The balance of the work week will remain chilled as we're under the influence of a trough of cold air aloft and high pressure at the surface. Through Friday, high temperatures are likely to stay in the 40's and lows will generally be near freezing in the city. While crisp, it's not arctic and it's not terribly cold. We've been colder. The weather pattern will change markedly over the weekend and 60 or warmer is not out of the question on Monday and perhaps Tuesday of next week.
Until then, however, a couple more crisp days are ahead of us. Tonight's lows will drop into the 20's outside of the city, around 30 in Philadelphia with clear to partly cloudy skies. Highs tomorrow will get into the middle 40's for the most part with a varied mix of clouds and sunshine. Tranquil as winds will be pretty light, on the order of 6-12 mph, but below average on temperatures thanks to that cold trough aloft.