Sunday, December 18, 2011
Forecast for Monday, December 19, 2011
A weak warm front will push through the region tonight and early Monday. The warm front will be followed by a cold front that should pass through our region Monday Evening. The front could be accompanied by sprinkles and flurries. Some areas could see an isolated rain or snow shower.
On Tuesday, this cold front will put on the brakes and move back north as a warm front. The warm front will arrive during the evening and night hours. There are some questions that still need to be answered in terms of exact timing and exact placement of disturbances riding along it. This can make a difference in the precipitation type north of the front. I still believe there is a shot at getting a period of wet snow, sleet, and even freezing rain in the Lehigh Valley and Poconos. This should be where the best lift will occur and steadier precipitation north of the boundary can cause evaporative cooling to take place allowing for initial rain to change to wet snow and sleet before the warm air advection wins and causes the eventual transition back to liquid. There is a slight chance there could even be a 1 to 3 hour window of sleet and wet snow mixed with rain as far south as the Philadelphia area.
In the Poconos, cold air may get dammed at the surface with the warm front hung up just to the south. This may allow for even a bit of freezing rain lingering into Wednesday Morning while areas in the warm sector are approaching 55 or 60 degrees!
On Wednesday Evening into early Thursday, the cold front comes through our region. Models have backed off on the threat for strong to high winds. It still does look like gusts of 30 to 40 MPH will be possible. We may see this change once again.
Another feature may try to impact us later on Thursday and Friday. Eventually, we may have to add rain or snow showers into our forecasts. For now we are forecasting cloudy intervals.
December 26 to 28 will be stormy according to long range trends. It is a little too early to say what may occur and how it will evolve...but remember if the cold air can get hung up...ice storm scenerios in the NW Suburbs and beyond can always be possible or some type of mixing event in the La Nina patterns. This could also present us a shot at some wet snow inland with rain along the coastal plain. But anyhow...watch this period of time for something down the pike.
Have a Merry Christmas and see you next weekend!