Let me start off by saying that there is a lot more to look at besides where the low pressure is on a weather chart. So many people have been asking lately..well why is this low going off the coast and the temperatures are so warm? Can a storm create its own cold air? All kinds of questions going around out there and yet no one is answering them. So we are going to attempt to answer some questions that you may have in this discussion.
First of all..the track of a storm system is only one aspect of a thermal or temperature profile. Is there high pressure to the north? Is that high sliding east? Which direction are the winds from? You can have a low pressure track off the east coast at 75 miles out and if you have an east wind with a high pressure sliding off to the east…then what that spells is easterly fetch off the atlantic ocean & warm air making inroads along the coast…
So lets look at the guidance tonight. Keep in mind from the beginning of tracking this event we have been using the NOGAPS as a flag towards the other models. That is another aspect people can not grasp. They cry the NOGAPS is not being consistent it went east..You expect and want the NOGAPS to be east because of its bias but when it is east ..if you take notice the global guidance then goes in the direction the NOGAPS was showing which was to the west. That is how the bias works. If it would keep moving west…then this storm would be going thru central PA and the snow would be well west. So with that in mind here we go…
First up is the GFS and we notice now it is actually seen the light of the rest of the guidance and now shows a low developing in the GOM. It started doing this at its 12 Z run and since then each run of the model has been trending west. GFS however..has no QPF on the western side of the storm , even though temperatures are cold enough to support snow. However..its also a more amplified system on its 00z run then any of its more prior runs.
GGEM..for the most part has always been west with this system and has also been one of the better performing models with it remaining towards the west. At 96 hrs though it is east of its former location but people are making it sound on the internet like its still not a coastal hugger when the truth of the matter is that it actually is.
If that is not a coastal hugger I do not know what you would call a coastal hugger. Furthermore there is talk that the system is not an inland system. This is all false to as this system travels to the east side of the Appalachians all across land.
Next up is the UKMET ..as you can see the UKMET is also a coastal hugger as well and also is an inland runner on the east side of the Appalachians.
The only model left to analyze is the 00z ECM. If you remember the 12 Z ECM was more east and as I been saying all day long yesterday..it was a hiccup run and would come back west. I was told i was wrong…Interesting thing was I was correct.
Here on the ECM you can also see this takes a very similar track as the rest of the guidance and is also what would be considered a coastal hugger.
So pretty much you can see that basically all guidance is in agreement on a western track close to the coast, the one different though is the GFS with no precipitation on its western side. However..this model is just playing catch up to the rest of the guidance and its means tell you that its going to be coming further west still.
So, I fully expect the GFS to keep trending towards its means.
However..i want to go back to the ECM model and break down the model for you in a PBP fashion.
At 84 hrs out the 850s on the ECM are from 0 to –5 from just to the N of KPHL extending east across C NJ..anywhere above that line you are below freezing in the 850 level.
Surface at 84..temperatures from KPHL south and east are 35-40 into CNJ. Anywhere north of there..as well as west is below 30 degrees.
At 90 hrs..from about ABE on south and east and into all but extreme NW NJ and then west into Central W Md the 850s are 0 to +5. Also those 850s extend across Long island. Anywhere west of that line or north of that line the 850s are 0 to –5.
Surface at 90 temperatures from KPHL south and east & into central NJ are 35-40 . Anywhere north of there..as well as west is below 30 degrees.
96 hrs ..850s are below freezing virtually everywhere with the exception of along the coast from NJ to Southern New England.
96 hrs surface..are in the 30s virtually all over between 30-35 with some pockets of 20s as well.
102 hrs 850s are below freezing every where with the exception of Cape Cod
102 hrs Surface temps are below freezing everywhere with the exception of 35-40 in Southern New Jersey!
That is the operational ECM 850s and surface temperatures. So basically supporting snow if you are inland and if you are along the coast you are looking at a more snow to rain type scenario IF and only if the ECM operational verifies as is.
The ensemble mean while AMPED has a different conclusion and it appear as if it would be cold enough to keep most places as snow..
Total QPF on the ECM is also below..as you can see it definitely has come more west..
(Edited cause Accuweather complained)
We will continue to keep the Level 2 Alert in effect but if guidance continues to go to what we are thinking then we will be upgrading to a level 3 later today with the 12 Z update or after the 00z update.
Our thoughts at this point have not changed with the original scenario map that was made a few days ago and we still think this could come as far west as over SNJ (alot of the spaghetti plots of the GFS were hinting and showing this) .however..if that occurs then we could also be talking about a dynamical situation where the storm is amplified and colder above and would pull that cold air down to the surface thru evaporational cooling. That my friends is how storms create there own cold air.
So to sum up anywhere from 50 miles or less to the coast with snow to rain along the coast (immediate) snow to a wintery mix..(30-50 miles inland) and then snow/sleet far N & W (60 miles)..with the potential of a significant accumulation of heavy wet snow and coastal flooding along the coast..beach erosion and strong winds.
Stay tuned for more updates on this system!
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