FEB 7th 2018---Front End Thump

Warm air advection will ultimately win out; esp through the coastal plain but but a front end accumullation is possible even along the coast. There may be some cold air damning that holds the cold air in place long enough for the coastal plain to snow for maybe 1-3hrs before the warm air pushes in leading to the potential for a quick but light accumulation (C-1 to 2") before being washed away by the eventual changeover to rain.   Further N&W the cold air will likely hold on longer leading to higher amounts, but also I expect a period of sleet and possibly freezing rain as below freezing temps at the surface will likely hold on longer than the low and mid levels.  Hre is the 12z 3k hi res NAM.  GFS, Euro and CMC come in with 6hr time stamps so this 1-3hr period isnt showing up well on the models for the coast.  Obv if the cold air is scoured out earlier then less front end thump.  If only there were an HP to the north.  

We should also pay attention to a backend switch back to snow, albeit light and might not accumulate more than a dusting, but it will occur at night and with dropping temps could cause a flash freeze similar to last Friday morning

Looks like a tough go up north with snow sleet and some freezing rain. Right now i would say a good 3-6 for us northern folks.

jimv45 wrote:Looks like a tough go up north with snow sleet and some freezing rain. Right now i would say a good 3-6 for us northern folks.

Jim, I think this a safe bet for us north of 84 and more the further north you go. Albany is looking in the 8-10 range.

Yea Hyde, Albany said they are not sure when the changeover will happen so this is subject to change up or down!!

Scott, Alex the writing is on the wall. Looks like the N and W crew cashes in with 10-18” between now and a Sunday with some mixing, while we get 2-3” and then heavy rain. Reverting back to the means. If the forecast holds I might just throw in the towel here st the coast But not beforeI head up to Orange County with my flamethrower and station myself on CPs front yard. Then I’m going to head up to mom and dads for the weekend. They got 3” yesterday, 6-10” Wednesday and another significant dump coming up this weekemd

Nina Esque Storm

amugs wrote:

Nina Esque Storm

Is start time still in the 5-7 range?

Winter storm watch up for my area, expecting 4-8 of snow and sleet.

Hey, jimv, 3 to 7 down here.Reminds me of that "sleetmageddon" storm we got here last year, 4 inches of sleet.Let's hope it rends colder so there is more snow than sleet.

Great video by Bernie. Explains how with a fresh injection of cold air coming in tomorrow in the wake of a weakening piece of energy, 540 line is NOT your r/s line. It will be more like the 545-550 line as wet bulb temps will be very cold. Says this cold air will be hard to budge and NYC and the coast could see 1-3" before the changeover even down to DC. Take a listen!
https://www.accuweather.com/en/videos/snow-and-ice-storm-coming-to-the-northeast/f4bzi5yte6o0cnlleinxd2ssq527igk4

Yea doc want the snow more and I think we get a good thump before the mixing, either way it going to be bad up here!

Yes, jimv, a terrible morning ans evening commutes on wednesday.Glad I'm retired and can look at it through my window,LOL.Just a little more S and E movement of this storm would get us to all snow and maybe in the 8 to 10 inch category.We are right on the edge.

aiannone wrote:Great video by Bernie. Explains how with a fresh injection of cold air coming in tomorrow in the wake of a weakening piece of energy, 540 line is NOT your r/s line. It will be more like the 545-550 line as wet bulb temps will be very cold. Says this cold air will be hard to budge and NYC and the coast could see 1-3" before the changeover even down to DC. Take a listen!
https://www.accuweather.com/en/videos/snow-and-ice-storm-coming-to-the-northeast/f4bzi5yte6o0cnlleinxd2ssq527igk4

Great video by Bernie and I hope that cold air wins out and hangs tough.Hoping for a favorable move of the storm itself to get into the heavy snow up in the HV.

Update - NWS colder

Winter storm watch is up for me way off to the northwest. They're calling for 5 to 9, but the way this winter has gone so far I fully expect the storm to either bust low or slide off to the south and east. My prediction: 1"-3".

TheAresian wrote:Winter storm watch is up for me way off to the northwest. They're calling for 5 to 9, but the way this winter has gone so far I fully expect the storm to either bust low or slide off to the south and east. My prediction: 1"-3".

Im really pulling for you interior folks. I think you will get your 6 inches. If we weren't on a public forum and if we were close buddies I prob would run with that last statement but since its a PG thread Ill leave it at that. Good luck to striking it rich with the white gold N&W

Central and Upstate NY should do really well with this system. Classic SWFE where the coast starts as snow but turns to rain as the low passes just to our N&W.

This is the coldest frame of the 18z NAM for the coaat



Looks like a C-1 inch of snow then a period of icing before changing to rain. N&W of NYC I can see you getting 2 to 4 inches, with some spot up to 6. As you head north from there you will hit 6"+ amounts.

Be careful traveling Wednesday at the onset. Looks like a mid morning start time

I think a lot of the totals being forecasted are too high, mainly by the NWS. Climatologically, these types of storms (*with this type of setup*) are generally only good for about a broad 2-6/3-7" event where it remains entirely snow, with isolated lollipop amounts of 6-9" in your orographically enhanced regions. Perfect example is the system we just had. I was looking at obs today, and 90%+ of the totals were in the 1.5-6" range throughout PA, NJ, CT, MA, and NY. Less than five obs through the ~100 obs I looked at were above 6". With the exact same type of setup, I see no reason to think that what climo suggests will not be a pretty darn reasonable approximation for this system as well. These systems, in my experience, have a strong tendency to underperform in comparison to what modeling typically shows in this type of setup. Why is that? Well, I think crystal formation habits certainly hinder accumulations, as you do not have not have strong precipitation processes occurring at defined layers in response to significant mid- and upper-level forcing mechanisms. Instead, you just have gradually rising air running up and over the colder air beneath it, allowing precipitation to develop at many levels throughout the column, and thus, exhibit multiple crystal habits based on the thermal profile. Duration is also a problem, as these events are usually quick-movers. Lastly, intensity seems to be generally overmodeled in many instances as well, which then decreases overall QPF. This fits with the fact that the forcing is mainly caused by the upslope, a gradual process, and not things as dynamic as strong mid- and upper-level energy. While there is some, the advection is usually the predominant force.

The NW short-range trend continues. 0Z NAM much warmer with this system...

Math23x7 wrote:The NW short-range trend continues.  0Z NAM much warmer with this system...

Not so much for the Hi RES there Mikey!!