Oct 23, 2011

Lezak's Recurring Cycle 1988-89

An Accuweather.com Weather Forum member messaged me recently asking about my confindence in the LRC and that he had heard/read somewhere that the LRC didn't work in 1988-89 to make a long range forecast. In other words, someone decided the LRC didn't exist in the years of 1988-89. I thought that to be a profoundly inaccurate statement and I felt obligated to analyze the 1988-89 LRC to prove it did indeed exist.

To prove the LRC in 1988-89 I began by gathering 500mb geopotential heights for Green Bay, WI for the months of Aug-88 through Jul-89. I use the University of Wyoming Department of Atmospheric Science website for finding the data and I use my extraction tool to manage the data. I then graph the data looking for trends. Once I find a trend I seek the Daily Archived Weather Maps from the NOAA Central Library U.S. Daily Weather Maps Project website. Looking at the maps I analyze the 500mb plots for consistency and magically the LRC appears.

(Green Bay, WI 500mb Geopotential Heights - Aug-88 through Jul-89)

(Oshkosh, WI Max Temp Deviation From Avg - Aug-88 through Jul-89)

Two sets of specific trends that I saw from the above graphs were instances of a 'dramatic' saw tooth type pattern. A 'signature' setup that was both visible in the 500mb trends and surface temperature trends. I labeled the two pattern comparisons ORG and GRN. Seems like the dominate feature in my neck of the woods was a recurring strong ridge in the ORG pattern and a recurring strong trough in the GRN pattern.

The days in comparison for the ORG pattern are Oct 31, Dec 9, Jan 19, Mar 1, and Apr 8.

(Green Bay, WI 500mb Geopotential Height Map Comparison - ORG)

(Green Bay, WI 500mb Geopotential Height Graphical Comparison - ORG)

(Oshkosh, WI Max Temp Deviation From Avg Graphical Comparison - ORG)

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The days in comparison for the GRN pattern are Nov 26, Jan 7, Feb 20, and Apr 3

(Green Bay, WI 500mb Geopotential Height Map Comparison - GRN)

(Green Bay, WI 500mb Geopotential Height Graphical Comparison - GRN)

(Oshkosh, WI Deviation From Max Temp Graphical Comparison - GRN)

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Following the patterns through time in the graphs and archived daily maps from the linked dates above it sure seems to me that there were cycling weather patterns. What do you think? For the entire data set for this analysis click here, it is in Microsoft Excel format. The DjVu Viewer is needed to view the maps and a download can be found on the NOAA Central Library U.S. Daily Weather Maps Project website. If there are any questions or thoughts on my research and analysis of the LRC or how I presented the material just let me know in the comments section of the blog. Thanks for reading!