A dangerous combination of heat and humidity will make it feel like 105°F to 110°F across the D.C. area this afternoon.
Just when you thought this summer wasn't going to be that hot, this week showed up. Temperatures over the past 4 days have seen highs in the mid 90s and the temperature hasn't feel below the 80 degree mark during the same time period.
- Excessive Heat Warning and Heat Advisory until 8pm
Today, an Excessive Heat Warning is in effect from Noon to 8pm for D.C., Arlington, Alexandria, Falls Church and the City of Baltimore. Other counties along and east of the Blue Ridge to the Chesapeake Bay are under a heat advisory for the same time period. Heat index values will soar to 105°F to 110°F this afternoon.
How "extreme" is this heat wave though? The heat has been getting extreme media attention, and though it is dangerous and potentially deadly heat, it is not uncommon in July. Remember, our average high is 89 degrees this time of year, so we're only averaging 6 to 7 degrees above the normal high temperature. In addition, this year hasn't even begun to touch the extreme heat from the last couple of years.
- July 2012 Heat
In 2012, July started off with a period of 8 straight days at or above 95 degrees. This included 4 days in a row at or above 100°F! That was just the beginning though, as the month accounted for 7 days at 100+, 16 days at 95+ and 22 90-degree days.
2011 wasn't much better, with only 3 100 degree days, 14 days at 95+ but a whopping 25 90-degree days. The coolest July in the past 5 years was 2009, when there were only 7 90-degree days for the month and only 1 day at 95 or better. I'm sure by now we are all beginning to miss cooler weather.
- Overnight Low Temperatures at or above 80°F for 4 days straight
One more thing that is noteworthy for this current heat spell is the fact that the overnight low temperature has not fallen below 80 degrees in 4 days at Reagan National Airport (if this holds up today with possible afternoon and evening storms). I checked with the National Weather Service and this has only occurred one other time back in 2011.