for April 13th

MSP weather records for this date include: highest daily maximum temperature of 84 degrees F in 2006; lowest daily maximum temperature of 33 degrees F in 1893 and 1928; lowest daily minimum temperature of 2 F in 1962; highest daily minimum temperature of 61 F in 1941; record precipitation of 0.94 inches in 1991; and record snowfall of 8.5 inches in 1928. Snow depth was 5 inches on this date in 1962.
Average dew point for April 13th is 31 degrees F, with a maximum of 64 degrees F in 1941 and a minimum of -2 degrees F in 1950.

All-time state records for April 13th

The state record high temperature for this date is 90 degrees F at Wheaton (Traverse County) in 2003; the state record low temperature for this date is -11 degrees F at Roseau (Roseau County) in 1950. State record precipitation for this date is 3.25 inches at St Cloud (Stearns County) in 1862; and state record snowfall for this date is 13.0 inches at Kinbrae (Nobles County) in 1892.

Word of the Week: VisualEyes

This is the name given to the new forecasting service provided by the United Kingdom Meteorological Office and intended to provide accurate, site-specific forecasts for those who manage wind turbines. This system provides map based visualizations of weather attributes on an hour by hour basis out to five days. Temperature, visibility, wind, and precipitation types are some of the forecasted elements needed by wind turbine managers to maximize the efficiency of these systems and to guard them against weather-inflicted damage from extremes.

Past Weather Features:

April 13, 1862 brought a large spring storm to St Cloud where it rained 3.25 inches. It continued to rain off and on for three more days producing a total of 4.22 inches and accelerating snow melt from the landscape raising the flow on the Mississippi River considerably above flood stage.

April 13-14, 1928 brought a strong spring snow storm to southern Minnesota. Downtown St Paul reported 12.8 inches, Farmington and Maple Plain received 12 inches, while Zumbrota, Faribault, New Ulm, and St Peter reported 10 inches. Following the snowfall overnight temperatures fell into the single digits.

After a snowy first two weeks of the month, April 13th brought record-setting low temperatures to the state in 1950. Many northern communities reported overnight lows ranging from -1 degrees F to -11 degrees F. Duluth reported a 29 inch snow depth on the 13th, while Grand Marais reported 23 inches of snow on the ground during one of Minnesota's coldest and snowiest Aprils.

April 12-13, 1962 saw another large spring snow storm move across the state depositing 6 inches at MSP and New Ulm, over 7 inches at Rochester, Fairmont, and Redwood Falls, and 8.5 inches at Tracy. Pipestone reported 11 inches of snow, a record that still stands.

A strong spring storm brought winds of 60-80 mph with rain, ice, and snow over April 13, 1964. Snow amounts from 6 to 10 inches were reported in NW Minnesota where roads were closed for a time. Ice build up brought down some power lines, and tipped many trees in central counties. A mixture of rain, sleet, and snow brought daily precipitation records to many locations including 2.59 inches at Bemidji, 2.55 inches at Bird Island, 2.40 inches at Itasca State Park, and 2.05 inches at Fergus Falls. In southern Minnesota near Rochester a tornado touched down at 3:00 pm and traveled three miles toward the downtown business district. It unroofed some buildings and broke out many windows. Fortunately there were no injuries or deaths reported.

April 13-14, 2003 brought a mini-heat wave to Minnesota. Strong south winds brought in an warm air mass on the 13th as temperatures soared from morning lows in the 30s and 40s F to afternoon highs in the 70s and 80s F. Wheaton was at the top of the heap with 90 degrees F. Temperatures continued warm into the 14th as over a dozen communities saw the thermometer climb into the 90s F, topped by 94 degrees F at Benson and Milan.


Warmer over the weekend, with a chance for showers and thunderstorms each day. Cooling down on Monday with a chance for rain and/or snow showers. Generally cooler on Tuesday and Wednesday, then a warming trend towards the end of next week. Chances for showers again mid-week as well.

Friday, April 6, 2012

More temperature records to start April

More temperature records to start April

Following a record-setting month of March, April started with some new high temperature records in the southwestern counties of Minnesota. On April 1st (April Fool's Day) Marshall set a new record with 78 degrees F, Pipestone had a new record 81 degrees F, Sioux Falls, SD set a new record with 89 degrees F, and Luverne set a new state record with a high of 90 degrees F. April 2nd brought more records with highs of 80 degrees F at Lakefield, 84 degrees F at Sioux Falls and Worthington, 86 degrees F at Luverne, and a new statewide record of 88 degrees F at Pipestone. And on April 3rd new temperature records were set with 79 degrees F at Redwood Falls, 81 degrees F at Windom and Pipestone, and 82 degrees F at Lakefield. Temperatures in southern and western portions of the state are averaging 13-18 degrees F warmer than normal for the month of April so far.

April 2nd also brought a round of thunderstorms to the state, some bringing large hail (up to 3/4 inch diameter). A few observers reported 0.30 to 0.50 inches of rainfall, but it was quite spotty.

Soil moisture still short, but improving in some places

University of Minnesota Research and Outreach Centers monitor soil moisture conditions for Minnesota's major crops. Last fall's (2011) measurements made it obvious that soil moisture storage was well below normal going into the winter season. For many areas over winter and early spring precipitation has been inadequate to help fully restore soil moisture to near normal levels for the spring. At Lamberton the final measurements from last fall showed 2.95 inches of stored soil moisture in the top 5 feet of the soil profile. Measurements made earlier this week showed that the profile moisture content had only "improved" to 3.09 inches of stored moisture, still roughly 2.5 inches less than average for this time of year. Further much of this moisture lies well below 3 feet and is out of the reach of crop rooting systems early in the growing season. So additional spring rains in April and early May are needed to recharge the upper layers of the soil for good germination and early development of corn and soybean crops.

For some areas, over winter and early spring recharge has been helpful. For example, at Waseca the final soil moisture measurements from last fall showed 4.67 inches of available moisture in the top 5 feet of the soil profile. The measurements made earlier this week in the same soil showed 7.37 inches of available stored soil moisture, an increase of 2.70 inches. This recharge came primarily from the Leap Day storm (Feb 29) which dropped 1.96 inches of rain, and the mid-March rains (Mar 20-23) which infiltrated the soil as well. Though this measurement is still below normal for stored soil moisture this time of year, this level of moisture is adequate for starting the planting season with optimism in the Waseca area.

Periodic seasonal updates on soil moisture values around the state will be available under the Agricultural Climate Information section of our web site.


Notes on early ice-out dates for Minnesota lakes

We have spoken in recent years about the obvious trend in earlier ice-out dates on Minnesota lakes. This year a number of lakes with lengthy observation records saw their earliest ice-out in history. The list below is compiled by Pete Boulay of the MN-State Climatology Office and available online here.

Lake Name County New Record Old Record Period of Record
White Bear Lake Ramsey/Wash March 19, 2012 March 21, 2000 85 years
Minnewaska Pope March 21, 2012 March 23, 2000 107 years
Green Kandiyohi March 20, 2012 March 22, 1987 83 years
Mille Lacs Mille Lacs March 26, 2012 April 2, 2000 56 years
Big Sandy Aitkin March 26, 2012 March 31, 2000 59 years
Bemidji Beltrami April 2, 2012 April 6, 2010 76 years
Leech St. Louis April 2, 2012 April 6, 2010 77 years
Vermilion St. Louis April 2, 2012 April 6, 2010 93 years
Perhaps the bill in the MN-Legislature to advance the date of the Fishing Opener to May 5th this year will provoke a movement to make a permanent change to an earlier date so there will be no more conflicts with Mother's Day weekend.

Weekly Weather Potpourri

Wednesday afternoon and evening brought 13 tornadoes to the Dallas-Fort Worth area of Texas, some that were large and destructive. Hundreds of homes and buildings were damaged, but no fatalities were reported thanks in part to timely warnings from the National Weather Service. Hail damaged more than 100 aircraft at the DFW Airport. It was the first outbreak of tornadoes this month, following 223 reports of tornadoes during March nationwide.

A recent paper by the U.K. Met Office scientists which appears in the journal Nature finds a possible link between industrial air pollution, volcanic activity, and the changes in the temperature patterns of the North Atlantic Ocean. Given the importance of North Atlantic sea surface temperatures to precipitation patterns across Africa and South America it is critical to understand how human caused pollution may affect ocean temperature patterns in the future.

For golf fans following the Master's Golf Tournament this week from August, GA, the Southeast Regional Climate Center has created a complete climatology for this event covering the period from 1934 to the present. You can find all the weather records you want. For example, there have been 15 years when no rainfall occurred during the tournament. Conversely it rained 2.67 inches on Saturday, April 7, 1973. More information can be found at the web site.

Despite the prevailing warm temperatures this season across the state of Minnesota, Silver Bay reported one of the coldest mornings in the nation on Friday, April 6th with just 16 degrees F. 

MPR listener question

I know that forecasters have warned us that possible freezing temperatures will occur in the Twin Cities yet in April, but what about snowfall. How often does it snow in April or May in the Twin Cities area?

Answer: Indeed, frost may be a possibility on Monday through Wednesday mornings, and yet again even later in the month. At least a trace of snowfall has been observed during the months of April and May in the Twin Cities 95 percent of all years since 1885. This is a remarkably high percent. The most recent years without any snow in April and May were 2010 and 2006.

Twin Cities Almanac for April 6th

The average MSP high temperature for this date is 50 degrees F (plus or minus 12 degrees F standard deviation), while the average low is 32 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for April 6th

MSP weather records for this date include: highest daily maximum temperature of 86 degrees F in 1991; lowest daily maximum temperature of 26 degrees F in 1939; lowest daily minimum temperature of 10 F in 1979; highest daily minimum temperature of 54 F in 1921; record precipitation of 2.58 inches in 2006; and record snowfall of 6.0 inches in 1928. Snow depth was 8 inches on this date in 1975.
Average dew point for April 6th is 28 degrees F, with a maximum of 59 degrees F in 1921 and a minimum of -3 degrees F in 1979.

All-time state records for April 6th

The state record high temperature for this date is 90 degrees F at Madison (Lac Qui Parle County) and Winona (Winona County) in 1991; the state record low temperature for this date is -22 degrees F at Karlstad (Kittson County) in 1979 and at Tower (St Louis County) in 1982. State record precipitation for this date is 2.67 inches at Dawson (Lac Qui Parle County) in 1997; and state record snowfall for this date is 18.0 inches at Fosston (Polk County) in 1947.


Past Weather Features:

A heavy fall of snow occurred in the southern part of the state back on April 6, 1928 with many places receiving 6 or more inches. Downtown St Paul reported 7 inches, Zumbrota 8 inches, Maple Plain 9.5 inches, and Fairmont 11.4 inches, still a record snowfall for the date there.

Another heavy snow storm occurred on April 6, 1947 bringing several inches of snow, and record setting snow to some northern Minnesota communities. Moorhead and Babbitt reported 9 inches, 10 inches fell at Blackduck, 14 inches at Red Lake, and 18 inches of snow was reported at Fosston. It was a Sunday and some churches did not hold services.

April 6, 1979 was perhaps the coldest in history across the state as most northern Minnesota communities reported below 0 F readings. For some observers the daytime temperature never rose out of the teens F that day. It was -5 degrees F as far south as Maple Plain.

A remarkable two-day heat wave occurred across Minnesota over April 5-6, 1991. Many observers reported daytime temperatures in the 80s F on consecutive days. Farmers were anxious to get field work done, but thunderstorms prevailed the rest of the month making soil conditions too wet.

An most unwelcome blizzard occurred April 5-6, 1997 across the Red River Valley when most communities were in the middle of a flood fight due to a rapidly rising Red River. Many areas reported 5 to 7 inches of snowfall with near zero visibility at times. A mixture of rain, sleet, and freezing rain fell elsewhere. Ice accumulated on power poles and lines knocking out power to many communities. Interstate 94 was closed for a time between Moorhead and Fergus Falls.

April 6-7, 2006 brought heavy thunderstorms to eastern sections of the state. The Twin Cities reported their heaviest ever April rainfall with 2.58 inches. Albert Lea reported 2.57 inches and Fairmont received 3.35 inches. Many basements were flooded in Martin County, and elsewhere a number of roads were closed due to high water.


Chance of showers over the weekend, possibly a few snow showers in the north. Chances for frost Monday, Tuesday, and Wednesday mornings around the state. Generally dry next week with daytime temperatures that are near seasonal normals. Some warming towards the end of the week.
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