We may not have officially broken 100° in Tulsa, but you would not know that given how oppressively muggy it has been for days on end. Our heat index has risen to nearly 110° each day for almost a week now. We paid for our very wet spring when the heat showed up.
Fortunately, the heat wave is breaking thanks to a seasonably strong cold front. As of Sunday evening, it was poised just north of the viewing area with numerous storms forming along it. These will pose a risk for locally damaging winds as they creep southward into Oklahoma overnight. Not everyone will end up with the rain, but those who do could pick up a quick inch in some cases. That would not be bad news since it has been well over 2 weeks since parts of the area have even had a tenth of an inch of rainfall on a given day (shown above). I can hardly believe that we are wishing for rain after the wettest start to any calendar year! In this type of heat, however, it only takes a week or two to dry out the ground.
Above is the risk area of severe thunderstorms into early Monday morning. These storms will gradually lose their punch the further south they go. We can’t rule out a heavy storm around Tulsa, but the higher threat is off to the north and east through 3 am. Thereafter, we expect just garden variety thundershowers to prevail along and behind the cold front. There might be wet roads for that morning drive, but some places will see the frontal passage occur with little ado.
After our stormy spell into Monday morning, the much-anticipated cooler air arrives. Monday will be a transition day as showers exit to the south with time and drier, cooler air filters in from the north. Monday will be the first day with a high in the 80s for a week. A refreshing north wind will usher in drier conditions that night, allowing nighttime readings to drop off into the 60s. By Wednesday morning, parts of the area may have temperatures bottom out in the 50s! That cooler air will be reinforced by a strong northerly flow in the jet stream all this week. It will keep the hotter air centered beneath the ridge across the western U.S. while we enjoy temperatures nearly 10° below normal. That temperature departure trend is shown below.
Gradually, south winds will return late in the week. Moisture will creep back and the mercury will climb a bit higher. By next weekend, we expect highs to return to the 90s. It will not be nearly as oppressive though. Our readings will be right at normal for midsummer. Dewpoint temperatures (a measure of moisture in the air) will remain in a fairly comfortable range as well. That will keep our heat index in check (below the century mark). In fact, there are no strong signs of temperatures climbing above normal again through the end of the month!
A wave of energy or two may interact with our returning moisture in about a week to generate some showers and storms again. It does not appear to be widespread and the storm systems appear weak. If anything, the added clouds will allow our warming trend to plateau as we move into the climatological hottest time of the year. Any cooling effect we can get by that point in the summer is rare and welcome news. Otherwise, we might be back to baking in near-100° heat before we know it. At least for now, we will be keeping the triple-digit temperatures at bay.