2012 Year in Review for Upper Michigan Weather

 

 Highlights of 2012's biggest weather events across Upper Michigan

 


 January 1st-3rd: Wind and Snow Event

     It was a snowy and windy start to 2012 as a strong area of low pressure developed over the Central Plains and then ejected northeastward into the lower Great Lakes. At the same time, a strong and vast high pressure system extended from Manitoba into the Dakotas. The pressure gradient between the two systems was very intense, allowing for strong northerly flow to cross Lake Superior. Peak wind gusts associated with the system were greater than 60 mph at Granite Island, Stannard Rock, and Rock of Ages. Several other observed peak wind gusts can be seen in Figure 1.  Along with the northerly flow associated with the surface pressure system, temperatures were cold enough for very heavy lake effect snow in areas favored by northerly winds. Several locations near Lake Superior received more than a foot of snow with this system, as shown in Figure 2.

 

Figure 1:  Observed peak wind gusts (mph) from January 1st through January 3rd. Figure 2:  Observed snowfall (inches) from January 1st through January 3rd.

 

 


  February 29th: The "Leap Day Low"

     On February 28th, a strong late winter low pressure system developed over the central Great Plains. Blizzard conditions occurred across South Dakota and tornadoes were reported from Nebraska to Illinois. By the early evening hours of the 28th, the system began to impact Upper Michigan (Figure 3). Heavy snow fell at times across much of Upper Michigan on the morning of the 29th, with the largest totals occurring around the Michigan and Wisconsin border.  A band of very heavy snowfall moved through the area and produced snowfall rates observed to be at or above 2" per hour.  This band lingered over the Wisconsin and Upper Michigan border as the system slowly pivoted from an east track to a northeast track, which generally favors an area of increased accumulation of snowfall to the northwest of the system.  After the track shifted, the band lifted northward at a more rapid pace and allowed for lighter accumulations to the north of the border. Snowfall totals were generally 4" to 7" north to more than a 12" near the Wisconsin border (Figure 4).  A few locations received nearly 2 feet of snow in north-central Wisconsin.

 

Figure 3: Surface map of features affecting the U.P as well as much of the Upper Midwest at 1:00 a.m. EST February 29th.
Figure 4: Snow totals from February 28th - March 1st.
 

 

 


  March 2nd-3rd: Heavy Snow across Eastern and North-Central Upper Michigan

     On March 2nd-3rd, a low pressure system moved from the mid-Mississippi valley, across Lower Michigan, and into Quebec, bringing plenty of moisture and support for snowfall across much of Upper Michigan. Once the system passed, eastern Upper Michigan saw between 4 and 10 inches of snow. As is typical, lake effect snow showers developed along Lake Superior with the northerly winds behind the system. This brought an additional 10 to 15 inches to the highest terrain of Marquette and Alger Counties during the afternoon and evening of the 3rd. The highest report received was 27.4 inches near the Hoist Basin (northern Marquette County). The heavy snow quickly brought the snow depth at NWS Marquette to 47 inches, the deepest snow pack since 1997. (Figures 5 and 6)

                                          

 

Figure 5: NWS Marquette parking lot: 47 inch snow depth.

Figure 6: Snow depth of 47 inches on March 3rd.

 


Mid-March: Summer Makes an Early Appearance

     Shortly after the 47 inch snow depth was achieved in early March at NWS Marquette, a ridge of high pressure anchored itself over Upper Michigan. This high pressure ridge brought record breaking warmth to Upper Michigan through the end of the month, quickly melting the snowpack in a matter of a week. The increased run off was a primary contribution to the rise of Great Lakes water levels to within 9 to 12 inches of normal by late March. Temperatures were not just warm by winter standards; they were warm by even early summer standards. In fact, daily temperatures were 35 to 40 degrees above normal during the week of March 17th-March 21st!  Highs were in the 60s and 70s, with even some low 80s. The warmest temperature was 85F in Harvey on March 21st, which is the same day NWS Marquette saw its record high broken by an astounding 32 degrees (81 vs. 49). Once all was said and done, March 2012 ended up being the warmest March on record for nearly all of Upper Michigan, and was actually warmer than April (39.7 vs. 39.0). The dark blue temperature trace on Figure 7 below shows the observed temperature range for each day in 2012. Notice that in March, the temperatures jumped well above normal, and even through existing records. Figure 8 focuses on the observations during the warm stretch in March. Even the observed minimum temperatures broke existing high temperature records for March! Prior to 2012, there had never been a low temperature above 44F in March, but every night during this week was in the upper 40s and 50s.

 

 Figure 7: Temperature trace for 2012. The dark blue line is the observed temperature.


 Figure 8: Observed highs and lows as well as records at the NWS office in March.

 

 


Late May: The Duck Lake Fire

     An unusually dry and warm spring in Upper Michigan primed the area for a busy fire-weather season. Wildfires are most probable on days when precipitation is lacking, temperatures are warm, and winds are gusty. One such day was May 20th, when a cold front swept across Upper Michigan. Although the front brought cooler temperatures and thunderstorms to the eastern half of Upper Michigan, precipitation was isolated and light, and winds remained gusty. Unbeknownst at the time, lightning strikes from these storms had started what would become the Pine Creek and Duck Lake Fires. Then, during the late afternoon hours of the 24th, the Duck Lake fire was discovered when a smoke plume appeared on satellite across a rural area of Luce County. The strong southerly winds gusting to 35 mph had quickly fanned a small fire that was ignited by a lightning strike several days earlier (Figure 9). By the morning of May 25th, the fire had expanded to 17,000 acres, and the gusty winds had switched to the west-northwest behind a cold front. This caused the fire to shift eastward (Figures 10 and 11). By the 29th of May, both the Pine Creek and Duck Lake Fires were nearly contained. The Duck Lake Fire burned a total of 21,127 acres, devoured 136 structures, and cost more than $3.6 million dollars to suppress. Thankfully, no injuries or fatalities were reported. The Duck Lake Fire was the third largest fire in modern Michigan history.

Figure 9: Picture of the Duck Lake Fire. Photo Courtesy of the Michigan DNR webpage. Photo by Richard Smith.

Figure 10: MODIS Satellite shows smoke from the Duck Lake Fire. From SSEC At University of Wisconsin Madison Figure 11: MODIS Satellite shows the burn scar (orange) from the Duck Lake Fire. From SSEC at University of Wisconsin Madison

 

 


June 8th: The Marquette County Tornado

     A subtle system passing southeast across Lake Superior during the afternoon of June 8th kicked off two supercell thunderstorms across north-central Upper Michigan. Supercell thunderstorms are characterized by rotation throughout much of the storm. They often produce a radar signature that looks like a hook protruding away from the storm (Figure 12). While most supercells do not produce tornadoes, the first storm developed a funnel cloud over the city of Marquette, and the second storm produced an EF-1 tornado across northwest Marquette County (Figure 13). A NWS Marquette crew surveyed the damage, which consisted of several groves of blown down and snapped trees as well as some superficial damage at an industrial site. It was determined that winds reached as high as 95mph within the tornado, which was on the ground for nearly 8 miles. The Michigan DNR was gracious enough to perform an aerial survey of the damage, which shows the converging (inward blowing) winds of the tornado by the alignment of the downed trees (Figure 14). This tornado was the only one observed in Upper Michigan during 2012.

 

Figure 12: Radar loop showing the lead supercell near Marquette and the trailing, tornadic, supercell over northwest Marquette County. Figure 13: Depiction of the tornado track (yellow line) with respect to northern Marquette County.

 
 

Figure 14: Michigan DNR aerial photo of converging downed and snapped trees (left) and the associated ground survey images from the same location (right).

 

 


 July 4th: Nature's Fireworks

     What originally looked to be a quiet 4th of July across Upper Michigan turned into an afternoon and evening of thunderstorms that postponed many festivities. A strong mesoscale convective system (MCS), or large organized cluster of storms, developed in North Dakota overnight from July 3rd to July 4th. As the system sped eastward into northern Minnesota early in the afternoon of the 4th, it was looking more likely that Upper Michigan would at least see some of the residual thunderstorms after they crossed Lake Superior. However, with summer in full swing, the increasingly thin cold marine layer over Lake Superior did not deter the cluster of storms during the late afternoon. The MCS then encountered a very unstable airmass across southern Upper Michigan, and continued its propagation east-southeastward, reaching western Upper Michigan in the early evening and central/eastern Upper Michigan in the mid-evening (Figure 15). Multiple reports of downed trees were received in central Upper Michigan during the evening. Near the town of Channing in central Upper Michigan, a small vortex of wind called a gustnado (like a tornado, but develops differently and is generally much weaker) formed on line of thunderstorms and brought down many trees around Sawyer Lake and Gust Newberg Park (Figures 16 and 17). The line of storms also created dangerous conditions along the shore of Lake Superior as winds gusted to 50mph. The storms could not have arrived at the worse time for many locations as the storms passed through central and eastern Upper Michigan in the evening and ultimately canceled many firework shows.

  

 Figure 15: Radar image from 9:15pm EDT on July 4th. Figure 16: Tree damage at Gust Newberg Park.
  

 Figure 17: Swath of wind damage and wind speed estimates near Channing, MI.

 

 


 November 23rd: Post-Thanksgiving Snow and Wind

     A low pressure system tracking across Lake Superior produced the first significant snowfall of the season for many locations along Lake Superior. Lake and terrain enhancement of the snow resulted in snowfall totals generally in the 5 to 10 inch range across the counties bordering Lake Superior (Figure 18). While not an overly impressive snow event by Upper Michigan standards, the storm was accompanied by very strong winds. The relatively warm waters of Lake Superior caused the low pressure "hang up" over the southeast portion of the lake. In combination with an impinging strong high pressure from the northwest, northerly winds increased across the Keweenaw Peninsula and the east half of Upper Michigan. Peak wind gusts exceeded of 50mph in some locations (Figure 19). The storm caused headaches for those traveling home after the Thanksgiving holiday.

 

Location Total Snowfall (inches)
Twin Lakes 14.0
Ironwood 12.3
Bergland 11.4
NWS Marquette 10.3
Greenland 7.5
Marquette 6.9
Cooks 6.8
Munising 6.5
Figure 18: Snowfall totals from November 23rd.

Figure 19: Peak wind gusts (mph) on November 23rd.

 

 


 December 20th-21st: Heavy Snow across Central and Eastern Upper Michigan

     Heavy and wet snow spread across all of Upper Michigan on December 20th and continued into the morning of the 21st as strong low pressure moved across southern Lower Michigan. Much of the east half of Upper Michigan was located in the western extent of the main snow shield and received 6-12 inches of snow. A significant difference in snowfall amounts between the shore and higher terrain occurred across north-central Upper Michigan as a hybrid system/lake-enhanced/terrain-induced snow resulted in snowfall amounts over a foot in Marquette and Baraga counties. In addition, wind gusts of 35-45 mph were common on the 21st, with a few spots in Marquette and Alger Counties seeing wind gusts greater than 50 mph. This created near-blizzard conditions, snow drifts of 3 to 4 feet in open areas, and treacherous travel conditions. Figure 20 shows the analyzed snowfall map from the storm.

  

Figure 20: Snowfall totals from the morning of December 20th through the morning of December 21st.

 

 


 A Record Breaking Year for Temperatures

     Temperatures have been warmer than normal throughout much of the United States this year, and the Upper Peninsula is no exception.  One of the major contributors to these above normal temperatures was the unprecidented warm March.  Temperatures remained above normal into summer, with several records being broken. This fall and early winter has been unusually warm as well, especially with respect to the overnight low temperatures. 2012 saw the most consecutive days with minimum temperatures greater than or equal to 10 degrees (277). Other interesting statistics at the NWS include the record number of days with temperatures greater than 32F in a single year (293, Figure 21), the record number of consecutive days with highs above freezing (237), and the third highest string of days above zero (301).

 

Days with Max T >32F

Ranking

Number of Days

Years of Occurrence

1

293

2012

2

292

1987

3

291

1999

4

289

1990,1998

6

283

2006

7

281

1981,1984

9

280

2010

10

279

2001

Figure 21: List of the most consecutive days with temperatures above freezing.

 

 


 Where is the Snow???

     A prevailing west-to-east flow of relatively mild Pacific air dominated the weather across the Upper Great Lakes through the beginning of the year. This pattern limited the number of Arctic air invasions, keeping temperatures above normal and limiting lake effect snowfall. By the end of February, seasonal snowfall totals were nearly 40 inches below normal before two snow storms impacted Upper Michigan from the end of February through the first few days of March (both highlighted in this review), which substantially increased snowfall totals. In the wake of the early March winter storm, a maximum seasonal snow depth of 47 inches was recorded at the NWS office on the morning of March 4th.  Exactly two weeks later on the morning of March 18th, in the grip of unprecedented record warm temperatures, the snow depth had been reduced to little more than a trace (Figure 22).  However, the rapid snowmelt produced no significant flooding as the melt occurred with no heavy rain eventsAs Fall 2012 commenced, mild Pacific flow kept arctic air in Canada. October snowfall was near normal as a result of a light, wet snow on Halloween. However, November and December followed with well below normal snowfall. Other than two winter storms (11/23 and 12/20), no significant snowfalls occurred across Upper Michigan to end 2012. Overall, much of Upper Michigan is running at 50-70% of the average snowfall for the current winter season.

 

Figure 22: Satellite loop from March 11th-19th showing the removal of the snowpack over less than 10 days.

 

 


 2012 Climate Summary

Finally, here is a general summary of temperatures, precipitation, and snowfall for 2012.

 

Year Overview

Value

Rank

Average High

53.2 degrees

Warmest

Average Low

34.6 degrees

Warmest

Average Temperature

43.9 degrees

Warmest

Precipitation

36.36 inches

20th Wettest

Snowfall

156.6 inches

19th Least Snowiest

 

Daily Extremes

Value

Date

Warmest Temperature

91 degrees

July 2nd, 3rd, 5th

Coldest Temperature

-12 degrees

January 20th

Wettest Day (Liquid)

2.21 inches

October 25th

Snowiest Day

18.5 inches

March 3rd

Greatest Snow Depth

47 inches

March 4th

 

Note that all weather records for the National Weather Service office in Negaunee Townwship date back to 1961.



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