Wavy clouds over the U.S. Capitol on Wednesday evening. (Jim Havard/Flickr)

The beat of cool days goes on. Today, the sun made a decent late-day appearance. That’s something of an oddity lately. It helped boost highs to around 70, despite that nagging east wind. The big upper-level low pressure system drenching areas to our southwest is finally on the move, which means increased rain chances for us.

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Through Tonight: An isolated shower is possible in the early evening, but the main swath will move in as we head into the overnight. Steadier showers become increasingly likely by about 9 to 11 p.m., particularly to the south, then spreading through the area. A few heavier showers and storms may mix in toward the sunrise period, but none should last long. Lows are in the upper 50s and lower 60s.

View the current weather at The Washington Post.

Tomorrow (Friday): Waves of showers or storms are a good bet as the slow-moving upper level low pressure system finally decides to wander by. Round one will end in the morning to midday, but skies remain mostly cloudy. If we do see enough sunshine and heating, it’s not impossible some severe storms will develop nearby, especially southwest of the area, with some weak tornado threat possible in any that form. Highs range from about 67 to 72. Winds will be from the east around 5 to 10 mph.

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

Pollen update: Grass pollen is moderate/high at 7.99 grains per cubic meter of air. Tree pollen is moderate at 46.01 grains per cubic meter. Weed pollen and mold spores are low.

Precipitation forecast through 8 a.m. Saturday, from the Weather Prediction Center.

Showery soaking: A somewhat long-duration rain event is incoming. While most of the time there won’t be heavy rain, the multiple waves could add up. Some storms that travel over the same regions might as well. By Saturday morning, the National Weather Service has much of the region with around one inch of rain. Higher totals are a better bet in elevated areas as terrain helps lift air and causes more rain to fall.

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