Mostly sunny, mostly chilly. (Tim Brown)

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

5/10: Cloudy and colder prevents me from being any bolder.

EXPRESS FORECAST

Today: Mostly cloudy. Highs: 42-47.
Tonight: Partly cloudy. Lows: 30-35.
Tomorrow: Partly cloudy. Highs: 41-46.

View the current weather conditions at The Washington Post headquarters.

FORECAST IN DETAIL

Down, down we go. Temperatures fall today and tomorrow, then Arctic air arrives Thursday. It will be our coldest December day in at least three years by Friday. A weather system approaches Saturday with potential for frozen precipitation Saturday morning into midday before rain later Saturday and another burst of warmer weather (50s!) by Sunday.

Today (Tuesday): Clouds shroud our skies most of the day as temperatures manage to push up only into the middle 40s. Winds are fairly light at least, and lowering humidity helps us dry out from yesterday. Confidence: High

Tonight: Partly cloudy and colder with lows into the lower to middle 30s along with light breezes.  We could see a stray flurry late at night or early in the morning toward rush hour. Confidence: High

Follow us on Facebook, Twitter, and Instagram for the latest updates. For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend…

Tomorrow (Wednesday): Partly cloudy with marginally colder temperatures (highs middle to upper 40s) and more breezy weather.  Winds from the north at 5-10 mph, but at least we’ve got a better shot of a few breaks of sunshine. Confidence: High

Tomorrow night: With some cloud cover around, temperatures fall only to the 30s most of the night before dropping through the 20s by dawn.  Winds pick up from the west and northwest at 10-20 mph with some gusts by early morning.  Confidence: Medium

A LOOK AHEAD

Thursday begins our excursion into the polar plunge with breezy conditions, temperatures holding in the 20s (wind chill makes it feel like teens at times) under variable sky conditions including some sunshine at times.  Temperatures fall fast into the late afternoon and early evening, hitting the teens fairly quickly.  Thursday night is nasty cold with temperatures plummeting through the teens in the city and with potential for single-digit lows and low teens for lows in the outer suburbs.  Confidence: Medium

Friday should start sunny and cold with temperatures lifting into the 20s and holding there in the afternoon as cloud cover increases.  Friday night aims for cloudy skies with lows in the teens and 20s with a chance of snow late at night. Confidence: Medium

The weekend is very tricky at the start, with a snow/sleet/freezing rain mix potential Saturday morning shifting to all rain either by midday or afternoon.  We have a chance at accumulating precipitation in the morning before the rain switch-over later in the day as highs reach into the 40s late.  Saturday night should hold in the 40s with more rain likely, while Sunday sees more showers, especially in the afternoon with temperatures moving much warmer into the lower to middle 50s.  Another arctic push arrives Sunday night.  Confidence: Low

SNOW POTENTIAL INDEX
A daily assessment of the potential for at least 1 inch of snow in the next week, on a 0-10 scale.

2/10 (↑): Still a low chance, but model agreement on frozen precipitation Saturday morning before changeover