Changes are brewing in the longer range and the latest JMA Weeklies illustrate this nicely.
Week 1
No changes are needed to the expected significant heat wave to open the month of July. Heat and humidity will reach excessive levels at times- heat indices of 100° to 110° at times. While isolated coverage of storms are possible a few of the days (primarily afternoon and evening variety), it’s a dry pattern, overall.
Week 2
The pattern is in a transitional period during this time frame as the upper ridge retrogrades west. While still warm, the hottest conditions will shift west under the upper ridge. The other take-away? An active northwest flow returns with an emerging “ring of fire” pattern.
Weeks 3-4
While perhaps a bit quick, the model reverses things entirely by the Weeks 3-4 time frame. There’s no denying we think the hottest period of the summer will be behind us by mid-July, and while this type pattern shown below is where we think the dominant overall pattern is heading for the second half of summer, the model may be a bit aggressive here. Regardless, the Weeks 3-4 time frame are expected to not only reverse, but turn cooler than average over the Great Lakes region.
