NY NJ PA Weather Forecasts

December Thoughts- the cold is on the way

9:45 AM

Over the past several weeks I have been strongly hinting at a cold start to December.  The various indicators I’ve been looking at to make these statements include the Stratospheric anomalies of late, the development of the MJO state, and the growth of snow cover over much of Alaska and northwestern Canada.

As the models start to come into line, there is a strong consensus from the GFS, ensemble guidance, and even the ECMWF that all point to a pattern change right after Thanksgiving.  The models are picking up on these events because the influence of the stratospheric warming working down into the troposphere is finally being realized.  As a result, there is a gathering of teleconnections all pointing to a cold set up for the East in December including the EPO, NAO, PNA, and AO indices.

Now the image to the left is blown up 70 MB temperatures for the period of July through this morning.  I circled two key areas that I want everyone to take note of.

First, I want to discuss the lag time of these warming events and impacts on the troposphere.  The warming events from all the research I read can take roughly 30 to 60 days to start to have an influence on the troposphere IF the warming is working into the lower levels of the atmosphere.  While, the stratosphere temperatures at this level basically stay average to above average since early October, the two spikes I believe will have an influence on how the pattern develops through this up coming month.

My theory for this month is that the first warming spike in early to mid October will continue to impact the development of the MJO going towards the last few days of November and support the development of higher latitude blocking.  The focus of the warming was centered over the Sea of Japan and Alaska, which strongly points to a negative EPO pattern and an upper low around the Aleutian Islands.  I’ve had these thoughts for some time and at this point I’m pretty confident in this outcome.

A persistent and strong trough will carve itself out over the Eastern United States for the first 10 days of December with temperatures running near to below normal for this period.  I think the coldest anomalies will be focused over the Great Lakes (watch out for Lake Effect!) and Mid West, however the change to cold will be felt towards the coast as well.  The lack of snow cover over southern Canada and the Great Lakes will initially support moderation of the air mass at the boundary layers.  However, if the snow machine gets cranking as I expect for the Great Lakes, I think this impact will be limited rather quickly.  Meanwhile, if my theory on how all this works out, the Sub Tropical Jet Stream will ramp up activity and develop an impressive plum of moisture and disturbances over the Southeast for early December.  The changing teleconnections should signal storm development and I think there is a threat for a storm for the December 6th to December 10 period.  Again, all of this is based on the development of the MJO reaching sectors 6 or 7.

We are still not at the point were the winter pattern locks in though.  While there are strong indications of blocking in the higher latitudes, the lagging off of the stratospheric temperatures for the end of October and early November, should start to signal a relaxation in the pattern.  I wouldn’t be surprised if a storm track from the western Gulf Coast to the central or eastern Great Lakes take shape for Mid December as the overall pattern reloads.  Temperatures will moderate due to the shift to the west of the storm track, however I would be wary of a possible ice event for interior sections as the Polar high pressure system should be well supported over southeastern Canada due to confluence at the base of a weakening Polar Vortex.

The second warming event unfolding now is far more impressive than the first with temperatures averaging 1 to 3 degrees Celsius higher than recorded data.  I am timing the influence of this warming for the end of the month sometime between December 21 and January 5th.  What’s interesting is that this warming is still not showing signs of waning of yet and the negative QBO would strongly support a continued warming event in the stratosphere.  If temperatures remain well above normal THEN we maybe looking at support for the pattern to lock in with a persistent trough over the Eastern two-thirds of the United States along with a weakly to moderate negative NAO state, a strongly negative AO state, and a negative EPO/positive PNA pattern established.

The end of December and the start of January looks to average slightly below normal and above normal in precipitation as the Sub Tropical Jet Stream continues to crank.

So to wrap things up, I expect a cold start to December as the changes in the atmosphere begin to unfold towards a cold season pattern.  The pattern for early December should exhibit an active storm track as well.  The pattern will relax with quieter conditions and a moderation in temperatures back to near normal, possibly slightly above normal levels.  A lake cutter type pattern should unfold as the trough moves back towards the Plains and eastern Rockies.  The pattern shifts once again and should lock in for the end of December with a return to colder temperatures and an active storm track.

Tags: Albany, aleutian islands, Allentown, anomalies, ao, Atlantic City, atlantic city weather, atlantic ocean, Belmar, Bridgeport, cape may nj weather, Citi Field, coastal waters, cold front, cold start, Connecticut, consensus, craigles nyc, current weather in new york, ecmwf, few days, Freehold, guidance, hail, Hartford, heavy rain, Islip, jackson nj weather, key areas, latitude, levels of the atmosphere, lightning, long beach island nj weather, Long Island, Long Island Sound, Long Island weather, manhattan weather, marine weather nj, mb temperatures, Mets, Mid Atlantic weather, 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, northwestern canada, ny weather 10 day, ny weather forecast, ny weather forecast 10 day, ny weather map, nyc weather map, ocean city, ocean city nj, 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, pna, point pleasant nj, Poughkeepsie, princeton nj weather news 12 nj weather, Reading, Scranton, scranton pa weather, sea of japan, seaside nj weather, snow, snow storms, spike, spikes, stratosphere, strong, Sussex, thanksgiving, thunderstorms, tides, tornado, trenton nj weather forecast, troposphere, 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