Enjoy the next couple days. Imperative! The hottest weather of 2018 (so far) could begin quietly as a seemingly low-level heat wave on Sunday. Mugginess may maul us by Monday, with triple digit heat-index levels through Tuesday. Fortunately today is very nice and tomorrow is quite passable as well. June high temperatures nearer average are what we’ll enjoy. Low humidity? Rarer!
Sunshine should win over any periodic clouds. North-northwest winds should remain moderate, around 10 mph. They help keep the air dry and well away from muggy “humid” conditions. Dew points stay in the upper 40s to low 50s, making high temperatures around 80 to mid-80s feel a degree or two less than the thermometer! Confidence:
Tonight: Starry skies dominate. Winds calm quickly after sunset, and temperatures head down from the 70s at a fairly steady pace through the 60s during the early morning hours. We may have a wide range in temperatures around dawn. Mid-50s in the coolest spots well away from the Beltway, mid-60s possibly as cool as we see downtown. A patch of fog is possible by dawn. Confidence: Medium-High
Tomorrow (Saturday): Hard to complain about another seasonably average-warmth-for-mid-June day. Mid-80s should be our high temperatures and, okay, it may not feel as amazingly comfortable as Friday but still NOT muggy. Perhaps some increasing clouds in the afternoon but generally bright conditions should win out. Winds look light and variable in direction. Confidence: Medium-High
Tomorrow night: Clouds may continue to slowly build but let’s call it partly cloudy, overall. Very light southerly breezes may help slowly increase the dew points toward palpably “moist” by dawn, but precipitation chances remain very low to none. Rest assured. The region should see a range within the 60s for low temperatures, warmest — near 70 — being downtown. Confidence: Medium-High
Sunday: Heat and humidity arrive. High temperatures may top out just below 90 in the luckiest spots north and west of town, but most of us see 90 to low 90s. Clouds may mix with sunshine at times and they may help ease our transition into heat-index values as high as the mid-90s. We’ll watch to see if a late afternoon shower or storm pops up, but chances are very low for now. Confidence: Medium
Sunday night: As dew points creep up further, toward steamy levels, our low temperatures don’t have much of a chance to cool. Low-to-mid 70s might be the coolest we see, thanks to light but steady southwesterly (warm direction) breezes. Skies stay partly cloudy and there’s a slight chance of an overnight shower or storm — check back as we get closer. Confidence: Low-Medium
Our heat wave may continue Monday and Tuesday with heat-index values at or above 100 degrees possible. Temperatures hopefully peak Monday with mid-to-upper 90s. Fingers crossed, stayed tuned. We should be less hot on Tuesday, perhaps lower 90s, but serious mugginess will make our bodies sweat like it’s still nearing 100. An isolated shower or even a strong storm can’t be ruled out, especially Tuesday. Remember to hydrate often and wear light colored, lightweight clothing. Confidence: Medium