If you're reading this, you made it. You've survived the heat wave of 2011. Sounds incredibly over-dramatic, no? Surprisingly, it isn't when one actually considers the severity of what was experienced over the past several days. Records were tied, then broken, and eventually many places just flat out shattered the previous records, and set new ones that we may not see broken for many years. The heat was oppressive, severe, and dangerous, with heat index values climbing near 120 degrees at times. The actual temperatures climbed into the triple digits. But many have asked, what made this heat so much worse than the heat we have experienced in the past? What made is feel so much hotter, so much more oppressive, and what made it so much more dangerous?  In a type of "post-mortem" look at the heat wave, we can draw upon certain meteorological factors that led to this heat wave being so dramatic. Featured image: Observed temperatures at 2:00pm on Friday July 22nd, 2011, just an hour before Newark NJ reached a record high of 108 degrees.

The heat wave actually officially began over a week ago at Newark, NJ, when the thermometer hit 90 degrees several days in a row (90 on 7/15, 94 on 7/16, 95 on 7/17, 99 on 7/18, 95 on 7/19). Wednesday, July 20th offered a break in the heat wave, as most of the area sat underneath briefly lower heights in the atmosphere. In other words, the big atmospheric ridge responsible for the heat that was to come was still back to our west. By Thursday, July 21st, the ridge was moving overhead. In fact, throughout the day, the temperatures in the mid levels of the atmosphere were increasing dramatically. The high at Newark that day was 103 degrees, breaking the old record of 102 degrees set back in 1991. Central Park reached a high of 97--at 1236pm thanks to a sea breeze front.

However, by this point, the ridge was established. What was changing was the flow of air in the low levels of the atmosphere, nearer to the surface. Those winds had turned south and southwest, advecting in very moist air with dew points over 75 F. The combination of high dew points and high heat can make the heat index soar--and that's precisely what occurred. Recall last summer, we dealt with a heat wave in early July, but the dew points were dramatically lower. As a result, the heat index was as well. That heat wave was much more "bearable". This one was not. Although the high temperatures on Friday were to be historic, the low temperatures overnight Thursday into Friday were as well--with Newark recording a low of 86 F at 532am, a record. Featured image: RUC (Rapid Update Cycle) model, showing the large ridge in place in the mid levels of the atmosphere Friday Night. 

During the day on Friday, the area broke out into nearly full sun, and the heat was on. Newark soared to 108 degrees fahrenheit by 240pm--an all time record high. An all time record high. Records like that are not easy to break. In fact, records dropped throughout the forecast area--at almost every reporting station. We've listed the high temperatures recorded below, and the records broken.

Newark, NJ (EWR): 108* (All time high) (Daily record was 101, 1957)
Central Park, NY (NYC): 104* (Daily record was 101, 1957)
LaGuardia, NY (LGA): 104* (Daily record was 101, 1957)
Kennedy, NY (JFK): 103* (Daily record was 98, 1998)
Islip, NY (ISP): 100* (Daily record was 96, 1998)
Bridgeport, CT (BDR): 103* (Daily record was 102, 1957)

That covers every major reporting weather station in the area---with new record high temperatures. Saturday featured more high heat and dew points--with Newark again reaching triple digits, recording a high of 102, a new daily record. The past two days have featured more moderated temperatures, but July as a whole has featured well above normal temperature departures.  In fact, it is on pace to be one of the warmest July's ever. As folks would tell you around here, after experiencing the heat this weekend, that doesn't come as any surprise.