Labor Day has passed and now is the time we move ahead into thinking all things Fall. Mother Nature just hasn’t caught up with that notion yet. Temperatures have been soaring into the mid to upper 90s for another afternoon on this Tuesday with heat index values topping 100°. It’s not unusual for this type of summer heat to hang on into the first half of September, but our average high temperatures really start to drop off this month. Today’s highs (shown below) are nearly 10° above normal. That average high temperature will go from the upper 80s now to the upper 70s by the end of the month. Cooler days really are on their way!
That will become apparent as we head towards the end of the week. A trough in the jet stream will translate eastward and send a cold front our way. The front will initially stall to our north, but be close enough to bring us unsettled weather as early as Wednesday night. Off and on storms may fire again into Thursday and perhaps even into the start of Friday.
The main event will likely hold off until Friday night when the cold front gets a big shove south. It will run into a hot, unstable air mass that could allow widespread strong to locally severe storms to fire along the front. There will be no shortage of moisture either - the remnants of Hurricane Newton from the Baja of Mexico region will funnel more moisture into the mid and upper levels of the atmosphere between then and now. Flash flooding could also be an issue. The timing isn’t nailed down, but these storms have the potential to impact Friday night football games so stay aware of this threat if you’ll be out that evening. Rain and storms may linger into part of Saturday, but for the majority of the weekend, we’ll enjoy cooler and drier air ushered in by a refreshing north breeze. Below is a basic surface weather map showing the passage of the front with a cooler air mass spilling in from the cooler, Pacific Northwest source region by Saturday morning.
This cold front will be the pivot point in a weather pattern change that may last for much of the rest of September. Reinforcement of that cooler air will likely come the following week as another upper-level wave rotates southeastward across the Plains from Canada. The 8 to 14-day outlook calls for cooler than normal temperatures in our region. This means that this cool pattern could last up until September 20th or beyond. That will mean highs in the 80s, possibly 70s with lows dipping into the 50s more regularly in Green Country.
Summer-lovers, this isn’t the last hot week we’ll see this year, but each time the heat returns in the next month or two, it will likely be a faded version of its former self. Now, with the loss of 2 hours of daylight since the summer solstice, this cooling trend is inevitable even if it isn’t gradual or consistent. The stair-stepping down to that Autumn chill has begun as our days grow ever shorter. In the meantime, head this summertime heat while it lasts!