Jan 28, 2012

Temperature Forecast Trends based on the LRC

Recently I updated my LRC Forecast Trend "Model" for dynamically setting the cycle length. I envision better resolution and an easy way to generate the trends for past and future years. Currently the formulas use a 50 day cycle length as a bias. The numbers are then offset based on cycle length to forecast a trend. It works like a dream as long as the cycle interpreter gets the cycle length correct. Fun stuff!

Effort is minimal to run the numbers for any location. My first attempt for locations other than my backyard stem from a few fellow Blogger friends who are somewhat LRC skeptics that have I been in communication with for a few years now.

Tim in Duluth, MN
Temperature Forecast Trend for Duluth, MN

WxWatcher near Columbia, MO
Temperature Forecast Trend for Columbia, MO

WX Ranger NW in Grand Coulee, WA
Temperature Forecast Trend for Grand Coulee, WA

Each trend tells a story of a different climate region. The Pacific Northwest being the most intriguing as it seems to be the most anomalous at this point. Regardless, the LRC is amazing and if you are reading this I am glad you may have some interest in following along! I will admit, I've spent a few hours on this particular project. I plan to add precipitation chances into it next. Then after that anything goes that we (LRC'ers) desire to toss into it for it to become a fully sensible long range weather trend suite of information. The greatest thing about the trend, thus far, is after each recurrence the validity of the it grows! Pin point accuracy for an unproven theory... WEEKS AND MONTHS IN ADVANCE! We will see how it plays out.

As always, 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!

Jan 22, 2012

Signature Event #1

October 11-16
November 25-30
January 10-15
(first posted Dec-8, 2011)
(updated Jan-22, 2012)

I am labeling this a 'signature event' because of the significant warm up, temps 10+ degrees above average, followed by a cool down bringing temps back to average or slightly below and the half inch plus of precipitation in each of the first two cycles, a little less than a half inch in the third cycle. The cycle duration around this recurrence is about 46-ish days. It's plain to see the trough was oppositely tilted from one cycle to the next. The high pressures on both coasts could be considered culprits for the tilting and the squishing of the November trough tightly together while the Atlantic high then aided in creating a 'cut-off' low to form. Perhaps slowing the cycle a bit. The January version of the pattern had hints of both previous versions within it.

500mb Plot Comparison
(click on the image for a larger view)

Radar Comparisons
(click image for the loop - 14MB)

(click image for the loop - 14MB)

(click image for the loop - 14MB)

500mb Height and Max Temp Trends

I am anticipating the recurrence of this pattern in middle January. I wrote the previous sentence back on Dec 8, and now with this update the recurrence of this pattern will take place near the end of February and beginning of March. Will it bring snow or will it bring rain? 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!

Jan 10, 2012

The "LRC Model" Versus The GFS Model

Last year I began comparing the long range Gloabal Forecast System or GFS forecast 500mb heights to a LRC based average of actual 500mb heights. It took a few forecast periods to get the calculation ironed out but this year beginning on Nov-23 I 'officially' started the comparisons.

How is the comparison made? On a daily basis the atmospheric soundings for a location are extracted and stored into a database. Every ten days the 192-384h GFS forecast atmospheric soundings for the same location are extracted and stored into the same database. As the numbers enter the database, a calculation is run to compare the number sets and dynamically update the trend. The X factor in the calculation is the LRC duration. This number allows the averaging of the actual heights to take place. Thus far this year the cycle is recurring roughly every 44-48 days. In November I chose 48 as the constant.

The criteria that I feel are meaningful with this comparison are listed below. The station used for the data is GRB, station number 72645, Green Bay, WI. Disclaimer: I admit to my lack of statistical knowledge.

Mean - Average difference from actual
Maximum - Highest difference from actual
Minimum - Lowest difference from actual
Range - Difference between Max and Min
Standard Deviation - How widely the difference varies from actual
Count - Amount of data samples
Confidence Interval - (only used to calculate confidence)
Confidence (95%) - Likelihood the forecast lies within the range specified

The above list suggests that between the dates of Nov-23 and Jan-7 the LRC model outperformed the GFS model (192-384h). Honing in on actual with a 95% chance of the trend being within +/- 106mb. The range in spikes from actual between the two was a 99mb difference creating an argument for the LRC model being a bit more stable. Click on the image above for the entire list of results.

The greatest output of the LRC model is it can be trended months into the future. Providing the ability to see pattern fluctuations weeks and months in advance and pin pointing specific dates for when they will recur. The graphical examples below are forecast trends for 500mb in Green Bay, WI and maximum temperatures in Oshkosh, WI. I would like to note that with seasonal fluctuations in the cycle duration it is important to interpolate these trends to the current cycle duration. Click on the graphs for the forecast trends into July, 2012.

(500mb Forecast Trend For Green Bay)

(Temperature Forecast Trend For Oshkosh)

As always, 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!

Jan 2, 2012

Oshkosh Winter Prediction - Cycle 1 Performance Review

How is the winter forecast based on the LRC performing as we begin a new cycle? I will admit my thinking in November was that long term climatology would prevail and not become the preventing factor in snow production as it has been thus far. The much advertised 'split flow jet' and 'bottled up AO' are the culprits in busting my snowy predictions this cycle. As for temperatures, however, the prediction of a warmer than average winter is steadfast. Overall the middle of the atmosphere keeps on the cycling and we can look forward to the 2011-12 LRC feature patterns again and again. Below are some numbers to quantify the first cycle forecast performance.

Days with Measurable Snow (0.1" or greater)
Cycle 1 = 13 days (Nov-16 thru Jan-2)
- Actual
- 5 days with 0.1" or greater snowfall.
- 14 days with Trace or greater snowfall.
- 38% accuracy

Total Snow Accumulation
Cycle 1 = 16 inches of snow (Nov-16 thru Jan-2)
- Actual
- 2.4 inches of snow
- 2.18 inches of precipitation. A 10:1 snow to water ratio would have equaled 21 inches of snow had it all been snow.
- 15% accuracy

The data trend leads me to believe that there will be enough warm spells to compensate for the majority of cold air events within each cycle leading to Above Average temperatures for the winter. The numbers tell me 1 to 3 degrees above average each cycle. Don't get me wrong, there will be some cold stretches this winter, there is no doubt about it, but with warm-ups scattered about may make the overall winter not seem so harsh temperature wise.
- Actual
- Daily Maximum temperatures are currently 4.5 degrees above the (81-10) 30 year average.

What should we expect in Cycle 2? The trends show a mild start to January with a cool down by the end of the month. February should continue with what we saw in much of December but hopefully this time around most of the precipitation will fall as snow. The most recent snowfall and wind event (Jan 1-2) should recur sometime around Feb-17. Sticking with the original forecast made back in November for this cycle, we should expect about 12 days with measurable snowfall accumulating around 17 inches. Temperatures should stay above average for the cycle once again. For an idea of when the precipitation may occur see the OSNW3 LRC Calendar 2011-12 and follow the blue highlighted dates. Remember to give or take a day, or two!

(500mb Forecast Trend For Green Bay)

(Temperature Forecast Trend For Oshkosh)

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!