It's Not The Heat, It's The Humidity!

We've heard many people say that over the years....and they most certainly have a point. Recently, the dewpoints have been hovering around 70F. That is very muggy air for us here in PA. Frankly, however, when the air temp is above 85F, it is quite capable of having much higher dewpoints. In fact, the air "wants" to have a higher vapor partial pressure of water in it. The graph below clearly illustrates that as the ambient air temperature increases, the partial pressure of water vapor can also increase. 

Many times people ask me why we don't get huge snowfalls like we can get heavy rain storms in the warmer months.  Well, if one scrutinizes the graph above, when the winter precip events roll around, there is much less water vapor for the air to work with at colder temps than in the warm season when the partial pressures of water vapor can be and are often substantially higher.  There is more than 4 times the water vapor in saturated air at 86 F than there is at 32 F!  And sometimes people say it is too cold to snow.  Well, there is a little bit of truth to that since as temps get increasingly colder, the air's capacity for water vapor partial pressure approaches 0 hPa.  Hence, the gelid continent of Antarctica is a colossal COLD desert!



I show y'all that just to help cool you off from this early season heat.  The most uncomfortable combo of heat and humidity I observed today was 93 F and dewpoint of 73 F!  The data below shows quite an uncomfortable day, that's quite sweltering....

The graphic below shows the uncomfortable dewpoints Thursday afternoon all the way up into New England.  The yellows, greens, and blues are very comfortable dewpoints.

A look at the numerical guidance for Sunday evening; much more comfortable air in terms of humidity and appreciably lower dewpoints!  It will feel very refreshing.

Peering even further into the future, the American and the European models are somewhat at odds.  The Euro shown below has a decidedly warmer solution than the the American GFS as there is a weak ridge over PA from a zonal flow across most of the country.

Whereas the GFS has a deeper trough with a pronounced NW flow leading to a much cooler and drier atmospheric solution.  Which is correct? It's difficult to get any insights on this as of this evening.  I'm rooting for the GFS!

You know, this early season heat is certainly what most fans of the sport would refer to as "baseball weather".   I'm not a big New York Yankee fan, but I for one am rooting for Derek Jeter on his quest to join the greats of the game.  Jeter has been nothing but an ambassador for the game.  This future hall of famer deserves all the accolades he'll receive when he reaches the 3,000 hit milestone.  My only question; will he attain this record by the summer solstice on June 21 at 17:16 UTC?  Only time will tell.

Enjoy your week's end!

Smitty

AA:  Unsettled weekend as front lies nearby.  Drier by Sunday afternoon/evening and becoming much more comfortable through next week.  Even for a Red Sox fan; Jeter is the man!