Sunday, January 01, 2012

Forecast for Monday, January 2, 2012

A cold front is currently sweeping through our region. Temperatures will drop behind the boundary, aided by the arrival of darkness. Winds will also pick up and become gusty. A broken line of rain showers will accompany the frontal passage and will push offshore by the middle of the evening. Skies will then become clear.

West-Northwest winds will turn quite strong and gusty on Monday. Winds will be gusting between 30 and 40 MPH, with some isolated higher gusts. This will turn on the Lake Effect snow machine. Scattered snow flurries are possible.

A reinforcing arctic cold front will arrive Monday Evening. This will boost our winds, drop the temperature further, and also provide another lifting mechanism to perhaps increase the coverage of the snow flurries. We may even see a period of snow showers or snow squalls develop. From a climatology point of view, our northern areas are favored from Mount Pocono down through North-Central New Jersey for the most widespread snow shower coverage in these situations. Additional snow flurries and snow showers are possible on Tuesday. Winds will fade on Wednesday, allowing for the lake effect machine to begin turning off.

Accumulation wise, it will be highly localized. On paper, it looks like widespread flakes and dustings. But, more persistent streamers could end up producing a coating to three inches of snow in a real narrow corridor.

Temperatures behind the arctic front will be bitterly cold for Tuesday and Wednesday. Upper twenties and lower thirties will be the best we can manage for this period. Overnight lows will drop into the single digits and teens. North and West of Philadelphia, negative wind chill values Monday Night and Tuesday Night are possible. Wind chills could get close to the criteria for a wind chill advisory towards the mountains.

There is a better handle on a weak clipper and associated warm front for later this week. It appears this is centered for Wednesday Night into early Thursday Morning. There will be a definite increase in clouds. The warm air riding over the cold air may also lead to a period of wintry mix or snow. The details about where this precipitation occurs exactly and just how much moisture there is to take advantage of remains to be seen. I have seen scenarios where overrunning becomes better defined and more apparent closer to the actual event and given the difficulty the models have had handling this pattern thus far, I will not go with a completely dry forecast at this moment.

Temperatures moderate for late in the week and early next weekend. This season, cold fronts seen seven to ten days out end up being delayed a day or two. Therefore, for now, we will keep Sunday in the fifties.

Some of our long range models have been suggesting colder air possibly coinciding with moisture between January 9 and January 16. Given our season disappointment to date and that this is well beyond day seven, we aren’t getting jubilant at the moment. However, La Nina patterns usually see a pattern reversal towards the end of the season that at least bring some chances towards the latter half of January into February.