March 23-24th The GFS Stands Alone!

To start this off lets just say that the next storm is becoming more and more interesting. 12 Z Guidance is in along with a portion of 18 Z guidance and as you are going to see..at the present time the Global Forecast System is standing all alone with what it is showing. Not so much in the track of the system per say but rather in the thermal profile.

So with that in mind lets look at what we have so far today..

The above is the 12 Z NAM and as you can see the 12 Z NAM at the 850 level would support a solid snowstorm. Surface temps are generally between 30-35 degrees so this would be a wet snow and probably some sleet as well. IF to be believed it would also be on the order of 6-12 inches with isolated higher amounts over a foot.

18 Z NAM is really not all that much different from its prior run ..

Now, usually the NAM can not be trusted because it is in its longer range (beyond 48 hrs)..However..the NAM seems to have some pretty good backing with what it is showing..just perhaps not quite as generous on the QPF amounts as the 12 Z.

The GGEM is another model that has been showing relatively excellent consistency with this system and would suggest that the same areas that the NAM sees as a snow/sleet storm , it would agree with.

While we do not have all the hours available with the UKMET..one can gather by looking at the hours that are available that the UKMET would be in agreement with the NAM/GGEM.

Even the 12 Z ECM is in agreement on the track of the system and even the thermal profile for the most part (slightly warmer in some locales) ..the one difference is the ECM is not as generous on the QPF but that can be attributed to the dry bias that the model can exhibit and it was also too dry for last nights system that went thru. So all & all..we have the GGEM/NAM/UKMET/ECM all in relatively strong agreement.

While we never use the NOGAPS for its thermal profile we notice that it to is in agreement with the rest of the models above as far as the tracking of the system is concerned.

The one model that is different is the GFS..

GFS seems slightly to progressive for starters but it gets warmer then the rest of the guidance and further to the north then the rest of guidance. It would essentially be a snow to rain scenario for the areas that the rest of the models would keep all frozen.

At this point and time the Global Forecasting system would have to be considered the outlier. Either that or its going to pull a coupe and all the rest of the guidance is wrong.

Teleconnections suggest that we have a negative NAO & a PNA that is going positive. The one thing that is not on our side for an east coast snowstorm is a very cold supply of fresh arctic air with a Negative AO. However…with a strong high pressure in place over SE Canada and the teleconnections we have in place this would be conducive for cold air to bleed into the Northern Mid Atlantic & Northeast and we see that has indeed been the case today even as the temps have not gotten out of the lower 40s when they were to be in the mid 50s.

So, we are still throwing caution into the wind with this system but at the same time saying that things are looking more and more favorable via guidance. We are fairly confident that portions of the area will see a measurable snowfall. Are we confident enough to suggest what the NAM is suggesting could happen? No. However..with the blocking that is in place the potential for a snowstorm is at least a legit potential.

So with all the guidance in relatively good agreement we are releasing a very early preliminary map which is mainly for scenario and potential which is subject to change!