Mar 28, 2011

Oshkosh Winters Of 1977-78 & 1978-79 Remembered & Finding Lezak's Recurring Cycle Within Them

With the fourth passing of the 'signature' storm in this seasons LRC and winter keeping a grip on the region I feel it is a great time to share the research I've done on the Oshkosh winters of 1977-78 and 1978-79. I decided to research these winters for a couple of reasons. The first being to learn the weather, climate and local history that accompanied the second all-time back-to-back snowiest seasons in Oshkosh's recorded history. The second reason being to find Lezak's Recurring Cycle within them and hopefully extend my learning on the theory by providing visual details on the patterns within the cycles.

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RESEARCH
Participation in discussions on the WeatherWatch12 blog since Oct of 2010 has led me to many great resources for learning about our atmosphere and the LRC. After attempting to find the LRC within previous years on my own with little success, a few lessons from Scott at LRCweather of ways to find the cycle quickly helped ignite the research process. The main lesson being "Top down is the better approach". Many LRC professionals state the basics of the LRC before they begin a discussion about it, and I will do that as well, word for word, below.

Basics of the LRC
* A unique weather pattern sets up every year between October 1st and November 10th
* The weather pattern cycles, repeats, and continues through winter, spring and into summer. Identifying the cycle length helps tremendously when making long range weather predictions.
* Long term long-wave troughs and ridges become established and also repeat at regular times within the cycle. These dominant repeating features are a clue to where storm systems will reach peak strength, and where they will be their weakest.
* The LRC is a winter-long pattern! There is a pattern! It isn’t just one long-wave trough, storm system, or ridge. It is a sequence of troughs and ridges that are cycling across the Northern Hemisphere.


I started my research of finding the LRC within the two seasons by collecting the 500 mb heights from Green Bay, WI for the months of August through July (U of WY Department of Atmospheric Science). I then trended the data noting where major swings were taking place. Those swings led me to specific dates to view archived daily weather maps and compare 500mb plots (NOAA Central Library U.S. Daily Weather Maps Project). Paralleling the archived daily weather maps of U.S. with the 500mb heights from Green Bay I was able to find a cycle length for each season. 1977-78 cycling about every 59 days and 1978-79 cycling about every 58 days.

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SUMMARY OF BOTH WINTERS AND LRC
The winter of 1977-78 was characterized by two very snowy periods in cycle 1 and cycle 2 lasting about 17 days each. 28.6 inches of snow fell between Nov 23 and Dec 9, and 16.1 inches of snow fell between Jan 19 and Feb 5. The deepest depth of the winter of 19 inches was recorded in early December. Overall snowfall totaled 66.2 inches falling on 37 days with a max 24 hour snowfall of 9.0 inches which came from the worst blizzard to hit the region in quite some time. Temperatures plummeted below zero 38 times bottoming out at -11 in late January. Winter lasted 116 days starting on Nov 30 and ending on Mar 25, according to the OSNW3 Winter Duration. Click here for the winter duration graph. Click here for the daily climate data. Click the image below for newspaper headlines from the Oshkosh Northwestern dating Jan 25-31, 1978 documenting what the folks of Oshkosh were dealing with that winter.

(Worst Blizzard Of Winter Hits - Jan 26, 1978)


I chose two specific events during this season to follow through the recurring cycle; the first measurable snowfall and the first six inch snowfall of the season. The first measurable snowfall event brought a small amount of precipitation and/or snow each time through the cycle. A cool down followed the light precipitation during cycle 1, 2, and 4 as a trough funneled in seasonably cool air to the region. Cycle 3 took on a different feel ushering in a warm up melting most of the double digit snow pack that lingered since January. Perhaps this was due to an omega block forming in the pattern as winter/spring transitioned. The first six inch snowfall event in cycle 1 brought a major snow storm/blizzard to the area in late January during cycle 2 dropping 9 inches of new snow and ushering in an eight day span of daily high temps in the mid to low teens. A trough digging south into Texas brought the cold and snowy times to the region during cycle 1 and 2. Perhaps seasonal affects to the cycle and a split flow were the culprits for cycle 3 and 4 not repeating a major storm in the region.

(First Measurable Snowfall - Nov 10-11, 1977)
This portion of the cycle took place about 61 days apart recurring on Jan 8-9, Mar 9-10 and May 9-10
Nov 10 - Jan 8, 60 days
Jan 8 - Mar 9, 61 days
Mar 9 - May 9, 62 days

Daily Weather Map Comparison (500mb map in bottom left) - 20MB
500mb Plot Graphical Comparison (14 day span centered on days in maps)

(First Six Inch Snowfall - Nov 29-Dec 1, 1977)
This portion of the cycle took place about 58 days apart recurring on Jan 24-26, Mar 23-25 and May 20-22
Nov 29 - Jan 24, 57 days
Jan 24 - Mar 23, 59 days
Mar 23 - May 20, 59 days

Daily Weather Map Comparison (500mb map in bottom left) - 30MB
500mb Plot Graphical Comparison (14 day span centered on days in maps)

The winter of 1978-79 was characterized by a persistent cold and snow that left an intensely deep snow pack that had a slow reprieve. Enduring back to back to back to back snow storms, the Jan 13 snow pack measured almost 2 feet and by Jan 25 the snow pack was at it's greatest depth of the winter, 28 inches. Not until Feb 23 did the snow pack fall below 20 inches giving the area a 20+ inch snow pack for 42 consecutive days. Overall snowfall totaled 87.5 inches falling on 44 days with a max 24 hour snowfall of 7.1 inches. This seasons snowfall total coupled with the previous seasons snowfall total of 66.2 inches is the second snowiest back-to-back winters in Oshkosh history coming in with 153.7 inches. The seasons of 1895-96 and 1896-97 are on top with 171.7 inches (the seasons of 2007-08 and 2008-09 are third with 146.0 inches). Temperatures dropped below zero 34 times with the coldest reading of -21 occurring in early January. Winter lasted 123 days starting on Dec 11 and ending on Apr 12, according to the OSNW3 Winter Duration. Click the link for the winter duration graph. Click the link for the daily climate data. Click the image below for newspaper headlines from the Oshkosh Northwestern dating Jan-Feb, 1979 documenting what the folks of Oshkosh were dealing with that winter.

(Anyone For A Picnic? - Jan 30, 1979)


With so many events taking place during this season I chose two random spots within the cycle that had a 'signature' to it and followed it through; A trough trudging it's way across the Great Lakes and a low pressure off the coast of southern California. The trough brought ridiculously cold air to the area in cycle 2 and abnormally cool air in cycle 4. Cycle 1 and 3 took a similar feel of each other keeping things typical for the season they occurred in as the air sliding down the trough wasn't from northern Canada but more from the Pacific Northwest. The low off of CA produced a mild surge of air during cycles 3 and 4. Cycles 1 and 2 did not produce the mild air as they had a northwest flow ahead of them, perhaps putting a seasonal twist into the pattern. Each occurrence of this particular pattern brought precipitation with it though, about a half inch each time. Cycle 1 and 2 dropped about 3.5" of snowfall each as well.

(Trough - Nov 6-8, 1978)
This portion of the cycle took place about 58 days apart recurring on Jan 1-3, Mar 4-6 and Apr 27-29. The amount of days to and from March seem a bit off, but I analyzed and re-analyzed and concluded on Mar 4. Perhaps a rookie mistake.
Nov 6 - Jan 1, 57 days
Jan 1 - Mar 4, 63 days
Mar 4 - Apr 27, 55 days

Daily Weather Map Comparison (500mb map in bottom left) - 30MB
500mb Plot Graphical Comparison (14 day span centered on days in maps)

(Low Pressure - Nov 23-26, 1978)
This portion of the cycle took place about 57 days apart recurring on Jan 17-20, Mar 16-19 and May 9-12.
Nov 23 - Jan 17, 56 days
Jan 17 - Mar 16, 59 days
Mar 16 - May 9, 55 days

Daily Weather Map Comparison (500mb map in bottom left) - 40MB
500mb Plot Graphical Comparison (14 day span centered on days in maps)

The "Firsts and Lasts" of both winters can be used as a quick comparison tool. Both winters started quick and snowy but only 78-79 was able to maintain and prolong the season into early April. Easy to tell from the list below that 78-79 was the monster of the two.

(1977-1979 Winter Firsts & Lasts)


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FINAL THOUGHTS
Regarding Oshkosh in general, the Oshkosh Northwestern from the 77-78 winter tells a tale of snowcoverd sidewalks becoming a problem throughout the city. The lack in enforcement of the city snow removal code clogged sidewalks and news of it peppered the newspaper . The following winter, 78-79, it was noted that snow blowers had been sold out in all of Oshkosh. I have yet to experience such snow depths while living in Oshkosh, but I am certain I would have been a culprit of having a too often snow covered sidewalk. I rarely shovel anything less than an inch and if it weren't for my hard working neighbors and a periodic melt, my sidewalk would resemble my driveway most of the time, usually snow covered. (proof that the times have not changed)

Regarding the LRC in this summary, it seems during March the cycle always had some anomaly pattern accompanying it compared to the same recurring patterns during the other cycles. I am curious if this is a seasonal thing that happens in Spring or just something that happened in this instance. The transition the cycle goes through as it breaks down is a high priority of mine to learn more of as summer approaches in 2011.

The data and graphs that led me to my conclusions can be found by downloading the Microsoft Excel file located here. The file contains highlighted areas of my research which include daily surface data, atmospheric sounding data/graphs and event specific information of both winters. The archived daily weather maps used in the comparisons are located in the specific discussions but can also be found in each seasons image gallery here (1977-78) and here (1978-79). Using the spreadsheet I linked above will allow one to pin point particular weather events and dates from this time period. Referencing the maps from the NOAA Central Library U.S. Daily Weather Maps Project would then allow one to see the cycle for themselves. I recommend using the maps to see other parts of the cycle from 77-78 and 78-79.

Due to the amount of time the task of obtaining the atmospheric soundings took, I've since created an Excel spreadsheet that runs a few functions with minor manual manipulation to help speed up the process, about 2 minutes per month. If interested in it, let me know, I would be happy to share.

I am certain all my research and findings regarding the LRC are up for debate as this is my first year following and learning the LRC. It is proof positive to me that the LRC exists. The LRC is fascinating and I am happy the idea of the theory has crossed my path.

If anyone reading this has a memory from the time period discussed, please share your words in the comment section of this blog. It would be much appreciated. Also if there are any questions about my research and how I presented the material just let me know in the comments section of the blog as well. Thanks!