eduggs

0z GEFS mean shifted towards the CMC a bit. We need a sharp trof that cuts off like the OP GFS to have a shot with this.

17 minutes ago, Heisy said:

CMC almost tries to pull same thing but ULL can’t get going and trough is a little too progressive. Icon has a gfs progression, but doesn’t have nearly enough juice with left over energy. Let’s get some support from ukie or euro tonight


.

Yeah the CMC was a definite improvement aloft compared to the past several runs. But a blend with the GFS would likely pinch off and miss southeast. An EC solution anywhere close to the GFS would be huge - would go a long way towards making some wintry precipitation seem possible. Any significant negative trend the next two cycles and this is probably dead.

12 minutes ago, MJO812 said:

Everyone starting to hype up the strat warming event .

 

Maybe a wild March just like 2018?

Meteorologists are the least scientific of all the pseudo-sciences. It's a faith based "science."

Long range strat temp modeling has high uncertainty. The regional effect of strat warming is highly variable. The long term correlation between modeled strat warming events and regional winter outcomes is very low. We've seen this year after year. What have we learned?

4 minutes ago, MD Snow said:

ICON says it's a legitimate chance of some showers for the Carolina's. Partly cloudy and around 50 for us. 

A decaying cutoff in the southeast is a definite possibility as well. It has been part of the ensemble spread for a day now and the delayed shortwave progression is trending towards it. But this scenario also leaves open the possibility of some cold-side precipitation further up the coast.

16 minutes ago, CIK62 said:

This is the only 24 Hour Period that has any chance of leaving an inch+:          The 20th  +/- a day has a tiny chance too.

And that right there is our best day 5 map of the winter thus far 

7 hours ago, SnowGoose69 said:

The Euro is probably closer to reality than the GFS...but the CMC/Icon idea of basically a miss or weak follow up wave is more likely.  The GFS failing to pull the entire baroclinic zone east and still taking a storm inland is probably not realistic at all

I agree with this. But there's a path there that would allow cold air to seep southward. Then a delayed wave, possibly a not-quite-squashed cutoff, could possibly rotate some precipitation back into the cold air before everything gets shunted east. I much prefer a miss east to a torched cutter followed by cold front. In this preferred scenario, a longshot sharper wave could give us something.

Not saying the GFS or EC will happen, but big fail for the Mets and amateurs alike who obsess over fantasy pattern changes, long range anomaly charts, ENSO states, and stratospheric warming events. The never ending quest for a simple causal relationship to predict snowstorms coming far out in fantasy land has led to an atrophying of actual mid-range forecasting skills. "Patterns" don't produce local snowstorms. Particular combinations of synoptic features do.

The Fri-Sat event has too many ways to fail, so I am pessimistic on snow chances outside of elevated interior regions, at least for now. However, a lot of Mets and amateurs drop the ball as forecasters because they obsess over long range anomaly charts, ENSO states, and the search for the mythical pattern change. Snowstorms are local phenomena that occur due to very specific, random interactions of synoptic features. They cannot be forecast reliably very far out in the future. If you keep scouring fantasy range for the perfect setup, you will miss the potential event hiding in plain sight.

1 hour ago, Stormlover74 said:

Gfs is 50s and rain

The GFS is the warmest of 0z so far. CMC, ICON, and UK are colder. Considering the lead in wave pushes warmth to Ontario, this essentially would have to be a rain to snow scenario best case. Two viable options for snow are a flat trof (CMC) or a high amplitude cutoff.  I think a stronger cutoff would be most helpful to wrap in some cold air, but models are not very supportive. The GFS has the right trof structure but the mid-level center tracks too far north. The 18z ICON had something maybe more workable, but it was an outlier.

A step back from the GFS and slight step forward from the CMC (but flat). Neither are inspiring. Status quo for now. Chances for snow continue to look slim outside the distant NW elevated terrain.

I did notice the GFS closing off 500mb... just too far north unfortunately. Also lower heights in Atlanta than Syracuse, however brief, is a trof worth paying attention to.

0z ICON is significantly warmer and wetter than the previous two runs. Aloft it shifted towards the model consensus. But it still manages to get flakes in the air on Saturday for most and probably has the best mid-level synoptic signature of any threat we've seen all winter. It's almost certainly showing a miss for most locally, but it's honestly not too far off from something better.

0z ICON coming in with a not unexpected shift towards the 18z GFS. Warmer and wetter than 18z. Hopefully the GFS makes a similar shift to meet it. Otherwise the multi cycle favorable trend may be over. The 0z ICON does manage to close off the mid-levels and get a coastal SLP going, but too late for most except primarily SNE. But can't say it looks too far off for something more widespread and wintry.

18z ICON and GFS once again slightly improved compared to 12z. 18z GEFS with another notable improvement as well, with the mean precipitation chart finally indicating a coastal SLP on Saturday with some cold-side precipitation.

Another slight tick better on the 18z GFS and ICON. The ICON is pretty far southeast now with the entire baroclinic zone, especially compared to other guidance. It already rotated a bit of snow through most places on the 12z. Only goes out to 120hrs at 18z though.

The 18z GEFS is also yet again better than last run. Much wetter on Sat through the Delmarva and back to the NW compared to 12z. Indicates more members showing a trailing coastal SLP with some precipitation lingering on the cold side.

49 minutes ago, mattinpa said:

Any chance we get colder than the 40s that are predicted? The projected temps would give a cold rain. But yes might as well watch it. It would be gone quickly also, but any event this winter is a big thing. 

I don't have any special prognostication abilities. The temperature is partly precipitation dependent. I think low 40s is a reasonable high temp forecast for Sat at this juncture. If it's dry on Sat with the frontal passage scenario shown on the GFS, we should hit 40 (e.g., with ~28 dpt) before cooling off after dark. But if there's precipitation like the EC or ICON show, it would likely be more like upper 30s dropping through the mid and maybe low 30s.

GEPS also noticeably improved over 0z. The longer each cycles avoids trending in the wrong direction, the more I'm compelled to get drawn in a little bit.

43 minutes ago, Maestrobjwa said:

Whatever the upside here (if there is any), it's clear the models are having difficulty with exactly how the pieces are interacting here. Would expect some jumping around still for another day or two.

Agreed. It's always difficult to accurately model anomalous events involving multiple shortwaves. The inter and intra-model spread does suggest more model jumping likely. I'm just happy to see the snow threat hasn't completely evaporated at this range like just about every "event" so far this year. The mean chances for 1" or 3" of snow are probably very low throughout the east coast coastal plain. But on the other hand, the high end is probably something like a 12-18 hour snow bomb somewhere along the mid-Atl coast. Maybe 1 in 20 chance of that or less. But at least some of the ingredients that make it remotely plausible are there.

8 minutes ago, Rtd208 said:

Yeah I think he is grasping at straws. 

We all know it's a low likelihood wintry threat. That's due to the antecedent conditions. But while many on here and other nearby regional forums obsess about low temperatures, tenths of snow accumulation, or long range fantasy pattern changes, I like to focus on mid-range forecasting of wintry events that are actually plausible.

A high amplitude longwave trof favorably aligned with the east coast is a major ingredient in snow threats for our region. Yes the other major ingredient is missing, but we've certainly spent lots more pages discussing threats of less potential significance already this winter.

The 12z EC looked like a positive tick to me, which follows the inter-model trends. Gets snow to the distant NW suburbs. Still pretty far off, however.

12z GEFS actually looks pretty good to me for Sat. It's the most threatening run in a while for wintry weather somewhere along the east coast. Red flags for sure, but it's hard to dismiss completely at this non-fantasy range.

12z GEFS looks like the best run in a while: weaker, more suppressed initial wave, more separation, sharper, and higher amplitude follow-up wave, and more precipitation along the coastal plain on Saturday. I'm not trying to overhype this threat. Expectations should be kept low. But I see more here than most of the other "threats" we've seen this Dec-Jan period. I've been shitting on almost every setup all winter, but this looks slightly different to me.

If I had to bet, I'd expect this evolves into either an inland, elevated wintry threat or a late developing miss to the east. As usual, so many things have to go right. But at least this time we can imagine a theoretical path to a win.

UK looks interesting. ICON has a little snow. GFS and CMC are disjointed but all show a high amplitude trof with low heights in the southeast. That's one way to get snow in the mid-Atl during a warm regime. Yes we're all fighting an uphill battle due to the antecedent warmth. But the OP runs and ensemble spread do offer some hope that is not out in fantasy land. Midrange, trackable potential hasn't materialized often this winter. Yes it's a low likelihood threat, but it's more viable than almost any day 5.5 threat we've had all winter.

6 minutes ago, Stormlover74 said:

Nah it's gonna be way too warm 

Yeah as soon as it became clear a few days ago that the initial shortwave was going to push into Ontario following the seasonal pattern, we knew we'd be facing an uphill battle with temperatures. That much is a given. But what we do have on most guidance is a high amplitude ridge-trof combo. The base of the trof reaches the GOM. Anytime we get that it catches my attention. Certainty more interesting than tracking the potential for a few tenths of snow that gets sublimated in 20 minutes.

14 minutes ago, Weather Will said:

12Z ICON too progressive, too far south east, but not a cutter….and a little snow for eastern areas.

 

The panels between 141hr and 168hr are not showing up on TT, but there is some snow between those time periods for much of the urban corridor. It's a little warm so not confident about accumulations. But it's a better wintry threat than we've had in a while. And the GFS, CMC, EC, and UK are also modestly threatening of some potential.

Next weekend continues to look to me like the best winter threat we've had in a while. There are red flags everywhere... namely the near total displacement of cold air prior to a potential coastal SLP. But the recent model runs of the GFS, EC, UK, ICON, and CMC all look potentially interesting. Certainty interesting enough to maintain tracking interest.