Timing is everything

It looks like we just may salvage a pretty great Memorial Day Weekend if everything works out right.

Back when I was getting started in meteorology, one "old school" technique we used was to time the "short waves" in the jet stream that produce precipitation. These mini waves are embedded in the jet stream, and produce lift and spin in the atmosphere ahead of them, and generate bands of showers and thunderstorms in summer.

Craig Edwards and I sometimes chat about these old school techniques with fond memories. Today's forecast models break down every conceivable parameter and display them in 6 hour increments. Often that's of incredible value, but sometimes the old school techniques still carry the day, and the forecast. Keep it simple, as they say.

The main short wave this weekend appears to be headed for Minnesota Saturday night. If it comes through then, we would see our best chance of rain overnight Saturday night into Sunday morning. If that happens, it will mean more sunshine during the day Saturday and Sunday, and warmer temperatures.

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Potential weekend precip timing

If the timing is off by 6 to 12 hours, we may see storms during the day, which will keep our temperatures down, so the passage of this wave is critical to the kind of weather you will experience this weekend.

Our spring has been cool and wet, but has also featured relatively low dew points. We have not seen big incursions of moisture rich Gulf of Mexico air moving north. That may change this weekend, and we may see and feel our first 60 degree dew point in parts of Minnesota Sunday.

Overall I still expect a pretty good weekend, with just a few hours of showers and thunderstorms. Let's hope we can get the timing right, and bring most of them through at night!

PH