Hot & Humid, Again.

As mentioned in yesterday’s blog, for this late in September this weather is a little ridiculous.  Although not setting any records, today’s max/min for Tulsa has been 97/75 as compared to the normal range of 82/60.  Of course that is only part of the story as the heat index has topped out at 107 as a result of dew point temperatures holding in the lower 70s this afternoon.  Actually, it could have been worse as those dew points were in the upper 70s for a time this morning, but mixed out into the lower 70s this afternoon which allowed the relative humidity to drop to 45% during the heat of the day.

Notice the max/min temperatures for today across the state, courtesy of the OK Mesonet.  Several locations actually did make it into triple digit territory this afternoon and of course heat index values were well into triple digit territory.  As mentioned, the dew points did mix out somewhat this afternoon and that trend is expected to continue in the days ahead. 

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That should allow our nights to cool off somewhat with upper 60s to lower 70s expected for tonight and the next several nights.  Also, our winds will remain light and from a S/SE direction for tonight and again on Wednesday so not much of a cooling breeze.  Fair skies again tonight but there should be more in the way of high level cirrus clouds for the next few days and that is why we have knocked our daytime temperatures back a few degrees for Wednesday and again on Thursday.

Despite this heat and humidity, the upper level pattern has a large high pressure ridge overhead which are often referred to as heat domes as you can see on the map.  This provides a formidable cap aloft allowing for only some daytime fair weather cumulus clouds.  That also keeps any shower/storm activity to a minimum and usually in the terrain favored locations of SE OK if at all.

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As the week progresses, this pattern will be changing as a rather strong low pressure system aloft will be developing over the Southern Rockies and will be slow to move eastward.  Here is the projected position for late Sunday which is reasonably close to yesterday’s solution.  The longer range guidance continues to have some inconsistencies regarding the movement and strength of the system as we head into next week.  But, until those issues get sorted out and we get better agreement, the bottom line for us suggests increasing cloud cover by Saturday along with a chance of showers/storms. 

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Better chances of showers/storms are then expected for Sunday and quite likely into the day Monday as you can see on our forecast page.  After that, the uncertainties are much more of an issue as the solutions diverge so for now will call for partly cloudy and little or no mention of rain.  That is certainly subject to change though.  At any rate, this could turn out to be a very wet system for us.  Am reluctant to get too excited about how much rain we may receive given the recent history over the last few weeks in which a number of systems looked promising but certainly under delivered.  At any rate, here is the 7 day QPF taken with a grain of salt.  It certainly does suggest the potential is there for a good soaking over the coming days.

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The clouds and showers will certainly give us a break in the heat over the weekend and into next week, but this is not a particularly cool system, at least not with respect to normal for this time of year.  Even so, any relief will certainly be welcome and looking further downstream, the 8-14 day outlook continues to suggest above normal temperatures.  Normal daytime highs are in the 70s by then so the above normal temperatures should translate into 80s for that time period which is at least some relief from recent days.  That time frame also looks to have a better than average chance of additional precipitation. 

So, stay tuned and check back for updates.

Dick Faurot