Sunday, December 16, 2012

Forecast for Monday, December 17, 2012

Already some poor visibilities are being reported throughout our region as a warm front struggles to come northward through the region. During the night, all indications point towards worsening visibilities and the widespread formation of dense fog. Visibilities will be less than one-quarter of a mile at times. Otherwise, scattered rain showers and areas of drizzle will keep the roads damp. When the sun rises in the morning on Monday, dense fog will continue across the region and it may never completely dissipate during the daylight hours of Monday, particularly north of the warm front. Temperatures will be a lot milder south of the warm front and the best chances for sixties are across the Delmarva. Meanwhile, the far northern fringes of our region will likely not make it out of the forties. Philadelphia will fall in-between with fifties expected. Yet again, this is a situation where there is a large bust potential given the warm front and low clouds. Temperatures may briefly cool in the evening before rising a bit ahead of a cold front.

A cold front approaches Monday Night into Tuesday with a wave of low pressure. Rain should develop across the entire area with an isolated chance for a thunderstorm. This low will strengthen as a strong area of high pressure builds in for Tuesday into Wednesday. The pressure gradient should tighten resulting in blustery conditions with gusts around 35 MPH at times. Temperatures don’t really cool off behind this cold front and therefore I anticipate highs to still reach into the fifties. Right now, I am optimistic with expected slow clearing on Tuesday. However, there is a possibility a few showers will linger on Tuesday Afternoon. 

A very strong low pressure area is expected to move across the Great Lakes late this week and this system will drive a powerful cold front through our area. Right now, it appears the timing of this cold front is slated to move in our region on Thursday Night before exiting on Friday. This cold front will likely be accompanied with a period of heavy rain and even a few thunderstorms. The high temperature on Friday may be recorded in the morning before falling throughout the day. A building ridge of high pressure and the very strong low pressure area could really tighten the gradient across our region to bring the first strong wind event since Sandy. The northwesterly or westerly flow will also likely develop lake effect snow bands with some snow showers and flurries reaching our area later Friday into the weekend. Some guidance wants to develop a clipper system with a more concentrated area of snow showers over the weekend. Overall, there is low confidence for the upcoming weekend weather.