nyc_temps_giss.jpgYesterday saw a weather double-triple. High temperatures reached 100 degrees at LaGuardia and Newark airports, both records. JFK also set a record high, albeit only 97 degrees. The cool spot was Central Park as the thermometer at Belvedere Castle only got up to 95. Hot as it was yesterday, today looks to be a little bit warmer. Yes, warmer. It barely cooled off last night –this morning's low in Central Park was 87– so it won't take much heating to surpass yesterday's temperatures. We are likely to score a quadruple-triple, with all four official local observation spots reaching the century mark. It should be hot enough to fry an egg on the sidewalk. If you decide to make a sidewalk omelet, take a picture and submit it to Gothamist Contribute.

In addition to the heat we're having an Ozone Action Day. Too much ground-level ozone and too many particles are making the air unhealthy to breathe, especially for the elderly, small children, and people with heart or lung disease. If you don't fit in one of those categories you’re not off the hook. Ozone is nasty to anyone who exerts themselves outside. During physical activity ozone penetrates deep into your lungs, where it is more injurious. The best advice is to slow down and stay inside as much as possible.

There's a slight, but growing, chance of showers and thundershowers this afternoon through tomorrow night. Little relief from the high temperatures is in store until a cold front passes. That welcome event looks like it will happen sometime Thursday night. Friday should be much cooler with a high of only 83.

The main reason Central Park was the city's cool spot yesterday is the park's vegetation. Streets, sidewalks, brick and concrete all absorb more energy from the sun and hold onto that energy much longer than plants and soil. Columbia University and NASA Goddard Institute for Space Studies scientists have compared satellite imagery of the city's temperature and vegetation distribution to see if planting vegetation on rooftops could cool the city down. The correlation between temperature and vegetation is striking. The warmest places are the most urban, while the coolest are the most vegetated.

Satellite map of New York City temperatures on 14 August 2002 from the NASA Earth Observatory.