Wednesday Afternoon Technical Discussion

Synopsis:

The large low pressure system that crippled much of the Midwest will slide off to our Northeast tonight leaving a strong northwesterly wind in its wake. This flow will cause lake effect and up sloping snowfall this evening and through the overnight hours before the gradient dissipates tomorrow. The end of the work week will be pleasant as an area of high pressure will center itself over the eastern seaboard. However, the pleasant weather will be short lived as another system will swing up the coast on Saturday bringing more precipitation to the state for the beginning of the weekend.

Short Term: (Tonight)

Much of the Alleghenies are currently under a wind advisory due to the tight gradient left in the wake of this powerful low pressure system. This will cause up sloping/lake effect snow showers across the mountainous portions of the state tonight and into tomorrow morning with the typical lake effect snow culprits getting the most accumulation.

Mid Term: (Thursday-Friday)

The remnants of this system will be a thing of the past by Thursday as the pressure gradient over Pennsylvania will finally begin to diminish. An area of high pressure currently developing the left entrance region of the Jet Streak associated with the current system will center itself over the eastern seaboard creating decreasing cloudiness on Thursday and mainly sunny skies on Friday. Also, this increased radiation during the day will cause temperatures to poke above the freezing mark Friday which may cause refreezing concerns for Friday night.

Long Term: (Saturday –Sunday)

Our next system will swing up the east coast Friday night and bring a mixed bag of precipitation to the state on Saturday. Currently, I believe that surface temperatures will be too warm for much of the state to see any significant accumulation. However, the 12z WRF/GFS, 18z WRF 0^oC 850mb, 274 700mb, and 540 500mb lines are all draped along the Pennsylvania mountain range so the more likely solution is snow to start near dawn on Saturday switching over to rain or sleet during the day and then finishing off as snow again Saturday night.  Higher elevations and areas of northwest Pennsylvania probably won't see this change over and regions near Philly most likely will see little to no snow so keep a close eye on it for the shifts to come!

RJ Patrizio