eduggs

Yeah, but only slightly. And nothing to support the explosive 12z GFS solution.

I like how even thought the UK misses east with the coastal, it produces a snowy Saturday with a plowable snowfall for I-95 N&W.

The GDPS shows 3 separate periods of snow - including weekend, daytime snow! It ends up as a fairly long duration light event with moderate snow accumulations region-wide. I like that outcome a lot. The GFS shows a high-end threat. That's a beautiful coastal storm evolution with NESIS potential. Things have been trending better for 2 days, but we might have reached the end of the trend. The UK backed off and the GEFS individuals are all east of and weaker than the GFS SLP except one weaker member near ELI. You could argue it both ways, but I prefer not seeing the OP GFS west of the ensemble spread. That's a red flag.

The Jan 25 event is still in the GEFS mean. In fact it's stronger this run than last. It's a major QPF signal for 11 days out and has been for several runs. Obviously a tiny model change at initialization will propagate across the entire globe over 11 days to result in huge differences at the regional/synoptic scale.

ECM-AI is west of 18z with the SLP and sharper with the trof. It's a scraper now. Very consistent trends across guidance. That's a solid improvement. 18z was well offshore and barely had a discernible coastal SLP. 0z forms a low and tracks it east of the benchmark.

I agree the 1-3" characterization is better. But the event is not quite over for I-95 by 120hrs on the UK. But only a few hundredths of QPF after.

I don't really believe in ceilings, especially beyond 24 or 48 hours or so. I remember Feb. 11, 2006 looked like a miss or fringe event 4 days out. 2 days out it looked like a plowable snowfall with a fantasy ceiling of maybe 8". Then the storm dropped 27" at NYC. If the synoptic scale features break right and the small-scale stuff aligns perfectly, sometimes there is no ceiling.

The GEFS improved again for Sunday (trof and individual members) even if QPF doesn't fully reflect the improvement.

The UK is similar to the GFS, but better. Accumulating snow to the coastal plain just NW of NYC. Nice h5 and surface almost as good as GFS-AI. Great 0z.

I'm not really sure what fast flow means here in context. In the past I think it referred to an anomalously strong jet stream across the Pacific that penetrated the North American continent with mild air. "Fast flow" seems to have become a scapegoat when anything fails regardless of cause. In this case the flow is straight out of central Canada and the flow looks seasonably fast, i.e., not too fast. The speed of a SLP is partly dependent on steering currents but also on the structure and degree of maturity of a trof. For example, a SLP may slow and stall near a cutoff upper level low even if the associated jet has winds speeds over 80 knots.

I think the 0z GFS is now one decent step away from a plowable snowfall. Last run it was 2 steps away. It's at least starting to look plausible when you loop 500mb

The GFS still isn't great for Sunday. A little 12z Canadian like with a mid-level low in the Lakes and a pos tilted trof structure

The GFS at 84hrs looks like it has a sharper shortwave with more vorticity crossing into North Dakota. I think that's the vorticity that sharpens the base of the trof a day or so later... we'll see... could be a slightly better trof for Sunday

Snows for 30 hours N&W of NYC on the ICON. Seems unlikely but fun to look at. A 6 hour period of steady rain or snow with flurries or light rain with the initial week overrunning seems more plausible.

The RDPS looks good at the surface. But at 500mb it looks similar to the 0z GDPS, which developed a cutoff low and curled it into the Lakes. The ICON digs the trof base further south and goes neutral tilt, which is more conducive to a coastal SLP.

ICON has snow I-95 N&W on Sun. The RDPS looks decent at 84hrs. Decent start to 0z.

There's a 96" in there in SW PA. But about 20" of it is from before/after to big storm.

Is cold air ever guaranteed at 41° N and 74° W? I count 3 separate rain events in the LR on both the GFS and ECMWF. In January that can't be that cold. No we don't forecast based on LR OP model runs. But it's risky to guarentee something in the face of directly contradictory evidence.

I can't speak for everyone but I suspect if asked today, most would be happy with an average Feb & March even if they finished below normal for the season.

See, we don't disagree. This was exactly the point I made 3 days ago that you dismissed. Long-range ensemble modeling hides critical shortwave details. That doesn't mean it shouldn't be used as a forecasting tool. But it does bias long-range "looks" positive because it smooths out wave spacing and interference issues.

There's no such rule. Accumulated snowfall is a poor metric for any kind of correlation, especially at an individual location. The complexity and variability of ENSO states also makes reducing it to a binary a poor choice for correlation. It's too early to toss January.

I made a perfectly legitimate point. Focus on that instead of me.

This ECMWF chart below looks a lot like something "clawing at the back" of the east coast trof for the 18th. This perfectly illustrates my point about being cautious about preferring a later threat based on averaged ensemble height fields.

The mid- and long-range continues to look really active for the north country with this clipper parade. And a lot of these events have better than typical dynamics. I can remember plenty of early Januarys that were dry frozen tundras up in the Dacks. Not this year.

I think it's more likely he'll present the underlying information that he uses in his analysis. He might also reread some of the citations at the end of the link he posted and sharpen up his own analysis. And then everybody benefits.