DC Hits the Drifecta

Now

Sunny, cooler, less humid. A few spots in the region, especially well to the north and east of the Beltway (NWS map out for maintenance) got some welcome showers last evening, but all 3 major airports saw only a trace, and National is now approaching the end of its fourth consecutive week without measurable precipitation. At this point, it would take at least 2" of rain the rest of the month to keep this September-October from being one of the top 10 driest such periods in 137 years of records. The driest, shown in the chart, was 1930 with 1.04"; this year's total so far is 0.60".

After yesterday's trifecta of temperature records and high humidity, the cooler temperatures and much drier dewpoints are a relief, but temperatures are still a good 10° or more above seasonal averages. By mid afternoon, most locations were in the low 80s, while dewpoints had dropped into the very comfy upper 40s. A reinforcing shot of cool air will accelerate the downward temperature trend tomorrow.

CapitalWeather.com chart from NWS data, photo © Kevin Ambrose

Tonight and Tomorrow

Mostly clear, then some clouds and much cooler. Lows tonight under clear skies will range from the upper 50s downtown to the low 50s in the 'burbosphere. Tomorrow will be much more Octobery: partly to mostly sunny and breezy with highs 65-69°. There is a slight chance of a passing shower in the afternoon.

For the outlook through the rest of the week and into the weekend, scroll on down to Jason's post below.

Mediarology

The second episode of the new PBS Wired Science series tonight is scheduled to feature a segment on the effect of global warming on gardening and also on where rubber duckies go to die. Showtime is 8pm on WETA 26 and WMPT 22 (your cable system may vary).

Planetary Weather

The NYTi reports today that NASA's New Horizons spacecraft, while getting a slingshot boost by Jupiter earlier this year on its way to Pluto, discovered lightning in Jupiter's atmosphere at both poles, the first time this has been observed beyond Earth. The spacecraft was designed and built, and is operated by, the Johns Hopkins University Applied Physics Lab in Laurel.