The coastal low/nor’easter that has been effecting the east coast for the last 3 Days and keeping temperatures down, has been a nuisance for some. And others say ah its just a regular fall rain. Well here is something that I noticed that we really need to keep an eye on.
When you look at the Nor’easter that is currently effecting us, it is spawned by a perfectly set negative NAO. Which is blocking over Greenland. The blocking is keeping the storm from moving anywhere too fast, which is why we are dealing with 3-5 days of rain. The NAO actually since the start of October has really been Negative, and aside from the first few days of the month, the temperatures have been at least average to bellow average in the mid-Atlantic and into the northeast..
Now why is this so significant. Well you really in the months of October and November want to look and see the weather pattern you are getting into, since in some scenarios that continues into the winter. The Trend is your friend. The last time as Accuweather Henry Margisuty pointed out in his video earlier today that we had blocking like this (NAO) (High Over Northeast Canada) was in the winter of 2010-2011. Note in that winter it was fairly snowy in Philadelphia, New York, and Boston. The prior year we also saw a similar set up to what we are seeing now. (Granted one was fall one was winter) This pattern set up earlier in the year of 2009-2010 and stayed until Late February. Now based off of this storm, it looks closer to the blocking of winter of 2009-2010. Why do i say so, well the storm is really being blocked from bringing in to much northward progression, so really if you are anywhere north of new york city you really are not going to be effected by this coastal low, besides the tides and those who are on the beach. Point is if this were winter or even December you would be seeing places like DC, Balt, Phily, And southeastern PA get hammered with feet of snow. Look at the temperatures in those areas which have averaged a good 5-10 degrees bellow normal with this one system. One knock on the past two winters has when we did have storms develop and ride up the coast there was no colder air to feed into it, thus a lot of slop storms and a lot more snow to rain events. This will have to be monitored through this month and November to see if this develops into a trend or if this storm is just an out-lier.
Now here is just a little forecasting tip, whenever you see a negative nao start heading towards neutral that is sometimes an indication that a storm system is brewing in that time period. So on and around Oct 18 look for weather of some sort to effect the eastern half of the nation. Another coastal storm maybe? The conditions are there, but we will have to watch it for later developments.
BATTLE OF THE SEASONS COMING UP OVER NEXT COUPLE OF WEEKS:
I have looked at the long range models for the past couple of days looking for some sort of consistency when it comes to the weather pattern. I have come to this conclusion though. This month we will see some wild temperature swings. Originally the cooler than average air will have a hard time making it past the mid-west but it will and will primarily effect those from Virginia North. Dont get me wrong, the southeast will cool down but it will be closer to average temperatures than anything else. The GFS has been consistent with the factor that a few cooler than average shots of air will come down from Canada over the next couple of weeks, and to be honest, looking at the negative NAO it should not be much of a surprise.
Now I am not saying that we will have a winter of 2009-2010 or 2010-1011 but just to realize the pattern we are in now resembles those years and to keep an eye out to see if this pattern will continue. This is the time of year to start watching things like this.