12:00 PM | **Accumulating snow likely in much of the Mid-Atlantic on Thursday night…significant weekend storm to bring rain, ice and/or snow...Arctic blast follows**
Paul Dorian
12Z NAM shows a lot of blue (i.e., snow) in the Mid-Atlantic region in the wee hours of the morning on Friday; courtesy NOAA, tropicaltidbits.com
Overview
An active weather pattern is setting up for the next several days with two systems to monitor and an Arctic blast by the early part of next week. Low pressure will push out of the Ohio Valley on Thursday and likely produce accumulating snow in much of the Mid-Atlantic on Thursday night. That snow could end as a period of light rain or freezing rain early Friday which could make for an interesting AM commute to end the work week. The weekend will feature a strong cold frontal system sliding towards the east coast and a strong storm will form along the boundary zone. That system may bring us some rain, but snow and/or ice are possible at the front end and also on the back end…many, many details still have to ironed out. What is quite certain is that the coldest air mass of the season will arrive late Sunday on the heels of the weekend storm and Monday promises to be very cold.
12Z NAM feature a wave of energy in the upper atmosphere early Friday which will support the surface low pressure system as it moves into the Northeast US; courtesy NOAA, tropicaltidbits.com
Thursday night/early Friday
A weak cold front will slide through the Mid-Atlantic region on Wednesday night and it’ll turn colder on Thursday just ahead of the next low pressure system. Low pressure will pull out of the Ohio Valley on Thursday and snow could break out in parts of the Mid-Atlantic region late in the day. By Thursday night, it is likely to be still cold enough for snow in much of the Mid-Atlantic; especially, on the north side of the PA/MD border. Accumulations are likely on Thursday night in the I-95 corridor with early estimates at 1-3 inches in and around Philly and NYC and a coating to an inch or two in the DC metro region. Late Thursday night and early Friday, there is a decent chance that the snow mixes with or changes to light rain or freezing rain which could make for an interesting commute on Friday morning.
12Z GFS forecast map for Sunday evening features very cold air pouring into the Mid-Atlantic region on the back side of the weekend storm; courtesy NOAA, tropicaltidbits.com
Weekend threat
A significant storm will impact the Mid-Atlantic region this weekend, but there are too many details to iron out before it is known how much precipitation will be frozen and how much will be in the liquid form. One thing is pretty certain and that is the notion that very cold air will follow the weekend storm for the early part of next week. By the weekend, a strong cold front will be sliding slowly towards the east coast. Strong low pressure will form along its boundary zone and head to the northeast from the southwest. It may be cold enough at the onset later Saturday for snow especially in areas to the north of the PA/MD border, but if the low pressure pulls up to the west of the I-95 corridor, then rain will likely become the predominate precipitation type and temperatures could jump to mild levels. However, there are still too many details to say for sure that this storm will slide up to the west of the I-95 corridor and a track slightly farther south and east will make a major difference. On Sunday, as colder air starts to arrive on the back side of the storm, any rain that is falling could change to ice and snow before winding down in the I-95 corridor. Temperatures could drop dramatically late Sunday as the Arctic air mass pours in and any wet roadways could very well freeze in a hurry (i.e., flash freeze). By Monday morning, we’ll be in the deep freeze around here with the coldest air of the season so far firmly entrenched in the Mid-Atlantic.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com