As you can see from the max/min temperature map for today, courtesy of the OK Mesonet, this has been another in a string of hot, humid days. Of course, the humidity made it feel even more so with heat index values well over 100, although the actual air temperature has yet to reach triple digits. But, relief is on the way as has been advertised all this week.
A rather strong cool front for this time of year will be moving across the state on Friday bringing not only some relief from the heat, but a good chance of showers and storms - some of which could become marginally severe.
A few showers or storms will be possible along the northern counties during the morning hours of Friday but it still looks like the afternoon hours will be the most likely time. The front itself should be located just NW of the I-44 corridor by noon and pushing on to the SE through the afternoon hours. SW winds ahead of the front will be shifting to the NW behind the boundary and then more northerly as we go through the day Saturday.
That veering surface wind profile (SW to W to NW) and relatively weak winds aloft is not particularly favorable for any organized storms, but the very unstable atmosphere could still produce some locally damaging wind gusts or small hail, so there will be a low-end threat of severe weather. That will be most likely for the more SE counties during the afternoon hours when the daytime heating will be maximized.
Increasing cloud cover by morning and mostly cloudy skies for Friday, along with the shifting winds, will provide a range of temperatures for the afternoon hours. Behind the front, daytime highs will likely be in the 80s to near 90 but the more SE counties could reach the mid-90s again before the front arrives.
This front is expected to push all the way to the Gulf of Mexico as the winds aloft become more favorable for cooler air to move well south for this time of year. Notice the upper-level wind flow as of about noon today and then compare it with the next map which shows the upper-level flow near midnight Sunday night. These maps are for approximately the 30.000-foot level, and the colors represent the location of the strongest winds at that level; in other words the jet stream.
Obviously, the more zonal or W-E flow that we now have at that level will be replace by a very strong ridge of high pressure aloft centered over the Rocky Mounties and a very deep (for this time of year) trough penetrating all the way to the Gulf of Mexico by Sunday night. That is what will allow that surface cool front to move so far southward over the course of the weekend.
As you can see on our forecast page, that has significant implications for our weather as we will be noticeably cooler this weekend and, although temperatures will try to recover next week, it will certainly not be to the level of recent days. Also, this NW flow pattern aloft typically produces a more unsettled period for us, so there will be at least a chance of showers/storms going into next week as well.
In fact, the 8-14-day outlooks continue to suggest below normal temperatures and above normal rain chances for that time period which would be expected with this type of pattern.
So, after dealing with heat and humidity for much of this week, we will be getting a decent break in time for the weekend along with a chance for showers/storms.
In the meantime, stay tuned and check back for updates.