Wisconsin Experimental Long Range Forecast - Summer 2018

Jun 8 2018 10:00 AM CST| 0 Comments | Wisconsin | Long Range Forecast

Methods

This is a brand new experimental forecast. I must put it on paper so I can track the accuracy and incentivize improvement. This is an area where we need to get better. This my first attempt and could be totally wrong (and have been wrong) about some or all of my forecast! Please use with caution until we can prove it's accuracy and make improvments!!!

Forecast thoughts are based on the top 10 Mar-May northern hemisphere teleconnection monthly analogs. Using climate trends over the top 10 analog years plus recent weather trends I will attempt to anticipate the next three months.

Big Picture

April brought record cold, May record warmth; so everything is on the table right now. It's fair to assume wild pattern swings will continue over the next few months. Current upper level pattern remains amplified and seems to be slowing down consistent with summer tendencies. The upper ridge seems to be settling in for the long haul in the south/southwest USA.

Wisconsin Weather
Wisconsin Weather

This is symptomatic of decreasing solar radiation and approaching solar minimum. It's tough because this process is scientifically under developed and it just takes time to learn (partially why I'm writing this). As the atmosphere contracts and colder air pushes south the pattern becomes more amplified and weather regimes have tendency to linger. Average weather tendencies have become dislocated on a monthly resolution often taking place in adjacent months (i.e Feb in April, July in May) and extremes usually come in pairs. What goes up must come down like standing waves in a swimming pool. When it rains, it rains a lot. I could certainly be wrong but this is my personal theory at the moment.

With a flip occurring in nino status from La nina to El nino (modiki likely) I would expect some volatile weather across the country during the summer. The drought conditions across the south/southwest US have a positive feedback on the upper level pattern reinforcing the ridging across the plains. Over the last couple weeks the trough was again displaced into the eastern half of the country bringing a tendency towards high pressure across the great lakes.This has a compounding impact on precipitation trends since June/July bring the biggest "lump sum" convective rain events of any time in the calendar year.

Summer 2018 Forecast

Wisconsin Weather
Wisconsin Weather

June - Cold and Dry

We are already 8 days into June so accuracy of the forecast could be biased if correct. Still the 3mo analogs are very supportive of colder than average temperatures across the eastern half of the country. This suggests that several days of below average temperatures are ahead of us. The latest medium range models (despite poor accuracy lately) show this in the form of more 40-60Fs at times during the middle of the month. A strong jet punches through next week, the precursor to these changes. Will be watching for severe weather across the region this weekend, potentially a Wisconsin event Monday or Tuesday? I'm not thrilled with how anomalies look in the southwest USA but we'll see how it goes.

July - Hot, slightly dry or near average precipitation improving drought conditions but not much different

Interesting warm spike across the center of the continent during June. The upper level pattern will look much the same, potentially pushing back north after June troughiness decreases to the east. I'm expecting the severe weather season to peak across Wisconsin in July as MCS systems move east off the ridge. I used 2006 as a severe weather analog simply because it's the only analog year available in the WPC daily weather map archive.

Aug - Cold and Dry like June

Well, if July gets hot then it's likely we will flip back in August into a pattern similar to June. Curious to see what happens.

Previous Forecast Validation

No previous forecast to validate against.


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