Pattern Change: Spring fever outbreak next week?

This is the time of year when meteorologists look for significant seasonal pattern changes. The upper air maps usually shift sometime in mid-May and feed warmer late spring, even early summerlike air into the Upper Midwest.

It appears that change is about to occur next week. The forecast models for next week suggest more consistent highs in the 70s and even a shot at 80 degrees.

For many Minnesotans, it's about time.

Jet stream shift

Meteorologists follow mean jet stream positions for broad forecast strokes. Dips in the jest stream (trofs) bring northwest flow blowing chilly spring air masses to Minnesota. That's what's causing our cool weather pattern this week.

Here's NOAA's forecast upper air map for 7 pm CDT Thursday.

Now, check out the upper air forecast for next week. See how the jet stream is predicted to lift north and relax? That will allow much milder air to seep north into the Upper Midwest next week.

Back to the 70s 

Forecast models are starting to pick up on the change. Highs in the 70s look more consistent starting next Monday.

I've often thought of 70 degrees as the most important temperature threshold in Minnesota. It seems to be the difference maker for our state of mind, seasonal wardrobe, and activities. It looks to me like our spring warm season sea change happens next week.

One more chilly week

In the meantime, we muddle around through one more cool week across Minnesota. Tuesday looks relatively nice. The next rain system arrives Wednesday. This system focuses the heaviest rain on Iowa and southern Minnesota. The Twin Cities rides the northern edge.

Northern Minnesota stays dry this week. Rainfall totals cluster around .50" across most of southern Minnesota. Heavy rainfall of 2" to 4" could fall across southern Iowa, Missouri, and Illinois. Not the best scenario for rivers still in flood there.

More severe weather training classes

Here's another round of severe weather training classes.