Saturday will feature mostly sunny skies and comfortable temperatures with highs reaching the lower to middle 70s giving the Washington Area a much needed break from the clouds and rain. Sunday will also be a nice day if you enjoy warmer weather and higher humidity. Highs on Sunday are forecast to reach the middle to upper 70s in Washington with our southern exurbs (Fredericksburg) potentially hitting the lower 80s (image below courtesy Pivotal Weather).
In addition to the warmer temperatures, dew points (the temperature at which the air is saturated) will increase out ahead of a potent cold front that will be approaching the DC Region from the Ohio valley during the afternoon hours. The warm temperatures, increasing humidity and steepening lapse rates (rate of temperature change with height in the atmosphere) will provide conditions ripe for some afternoon and evening thunderstorms.
The image below (courtesy Pivotal Weather) shows dew points climbing into the middle to upper 60s by 5pm on Sunday. The higher humidity will be fuel for a line of thunderstorms moving southeast out of Ohio and Pennsylvania during the day on Sunday.
Latest North American Model (NAM) showing a line of strong to severe thunderstorms along a cold front sliding southeast out of Ohio and Pennsylvania and into the Washington Area after 22z (6pm).
The main threat with these storms will be hail and gusty winds in addition to cloud to ground lightning and heavy rainfall.
The good news is that behind this front, skies will be sunny on Monday with low humidity and highs in the middle to upper 60s!