Clear, Cool Tonight; Ozone Alert Thursday.

Sunny skies and light winds at this time of year can and often does lead to air quality issues and that is why an ozone alert has been issued for Thursday, the first one of the season. 

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Fortunately, we have very dry air in place which will allow for a nice cool down during the overnight hours and low humidity levels during the heat of the day.  As an example, the max/min for today has been 84/58 but the minimum relative humidity during the warmest time of the day bottomed out at 33% this afternoon.  Notice the max/min values across the rest of the state today and keep in mind that the normal values for Tulsa at this time of year are 85/65. 

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Thursday will be similar as temperatures tonight will again drop into the 50s, afternoon highs will rise into the mid 80s, and the relative humidity will drop into the 30% range once again.  One thing that will be different though is the brisk NE winds we had earlier today will be calming down tonight and will become more SE but only around 5 mph or so for much of Thursday.  Together with full sunshine those conditions can result in air quality issues as mentioned above.

Friday will see somewhat stronger southerly winds as you can see on our forecast page and even stronger southerly winds will then prevail through the weekend and well into next week.  That will reduce the air quality problems but will also bring a return to warmer, more humid conditions making the combination of heat and humidity more of an issue.  For example, the dew point temperature which is what determines the discomfort level will be rising from the current level of lower 50s into the upper 60s and perhaps even lower 70s by late in the weekend or early next week.  Anytime the dew point is above 65 results in at least some level of discomfort but when it is in the 70s, that is when the discomfort level(i.e. the heat index) really becomes an issue.

That also means our nights will be much warmer after the pleasant conditions of tonight and again Thursday night and our days will have more heat and humidity issues to deal with for the weekend and next week.  Despite the increasing low level moisture, conditions aloft will not be particularly supportive of much in the way of any showers or storms.  A system will produce some storms in W OK late Thursday which will try to make a run at this side of the state that night, but those will likely fall apart before making much if any impact for E OK.  We will have a little more cloud cover from time to time, but still mostly sunny skies will be the general rule.

A stronger storm system will make its presence known along about the middle to latter part of next week, but right now that system does not look to have that much influence on our weather.  We will have at least a chance of showers/storms starting along about Wednesday of next week but between now and then our chances are pretty much in the slim to none category.  Given the mostly sunny skies and stronger southerly winds in the days ahead, that also means we will be drying out and quite frankly will need a good soaking rain by then.  The 7 day QPF is not particularly optimistic for any heavy rains or anything more than scattered showers/storms and that would most likely be at the end of the time period anyway.

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The 8-14 day outlook does suggests a better than normal chance of showers/storms for later next week and through the following weekend, but it remains to be seen if that activity will actually materialize.  It also suggests temperatures will average near normal through that time period.  By then, our normal daytime highs are in the upper 80s to near 90.

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So, stay tuned for updates.

Dick Faurot