Krs4Lfe

As we know, a positively tilted trough doesn't allow the storm to ride up the coast which would push the boundary layer further south and therefore, the risk for snow as well

Interestingly enough (and we may have to go back into our memories for this one), this storm is behaving somewhat opposite of the 3/8-3/9? (might not be exact date) storm in 2019. The first signs of that one coming far north and mixing significantly in NYC and the surrounding areas was the storminess in the south the day of and day prior to the event. The latent heat released by the severe outbreak pushed the storm further north, similar to what we see with tropical cyclone steering (moving towards the warmest waters if at all possible.) The severe storm outbreak today didn't appear to materialize, and if that trend continues through tomorrow, that could definitely be a result of a more positively tilted trough.

Homenuk on twitter says if the trend continues, there might be significant changes to storm forecast. Even still, we know that north and west trends in the last hours leading up to storms are real, so ideally, we would want this to trend as far south as possible, to counter the north/west trend that we'll probably see tomorrow night.

I would issue a word of caution to everyone living in the NYC metro area and down to the coast while viewing the NAM and HRRR. Even if that very heavy snow verifies, it would take several hours of that to accumulate considering it's not a nighttime storm, temperatures will be starting off in the upper 30s, and at its coldest, we're likely to get down to around 34. Accumulation, even if the snow is that heavy and persistent, would still only lead to accumulations on vegetation and colder surfaces. I wouldn't expect much in the way of road impacts

Once we saw the north trend yesterday, it became apparent it wouldn’t stop. With a more amped up storm, and lessening confluence, this northward trend will likely continue. Not to mention the warmth leading up to the storm which would cut back on totals anyway. Not expecting more than an inch of slush here anyway.

Even still, taking the latest GFS verbatim, that’s some pretty heavy snowfall at around 33 degrees or so. Accuweather calling for about an inch or so. Now if the storm trends more north, then all bets are off. But verbatim, that looks like some pretty heavy snow.

That’s not a bad look. 32 line is right near NYC, and there’s heavy precipitation during that time.

I have to say, one thing that does perplex me are the official forecasts (NWS, TWC, and the cable weather news networks) calling for almost nothing here in NYC. Over the last 24-36 hours, almost every model run has shown 5+ for NYC. I wonder what their rationale is. Maybe the north trend will continue, or lack of cold air leading up to the storm? Seems to be a big disconnect between the model data and the humans that are making the forecast.

Again, and this can be said numerous times over. When winter is almost non-existent for most of the nation, it's harder for there to be any sustained cold, let alone snow, over here in NYC and for many in the region. The source airmass continues to be horrible, and two PAC extensions (one during December), and one during late jan- mid feb, are arguable the worst times to have torches across CONUS. That's why snowpack is near record low, and why almost no where outside of mountains has seen significant snowfall this winter (outside of a brief pattern in early-mid January). Until that changes, there's not much to separate 2024 from joining the ranks of 2012, 2020, 2023 as ratter winters.

For many in the NYC metro, its a heavily mixing scenario. Looking deeper into the storm configuration, the confluence appears to pressing less over the past few runs, which is what leads to less snow and more mixing for the area. Without significant high pressure press from southeast Canada (where we would see our confluence pushing down), then this is only the beginning of the north trend, not the end of it. And if it's only the beginning... then we know what happens next.

I'm not sure how much we realize that this winter has been one of the mildest on record for CONUS. 2012, 2020, and 2023, despite having similar impacts in our region, had much more elsewhere. I have never seen this level of warmth and lack of snow across the country. Aside from a 2.5 week period in early- late January, winter has been all but absent for this entire season. The Pac jet torched CONUS in December, and the jet extension did that yet again for late Jan and early Feb. December is usually quite active across the northern tier, and late Jan- mid Feb is peak climo for most of CONUS. During these two critical periods, winter almost never came. That can be evident even by The Weather Channel's automatic storm naming mechanism. When 2+ million people are under winter storm warning/blizzard warning/ice storm warning, a winter storm becomes named. There have only been 11 of those since November, a record low. 2022 held the previous record with only 12 of those (made it up to the L storm around this time in Feb 2022). Uncharted territory here, and we're all still seeing the consequences of it.

That's how you know the storm is likelier to shift north, or at the very least, unlikely to see the confluence pushing further south.

Absolutely. Even if all the changes haven't been reflected in the surface yet, looking at the upper levels, when there is more phasing, there will be further north movement.

Only with further push of confluence and maybe the shortwave digging more back in the southwest. Other than that, the north trend has only begun, I'd think.

For now, that's not a bad place to have it, but ideally, we'd like to see some more confluence pushing down, as we know these storms tend to have a north and west trend leading up to impact. I'd expect this trend to continue.

Heaviest precip centered around NYC metro and CT for early Tuesday afternoon. That being said, it's a bit warm for the area, verbatim at least. That 32 line is quite north.

One thing to keep in mind is that oftentimes when we see western ridging and eastern troughing showing up (blues over our area), we tend to get excited. But those blues merely indicate colder than average, and oftentimes, stormier than average. As we've seen this winter and last winter, without proper cold air, you can have a few day average of blue contours, without there being snowfall in the region. So let's not get *too* excited with these depictions, as it can still lead to a cold rain, considering how much we're lacking snow and cold across CONUS.

I usually keep my thoughts for long range, but I figured since I'm a bit new at posting, I'll make one for this upcoming storm. As far as the threat for this storm goes, it is increasingly likely that there will be an at least a moderate-level storm for most of the region. What we would want to see more of is confluence pushing down, and separation of the northern stream and the southern stream. Ideally, if we had cold air in place, we would want a more amped solution and phasing between the northern stream and southern stream, but considering its a very warm weekend coming up, cold air will be scarce for this storm. Therefore, in order to get snow from the NYC-boston corridor, (where snow has been almost non-existent since Feb 2022), a further push of confluence would be the best scenario (as it's likely we see a last minute northwest trend anyway, as we almost always do).

It looks like over here, we'll peak around 57 degrees on Saturday, down to 51 on sunday, and then cooler for next week in time for the pattern change. Given that the 2/13 storm is likely to assist in initiating the pattern change, it may unfortunately be too early to expect any sort of snowstorm for the region. I believe the 12z GFS depicting a regionwide rainstorm is the likeliest option, given the torch weekend that we are heading towards. After that, it appears we have more cold air to work with, which would aid in producing snow for other storms that form past the mid-February range. Unfortunately, the background state naturally becomes warmer from this point on, and it will become harder for it snow (climatologically). So while we are heading towards a colder regime, it will take more than that to snow, and time continues to tick on. Regardless, the favorable pattern is just about 1 week away, it's a good pattern, but doesn't guarantee much of anything.

In terms of the forecast pattern change around 2/13, it still seems like we're moving into a colder/stormier regime. A few things to note however: 1. It doesn't take much to be colder and stormier than we are now, as we will have torched the first half of February anyway 2. Even with the spike in the +PNA and western ridging, combined with the east coast troughing, it appears that there's a risk for storms to crash into the west coast. While that appears to be the risk, it can also be a positive if the storms undercut the ridge and move through the Southwest 3. Persistent storminess (as indicated by above normal precip anomalies) look likely along the southern tier, and then just offshore in the Atlantic. That indicates storms riding through the south and then attempting to move up the coast, but low pressure over southeast Canada pushes that out to sea 4. In short, it appears that this pattern change will indeed happen, it will become colder than it is now, and there will be more storminess across CONUS. But too many variables come into play for seeing snow in this region. For now, I don't see those variables. I see colder and stormier, but not what is needed to drag this winter out of its abysmal state that it's in for much of CONUS. Still shocks me to see how aside from a 2 weeks in January, snow has been non-existent for much of the nation

In essence, pretty much everything you’d want to see for a projected pattern flip is on the table starting mid month. Big western ridging, heights building around Greenland, a backlog of storms in the North Atlantic, and an active STJ. Antecedent cold air will be greatly lacking at a minimum, if not completely missing at all. Snow cover across CONUS is even lower than 2020 and 2012, and once you get further in the season; an existing snowpack helps reinforce cold air even more. Unfortunately, we’re moving out of peak climo for snow soon, but storms can occur regardless. As much as this pattern looks great, and it can play out great as well, I’m not sure it will. The timing of cold air would have to be spot on. And we would need constant storminess in order to make up for what we haven’t had so far this winter. A tall order, this is. In a pattern like this, this is the best option to get it done. I’d wager that it’s unlikely at this point, but this would be the pattern to get it done, if it does happen.

Quiet on here tonight. Can’t say I’m surprised given the quiet weather pattern that has shown up. Still remarkable at how inactive this winter has been for the whole nation. December was historically inactive, January had a snow blitz for the first 3 weeks, and then everything shut off for the past week. Even The Weather Channel’s winter storm tracker has only had 10 storms since November! February looks to remain almost historically warm and inactive over the next 10 days, outside of Rockies and points to the west coast. And even then, most places outside very high elevations won’t be cold enough for snow.

An encouraging sign to see is that it appears the pattern change is holding serve through time. This week, the pattern change has been indicated for around 2/13 or so, and so far, that look has held. Everything we’d want to see in a pattern change is there. Big spike in +PNA with a large western ridge, an eastern trough that is centered around Ohio River Valley and areas just eastward, heights building south of Greenland, and a funneling of cold air from the Hudson Bay Area (as indicated by blues extending from there down through the east coast). Does this mean that the pattern will produce? No. If anything, December 2022 taught us that, and for the NYC area, January 2024 just gave us a second lesson on that. But, it would be highly improbable that winter weather stays clear from the area during this pattern change. After all, 12/2022, and 1/2024 still had winter weather for our neighbors in this region, although NYC seems to be in a sort of a snow hole of sorts. In short, things are looking better for the area. Doesn’t mean they’ll produce, but with this pattern? It would be nearly impossible to see *nothing*.

The lack of winter weather across CONUS continues to amaze me. Last year, arguably one of the worst if not *the* worst for snow regionwide, other parts of the nation were doing well. In particular, from the west coast to the upper Midwest. Even in 2020, most of the northern tier was doing better. Outside of 3 weeks in January, our PAC dominated winter has led to very little snow and even smaller snowpack/ sustained cold temperatures across the nation. Aside from a few areas, this ranks even lower than 202, 2012, 2023 with nationwide snow averages. The PAC jet in December did us all in for that month, and it appears the next 2 weeks will be rather quiet nationwide. Hard pressed to find such little winter activity this winter across the nation. Take this info as you will….

Well that's a decent look for a few reasons. Let's break down the positives 1. Jet streaming across the pacific ends up breaking off, with storminess/moisture moving through north Mexico 2. That storminess takes on a STJ look, with storminess accompanying that jet streak across the south and mid-atlantic, which will obviously lead to an active weather pattern of some sorts 3. Ridging over west coast (+PNA) must lead to a trough on the downside of that, which could get caught up in the jet streak 4. There's some low pressure around Newfoundland, and high pressure ridging south of Greenland, all of which could help lead to a "blockier" scenario Let's break down the negatives 1. The western ridge isn't in the most ideal position, with the highest anomalies being just offshore the west coast 2. High pressure isn't anchored in southeast Canada, which is arguably the best spot to reinforce cold air to meet up with this stormy look 3. Due to the ridge axis being right off the west coast, the trough would likely be over central US, giving a chance for heights to rise along east coast. That would help us avoid suppression, but *could* lead to some inland/coastal huggers if this look were to verify