HOT once again today, with highs into the 90s in many areas.  However, it was a bit less humid.  Did you notice?  The dewpoints were LOWER today (in the 50s for many, rather than the low 70s we had yesterday)!  Remember, air temps are how we measure how hot/cold the air is – and dewpoints measure how humid/dry the air is.  Make sense?  Well, it is a little tricky to understand.  I was trying to explain it to a Twitter follower yesterday, but found it difficult to have an effective conversation that’s limited by 140 characters.  I guess that’s what we have blogs for?  Lucky US!

Let me see if I can do better here… You see, dewpoints are a MUCH better gauge of how humid it is when compared to another value known as “relative humidity.”  That’s because relative humidity (from here on to be referred to as “RH”) is relative to temperature.  So on a hot and humid day, like yesterday, RH can be very misleading.  Here’s an example:  I think we can all agree that a dewpoint (from here on out to be referred to as “dewp”) of 65° is pretty muggy.  That’s about a 3-4 on the famous “Frizz Factor.”  Let’s just say that the dewpoint for the day is 65°… and the air temp is 70° = RH of 86%.  If you saw a RH of 86%, I’m sure you’d think “DANG.  That IS muggy!”  Well, on a different day our dewp is still 65°, but our air temperature is 100°.  Because RH is relative to temperature, our RH value has gone down to 32%.  If you saw a RH value of 32%, you’d probably think it’s dry outside – but you know better.  The dewp is still 65°, and we’ve already agreed that that feels MUGGY.  Making sense yet?  Let’s go further on this:  Dewps are called “dew-points” because it is the temperature the air needs to cool to in order for “dew” to form (think of dew forming on grass… condensation).  It is widely accepted that a good threshold for dewps is between 60-65°… higher = uncomfortable, lower = comfortable.

You know how we also talk sometimes about “heat index?”  Well, this is a connected concept.  The heat index or “how it feels” is based on the connection between air temp and moisture content of the air.  But why is that?  Well, it’s time to get sweaty… like for real.   You see, sweating is our body’s way of cooling us off – but why is that?  It’s not the SWEAT that cools you, but rather the EVAPORATION of your sweat that cools you!  Evaporation is a cooling process!  It’s as if your body is creating it’s own little AC unit around the body.  The problem is, when the dewpoints are high, the moisture content of the air is high – and the air DOESN’T WANT YOUR SWEAT.  The air is already full of moisture and so the necessary evaporation process of your body’s sweat isn’t happening, so you are NOT getting cooled off.  Don’t believe me?  Try going out for exercise on a hot and humid day.  You’ll be able to ring your shirt out when you return!  On a similarly hot  day with lower dewpoints (<60°), your shirt may even be dry!  Well, as long as you remembered your “Speed Stick.”   That’s why on days when it is hot AND humid, the “real feel” or “heat index” is even higher… because your body is unable to cool itself off.  Interesting, I know!  And also very entertaining with all of the GIF’s and pics I used.  You’re welcome.

Back to the forecast:  The dewpoints were lower today, making the heat a little more bearable (for some… there were still plenty of complainers on Twitter).  Tomorrow, the humidity goes back up – but the temp goes down.  I’m here to tell you – while it’s a little “relative relief” from the heat tomorrow, with the humidity on the increase, it may feel just as hot!  We’re also in for scattered showers and storms tomorrow (do you like how I conveniently buried that at the bottom?).  As always, it’s really tricky to pinpoint exactly WHERE and WHEN these summertime showers/storms set up, but I think the main theme for tomorrow is “splash and dash” and mainly during the middle part of the day.  Just have the rain-gear handy.  Better to prepare for the worst and hope for the best.

It gets HOT again on Monday – and humid too.  Sorry to say… there’s really no BIG relief from the heat on the way.  Though, there will be some relief from the humidity.  A front moves through overnight Monday and early Tuesday to bring us some drier (and a bit cooler) air.  That front could fire up some more showers and storms.  We’ll have to keep our eye on this during the timeline of late Monday into Tuesday.  While we’re enjoying highs in the 80s Tuesday- (maybe) Thursday, enjoy it… but don’t get too used to it.  We may have a shot at a HEAT WAVE by the end of next week.  Remember, a “heat wave” is defined as 3-consecutive days of 90° temps +.  We had two, yesterday and today, but we won’t get there tomorrow.  JUST WAIT. Thursday, Friday, Saturday, Sunday – we may make a run at it.  But we won’t be running in it.  Looks too hot for that.  

Enjoy the rest of your weekend. – Breezy