USCAPEWEATHERAF

And lift is measured in microbars, the lower the number, the greater the lift. -10 to -15 microbars are decent lift, while -30 to -34 microbars is extreme lift!

Again the zone of best dendrite growth is wherever the -12 to -18C temps are layered. When lift dissects this zone, that is when ratios are best and snowflakes are dendrites.

500mb is too high for the DGZ especially one in a winter storm that can produce a foot plus! The levels are likely a lot lower between 820mb and 675mb

Tip remember the Blizzard of Jan 15 and the Boxing Day 2010? Both storms a trailing shortwave was forecasted to interfere with the lead shortwave in the overall long wave trough. The JAN 15 storm was forecasted by models seven days in advance, they lost it within the 4-6 day window and brought it back within 72 hours as the EURO caught onto first. The question was the interaction between the lead and trailing shortwaves. The 12z GFS today has improved the western Rockies ridging heights, but the shortwave is already entering the backside of the long wave trough. Again, I am not sold in either direction. There are three clear signs that make sense...1.) strong presence of arctic air in place and locked in by a strong -NAO block in Greenland and Iceland, and 50/50 low, 2.) there is a storm present and a lot of moisture involved, 3.) someone will see over 15" of snow, questions become placement of the track of the low and eventual H5 dynamics as the system passes 75w. Again, there will be a strong gradient in the precipitation shield. Someone will see deformation bands, someone will have a long duration event, and OES will prolong the event!

Every model doing what exactly?

Perhaps leaning towards a more amped, westward leaning pattern!

The storms like DEC 2010 where the band brought a foot of snow to the eastern half of Cape Cod the Monday before the Boxing Day. There are plenty of examples of shortwaves being dampened too quickly, can I name every situation, no I can't. However, that does not mean I am spewing crap off the top of my head. Every situation is different, but today's storm could be a signal that the pattern is more favored to amplification than models would indicate. yesterday the storm for today was forecasted to bring a band quickly through the Cape and then offshore, however, judging by radar, that band is aimed right at the Cape and Islands and is not moving until the backside slides through, currently over western CT. Lean towards amplification.

Look off the top of my head, various nor'easters like Jan 15, Jan 05, DEC 04, FEB 13, JAN 16, were all forecasted at some point within this time range to dampen out, or be suppressed to the south of the region for various reasons. Not one unique reason was the cause for every event. However, there were causes for concern. When the EURO over amped the Jan 15 storm 48 hours out, everyone jumped on its bandwagon and I kept saying Cape Cod will not rain because the pattern screams east. I am saying from the experiences I have seen over the last ten years alone, the ones that do the most swinging back and forth seem to produce the most snows. Jan Bomb Cyclone of 2018 the Valentine's Day Blizzard of 2017, these are more types were the swinging was clear. The big one's always swing, except the only real case against, was the Super Storm of 1993.

Look, the models want to close off at H85 and H7 and the H5 level almost closes off on the GFS. Other models close off at H5!

Why do I have to answer your question? Would you answer mine and tell me why you give up on a storm so quickly?

You guys might wilt when a model doesn't show what you want in your backyard, but I don't sway every run that changes its ideas. I have seen instances where this happens numerous times in the past only for the last second nailing. This storm should produce a foot plus south of the Pike, southwest of BOS. Plymouth should see 16"+

I am not buying the dampening shortwave as it moves northeast underneath Long Island. That just does not sit well with me and we could see in the last 48 hours that the trend is for a stronger shortwave as it passes 40N and 75W.

Considering our storm today was more amplified than the models showed 24 hours out, I would lean towards the UKMET, EURO, CMC and ensembles then the GFS and NAM!

The one thing that the models are beginning to come to a consensus on right now is that a longer duration system with an OES component prolonging the ending of the snow on the Cape with strong NE to NNE winds. The limiting factor to a good event is the 850mb temps which warm later on. However, this storm looks like a powerhouse even if the surface low does not behave accordingly. I will take the UKMET 00z run this morning, even though its resolution is too coarse for the coastline.

Just made up drama that does not need to occur!

What is everyone looking at with the GEFS mean? While yes the mean might be southeast, but the bend and anomaly is to the northwest, the bend is to the northwest where most members are located, not southeast. Might have a few members that are strong and skew the mean to the southeast, but that does not mean the majority of members agree on a southeast tug, they are more northwest!

Precip should not be something you hammer on at this point, watch track and H5 adjustments!

I know the NAVGEM is rarely used these days due to being outdated and not really high resolution fields anymore, but it does have a progressive tone to its forecasting and we were told to have a red flag to the progressive side of the solutions envelope whenever the model was more amped and further northwest. Well the 18z NAVGEM was just as similar to the 84 hour NAM.

00z GEFS mean is actually more west and northwest than the operational. Also the individual members are more west and northwest of the mean with more members than previous runs, they also prolong the precipitation more from hours 78 to 96.

I am never sold on the GFS during a progressive like season in the LA Nina driven northern branch with its heavy biases towards progressive patterns. Will or anyone who has been paying attention, does the new GFS have the biases the old GFS did with the progressive tendencies, I found that the previous GFS had a tendency to be quite progressive over the East Coast prior to storms. Within the 3-7 day window!

We have seen models do this cat and mouse dance numerous times before in the big storms. For the 3-4 day window where the storm might be tracking too far southeast for any meaning full impacts, the models would have a tendency to first under sell the intensity of the energy moving onshore the western CONUS and also losing the organization of the trough as it heads stateside across the plains. However, within 48 hours, the trend would be for a better sampling, and a better consolidated piece of energy. If I am not mistaken once such occurrence was the FEB 2016 SNOWICANE that missed by 100 miles, but the H5 and H7 circulations were large enough, it brought almost a foot of snow to the SE New England areas, especially BOS SE.

Actually the H5 shortwave and long wave trough look a lot healthier through 61 hours on the 00z GFS. In fact the southern energy that rounds the base of the long wave trough is more neutral tilted almost leaning negative as the main shortwave leans negative. Overall there is more pure balance to the long wave trough. Better organization leads to a better storm overall.

yeah

I honestly can see how it would rain with the storm tracking just south of Islip by like 50-100 miles. That brings in a strong southeasterly low level flow into the coast. Our surface high would not be strong enough to keep the cold air locked in with a southeast wind!

Oh and also the NAM is still south of central LI with the surface low at 84 hours, which means it is still producing snow over the region and any rain changed back to snow!