U.P. weather in 2006—A look back, by Matt Zika

U.P. weather in 2006—A look back
Despite periods of prolonged chill in February and early March and September through early November, 2006 will go down in record books as one of the top five warmest years for much of the Upper Peninsula.
At the Marquette National Weather Service Office in Negaunee Township, 2006 is tied with 2001 as the third warmest year.
January was the warmest on record almost everywhere across Upper Michigan. April, July, November and December also gave us well above normal temperatures that placed these months among the warmest on record.
The year was very dry, especially over the north central and west, despite a few notable widespread heavy precipitation periods. The six-month precipitation deficit from June through November reached eight inches in the north central counties and exceeded four inches in many places west of Munising and Iron Mountain. Annual precipitation in the north central and west was only eighty to ninety percent of normal. At the Houghton County Airport, 2006 was the fifth driest year since 1952.
The combination of below normal precipitation over much of the Lake Superior drainage basin and the above normal temperatures caused Lake Superior water levels to plummet to near record low levels by fall. Since there was, in general, more precipitation over the central and lower Great Lakes through 2006, Lake Michigan and Lake Huron water levels did not fall as sharply.
The lowest temperature observed across Upper Michigan in 2006 was 27 degrees below zero in Champion on February 26. The highest temperature was 101 degrees at Thousand Island Lake in Gogebic County on July 15, 16 and 31.
The year started out on a warm and snowless note with a west-to-east flow of Pacific air dominating the United States. January’s mean monthly temperatures were ten to fifteen degrees above the 1971-2000 norm. January was the warmest first month on record at almost all reporting stations.
The unprecedented warmth persisted into the second week of February, but winter roared back with a vengeance by mid-month with a major change in the upper air pattern to a deep trough over eastern North America. Despite the early warmth, mean February temperatures ended up one to three degrees below normal over western Upper Michigan.
The thermometer fell below zero somewhere in Upper Michigan almost every night after February 15. February snowfall and precipitation ended up above normal almost everywhere. At Newberry, February was the snowiest (61.9 inches) and wettest (4.55 inches water equivalent) on record. At most other reporting stations, the month joins the list of top ten snowiest second months.
The intense cold of late February persisted into early March, but the chill eased by the beginning of the second week. Although there were periods of cold weather until the final week of March, overall mean monthly temperatures ended up one to three degrees above normal. Warm and dry weather was the rule in April, as a persistent upper ridge settled in over the Great Lakes and southeast Canada. Monthly temperatures ran four to eight degrees above normal under the ridge, and April became the warmest on record at Ontonagon and one of the top ten warmest almost everywhere across west and central Upper Michigan.
The lack of moisture made April one of the top five driest on record. Although the warm and dry pattern that characterized April weather lingered into the first week of May, a deep trough developed over the Great Lakes at mid-month. The result was a much cooler and wetter two weeks that greatly alleviated growing drought and wildfire dangers. As much as 6.5 inches of rain fell in northern Marquette County in two days, causing minor flooding. The 5.13 inches of rain that inundated the City of Marquette from the morning of the 11th to the morning of the 12th was the greatest twenty-four hour precipitation total on record since 1948.
More heavy rain developed over the south central Upper Peninsula during Memorial Day weekend, as very hot air in the Plains surged into the Upper Great Lakes. In a short period of time, more than two inches of rain fell from Iron River to Iron Mountain and Escanaba during the morning of May 28, causing some flash flooding.
Maximum temperatures on Memorial Day surged into the 90s overall, but the Keweenaw Peninsula and downwind of Lake Michigan, reached a blistering 98 on the west side of Marquette. Morning lows on May 29 remained above 70 at a number of locations across the west as well.
Despite a mid-month chill, the anomalous warmth at the beginning and end of May pushed monthly temperatures up to two degrees above normal.
There were some typical scattered summer thunderstorms during the month of June. Some of the thunderstorms dropped up to three inches of rain, and one of the thunderstorms on June 17 produced a lightning strike that resulted in a fatality near Wakefield in Gogebic County. For the most part, however, the northwest flow east of a building ridge in the Plains caused the weather pattern to turn dry again after the wet period in May.
After a relatively tranquil June, July weather turned much more extreme. The building upper ridge in the Plains became the dominant influence on Upper Michigan weather and caused periods of searing heat across Upper Michigan. The hottest weather occurred from the 13th to the 17th and again from the 25th to the 31st.
Despite some cool periods when temperatures fell as low as thirty-six at the colder interior locations, July mean temperatures ended up two to five degrees above normal, warm enough to place July in the list of top ten warmest at all reporting sites.
As is often the case in summer, July precipitation was highly variable and depended on the track of opportunistic thunderstorms. In general, places near the cooling and stabilizing influence of the Great Lakes saw fewer showers and reported less rainfall. There were several occurrences of widespread severe thunderstorms in July.
A boat on Lake Superior near Munising was struck by lightning during one of the thunderstorms on July 14, resulting in minor injuries to three boaters. A cluster of severe storms struck the north half of Upper Michigan during the early morning hours on the 16th. Northern Houghton County was especially hard hit with large hail, damaging winds and torrential rainfall up to three inches that caused some flooding. An even more widespread outbreak from the afternoon on the 28th into the early morning hours on the 29th caused nearly fifty reports of strong winds or large hail throughout west and central Upper Michigan.
In contrast to July, when the thermometer broke the 90-degree mark repeatedly, August temperatures were much less extreme. The mercury never rose above 88 degrees anywhere over west and central Upper Michigan in August. Although there were few extremes of temperature in August, that was not the case for precipitation.
Conditions ranged from very dry over the Keweenaw Peninsula to wet over portions of the south and east, which were struck by more thunderstorms. Low pressure systems sliding through the Lower Great Lakes brought periodic rains to the area. Munising reported a monthly rainfall total of 5.89 inches, qualifying August 2006 as the third wettest on record.
A deepening upper trough over the Great Lakes in September caused monthly temperatures to run below average overall, but the east and, for the first time since February, there were widespread below normal monthly readings. September temperatures finished as much as 1.5 degrees below average over the west, but up to a degree above normal at Newberry.
The first half of September featured near normal temperatures and dry weather across the entire Upper Peninsula before the trough developed. There was increased storminess and more frequent outbreaks of cooler Canadian Air. June through September rainfall deficits approached five inches over parts of the north central Upper Peninsula.
There were a few warm days in early October, but overall very cool weather was the rule, as the upper trough remained anchored over the Great Lakes. October mean temperatures were 1.5 degrees below normal at Newberry to 4.5 degrees below at Ironwood, cool enough that areas from Marquette and Iron Mountain to the west experienced one of the top ten coolest on record.
Since the cold air was relatively far south for the season, the main storm track also was farther south. The result was below normal precipitation over many areas. Even though the precipitation was not continuous and mixed with rain over lower elevations, over twenty inches of snow and two inches of water equivalent precipitation fell at a number of spots in a swath from Ironwood to Houghton and the Huron Mountains. Twin Lakes in Houghton County measured 26.6 inches of snow and 3.65 inches of liquid precipitation when winds gusted as high as 45 mph over the Keweenaw Peninsula.
This storm was so significant that October 2006 is now the snowiest on record in Ontonagon and the second snowiest in Ironwood. Since the central counties of Upper Michigan for the most part missed this storm, monthly precipitation totals in these areas were as low as fifty percent of normal.
The cool weather of October lingered into early November, but then the upper air pattern underwent a significant change as the upper trough gave way to a west-to-east flow of warmer Pacific air by the end of the first week. This pattern dominated the Upper Great Lakes until just before the end of November and caused monthly mean temperatures to run from 3.5 to 5 degrees above normal. Most of the moisture-laden low pressure systems remained to the south in the Lower Great Lakes and the lack of cold air reduced lake-effect snow.
Precipitation and snowfall across much of the Upper Peninsula were well below average and paltry enough to rank the month in the top ten driest in many places. For the first time since 1948, only a trace of snow fell at the official observation site in Marquette.
Except for the first week of December when an upper trough and arctic air were in place over the Great Lakes, the west-to-east flow of Pacific air remained the dominant influence on the weather. The average December temperature was 7.5 degrees above normal at the Marquette National Weather Service Office, making it the third warmest December on record.
At the Houghton County Airport, the average temperature was 7.1 degrees above normal, which tied it with the warmest December ever. Most other locations across the Upper Peninsula also experienced a top five warmest December. In addition, for only the third time since the 1930s (1952 and 2001 were the other years), Iron Mountain did not have a temperature below zero.
Most of the major storm systems missed Upper Michigan again in December. So, except in areas near the Great Lakes that saw significant lake effect snow when arctic air dominated the first week of the month, December snowfall and precipitation ended up below normal. In fact, many locations across the U.P. did not have snow on the ground for Christmas for the first time in more than ten years.
Visit www.weather.gov/mqt for details.
—Matt Zika, National Weather Service

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