Friday, November 25, 2011

Forecast for Saturday, November 26, 2011

It was a gorgeous Black Friday with ample sunshine and mild highs in the sixties. For Saturday, a duplicate is in store with highs in the sixties and abundant sunshine expected.

On Sunday, ahead of a cold front, we expect increasing cloudiness with a chance for a few showers on Sunday Night into Monday. There is a great deal of uncertainty between Sunday Night and Wednesday Night. The computer models are having difficulty handling waves of low pressure along the cold front and their position and timing when they should eventually affect the Middle Atlantic. One noticeable difference from last night is to delay the onset of the heaviest rain. Some models are also showing some colder air catching up to the tail end of the precipitation on Wednesday which would result in perhaps some wet snowflakes or sleet pellets mixing in at the end, especially in the Poconos. At some point during the Tuesday and Wednesday timeframe, I do expect a six hour window of heavy rain of around an inch or two and possible thunderstorms which may cause poor drainage flooding and a rise on our smaller creeks and streams.

Overall, the GFS from 12z is the fastest with the clearing. The European model remains one of the coldest solutions, although it shows much less snow from previous runs. The newest NAM from 18z (using caution since it is an off run) now doesn’t even have the band of heaviest precipitation swinging through the region in the entire 84 hour stretch and has the low pressure center much further south. This system has the potential to tap into Atlantic Moisture and is currently leading to a very low confidence forecast.

Assuming clearing isn’t delayed further, we will forecast sunshine for Thursday and most of Friday. The Lake Effect machine could be turned on later this week.