Unseasonably Cool Pattern Giving Way to Stormy Stretch Again
Green Country has been treated to a much-deserved period of cool, and more importantly, dry weather. The drop in humidity has come with a nice drop in temperatures at night as well. One spot in Green Country bottomed out in the 40s this morning as the map below shows. These readings were at least 10° cooler than normal. By Thursday morning, we could be in record cool territory with widespread low 50s and upper 40s. Getting below 60° by mid-June is often a feat in our area.
Between now and that chilly morning will come a round of showers and storms (depicted in our Futureview Model below). A cold front is on its way and will arrive Wednesday morning with a broken line of showers and a few weakening storms. These may be severe to our northwest tonight, but not likely be too potent by the time they reach us in the wee hours. These may continue to linger past sunrise in areas south of Tulsa, but most of our Wednesday will dry. Reinforced cooler, drier air arrives tomorrow with a sprinkle or two possible in the afternoon. Overall, this front will extend the nice weather all the way until Friday.
All good things come to an end and the first in a series of storms will arrive by the weekend. As early as Friday, in fact, a slow-moving cluster of storms may push in from the west as our jet stream flow turns zonal. That means we’ll get a west-to-easterly flow of upper-level winds. This pattern induces Gulf moisture to return our way and is often a conveyer belt of storm systems. Unfortunately, that means repeated heavy rains and storms, some of which could be severe by Saturday.
Above is the jet stream flow super-imposed with potential rainfall. The difference between the jet stream now and a month ago is that the speed is a lot lower, which means storms will be slower to move. This, combined with a cold front stalling out nearby by Sunday means our flooding risk will be high. Below is the amount of rain we may see over the week. Obviously, the amounts will vary much more than depicted here, but represents an average – one that could readily lead to additional stream and river flooding. Even into the following week, this conveyer belt of storm systems will continue to send more rounds of storms our way with an outlook for above-normal rainfall all the way to around June 25th.
High winds, hail and even a few tornadoes are possible in this stormy stretch though the lower wind speeds aloft are less than ideal for higher-end thunderstorms. Regardless, this is not a pattern we want to see return. Our current dry stretch won’t be long enough to drain away enough water from our reservoirs or soils to significantly limit the flooding threat. The silver lining? 90° days will be limited likely until July! By then, rain will hopefully be harder to come by. For once, I am really hoping that summertime ridge takes hold sooner rather than later.