Extreme Cold, Snow & Sleet: SECS 1/24 - 1/26

[weatherpruf]

4 minutes ago, Astoriaweather said:

There was a storm in March 2017. Was supposed to be all snow. 15 to 20 inches was forecast.  In Manhattan, about 6 inches fell quickly during the morning time and then it turned into a massive, pounding sleet storm that persisted well into the evening.  It was a huge bust. But It then froze the next day. And, despite it being March with March Sun, the snow/ice was so packed that it stayed on the ground, even in the city, till late March.

i remember that, as mitchell volk himself weighed in the night before with doubts about a blizzard that big in march in nyc, based on history. mitch was iirc the retired met for the mayor's office or something. he was correct. it still was a decent storm for more interior areas. of course. 

[hooralph]

1 minute ago, NEG NAO said:

really left their options open - 6 inches to over a foot- BIG DIFFERENCE

Perhaps because the storm is still almost 72 hours away?

[SACRUS]

 

 

Euro updating

 

[NEG NAO]

1 minute ago, SACRUS said:

 

 

Euro updating

 

lets see if those recon flights had any affect on the Euro - didn't seem to make much of a difference with the other models at 12Z

[Nibor]

Looks like slightly less phasing on the Euro out to 66

[weatherpruf]

Just now, hooralph said:

Perhaps because the storm is still almost 72 hours away?

people were jonesing for a big daddy and we aren't getting one, barring some miracle, and now they are not going to be happy with more normal amounts. 6 of snow with sleet on top is just barely above run of the mill; even 10 is not the apocalypse some people want. but think back to last year, or other years when we couldn't buy anything but 2-3 inches of sleet for an entire winter. in my heart i think we probably end up with lower amounts in a setup like this, but no one designated me the weather wizard. get some salt and shovels ready, as always, milk, bread, butter, beer....a winter storm is coming!

[Nibor]

 

[Joe4alb]

definitely appears like there will be less interaction here (I would post but I can't attach images larger than 133.77kb) 

[SACRUS]

 

 

 

[Stormlover74]

16 minutes ago, WeatherGeek2025 said:

Long Island is getting way more than 4 inches

Yeah I'd bring that 6" line south a bit.  Even if they mix Monmouth on north east should do better

[mattinpa]

2 minutes ago, weatherpruf said:

people were jonesing for a big daddy and we aren't getting one, barring some miracle, and now they are not going to be happy with more normal amounts. 6 of snow with sleet on top is just barely above run of the mill; even 10 is not the apocalypse some people want. but think back to last year, or other years when we couldn't buy anything but 2-3 inches of sleet for an entire winter. in my heart i think we probably end up with lower amounts in a setup like this, but no one designated me the weather wizard. get some salt and shovels ready, as always, milk, bread, butter, beer....a winter storm is coming!

Most models are saying at least 8 which is pretty significant. I think 8-12 inches for all the big cities. 

[Wxoutlooksblog]

6 hours ago, jm1220 said:

It’s really not overly complicated, if we have a strong 700/850 low go NW of us, we will mix eventually-plain and simple. That means the winds at those levels are from the south and a warm direction. It doesn’t matter that the surface is cold. We could have a lot of snow fall before then but the same mechanism driving all the moisture from the Gulf also brings warm air. If the snow comes in like a wall it helps hold the warm mid level air back and we can pile it up quickly, if it comes in like shredded garbage it will disappoint and we get sleet sooner. We could also dry slot before or as that warm air arrives since dry air will pivot around the mid level lows from the south. We need the mid level confluence to force a further south transfer. If se see that retreating we have a typical SWFE setup. There’s the other possibility of a coastal system bringing snow back in but I think that won’t be determined until we’re closer in.

Perfectly stated. And we do not know the answer for sure yet. We have two distinctly different schools of thought in the modeling.

WX/PT

[Stormlover74]

Should be 12 hours of snow on the euro before any flipping

[steve392]

Do either model show a rough guesstimate to start times?  One new channel was saying Saturday morning through Sunday others saying late Sunday through Monday. 

[Wxoutlooksblog]

1 minute ago, Wxoutlooksblog said:

Perfectly stated. And we do not know the answer for sure yet. We have two distinctly different schools of thought in the modeling.

WX/PT

And the answer may be in what happens with the 50/50 low and antecedent HP. And we have different schools of thought on that as well.

WX/PT

[Snowlover11]

1 minute ago, steve392 said:

Do either model show a rough guesstimate to start times?  One new channel was saying Saturday morning through Sunday others saying late Sunday through Monday. 

4-8am Sunday Morning

[psv88]

Euro looks colder to me for the coast

[Wxoutlooksblog]

2 minutes ago, steve392 said:

Do either model show a rough guesstimate to start times?  One new channel was saying Saturday morning through Sunday others saying late Sunday through Monday. 

Morning or mid-day Sunday into late Sunday night or early Monday.

WX/PT

[SACRUS]

 

 

[Prue11]

6 minutes ago, Wxoutlooksblog said:

Perfectly stated. And we do not know the answer for sure yet. We have two distinctly different schools of thought in the modeling.

WX/PT

This may be become a nowcast event to determine if or where the mix line sets up

[MarcmmKU]

Looks like euro went south/colder. Thank god

[mob1]

2 minutes ago, psv88 said:

Euro looks colder to me for the coast

Probably a touch warmer than 6Z aloft as sleet moves in just a tiny bit earlier. Still a good run, with 7+ inches (at 10 to 1) accumulated by the time sleet moves in. 

[SACRUS]

1/22 12z total QPF storm

 

 

Total snow / sleet (10:1)

 

[Prue11]

In all honesty I was hoping a few days ago this could be a 1-2’ event I guess it’s still on the table but my confidence is definitely lower. I’ll enjoy anything we get 

[Winter Wizard]

Ceiling on this is very high, there will be a large swath of 12"+ totals across the Northeast. For the City and coast itself however, there is a twofold concern related to the transfer from primary low to secondary: mid-level warming and arguably more consequentially the dry slotting. I would not be 100% on major totals at this point, but potential is there. First bonafide MECS in 5 years. 

[Brian5671]

Just now, Prue11 said:

In all honesty I was hoping a few days ago this could be a 1-2’ event I guess it’s still on the table but my confidence is definitely lower. I’ll enjoy anything we get 

1' possible but not enough QPF for 2 feet

[Joe4alb]

actually considerable improvements in the upper levels on the Euro. 850 colder with a weaker low to our west. Good signs. 

[riverrat]

1 minute ago, Winter Wizard said:

Ceiling on this is very high, there will be a large swath of 12"+ totals across the Northeast. For the City and coast itself however, there is a twofold concern related to the transfer from primary low to secondary: mid-level warming and arguably more consequentially the dry slotting. I would not be 100% on major totals at this point, but potential is there. First bonafide MECS in 5 years. 

This

[winterwarlock]

I think 6-12 region wide is a good early call

[donsutherland1]

My thinking about an upcoming significant snowfall in and around New York City remains intact following the 1/22 12z model cycle. Overall, the City remains on course to see its biggest snowstorm in nearly four or five years.

The storm will likely attain a Category 3 or, less likely but still possible, Category 4 rank on the Northeast Snowfall Impact Scale (NESIS). NESIS is based on a combination of the area affected by the storm, population in the affected areas, and snowfall amounts.

During the height of the storm, the dedridritic growth zone (DGZ) will have temperatures between -17°C and -12°C as per the soundings from multiple models, which is close to ideal for snow growth. The layers below it will be well-saturated, and surface temperatures will be very cold, reducing the risk of melting/riming. As a result, well-accumulating dendrites will be the predominant snowflake. Ratios during this time will probably range from 12:1 to 15:1. 

A classic paper can be found here: https://www.wpc.ncep.noaa.gov/research/snow2a/snow2a.pdf

Later on, warmer air will push into the mid levels (mainly between 650 mb and 800 mb), which will lead to a transition to lower ratios and then sleet for parts of the New York City area, including the City and nearby suburbs. There's a small chance that the storm could end as some freezing drizzle as it pulls away early Monday.

Taking into consideration the DGZ conditions, historic data for snowstorms with 1" or greater QPF, the various 12z model solutions, it appears that a good initial estimate for storm total snow and sleet in New York City and nearby areas will fall in the 6"-12" range. Areas to the south and east of New York City and its nearby suburbs could see 4"-8" amounts. Areas with 12"-18" are possible well north and west of New York City, most likely in parts of northeastern Pennsylvania, Orange County, Dutchess County, and Sussex County. A reasonable floor for New York City is 5". A reasonable ceiling is 14".

There remains a degree of uncertainty concerning mid-level and surface storm evolution and tracks, and a potential primary-secondary storm handoff. Model skill will improve markedly within another day. Estimates could be revised based on the subsequent guidance, as needed, but the initial estimate is probably a reasonable starting point. Areas north and west of New York City where ratios could be higher for a longer period of time and mixing could be less of an issue, will likely see higher amounts than New York City.