All Weather News

A Tropical Feel In The Air

6 Jul 2013, 2:25 pm

That is probably what many folks in the northeast corner of the nation are saying about their weather.  It is just down right unbearable to be out and about when the air is so packed with moisture, that you feel like you are in a sauna.  Factor in higher than normal temps and sunny conditions, and you have a steamy situation.  Especially in some of the major cities, where Heat Advisories are in place, that is where if you don’t have a way to stay cool or exert yourself too much, you could be in some serious trouble.



A little side-by-side comparison of some cities shows that they are experiencing the same conditions, even though they are separated by a long distance as well as being further south than others.  By mid-day on Saturday (today), temps for those cities up above were all around the low to mid 90s, but not all temperatures feel the same, especially when you factor in the dewpoints.  The higher the number, the more uncomfortable, tropical-like the air feels.  When you get dewpoints into the 70s, you are in some very humid air.  In Philly, it feels like 99° but in Palm Springs, it feels like 93° when the dewpoints are lower, in a much more comfortable realm.


These cameras here also so how hazy and sticky it feels in the air, whether you are in the northeast, the southeast or southwest.  NYC feels closer to triple-digit-heat when you factor in the 71° dewpoint, while in Phoenix, the temps feel just about what they show on the thermometer when the dewpoints are lower.  That dry heat does help make high temperatures more bearable, but to me, hot is still hot.


The reason why the northeast, and much of the eastern seaboard, is simmering under a hot and steamy blanket of moisture, is because of the jet stream and the Bermuda High.  That “H” over the western Atlantic Ocean has been inching westward for a while now, and the jet stream can’t go through it, it has to go over it.  As the jet stream does so, it along with the Bermuda High Pressure System, help to funnel warm, tropical-like moisture from the Caribbean Sea, the Gulf of Mexico and the Eastern Pacific Ocean, all the way up into the Canadian Maritimes.  That plume of moisture has been responsible for the soggy conditions in the southeast, where several inches, to a foot or more of rain has fallen across the Gulf Coast and further inland.


The satellite/radar imagery from earlier today shows the clouds moving across the area, from the Ohio River Valley, towards central Maine, in a big arch, riding along with the jest stream.  Where there are some clouds overhead, those areas have a little bit of shade from the Sun.  But along the coast, from Boston to Philadelphia, there is plenty of sunshine that is heating up the air and making that humid airmass become stifling.


There is plenty of warmth up in the northeastern corner of the nation.  The daytime high temperatures all in the northeast are well above normal levels, by as much as 13° in Boston, for example.


Check out these dewpoints that were popping up mid-day on Saturday (today)! Mid to upper 60s to low 70s?!  Factor in temps that are already in the 80s further inland and 90s along the coast, and you have a very stuffy air all around you.  You’d likely break a sweat just going out to get the mail or taking the dog for a walk.  On days like this, I’d recommend staying indoors in the A/C and lay low. Or if you have to go out and do some activities, drink plenty of water, and don’t over exert yourself.


The meter above shows how the air feels when the dewpoint numbers begin to climb.  This is the Summer time and we typically get humid conditions but some days, when the dewpoints are really high and the Sun is out beating down on top of us, it makes the air feel just down right oppressive.


Speaking of oppressive conditions, some areas have been leaning towards that way when the heat index numbers started to climb.  Heat advisories have been in place across portions of Mass., Rhode Island, New Hampshire and Connecticut.  But the conditions there should get better by Sunday.


Down in the NYC area, all five of the city’s boroughs are under a heat advisory, as well as portions of NJ and eastern PA.  Temps are in the low 90s but feel near triple digits when the humidity is factored in.  In those cities, the heat can be incredibly unbearable with the “urban island” effect there and so many vehicles and buildings using A/C, putting more heat in the air.

Over in around the city of Philadelphia, Trenton and Wilmington, the heat and humidity is so bad, that an Excessive Heat Warning has been in place since Friday.  The air can feel above 100°!  The humidity is the big problem out there, with the air so packed with moisture that the body can’t properly cool itself down when it gets hot and then you end up having heat related health issues such as heat stroke, dehydration, and fainting and swelling.

So I’ve mentioned the Heat Index up above, but what is it?  Well it is an index that takes the relative humidity and air temperature and combines them together to get a perceived feel of how the air is to people.   For example, a 90° temperature feels like 91° when the humidity is around 41%.  But when the humidity level rises about 30%, suddenly 90° feels more like 105°, and brings you up from being in the “extreme caution” category to the “danger” category.


The “Jersey Shore” would be the perfect place to go to escape the heat.  As a former NYCer, I remember the usual journey from the city on a Friday afternoon to get out of the hot urban jungle and go towards the cooler coastal areas.  Whether its the NJ shore, the Long Island shore or CT shore, it always felt so much better by the waters.  And I, of course, wasn’t the only one to be on that journey.  The evening rush on a Friday afternoon in the Summer was the worse with an increased amount of volume was on the roads.

Here are some tips from the Center for Disease Control and Prevention (CDC) on how to stay out of danger when dealing with this kind of heat and how to recognize the symptoms of heat-related health issues.  Remember to check on your family, friends and loved ones, especially those that are dependent on others, never leave a pet or a child alone in an unattended car for a second in this heat, and limit your outdoor activity if you have to do something.

Take care and enjoy the rest of your weekend!  Stay cool, northeast!

Meteorologist Addison Green (Twitter: @agreenWNTV)


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