NY NJ PA Weather Forecasts

Evening Thoughts On Christmas Storm

11:21 PM

As the model guidance for the 00Z NAM and 00Z GFS came in, my thoughts centered on a question that bugged me about the end of next week.  Just how cold will the boundary layer be?  Do the models introduce the impact of a one to two feet snowpack, which will keep the boundary layer cool if not downright cold.

The overall idea for the upper level pattern is that the high latitude blocking is expected to relax for a short time.  This is not an unreasonable development as even the most persistent upper level blocking tends to break down for a short time before a strong return.  Further, there is strong agreement that the negative EPO ridge will be slightly further to the west than in previous set ups, which will allow a trough to dig into the Southwestern United States and leads to a ridge building over the Southeast.  However, there area  few issues that trouble me with the overall 500 MB pattern.  For example, the MJO state does not support a negative EPO ridge to be as far west as guidance suggests.  The MJO wave went from a neutral status to stage 5 (La Nina supported) to rapidly a stage 7 position.  This development in the guidance MAY be the influence of the MJO briefly in stage 5, but the duration would suggest a colder pattern at a quick rate.

More importantly though, I don’t like how the model guidance is handling the 500 MB features.  For example, in the ooZ GFS run this evening suggests that the ridge will be building north while a strong Polar Vortex drops south.  Something has to give here, and I think this ridge is going to end up further east.  However, what is really interesting is the strong convergence and confluence that develops at the upper levels with this pattern and even more impressively if the ridge is further to the east.  If the ridge is further east, this means the upper low over the Plains may end up further east and the strongest PVA is focused towards the coast rather than over the Ohio Valley.

A strong ridge over the eastern Great Lakes makes this forecast much more complicated, especially with a 12+” snow pack to keep the boundary layer cool at the surface.  It should be noted that even the ECMWF 2M temperatures keeps the majority of the region below freezing into Friday morning. There is growing support for a CAD developing through Friday night, and the increasing thermal gradient at the coast line would support strong isentropic lifting over the region.  Given that Arctic air does not like to retreat quickly, and certainly not in a six hour period.

I believe as the guidances gets to a point of optimal resolution that the guidance will  illustrate the potential for secondary cyclogenessi along the Mid Atlantic coast.  I would look for a period of snow, sleet, and freezing rain on Thursday night into much of Friday before any change over to rain.  I believe the influence of the snow pack along the coast will have a stronger influence on this future storm than some believe.

More on this potentially dangerous situation tomorrow mornng!

 

Tags: 00z gfs, 00z nam, Albany, Allentown, Atlantic City, atlantic city weather, atlantic ocean, Belmar, boundary layer, Bridgeport, briefly, cape may nj weather, Citi Field, coastal waters, cold front, confluence, Connecticut, convergence, craigles nyc, current weather in new york, duration, Freehold, friday night, hail, Hartford, heavy rain, Islip, jackson nj weather, la nina, lightning, long beach island nj weather, Long Island, Long Island Sound, Long Island weather, manhattan weather, marine weather nj, Mets, Mid Atlantic weather, Model Guidance, New Jersey, New Jersey coast, new jersey shore weather, New Jersey snowstorms, New Jersey Weather, New York, New York City, New York City Weather, New York snow storms, New York Weather, new york weather today, Newark, newark nj, newark nj weather, nj local weather, NJ Weather, nj weather 10 day forecast, nj weather forecast, nj weather radar map, nj weather report, northern Mid Atlantic, northern Mid Atlantic weather, ny weather 10 day, ny weather forecast, ny weather forecast 10 day, ny weather map, nyc weather map, ocean city, ocean city nj, ooz, pa weather alerts, pa weather forecast, pa weather map, pa weather radar, pa weather report, past new york weather reports, Pennsylvania, Pennsylvania weather, Philadelphia, philadelphia pa weather, Philadelphia Weather, Phillies, point pleasant nj, polar vortex, Poughkeepsie, princeton nj weather news 12 nj weather, Reading, Scranton, scranton pa weather, seaside nj weather, set ups, short time, snow, snow storms, snowpack, stage 5, strong, Sussex, thunderstorms, tides, tornado, trenton nj weather forecast, Trough, two feet, ups, vortex, weather and nyc, weather doylestown pa, weather easton pa, weather edison nj, weather for nyc, weather for pa, weather forecast pa, weather in new york, weather in nj, weather in nj today, weather in ny, weather in nyc, weather in nyc today, weather in pa, weather indiana pa, weather map, weather montclair nj, weather new brunswick nj, weather new york, weather new york city, weather newark nj, weather nyc, weather nyc forecast, weather nyc ny, weather ocean city nj, weather of nj, weather of nyc, weather princeton nj, weather scranton pa, weather union nj, weather wayne nj, White Plains, widlwood nj, Wild Wood, wild wood nj weather, Winter, winter 2009, winter forecast, winter predictions, winter weather 2009, winter weather advisory, winter weather forecast, winter weather predictions, yahoo weather nyc, Yankee Stadium, Yankees