Steam town redux: Stuck in the 90s

If you haven't felt heat like this in awhile, you must have been out of town.

For the 15th time this month, and the 24th time this year, the official temperature in Philadelphia hit 90 today, and was up to 93 at 2 p.m. at the airport.

Yes, that's a lot of 90s. The long-term normal for the entire year is 26 days of 90 or better, with 17 of those by the end of July.

The region is getting a minor puff of relief today in that the air isn't quite stuffed with water vapor, the relative humidity has dropped below 40 percent, and the heat indexes are staying in the 90s.

But Wednesday could be significantly more uncomfortable, as the combination of an approaching front and an area of heat-pumping high pressure over the Atlantic combine to brew a water-vapor broth over the region.

Heat indexes could hit 103 tomorrow afternoon, thus the continuation of the excessive-heat warning, even though it seems as though one has been in effect since the end of June.

As that ponderous front approaches, thunderstorms are quite likely from midafternoon on into the night Wednesday, with as much as a half-inch of rain. The National Weather Service notes the atmosphere may be highly energized, so don't be surprised if storm watches go up Wednesday along with the heat warning.

By Friday, the atmosphere will have calmed and cooled down, and dry air should provide significant relief, said Kristin Kline, at the weather service office in Mount Holly.

The weekend right now is looking splendid and comfortable, and you won't have to look at the utility bills until next month.