NY NJ PA Weather Forecasts

Watch Out For Early December

A continued theme from the December forecast, looks like model guidance is strongly jumping onto the idea of a very cold start to December for much of the CONUS.  We have a strong PNA ridge developing for the start of December, but also some other interesting features.  A strong upper low over California is expected to develop and has the support of pretty much every long and medium range guidance I can find.  This upper low over California would help to sustain the PNA ridge and also suppress the sub tropical jet from building any ridge over the Southeast.  Meanwhile, the upper low that sits over New England this week helps pull the ridge over the north Atlantic over Greenland, suggesting a strong negative NAO to develop for early December.  Before hand when model guidance suggested the negative NAO pattern, the Pacific pattern just didn’t support the development.  This time the Pacific pattern does support the development! 

So what does this mean to you besides looking at a 500 MB map with a bunch of twisting and turning lines?  The answer is cold AND stormy weather conditions will be expected for early December.  I think the arctic train visits the Plains first before the East coast, however I think the main question here is the potential for a potentially major storm for the East coast in this set up.  The storm track would be suppressed so I think the potential decreases significantly as you head north.  However, I wouldn’t count out the forecast area in this pattern at all.  The trigger to me is the Arctic air interacting with the very warm and unstable air over the Gulf Coast and off the East coast, specifically the Gulf Stream.  This interaction should lead to cyclogenesis along a frontal boundary and the potential for a wide spread overrunning event over the South and a Miller A storm track to develop.  A Miller A storm track usually begins in the Gulf Coast region and moves towards the East Coast.  I expect the potential for this type of storm around December 3 to December 6.  Some guidance is already hinting at this potential including several GFS and ECMWF ensemble forecasts.

Tags: Albany, Allentown, arctic air, area, Atlantic, Atlantic City, Belmar, Bport, cold, cold start, Connecticut, continuation, CONUS, cyclogenesis, east, East Coast, ecmwf, england, ensembles, forecast, forecast area, forecaster, Freehold, frontal boundary, gfs, greenland, guidance, gulf coast region, Gulf Stream, Hartford, interaction, Islip, Jets, Long Island, low, lows, Maine, map, Model Guidance, models, nao, New England, New Jersey, New York, New York City, Newark, north, Pennsylvania, Philadelphia, plains, pna, Poughkeepsie, Reading, Ridge, s, Scranton, south, Southeast, specifics, Storm, storm track, storms, stormy weather conditions, Sussex, train, Tropical, tropics, unstable air, warm, watches, weather, White Plains, Wild Wood, wills