Dec 15, 2011: Colder Weekend Ahead

A dry cold front affected the region today, bringing widespread cloudy skies and scattered showers. The immediate NYC area ended up staying dry today without rain, although very small details such as exact locations where it will not rain are difficult to forecast more than a few hours in advance. Temperatures ended up slightly warmer than expected, peaking in the mid 50s inland, upper 50s in the immediate NYC area, and in the mid 50s in Long Island and southern Connecticut. Today’s high temperatures once again ended up well above average, ending up 16 degrees warmer than average in Central Park and making today Central Park’s 9th day so far this month above 50 degrees. In comparison, even December 2006, which was a mild and snowless month, did not have this many days above 50 degrees through 12/15.

Colder temperatures will gradually return, but will be slow to do so, with mild temperatures staying around again tomorrow, reaching the lower 50s in parts of the immediate NYC area and Long Island. A stronger yet transient trough will move through the region this weekend, bringing high temperatures back into the mid 30s to lower 40s with partly cloudy skies. Not so surprisingly, temperatures will warm up once again by next week, reaching the upper 40s in NYC on Monday, followed by more rain for the middle of next week with temperatures potentially reaching the 50s once again.

Tomorrow’s Outlook:

As a colder air mass begins to move in, slightly cooler yet warmer than average temperatures are expected tomorrow across the area along with mostly to partly sunny skies. Temperatures tomorrow will rise into the mid to upper 40s inland and the upper 40s across the rest of the area, with lower 50s expected in parts of the immediate NYC area and Long Island/S CT. Breezy northwest winds are expected.

Weekend Outlook: Colder Temperatures Briefly Return

The aforementioned trough will move into the region on Saturday, bringing colder temperatures for the weekend. A wave of low pressure will move through the southern Mid Atlantic on Friday night, bringing partly to mostly cloudy skies across the area with scattered showers getting as far north as Cape May, NJ and Washington DC. With cold temperatures aloft, these showers could mix with a little non-accumulating snow in parts of central/northern Virginia. Partly cloudy skies will continue throughout the day on Saturday, with high temperatures reaching the upper 30s to lower 40s inland and the lower 40s in the immediate NYC area, Long Island, and southern Connecticut.

As a coastal low pressure will develop well offshore, a weak disturbance will move through the Great Lakes into the Northeast on Saturday night, bringing widespread snow showers into the western Northeast. The best risk of flurries/snow showers will be focused over the eastern Mid Atlantic, specifically towards SE Pennsylvania and potentially parts of Maryland/Delaware, as well as eastern Massachusetts. Although no widespread snow showers will fall in the NYC area, there is a slight potential for isolated flurries west of NYC. Temperatures will cool down again on Sunday with partly cloudy skies, reaching the mid to upper 30s inland and the upper 30s across the rest of the area, potentially slightly passing 40 degrees in parts of the immediate NYC area.

Next Week’s Outlook: Warmer Once Again, Rain Returns By Mid-Week

As a low pressure well to the north of the region pushes out the trough, a ridge will once again begin to build into the eastern US, with mostly sunny skies and warmer temperatures returning for Monday, reaching the mid to upper 40s across the area. Although this ridge will not be as strong as some of the other ridges in the East earlier this month and in November, the area will still end up under the warm air mass, with above to well above average temperatures lasting through next week. The low pressure to the north will bring its cold front just to the north of the area, with mostly cloudy skies and isolated showers expected for Tuesday with slightly cooler temperatures expected.

A storm will approach the area towards Tuesday night into Wednesday, but the exact location and timing of the storm are still uncertain as the forecast models are still having issues with handling the set up for this storm. The ECM model until recently attempted to take the storm well to the north of the area, but recent runs have adjusted towards the further south GFS model, tracking the storm through the Northeast. Regardless of the track, rain is expected to affect the area sometime between Tuesday night and Wednesday night, and depending on the location of the storm, temperatures may warm up again into the lower to potentially mid 50s in parts of the area, especially if the storm does track through the Northeast as currently modeled. Temperatures will cool back down into the 40s for late next week with dry conditions likely to return. Friday night’s update will include more information on the outlook for next week, as well as a brief discussion on the longer range outlook and what the area can expect through the rest of December.

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