It’s the most commonly asked question Oklahoma meteorologists have been asked recently. We jumped from winter’s last gasp in April to the hottest May on record for Tulsa so far. Severe weather outbreaks have been conspicuously missing from our forecasts and the heat index is becoming an increasingly covered topic in our weathercasts. In short, May has been resembling June… scratch that… July!
It doesn’t mean we’re done with severe weather season just yet. As we saw last weekend, we still have the ingredients in place for at least some severe weather including tornadoes. We are entering an unsettled weather pattern over the next few days, but not the type we typically see this time of year. Instead of organized supercell storms or powerful squall lines, we’ll have the garden variety showers and storms bubbling up each day without much severe weather potential. On Wednesday and Thursday, brief downpours with lightning and gusty winds will affect scattered areas of Green Country. While a severe storm can’t be ruled out, one major ingredient is missing for anything sustained.
That missing ingredient is a jet stream. Winds aloft have dropped off significantly with the main track of stronger upper level winds riding along the U.S.-Canadian line. That is its average position two months from now. In other words, the summer doldrums have settled into Green Country early. The map above shows the overall weather pattern with only minor waves affecting us due to weak flow aloft. A jet stream helps create wind shear and organize rotation within storms. Without it, we get the more benign variety of “popcorn” storms.
A weak upper-level wave triggers daily storms through early this weekend before the pattern shifts to a more northwesterly flow. Decreasing storm coverage is expected after Wednesday with the chance of storms temporarily dropping for much of the holiday weekend as a weak cold front pushes into the area. The emphasis is on “weak” as temperatures will only rise with more clearing in our skies by Sunday and Memorial Day. Below is that holiday weekend forecast as we see it now.
The heat will slowly build for the rest of the week with highs push 90° by Friday. Heat index values may near the century mark by the weekend for parts of the area. It’ll be high time to hit the pool or lake! There is a bit of a cool-down expected next week, but temperatures likely remain above normal, almost assuredly making this one of the warmest Mays on record for Tulsa. Below is the departure from normal our highs will be in the week to come.
We keep joking in the weather office that June will revert back to May-like weather with the jet stream diving back south sending stronger storm systems our way. However, our longer range computer models tell the opposite story. In fact, a more defined ridge in the jet stream seems to form sometime in the first week of June and that is the characteristic cut-off for our storm season. Below is the longer range outlook through the fifth of June showing most of the country seeing an early season heat wave.
Another sign of the changing seasons is a potential tropical system moving into the Gulf of Mexico. While Hurricane Season doesn’t officially begin until June 1st, a rare pre-season Tropical Storm is very possible by the weekend, moving into the northern Gulf Coast. Those planning a beach vacation for the holiday weekend will want to watch this system closely. There’s even a slight chance it could bring us some tropical rains early next week.
The early arrival of summer is not a great sign for the ongoing drought over the northwestern half of the state. If we can’t get our usual spring downpours, then it’s even less likely summer would bring any relief. We’re hoping that we can at least see some good spring rains before true summer takes hold. The severe weather drought across much of the country is certainly much more appreciated. Even so, we can’t write it off quite yet. After all, this IS Oklahoma.