This morning's water vapor satellite image is pretty cool. The moisture for today's rain can be easily traced back to a huge line of thunderstorms way out in the Pacific Ocean. Also of note is the razor sharp boundary between the wet Pacific air and the very dry tongue of air that is behind the cold front that is approaching the East Coast. That front will arrive late this evening and quickly shut off the rain. Before the front arrives we can expect fog and the occasional shower. Luckily for those of you waiting for the tree lighting it looks like the heaviest rain will stay west of the city. The temperature today is being driven more by mild air than the sun, so the day's high in the upper 50s won't be reached until well after sunset.
Clear skies and cooler air will rush in soon after the cold front passes. A strong northwesterly breeze will keep the temperature in the upper 40s for much of the day tomorrow. That's almost exactly normal for early December. The winds will calm down by Friday setting us up for a mild, sunny, weekend with highs near 50 on Friday and Saturday rising to the mid 50s on Sunday.
2015 has turned out warm
Given the brutally cold months of January, February and March, one would have been hard-pressed to think that 2015 would wind up warmer than normal, but that is almost certainly going to be the case. The graph above shows the temperature digging itself out of the cold winter hole with which the year began. The third coldest February on record has easily been countered by the second warmest May, third warmest August, and record warm months of September and November. There is no hint of a cold air outbreak happening in the next couple of weeks (and not until after Christmas if you put stock in AccuWeather's extended forecast, which you probably shouldn't do), it already seems clear that December will be another mild month.