AS of 00z yesterday evening models continued to come into better agreement with the track of the low pressure system that has the potential to bring a moderate snowfall to the region. So without further hesitation lets look at the 00z guidance. For the purpose of this discussion we will be looking at hours 48..60 & 72 .
First model up is the European Model. This model does not have an image available for 60 hrs ..however at 60 hrs it is in the same spot as the UKMET but slightly deeper. While the ECM has trended stronger with the low pressure and even more westwards it still is lacking on QPF as it only brings about 1-3 inches to the area.
Above is the 00z UKMET and the one difference that could be making the difference from the ECM above the UK..is you see that at 48 hrs ..the UKMET actually has a surface low reflection where the ECM does not. You can also see that while its in the same spot as the ECM at 60 hrs it does end up deeper and further west then the ECM by the end of the run. UKMET would be supportive of around a 4-8 inch snowstorm across the region.
00z GFS above has been one of the models that has been weaker with this system but has been trending stronger. It was also one of the models that was on the eastern edge of the western edge of the Gulf stream which if you recall i mentioned about watching the models to see if they would develop the low in the greatest thermal gradient which is the western side of the gulf stream. This is exactly what the GFS does with its 00z run as it has now come NW.
00z GGEM..perhaps another model that has been consistent with this system and a further west track as well. The only difference with the GGEM is at 72 hrs it is slightly further west then the GFS and ECM. However..as you will see the further west models have the correct idea.
The NAM @ 00z , which was another one of the models that had been most consistent with this system..came in a lot further south which resulted in colder but also created what looked more along the lines of a convective feedback low to the south which then robbed the main storm of moisture and energy..so it ended up further south and then east then the other guidance. If you take away that convective feedback you would have has a solution more NW and consistent with prior runs. And just to show that this was indeed the case..here is the 6 Z NAM..
You can see that indeed the NAM has gone back to its consistency and 00z was just an off run.
As much respected Pro Met Baroclinic Instability just stated..its good to see the NAM come back to reality! So..thats all the 00z guidance with the exception of one model..The 00z Nogaps..perhaps the model that has been leading the way with this system once again with having a west track and never wavering.
As you can see at 60 hrs it is actually slightly west of other guidance so yes this does imply we could end up slightly more west with the global guidance. Now you will notice at 72 hrs where it ends up is in relatively the same location as the 00z NAM was and even the 00z GFS. This is an indication because of its SE bias that at that time the low pressure would be further west which is why the models like the UK and the GGEM with its more west track are more correct. 6 Z NAM also corrected towards this as well.
One thing has become clear to me during the day yesterday and that is people really do not want to learn. They want to insist that the NOGAPS is a horrible model. However, the reality is that the NOGAPS has led the way with a more western solution on every system this winter season so far..and the rest of the models end up trending to it. The NOGAPS in reality is probably one of the better models this winter season when it comes to individual storms and you will see that with the very next storm as well.
So in summary the model that stands out as far as an outlier is actually the ECM with its low QPF output as all other guidance brings a moderate snowstorm to the region. At this present point and time I see no reason to change from the prior thinking of 4-8 in Central PA to 6-10 from eastern PA , SE PA , NJ (NW) into NYC and into the SNE area.
Due to having to do another update for yet another storm…we will hold off on issuing a preliminary map until later this afternoon.
Stay tuned for more information on this developing storm system!
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