January 19-20th Winter Storm Threat

[tdp146]

16 minutes ago, purduewx80 said:

deep thunder much like the ukmet is even more supressed on the 12z run; jackpots the city w/ 12-18" and is an all snow event.

A bit off topic- but what does IBM intend to do with 'deep thunder'?  Will it become 'operational' or is it still experimental? I know it's been around for more than year at least  Do they intend to sell the data to governments/private users through a weather consulting business? 

[SnowGoose69]

54 minutes ago, bluewave said:

While I don’t believe this page has been updated recently, the UKMET is often too far south with lows from recent observations. 

https://www.wpc.ncep.noaa.gov/mdlbias/biastext.html#UK

• The model tends to lower surface pressures too much and too far south and often implies synoptic-scale fronts too far south.
• Often too low with heights along the southern ends of short wave trofs, resulting in a southward displaced storm track

Generally it’s only the case with strong coastal lows deepening under 990mb.  I have not noticed the UKMET SE bias as much in systems that aren’t developing over the gulf steam or off the east coast 

[NJwx85]

EPS mean still has several inches for the NW burbs.

[SnowGoose69]

2 hours ago, Ericjcrash said:

Yeah, but I think he meant often times they are hand in hand.

The Euro and UKMET have rarely agreed this season on significant systems beyond Day 3 for whatever reason. 

[Treckasec]

The UKMET was too far south in the long/medium range with the previous system (remember having trouble finding the MSLP low because of how south/weak it was on the UKMET?) ... And considering it seems to be a known bias, I wouldn't recommend getting to giddy unless it's supported by more reliable models and ensembles (such as the EPS, and even the GEFS to an extent)

 

The Deep Thunder model seems to gather attention every so often, and then become obscure again ... I can only remember one forecast from the Deep Thunder model around a year or two ago, where it projected close to a foot of snow in my area (this was around the 84 hour tracking range), where in reality, the storm ended up more repressed and with much less snow... I wish I had maps to support this, but sadly, I can only go off of memory... My main point here is that despite the promising press surrounding this experimental model, I think that it is best to not hug the model—or any for that matter—without stronger model support and consensus.

 

Overall, it seems that models are tending towards more rainy solutions, followed by "vodka cold," as some like to say... :0)

At this juncture, colder solutions and trends are certainly possible, but I think that tempering expectations and not being swept up in the model hype is the best thing to do for now. 

[USCG RS]

The UKMET was too far south in the long/medium range with the previous system (remember having trouble finding the MSLP low because of how south/weak it was on the UKMET?) ... And considering it seems to be a known bias, I wouldn't recommend getting to giddy unless it's supported by more reliable models and ensembles (such as the EPS, and even the GEFS to an extent)

 

The Deep Thunder model seems to gather attention every so often, and then become obscure again ... I can only remember one forecast from the Deep Thunder model around a year or two ago, where it projected close to a foot of snow in my area (this was around the 84 hour tracking range), where in reality, the storm ended up more repressed and with much less snow... I wish I had maps to support this, but sadly, I can only go off of memory... My main point here is that despite the promising press surrounding this experimental model, I think that it is best to not hug the model—or any for that matter—without stronger model support and consensus.

 

Overall, it seems that models are tending towards more rainy solutions, followed by "vodka cold," as some like to say... :0)

At this juncture, colder solutions and trends are certainly possible, but I think that tempering expectations and not being swept up in the model hype is the best thing to do for now. 

While I agree with you sentiment, here it's about phasing. The Ukie tends to want to phase so the fact its not tells me it should be given a bit more credence. The Euro and GFS are both phasing quickly with the PV. The Ukie is not. Therefore I would not just outright throw it out. Just my two cents.

 

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[purduewx80]

22 minutes ago, tdp146 said:

A bit off topic- but what does IBM intend to do with 'deep thunder'?  Will it become 'operational' or is it still experimental? I know it's been around for more than year at least  Do they intend to sell the data to governments/private users through a weather consulting business? 

Yes, it will become "operational" and will see an upgrade sometime this year. Ultimately, we will have a 3km "nest" and it will be renamed GRAF. DT can already be seen via IBM's The Weather Company (fka WSI) site, which many TV mets have access to.

[SnowGoose69]

1 minute ago, USCG RS said:

While I agree with you sentiment, here it's about phasing. The Ukie tends to want to phase so the fact its not tells me it should be given a bit more credence. The Euro and GFS are both phasing quickly with the PV. The Ukie is not. Therefore I would not just outright throw it out. Just my two cents.

 

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The Euro is likely going to end up being too far north.  I don’t necessarily think the UKMET is right either but the models aren’t seeing any impacts of CAD yet or the earlier start of the precipitation.  You’ll start seeing as we get inside 96 that precipitation is moving in earlier and the CAD is stronger 

[purduewx80]

no one model is more likely to be correct at this juncture than another. best bet is to look at the range of solutions and realize reality will be somewhere in the middle. 

[forkyfork]

Just now, SnowGoose69 said:

The Euro is likely going to end up being too far north.  I don’t necessarily think the UKMET is right either but the models aren’t seeing any impacts of CAD yet or the earlier start of the precipitation.  You’ll start seeing as we get inside 96 that precipitation is moving in earlier and the CAD is stronger 

the cold air isn't going to give up its ground easily

[Yanksfan]

45 minutes ago, Gravity Wave said:

The EPS is showing less interaction between the system and the PV. Positive trends at 12z even if the surface still looks bad for us.

Can someone tell me why there is a delay in the surface reflection when there are changes in the upper levels?

[SnowGoose69]

Central Park should end the snowless streak Friday.  Most guidance today was continuing to be flat giving a better chance the boundary layer doesn’t torch too quickly.  Barring bad measuring tactics I would be surprised if it doesn’t get broken 

[Treckasec]

Just now, USCG RS said:

While I agree with you sentiment, hear it's about phasing. The Ukir tends to want to phase so the fact its not tells me it should be given a bit kote credence. The Euro and GFS are both phasing quickly with the PV. The Ukie is not. Therefore I would not just outright throw it out. Just my two cents.

Sent from my SM-N960U using Tapatalk
 

That deeper model analysis/interpreting is very important!! I don't know about UKMET's phasing biases and if it has a tendency to phase more often than not, though I would imagine its south bias suggests that it is less likely to phase(?), but that's just a guess...! The specifics of each storm will affect models in different ways of course... I'm inclined to hedge against snowy solutions for areas close to the coast and farther to the south though! My reasoning is certainly not very scientific, nor as educated as the logic an actual meteorologist/forecaster may use, haha... The tendency with recent storms on models *seem* to be a north trend, though these patterns/trends may certainly be broken at any time ... But with models (such as the EPS, GEFS, and their OPs) trending away from more suppressed storm tracks with snow tracks favorable for snow/all snow, I feel that getting a true snowstorm is becoming less likely... For this specific storm at least!

 

But like forkyfork just posted, there is a pretty darn strong high in place, so CAD (and the high's push on the low pressure in general) may be being under-modeled at the moment! With that said, I still stand by the idea that this storm should be more rainy than wintry, but considering how many model runs there are left to sift through before models converge on a solution, I guess we can't really settle on a solution at all! Just keep observing the trends...

[David-LI]

Such a long way to go with this threat. The low is still about two days away from coming onshore.

[forkyfork]

11 minutes ago, bluewave said:

They are probably underestimating the CAD near the surface. But the WAA above 950 mb may turn out to be stronger. So it could mean some areas progged as snow now may get more ice instead.

we routinely see the sfc trend colder while the mid levels remain warm or trend warmer. the front end thump is a big wildcard that won't be resolved until we're in the meso model range

[SnowGoose69]

In other news the system after looks increasing likely to be a cutter.   I’m not sold anymore the month averages below normal if we torch for a day this weekend and again mid week next week for 1-2 days.  The weeklies continue to verify well dating back to late December.  They didn’t really turn things 100% great til 1/25 or later and that’s probably where we will be at 

[Brian5671]

3 minutes ago, SnowGoose69 said:

In other news the system after looks increasing likely to be a cutter.   I’m not sold anymore the month averages below normal if we torch for a day this weekend and again mid week next week for 1-2 days.  The weeklies continue to verify well dating back to late December.  They didn’t really turn things 100% great til 1/25 or later and that’s probably where we will be at 

if we have 2 warm cutters, there's little chance that Jan finishes below normal-especially if the cold air underperforms as well.   (will depend on whether there's snow/ice cover for radiational night time cooling which could add or subtract several degrees either way)

[SnowGoose69]

13 minutes ago, Brian5671 said:

if we have 2 warm cutters, there's little chance that Jan finishes below normal-especially if the cold air underperforms as well.   (will depend on whether there's snow/ice cover for radiational night time cooling which could add or subtract several degrees either way)

This weekends system won’t likely warm us for a long duration. The next one if it goes into the Lakes could be a 2-3 day deal for sure.  

[Sn0waddict]

18z icon is still a great hit.

[NYCweatherNOW]

Icon is just a bit better which was already good. Snow to ice 

[MJO812]

1 minute ago, Sn0waddict said:

18z icon is still a great hit.

Colder than 12z and further south

[Ericjcrash]

1 minute ago, Sn0waddict said:

18z icon is still a great hit.

It's even better than 12z.

[NYCweatherNOW]

According to icon 18z we’d get some extremely heavy snow turn to ice. That’s worse than just a snow event like ukmet shows. By the way icon only goes out to 120hrs and the storm is halfway done. This would be a disaster!

[NJwx85]

Be careful when looking at the ICON precip type graphics. For example this panel shows rain well up into the Hudson Valley, but surface temps are 10-15 degrees below freezing if not colder in some places.

 

[NJwx85]

Rain falling at 20 degrees would freeze on contact, even on treated surfaces.

[Ericjcrash]

Just now, NJwx85 said:

Be careful when looking at the ICON precip type graphics. For example this panel shows rain well up into the Hudson Valley, but surface temps are 10-15 degrees below freezing if not colder in some places.

 

City (would) stay subfreezing 

[TJW014]

4 minutes ago, NJwx85 said:

Rain falling at 20 degrees would freeze on contact, even on treated surfaces.

I'm concerned, that if we do get a changeover to rain for a period, it washes away all that salt, then, once it changes back to snow, you'll get a sheet of ice on the roads.

[Gravity Wave]

GFS is colder and further south with the Friday system.

[NJwx85]

2 minutes ago, Ericjcrash said:

City (would) stay subfreezing 

This is one of those setups where someone could easily get 8-12" on a front end thump before any changeover if precip comes in fast. I don't think we can avoid the mid-levels from warming eventually however. As many have said, this could very well be an ugly icing situation Sunday afternoon into Sunday night. 

[NJwx85]

1 minute ago, CarLover014 said:

I'm concerned, that if we do get a changeover to rain for a period, it washes away all that salt, then, once it changes back to snow, you'll get a sheet of ice on the roads.

I don't think you have to worry much about snow or ice down in Toms River. Even the snowiest models give coastal NJ all rain.