Hopefully you had a chance to soak in the relatively cool July air this morning. Tulsa bottomed out at 66°, the coolest it has been in 2 weeks. This brief relief came about thanks to drier air wedging into northeast Oklahoma behind a backdoor cold front. Unfortunately, the muggy air didn’t go far. It pushed all the way to about I-40… and is now lifting north again. With it, will return the chance of storms in the coming days.
Not everyone is going to see the rain. The increasingly hot and humid air mass will fuel scattered storms beneath weak upper-level disturbances drifting from west to east across the region. Starting midday Monday, these popcorn showers and storms will form pretty much at random and dissipate quickly from their point of formation. If you get caught beneath one, you’ll get a nice, heavy dose of rain, frequent lightning and some gusty winds. Higher chances lie southeast of Tulsa both Monday and again Tuesday. The chance of rain will slowly dwindle into Wednesday when we’ll be lucky to see isolated thundershowers firing up. The rain chances dwindle as the summer heat ridge grows stronger over Oklahoma.
That leads us to phase 2 of the forecast: triple-digit heat. Initially, it will only be the heat index topping the century mark (happening as early as Tuesday). However, by the weekend, Tulsa may finally see its first 100° of the year. We’ve hit 99° several times now, but that darned humidity is keeping us from official triple-digit highs. That’s often the case early in the summer. However, we are barreling forward into mid-July where it’s hard to avoid at this point. Our average first 100° day is July 10th and 2018 won’t likely stray too far from climatology on this one.
It doesn’t appear the “Heat Dome”, shown above, will weaken much in the coming weeks. The storm track is locked firmly along the U.S.-Canadian line and the best we can hope for in terms of heat relief might be for drier air to eventually mix back into eastern Oklahoma. There appears to be that trend about a week from now when dewpoint values drop, lowering the heat index closer to the actual temperature. There’s an outside chance a cold front could reach Green Country between now and the end of the month, but our computer models don’t really support that in our projected upper-level pattern. Below is that longer-range outlook for temperatures. I doubt we’d end up with any records being broken, but it’ll be a serious heat nonetheless.
And unless you are watering your yard, these are the conditions that lead to our typically summer brown out in (not-as) Green Country. After Wednesday, that chance of rain is next to nothing for at least a week, if not longer. By that point, we’ll be in full-blown summer mode in Oklahoma. This means the drought will worsen (at a moderate stage for much of northeast Oklahoma) and our rainfall deficit for the year (currently over 6”) will grow. Let’s hope for some widespread rainfall before the unabated summer heat takes hold again.