Monday Night Technical Discussion

Synopsis

 Two clippers will swiftly make their way into the state for the beginning of the week, bringing snowfall across the state. A third clipper system will near the region towards the end of the week potentially creating a mess for northern PA, and slightly warmer temperatures will follow for the weekend.

 Short Term (Monday Night thru Tuesday Night)

 The first clipper is already producing snowfall across much of the state and will continue to move east throughout Monday night, with a few snow showers lingering early morning Tuesday. The heaviest snowfall will occur in southwestern portions of the state near the ridges and valleys. Both 18Z NAM and GFS agree with up to 6" near Latrobe and heavier accumulations along the ridges. An average of 1"-2" of snow will fall state wide with a heavier 2"-5" near Pittsburgh as the first clipper exits the region early Tuesday morning. Much of Tuesday will be dry, but a second clipper will make its way across the state much quicker than the previous clipper, adding 1"-2" of additional snowfall Tuesday night. Both 18Z GFS and NAM agree on snow fall from the clipper beginning to fall near Erie around 02Z on Wednesday and snow showers completely dissipated in the eastern portions of the state by 12Z Wednesday.

 Long Term (Wednesday thru the weekend)

 A northwesterly flow associated with the low will follow the exit of the second clipper for Wednesday, producing lake effect snow near Erie during the morning. High pressure will make its way into the state Wednesday afternoon, and clouds will begin to clear overnight. Warm air advection will increase temperatures across much of the state, especially in southwestern PA, due to a mean southwesterly flow associated with the high pressure to the east. Thursday night a third clipper will move near the region. The 00Z NAM shows a threat for rain across southern PA with a wintry mix to the north and snow in higher elevations, but the 18Z GFS has the precipitation associated with the clipper staying north of us. A separate system to the south of us will also attempt to move into the region Friday. The 18Z GFS shows most of the state remaining dry for the day as a short wave keeps the precipitation south of us, but the 00Z NAM phases the approaching system from the south with the clipper. The retreating cold air provides a possibility for freezing rain and mixed precipitation for northern portions of the state and rain to the south Friday morning. A cutoff low will develop over Colorado, creating a strong ridge over the northeast. Warmer weather will follow for the end of the weekend and the beginning of next week, but a system will approach the area next Monday. Continue to watch for this event, as significant rainfall is possible.