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Thank you for stopping by the Weather Watch 12 blog! With quiet weather in store for Tuesday, I want to focus on the much anticipated warm-up that is finally showing up in the 7 day forecast. The likely warm-up has been discussed here in the blog numerous times over the past month and a half. So how is forecasting a big warm-up over a month in advance possible?
When making long range forecasts I use a weather pattern theory called the LRC. The LRC states a unique weather pattern sets up each fall, and then begins to cycle or repeat. Knowing the cycle duration(around 50 days this season) allows for accurate long range forecasts to be made.
Back on February 27 I made this statement right here in the blog when looking ahead to early April.
While many are hoping for an early Spring, I just don’t see it this year for Wisconsin. However, I do think the first good chance at highs in the 70s may be around April 7-11.
Then on March 29 when I issued the long range April forecast I was even more specific!
This part of the pattern has occurred like clockwork in the 3 previous times through the cycle. Each time producing a stretch of 2-3 days with temperatures at least 10 degrees above average! I think the warmest days should occur somewhere between April 7-11, and the first 70s of the season are possible.
Each time the big warm-up came crashing down as a storm system moved into the region. I expect that storm system to occur again around April 11 give or take a day or two.
Until late Monday, most models had highs no where near 70 for Saturday or Sunday, but if you have been watching WISN 12 News over the past 3 days I been discussing a big warm-up for next weekend based solely on the LRC! I will admit it is tough to go against the grain when mid-range models say one thing, and my experience tells me something else.
Here are the reasons that I stuck with the warm-up. I compared the past 2 times in the cycle, to what the models were forecasting for this coming weekend. Here is the 500mb map from January 1, 2011, or 2 cycles ago. The key feature is the upper level low over Minnesota and its position.
Now look at the last time this part of the pattern repeated…around February 20-21. Keep in mind this is at the 500mb level, or in the middle of the atmosphere. The upper low of interest is over South Dakota and Minnesota.
Now let’s look at how the GFS(Global Forecast System) computer model on Monday was handling this same feature that will repeat this weekend. The map below is from the 12Z GFS and is valid Sunday Night. This model shows the upper low over northeast Iowa. This would mean temperatures would be cooler…as the warmer air at the surface would be farther east and south.
By looking at the previous 2 times through the cycle, I was confident that the model was forecasting the position of the upper low too far east. With a farther east forecast, surface temperatures would be much cooler in southeast Wisconsin. By using the LRC and previous parts of the pattern(also looked back to November) I was able to determine that there was an error in the model, and that I should stick with the much warmer solution.
Without the LRC there would be no way for me to know that weekend highs should be well above average!
After the 6pm news was complete on Monday, April 4 I wrote down the highs that all stations were forecasting for this coming weekend.
- WISN Saturday: 63 Sunday: 68
- Other stations forecast range Saturday: 50-57 Sunday: 50-54
Certainly anyone could be right at this point, and we can only look back after the weekend is complete. But I just wanted to show this to highlight that not all weather forecasts are the same or formulated in the same way.
I look forward to this weekend and possibly our first run into the 70s! We’ll also watch for storms as the cold front pushes in. A lot to look forward too in the coming days!
What are your thoughts on this weekend and the LRC? Just let me know in the comments section of the blog.
Have a great day!