For the middle of September, this is a little ridiculous. Notice the maximum temperatures for today and also the max heat index values. Certainly more like the middle of summer than a few days before the calendar start of fall. To put things in perspective the normal max/min for this date here in Tulsa is 82/61 and the numbers for today were 97/70, neither of which was a record. But, with dew point temperatures holding in the mid 70s throughout the day, that combination pushed heat index values up to 109 here in Tulsa. The minimum relative humidity this afternoon only dropped to just below 50%....Ugh!
For tonight, those high dew points will keep things from cooling off much despite fair skies and a light SE breeze. Morning lows in the upper 60s to lower 70s will be the general rule and a few degrees warmer in the urban environment. As we go through the day Tuesday, a few high level clouds and a few fair weather cumulus clouds will not do much to hold temperatures down and daytime highs in the low-mid 90s are expected. Heat index values will likely top triple digits but should not be as extreme as today. The reason for that is the dew points are expected to mix out somewhat over the next few days, but it will still be extremely uncomfortable during the afternoon hours and heat advisories may once again be required.
Wednesday and Thursday should see a little more in the way of high level cloudiness which should hold our daytime highs down into the lower 90s for the most part. That is still at least 10 degrees above normal though and our nights will not be seeing much relief either with morning lows in the upper 60s to near 70. A light S/SE wind will not be providing much in the way of a cooling breeze either. As far as any cooling showers/storms, cannot rule out one or two over the terrain favored locations in the more E and SE counties during the heat of the day, but those will be very isolated at best.
The reason for this September heat wave is a high pressure ridge aloft that has built over the state as you can see on the afternoon 500 mb height chart, or about 18,000’ up.
However, as the week wears on the pattern aloft will be changing with a rather strong storm system moving into the Southern Rockies associated with the remnants of what is now hurricane Paine. But, that system is expected to be stalling out by the coming weekend.
However, that change in the pattern aloft will be spreading more cloud cover our way and will also provide at least a chance of showers/storms by Friday and more likely through the weekend. Since the main storm center looks to stall out well west of us, then the best chances for showers/storms looks to be over the more western counties, but at least this combination will help bring temperatures down as you can see on our forecast page. Even so, temperatures still look to be above normal through the weekend and into next week.
Looking further downstream, temperatures are still expected to be warmer than normal going into the following weekend as you can see on the 8-14 day outlook. Normal daytime highs are in the 70s by then so the above normal temperatures should translate into 80s for that time period which at least is cooler than we will be for much of this week. That time frame also looks to have a better than average chance of additional precipitation.
So, stay tuned and check back for updates.