D.C. area forecast: Increasing heat, humidity and storm chances, then big-time relief by midweek

Today’s Daily Digit

A somewhat subjective rating of the day’s weather, on a scale of 0 to 10.

6
Hotter and a bit more humid, plus a little better chance for p.m. storms drops the digit down a point

Express Forecast

Today: Partly sunny, hot and humid. 30-40% chance of p.m. storms. Highs: Low-to-mid 90s.

Tonight: Mostly cloudy and muggy. 30% chance of showers/storms. Lows: Low-to-mid 70s.

Tomorrow: Still warm, 60-70% chance of p.m. storms. Highs: Near 90 to low 90s.

FORECAST IN DETAIL


Radar & lightning: Latest D.C. area 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.

In a long overdue turn of events, the weekend does not feature the the finest weather of the week this time around. Today is by no means a clunker, but building heat, humidity and storm chances today (and into the first part of the work week) are not nearly as enjoyable as weekends past. Storm chances are greatest Monday and Tuesday, when we must also watch for the threat of severe weather moving through. Big-time relief is on the way, though, as a cold front passage on Tuesday leads to a midweek feeling more like late spring than the middle of July!

Today (Sunday): A bit of upper-level energy swinging through overhead mixes some clouds in with the sun. Temperatures surge regardless, all the way to highs in the low-to-mid 90s. Meanwhile, winds from the southwest near 10 mph keep the dew points up, so it’s a muggy day out there. That upper-level energy combined with the heat provides a 30-40% chance of showers and thunderstorms, most likely after 3 p.m. While they may be hit or miss, a few could produce strong to severe winds. Confidence: Medium-High

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Tonight: We lose the energy from the daytime heat, but the upper-level energy helps keep a 30% chance of showers and storms going into the overnight. Any activity should be scattered, and should become less intense as the night goes on. Otherwise, it’s mostly cloudy and muggy, with light winds and lows only dropping to the low-to-mid 70s. Confidence: Medium-High

For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through midweek…

Tomorrow (Monday): We’re still ahead of an approaching cold front, keeping us in the hot and humid air mass. Even with partly to mostly cloudy skies, there’s enough sun to push highs to near 90 to the low 90s. By mid-to-late afternoon the front could very well trigger showers and thunderstorms (60-70% chance). Some of these could be strong to severe with the potential for damaging winds and some hail. Winds remain from the southwest around 10 mph, but gusting higher in the vicinity of any thunderstorm development. Confidence: Medium

Tomorrow night: Storm chances continue at 60-70% into the evening and could still be strong to severe, before likely losing their punch after dark. Coverage should diminish overnight, though a few storms may manage to hang together as they work their way east of the area. It’s mostly cloudy and continued humid through the night, with lows in the low-to-mid 70s. Confidence: Medium

A LOOK AHEAD

There are plenty of factors that could increase or decrease the potential for severe storms (with heavy rain and damaging winds) on Tuesday, including the timing of a strong cold front and leftover clouds from previous storms. Either way, we’re expecting a good chance of showers and storms (60-70%) developing at some point during the day and perhaps lasting into the evening. Look for still-humid highs in the upper 80s. By the overnight hours the cold front should be by us, with cooler and drier air moving in (YAY!) as lows dip to the 60s. Confidence: Low-Medium

Wednesday and Thursday look just perfect! The return of the Nice Day Sun to the blog looks likely, as does a good dose of actual sun as cool Canadian high pressure takes control of most of the eastern U.S. Daytime highs top out in the upper 70s to mid-80s and dry air (dew points in the 50s, maybe 40s?) make being outside a welcome joy compared to the several days prior. Confidence: Medium

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