Sunday, July 21, 2013

Heat Wave's Impact Noted, But Not Notorious

Whether or not we hit 90 today (and we will come close), the current heat wave we're in is not the longest nor anywhere close to the longest in recent memory. We've had three streaks of ten or more days in the last fifteen years, two other streaks of nine days.

It is an above average heat wave historically for Philadelphia, however, in terms of its intensity given the seven day duration of the heat wave.

Using our heat wave index calculations, the average score for a heat wave that reaches seven days in Philadelphia going back to the 1870's is 92.5.  This year's seven day heat wave scored 117, which ranks it eighth out of 50 seven-or-more day heat waves.  The highest score on our index at day 7 is 155, set in the July '93 heat wave (that heat wave had eight 95 degree or higher days in a row).

Our heat wave index calculates duration plus temperature intensity for both high and low in a heat wave, increasing the score through the course of a heat wave for the compounding "ugly" factor.

There has been at least one heat related fatality in the city and another in Wilmington from this heat wave.

What is notorious, if you have been keeping track, is our streak of consecutive days where we have been at or above 70. We're in the midst of day 28 today...breaking our long-standing record of 26 set in 1876, tied in 1995.