Thursday, July 05, 2012

Another Sunny Scorcher

The 5th of July shapes up very similar to the 4th in terms of heat as the Delaware Valley shoots for the 8th straight day of 90 or hotter.  Temperatures, starting off around 80 in the city thanks to cloud cover (and a few storms lurking around parts of the region) hanging tough overnight and preventing any "cooling", will jump to around 95 this afternoon with mostly sunny skies for the duration of the day and northwest breezes at 10 to 15 miles per hour.   Given that dew point values will drop back to around 60 to 65 in the city, heat index values will probably top out in the upper 90's this afternoon at peak heat.  Close enough to warrant continuing the heat warning for the Delaware Valley.  Elsewhere, heat index values will range from 95 to 100 across the region, with lower values northwest and higher values across the Delmarva where heat advisories are out again this afternoon.  While the city and points north will be dry, a thunderstorm can't be ruled out south of Dover this afternoon as a weak boundary slips south through our region today...the boundary does little to cool us but does provide a lessening of humidity for today and tomorrow.

The current trends suggest we stay above 90 through Saturday and then flirt with 90 on Sunday as a cool front slides through the region early in the day.  There might be enough residual heat around to nudge us to 90 for a high in the afternoon depending on how much sun we get...but that's a few days away yet.  Until then, the heat remains in full blast effect.  Saturday's heat might be the worst of the stretch...and with an added kick of humidity.  Excessive heat warnings are out through Saturday for the Delaware Valley, with excessive heat watches out for South Jersey and Delaware's southern two counties for Saturday afternoon since the combination of heat and humidity may nudge heat index values towards 110 on Saturday afternoon south of the city.