Unsettled weather will be present for much of the remainder of the week, from Tuesday through Thursday. However, the main story may be a potential winter weather event which is bringing a forecasting headache Wednesday Night through Thursday Morning. The forecast will begin with a frontal boundary to our west on Tuesday morning. Temperatures will be mild with showery activity in the area, as well as areas of dense fog. Throughout the day, mostly cloudy conditions are expected with temperatures in the upper 50's to near 60.  This trend will continue through Wednesday morning, when the front will sag closer to the area. Meanwhile, across the middle of the country a significant disturbance in the middle of the atmosphere will begin to move eastward. The key to the forecast will be how this feature interacts with the frontal boundary near or just east of the area Wednesday night into Thursday morning (timing, positioning of the front, etc). Forecast models have been persistent in developing a strong storm system along the front, which would produce heavy rain that would eventually change over to snow from west to east. Pictured right: NAM model showing a low pressure system off the New Jersey coast with significant precipitation over the area -- in the form of rain changing to snow.

This provides a major headache in the forecast -- as the changeover becomes extremely unpredictable. We've seen these before (October 29th, anybody?). The changeover area can depend on several things, including the intensity of the precipitation, the degree of cold air at different levels of the atmosphere, and the exact track of the storm. For example, the GFS is farther south and east than the NAM model. One would presume it would be colder. However, the NAM has so much heavy precipitation that it effectively dynamically cools to column over Northwest New Jersey to allow for a moderate snowfall. In situations like this, it is important to highlight the things we are most sure of. First, we are sure that the chances of getting accumulating snow along the coast are very low. There is very little cold air present before the storm system, it works in during its impact. Which means the coast will take the longest to changeover. Second, we know that the models have been very inconsistent. This means that we should be very cautious with our forecasts moving forward. Finally, we know that such a dynamic system can produce snowfall away from the coast, even with a poor airmass prior to the storm. The cold air being drawn in could do so just in time for inland areas. Pictured left: NAM model simulated radar and clouds for Thursday morning, December 8th 2011 showing a dynamic storm system affecting the area with heavy precipitation.

All of this said--we will highlight the potential for moderate to heavy rain changing to snow west of New York City Wednesday Night into Thursday morning. The potential for moderate accumulations has been relegated to areas with higher elevations, and NW New Jersey, SE New York, and NW Connecticut. In the city and areas east/along the shore, we included a changeover to snow that will be of shorter duration than areas inland, and did not include any accumulations. Remember that this forecast is highly uncertain and subject to change. Note that the below forecast is for New York City only. The forecast for the entire area will be posted within the next hour (link will be posted on Facebook & Twitter accounts).

THE FORECAST AT A GLANCE...

Tuesday: Cloudy with showers likely. High near 61.  Southwest winds around 10 miles per hour. Chance of precipitation is 70%. New rainfall of 0.05" to 0.15" possible.

Tuesday Night: Mostly cloudy, with a chance of showers. Overnight low near 45. Southwest wind near 10 miles per hour.  Chance of precipitation is 70%. New rainfall of 0.10" to 0.20" possible.

Wednesday: Cloudy with showers likely. High near 61.  North winds around 10 miles per hour. New rainfall of 0.10" to 0.20" possible.

Wednesday Night: Mostly cloudy, with rain likely, changing to rain and snow. Overnight low near 35. North wind near 10 miles per hour.  Chance of precipitation is 70%. New rainfall of 0.25" to 0.50" possible. New snowfall accumulations of less than 1.0" possible. 

Thursday: Cloudy with rain and snow likely, changing to snow and then dissipating from west to east. High near 46.  North winds around 10 miles per hour. New snowfall accumulations of less than 1.0" possible.

 Article written by JH. Published December 5th, 2011 at 11:45pm. Looking for a forecast? Use our new Forecast Beta tool to see the latest forecast in your specific area for the upcoming week, or view our Technical Forecast Discussion for the more serious weather enthusiasts. Also, check out our new Forecast Overview tab. For up to the minute details on forecasts, watches, warnings, and alerts, follow us on Twitter and Facebook.