Radar & lightning: Latest regional radar shows movement of precipitation and lightning strikes over past two hours. Refresh page to update. Click here or on image to enlarge. Or see radar bigger on our Weather Wall.

We touched 90 today, for our lucky 21st instance of reaching that threshold in 2014. We’ll probably get 90-degree day number 22 Friday.  The steamy air mass could fuel an isolated storm or two this evening, with somewhat better odds to close out Friday.

Through Tonight: A 15-25 percent chance of storms through around sunset, with the highest chances in our western areas (Loudoun and Frederick counties).  Otherwise, a muggy, partly to mostly cloudy, and quiet summer evening with early morning lows in the mid-70s downtown, with upper 60s in our cooler suburbs.  Very light winds from the southeast.

Tomorrow (Friday): Partly sunny, hot and humid for the balance of the day.  Highs are near 90, with a heat index as high as 95 (dew points near 70).  There’s a 30 percent chance of showers and thunderstorms, with the windows from 4-8 p.m. most likely.

See  David Streit’s forecast through the weekend. And if you haven’t already, join us on Facebook and follow us on Twitter . For related traffic news, check out Dr. Gridlock.

Pre-dawn, September 1. (Kevin Wolf, via Flickr)

Pollen: Trees counts are LOW, grass counts MODERATE, weed counts MODERATE-HIGH, and mold spores MODERATE-HIGH.

Global Precipitation Measurement (GPM) mission unveils initial images


The most accurate and comprehensive collection of rain, snowfall and other types of precipitation data ever assembled now is available to the public. This new resource for climate studies, weather forecasting, and other applications is based on observations by the Global Precipitation Measurement (GPM) Core Observatory, a joint mission of NASA and the Japan Aerospace Exploration Agency (JAXA), with contributions from a constellation of international partner satellites.


Read more at NASA.gov: International Global Precipitation Measurement Mission Data Goes Public.

See also, from Climate Central: NASA Releases Blizzard of Precipitation Data and my earlier story on GPM: NASA launches game-changing satellite for tracking global precipitation