Pattern Change After Weekend For Oklahoma

Through the day yesterday, there have been very few triple digit temperatures on this side of the state as you can see from this map, courtesy of the good folks at the OK Mesonet. 

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However, that all changed today since many of us marked the first triple digits of the summer as you can see on the next map.  In fact, for Tulsa the range was 80/101 as compared to the normal of 73/94 to put things in perspective.

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Unfortunately, many locations will likely see triple digits again on Saturday and quite possibly on Sunday with lots of sunshine both days and relatively light southerly winds.  In addition, the combination of heat and humidity will put the heat index values back at or above 105 during the afternoon hours so heat advisories will be in effect again for Saturday afternoon and quite likely Sunday afternoon.  Not only that, but we will not be getting much relief at night as the urban environment will only be dropping to near 80 for the early morning hours and the more rural locations generally in the 70s.

But, there is some relief in sight as you can see on our forecast page due to a pattern change with the wind flow aloft.  This next map shows the upper level flow at about the 18,000’ level as of early this afternoon.  Notice the dominant ridge of high pressure at that level, or what is referred to as a heat dome.  Underneath systems such as that the air is generally subsiding which is a warming, drying process leading to lots of sunshine and hot, dry weather.  Within those large high pressure ridges there will be some weaknesses which can result in a few, very isolated showers/storms but the general rule for systems such as this is the widespread hot, dry conditions.

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Now, notice the next map which shows the same level only for the early afternoon of Thursday of next week.  You can see that dominant ridge has retrograded well to the west putting OK into a NW flow pattern aloft.  That is a more favorable pattern for our state, at least at this time of year, to see better chances of showers and storms and quite possibly some very heavy storms at that. 

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As that transition takes place, we will start to see more cloud cover and a better chance of showers and storms starting along about Monday of next week and continuing through the end of the week.  That is not to say we will have a rain out every day, but there will at least be the possibility of rain.  Along with those changes also comes a break in the heat with temperatures expected to be closer to normal for much of next week as well.

After that, the pattern is not particularly supportive of a return to the dominant heat dome that is currently in place.  In fact, the 6-10 day outlook suggests near normal temperatures and a better than average chance of additional showers and storms.  Hopefully, that outlook will verify.

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So, stay tuned and check back for updates.

Dick Faurot