9 things to know about Sunday’s extreme heat
Could Sunday be the hottest day of 2015 so far, with near-record high temperatures?
Forecast high temperatures across New Jersey on Sunday range from 91° to 98°. The "coolest" spots will be in the northwest corner of the state and along the Jersey Shore... But 90s are still very possible in both locations too.
Keep in mind... Temperatures are measured and forecasted in the shade. So if you are in direct sunlight, it will be significantly hotter.
As you know, temperatures don't tell the whole story... Typical of summertime weather in the Garden State, a very humid air mass has settled on top of us. That will lead to downright tropical conditions combining with the very hot temperatures.
Dew points will peak at about 75° on Sunday. That means the heat index (also known as the "apparent temperature" or "feels like temperature") could be as high as 111°. Yuck.
Yes, we will be within a few degrees of Sunday's record high temperatures. The records for July 19 at New Jersey's three climate reporting sites are:
- Newark: 100° (2013)
- Trenton: 99° (1991)
- Atlantic City: 99° (1942)
Hottest Day of 2015 So Far?
Sunday will probably become New Jersey's hottest day of the year so far. Here are the heat statistics through July 18, 2015...
- Newark: 9 90+ degree days... hottest was 93° on 6/23
- Trenton: 6 90+ degree days... hottest was 92° on 6/12
- Atlantic City 6 90+ degree days... hottest was 94° on 6/23
Excessive Heat Warning
In anticipation of Sunday's heat, the National Weather Service has issued an Excessive Heat Warning for the Philadelphia metro area. (Temperatures are generally hotter around cities as the concrete and asphalt of urban centers absorb heat better than surfaces in rural areas.) On our side of the Delaware River, this warning includes Mercer, northwestern Burlington, Camden, and Gloucester counties.
The warning is in effect from Noon Sunday until 8 p.m. Monday. (Yes, that means the heat will continue beyond the weekend with Monday morning lows in the 70s and highs again in the 90s.)
As the name implies, an Excessive Heat Warning means heat index values above 100° could become dangerous if proper precautions are not taken. This isn't your "regular ol' hot day" - we all need to take this kind of extreme heat and humidity seriously, and potentially change our daily routines or scheduled activities to accommodate the potentially dangerous weather.
A step down from the aforementioned warning, a Heat Advisory means heat index values are expected to climb above 95° for a significant period of time.
The Heat Advisory is in effect for the following New Jersey counties from Noon to 8 p.m. Sunday: Bergen, Passaic, Hudson, Essex, Union
The Heat Advisory is in effect for the following New Jersey counties from Noon to 10 p.m. Sunday: Sussex, Warren, Morris, Hunterdon, Somerset, Middlesex, Monmouth, Ocean, southeastern Burlington, Salem, Cumberland, Atlantic, and Cape May.
(The difference in expiration times is just a technicality, caused by differences in criteria and judgment between the National Weather Service offices in Mt. Holly and Upton.)
Again, the bottom line is that it's going to be very hot and humid. (No kidding...) You'll face some fierce heat, especially during the afternoon and early evening, and you might again consider canceling or amending outdoor plans accordingly.
Air Quality Alert
Strong summertime high pressure not only brings danger from heat and humidity, but also poor air quality. As air pollution and ground-level ozone gets trapped near the surface, concentrations may become unhealthy. For Sunday, the New Jersey Department of Environmental Protection has issued a "Code Orange" air quality alert for all 21 counties in the state.
Orange is the third highest of six levels on the Air Quality Index, and means the air will be "Unhealthy for Sensitive Groups". Although most of the general public will be unaffected, a select few are at greater risk. This includes older adults and children, in addition to persons with heart and lung disease (including asthma). It is highly recommended that these groups in particular avoid strenuous activity or outdoor exercise, especially during the afternoon and early evening hours.
Yes, we've all experienced hot days before. And I'm sure you already know how to stay cool during a New Jersey summer day. But it's important to realize that Sunday will be abnormally "extreme heat" - and if you plan to work or spend any time outside, you will need to take extra precautions.
Strenuous outdoor activities should be limited to early morning or evening. Plan to wear lightweight, loose-fitting clothing and take frequent breaks from the heat (ideally in an air-conditioned location). Obviously, staying hydrated is also extremely important. And take care of your pets... You wouldn't want to be stuck out in the heat wearing a fur coat!
The danger here is heat exhaustion. If someone is overcome by the heat and humidity, move them to a cool place immediately. If that person stops sweating, experiences nausea or vomiting, develops rapid breathing and/or a racing heart rate, or has a body temperature of 104° or higher, that is heat stroke and is an emergency - dial 911 immediately.
This streak of hot weather will continue beyond Sunday, as forecast high temperatures for Monday and Tuesday are also in the 90s. If true, this stretch will meet the technical definition of a "heat wave" - 3 consecutive days of 90+ degree temperatures.
There's no big cooldown in sight either, as Wednesday through Saturday look to bring high temperatures at least in the upper 80s.
Stay cool, stay hydrated, be safe, and be smart!