COOLER DAYS ARE HERE AGAIN...
A strong cold front has barreled its way through the upper Midwest setting the stage for what will be one of the coolest starts to June in recent memory. The chill does have strong support from the Madden Julien Oscillation which is projected to cycle through phases 7, 8, and 1 between now and June 14th.
The MJO's convectively induced energy field in the western tropical Pacific results in a downstream pattern over the United States that fosters a significant ridge off the Pacific Northwest. That opens the door to cool Canadian air masses to spill into the Midwest. The temperature anomalies for phases 7, 8, and 1 on the right of the phase diagram above, shows the strong correlation to below normal readings in the central part of the nation.
Here's the 500mb jet configuration showing the tendency for a trough to exist in the center of the nation. This is the predicted flow going into June 8th on the GFS.
Over the 10 day period June 3rd through June 13th, temperatures are shown running 8-12 degrees below normal per day.
June 10th the GFS indicates late day temperatures as much as 20 degrees below normal.
That could result in highs holding in the 60s...no better than 70. Typical highs are creeping above 80 by then.
The GFS even paints lows in the 40s around June 10th. Very impressive considering how short the nights are which greatly limits the atmospheres ability to cool. Conversely, highs in the 60s are just as impressively low with the power the June sun possesses.
The silver lining is the fact we are not in January. If so this would be a frigid set-up with sub-zero lows, nasty wind chills, and perhaps snow. However, in June the pain will be limited to highs in the 60s and 70s, along with nighttime lows well into the 50s. I don't want to make this sound worse than it is but relative to average these are very significant departures, especially when you consider the duration of the chill which could last a solid two weeks. The Climate Prediction Center sees the writing on the wall too with a 70-80 percent chance of below normal temperatures.
I don't expect any worthwhile precipitation chances until late Saturday at the earliest. That means we have some really pleasant weather ahead with highs Wednesday through Friday in the low to mid 70s. Partly sunny skies Wednesday will give way to abundant sunshine and minimal humidity the remainder of the week.
This weekend clouds will be on the increase Saturday as well as temperatures. Much of the day looks dry but shower and thunderstorm chances return late in the day, especially Saturday night and Sunday. Highs Saturday may reach the upper 70s before cooling into the mid 70s Sunday. Cloud cover will dictate just how warm we get either day.
Once we get back into rain chances over the weekend and into early next week, light to moderate rains are possible. That said, models are showing a significant spread in where the more substantial rains might fall. The EURO is generous with its amounts across much of my area.
The GFS splits them to the north or south.
It will take awhile before models come to agreement so for now we will enjoy our quiet cool weather pattern that will take us through the rest of the week. Happy hump day and roll weather...TS