8/14 – The Chief’s “Excessive Heat Warning” Monday Afternoon Forecast
An area of low pressure over-southern Minnesota will move to the Mid-Atlantic states by Tuesday night, dragging the trailing frontal boundary into the local area during the daylight hours on Tuesday. Calling a frontal boundary that is moving into our area in August a cold front is a bit of a misnomer, because there isn’t going to be anything “cold” about it. Slightly less hot, certainly, somewhat drier air, that too. However, any hopes for significant coverage of rainfall continues to diminish for most or all of the area. I’m not seeing any significant low level forcing to aid in the development of showers and storms. Just as has been the case for about the last week, isolated development can’t be ruled out, especially near converging lake and sea breeze boundaries in the late afternoon hours, but not seeing any signals for anything more than that.
Today’s temperatures are going to be a lot like the last several days with most of the area in the 98-103 range. Heat index values in the 110-116 range will continue to be common today, and no change to the Excessive Heat Warning for today. Drier air continues to shift southward into and through the area Tuesday night into Wednesday as the upper trough axis passes east of the area. This will shift most or all precipitation that does develop offshore or at least to the lower portions of the coastal counties. Unseasonably dry air will move into the area with precipitable water values falling below 1 inch, which is pretty much at climatological minima for mid-August.
With the exit of the upper feature to the east toward the end of the week, the upper ridge will come charging back to the east by the weekend. The main question will be how far north the center of the ridge relocates. Current indications are that the center will be farther north than the last several iterations, over Missouri and/or Iowa instead of Arkansas. That may be far enough north to place most of the area into easterly low and mid-level flow. That may allow for somewhat more “normal” August convective trends as we get later in the weekend, in other words, scattered afternoon thunderstorms. Not going to jump on this whole-heartedly quite yet, but it is at least headed in that direction.
