May—I mean March—continues on a mostly warm note.

Yeah, we've had a couple of days where low clouds and fog have wrecked temperature forecasts and we didn't get as warm as hoped and hyped. Thanks to the natural air conditioner known as the Atlantic Ocean—where water temperatures are around 50 degrees—and a high pressure center that was to our east, a weak southeasterly flow has been the culprit in bringing a couple of mornings of low clouds and fog inland and resulting in mild, but not as warm, temperatures on a couple of occasions last week.

But we also did break 70 on three occasions last week. Through Saturday, we're on pace for the fourth warmest March since 1872 in Philadelphia with two weeks still ahead of us.

We will have to contend with low clouds and fog on a couple of mornings this week—the best chances for persistent cloud cover and temperature forecast busts are Tuesday as a weak disturbance and a high pressure system position themselves perfectly to throw Atlantic air into the region.  We could see some showers—perhaps a thunderstorm on Monday night into Tuesday morning as well.  This disturbance will fizzle out over the course of Tuesday and the high pressure center will gradually nudge a bit to our south as it positions itself near Cape Hatteras. This will result in a much more optimal setup for warmth later on this week.

The question becomes whether or not we hit 80 degrees at some point this week. The best chances for this will be either Thursday or Friday, with the hat tip as of now toward Thursday. I would not be surprised if the city reaches 80 on Thursday afternoon, but for now, we're just going to forecast upper 70s.  

The party of mildness, though, will gradually come to an end as the ridge of high pressure breaks down a bit and a cool front slips down from Canada.  There's some uncertainty regarding exactly when the front will slide through on Friday, but if it's a bit slower in moving through, we could approach Thursday's temperatures on Friday as well.  

Another shot of thunderstorms and showers are possible on Saturday and perhaps Sunday, as a persistent low pressure system in the Plains and Midwest finally nudges east and northeast and the ridge of high pressure wanes. Uncertainty is in the forecast for this weekend as well, but temperatures should still be mild compared to the average for this time of the year.  

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Tom Thunstrom is the editor and publisher of Phillyweather.net. You can follow the site on twitter @phillywx.