December Model Discussion

[NorthShoreWx]

No sign of any warm up for the next 16 days on the 0z27 Op GFS.  High amplitude ridge west, trough east with bits of the PV rotating close to the NEUS throughout.   None of the relaxation of the pattern that was shown on the 18z run.  0z would be a fairly epic cold start to January if it verified, but these runs have not exactly been models of consistency.

 

[Paragon]

4 hours ago, NorthShoreWx said:

No sign of any warm up for the next 16 days on the 0z27 Op GFS.  High amplitude ridge west, trough east with bits of the PV rotating close to the NEUS throughout.   None of the relaxation of the pattern that was shown on the 18z run.  0z would be a fairly epic cold start to January if it verified, but these runs have not exactly been models of consistency.

 

I was listening to the forecasts for NE PA (my second home) and their long range forecasts are calling for a very cold January.

[Paragon]

10 hours ago, EastonSN+ said:

Just saw that. A lot colder in the lr than previous runs. Perhaps models breaking down pattern too early before.

I've often wondered about that.

Sometimes you can get a historic storm that defines the pattern that occurs thereafter. 

I think that's what happened with Boxing Day 2010.  I don't think that winter would have transpired anything like it did if that storm hadn't happened.  The forecasts before it were for a relatively snowless winter and we had the best 5 weeks I've ever experienced.  I don't think the cold would have been like it was without that storm and I don't think the storms thereafter would have been as great as they were either.

Maybe if we get a big storm around Jan 5-6, the anniversary of the Jan 1996 blizzard, it will define the pattern for the next few weeks too.

[MJO812]

Euro is weaker with Saturday but still some accumulating snow

EPS shifted west compared to past runs for Saturday.

Euro now has a  coastal around Jan 4.

[donsutherland1]

The EPS now has a mean snowfall figure of just under 2" (1.5" on a trimmed mean that excludes the 5 lowest and highest amounts). 6 members show 4" or more; 3 show little or nothing. 60% have 1" or more, 30% have 2" or more, and 15% have 3" or more. Statistically, the highest 10% of outcomes would be 4.3" and the highest 5% would be approximately 4.7" (vs. 4.0" on the 12/26 12z EPS). These statistics take into consideration both the EPS and operational ECMWF. It's still early, but the combination of the ECMWF and EPS may be starting to hone in on the potential of a 1"-3" snowfall (more on Long Island and to the north of NYC) across a good part of the region.

[MJO812]

47 minutes ago, donsutherland1 said:

The EPS now has a mean snowfall figure of just under 2" (1.5" on a trimmed mean that excludes the 5 lowest and highest amounts). 6 members show 4" or more; 3 show little or nothing. 60% have 1" or more, 30% have 2" or more, and 15% have 3" or more. Statistically, the highest 10% of outcomes would be 4.0" and the highest 5% would be approximately 4.7" (vs. 4.0" on the 12/26 12z EPS). These statistics take into consideration both the EPS and operational ECMWF. It's still early, but the combination of the ECMWF and EPS may be starting to hone in on the potential of a 1"-3" snowfall (more on Long Island and to the north of NYC) across a good part of the region.

I think it would be slightly more than 1-3 with the ratios.

[NEG NAO]

7 minutes ago, Snow88 said:

I think it would be slightly more than 1-3 with the ratios.

what is the total liquid amount that is forecasted to fall and what would be the accumulation totals at 15:1 - 20:1 and the slight chance that it was even higher ratio ?

[MJO812]

21 minutes ago, NEG NAO said:

what is the total liquid amount that is forecasted to fall and what would be the accumulation totals at 15:1 - 20:1 and the slight chance that it was even higher ratio ?

I think this comes west and we get several inches. Gefs is starting to get a clue. Some nice eps members.

[donsutherland1]

33 minutes ago, Snow88 said:

I think it would be slightly more than 1-3 with the ratios.

It very well could be. A light to possibly moderate event still appears likely.

[PB COLTS NECK NJ]

7 minutes ago, bluewave said:

You can't know where that favorable DGZ sets up until we get to the short term forecast period.

 

I am putting my hand over that feature because I don't know if it's real in that spot.

I am looking for the deepening to drag the . 4 line west and then go off at 15 to 20 to 1.

It needs some work and another full day of sampling the N stream which will answer that question for me.

It's precisely why I don't give up on the EC 4 to 6 days out.

[PB COLTS NECK NJ]

4 minutes ago, bluewave said:

Norluns are short term forecast challenges. I wouldn't want to try to pin down the exact location until we get to within a day or 2 of the actual low developing offshore. It may take until we get within HRRR range to know. 

I agree , thats why I am ignoring it in the forecast.

There are several 990 lows tucked far enough west that will allow .4 to come west to the coastal sections and it's 15 to 1 based on the airmass and as much as 20 to 1 where the best lift appears.

If a norlun sets up then that area hits the JP.

I am not taking that into consideration yet.

[PB COLTS NECK NJ]

7 minutes ago, bluewave said:

I agree with you that such a strong and cold TPV bowling ball will produce a nice localized JP for somebody with a sharp fall off away from the main zone. The Euro has been hitting eastern LI but I don't know if I can trust the placement so far out in time.

 

Chris , knowing your location I can see the smile from here....

Just need .4 , but if that IVT sets up in Suffolk ,  PSV and Ed will be very happy 

[LongBeachSurfFreak]

55 minutes ago, PB COLTS NECK NJ said:

 

I am putting my hand over that feature because I don't know if it's real in that spot.

I am looking for the deepening to drag the . 4 line west and then go off at 15 to 20 to 1.

It needs some work and another full day of sampling the N stream which will answer that question for me.

It's precisely why I don't give up on the EC 4 to 6 days out.

Exactly what I have been saying that last few days when the usual suspects claimed victory. I’ll make my final call after tomorrow nights runs.

The other funny thing is the pattern moving forward. The usual suspects would have you think we should break out the shorts. Yet we may be in for the longest and strongest sustained period of cold since the late 70s. At some point moisture will get involved 

[NJwx85]

I've personally liked this threat from the beginning. I always thought this was the one to watch vs the one for Christmas.

The problem I am seeing is that the flow is a bit too progressive and the shortwave coming down just after New Years is helping to kick the initial energy East. 

We need something to buckle or amplify the flow.

[Yanksfan]

With the QBO in our favor along with a solar minimum, where the heck is the -NAO? For the past several years we just can't get this feature during the winter months with any regularity. That would of surely helped with the progressive flow issues we're enduring currently.

[SnowGoose69]

The 12Z CMC still has the event this weekend but this may still end up sliding more south towards PHL or DCA or just evaporating entirely 

[Ericjcrash]

5 minutes ago, SnowGoose69 said:

The 12Z CMC still has the event this weekend but this may still end up sliding more south towards PHL or DCA or just evaporating entirely 

Definitely dried up this run, brings the goods next week though . 

[Yanksfan]

12z Canadian and GFS both show a strong Miller A event in the Jan. 4-6 time period albeit the GFS is a close miss.

[donsutherland1]

With respect to the possible 12/30-31 event, the GFS again shows little or no snowfall although it is slightly improved from the 6z run (surface and 500 mb, but the changes were very small). The CMC brings 1"-2" locally somewhat higher amounts to the region. The NAM and extended RGEM brought coatings to 0.5" (more on the NAM than the RGEM). It's still early to get a good handle on ratios, but something in the 12:1 to 15:1 range looks more likely than 10:1.

The combination of the forecast pattern (above normal snowfall potential for the 12/29-1/7 period; roughly 80% above the climatological frequency of measurable snow events) and the 0z EPS/ECMWF runs leads me to give greater weight to the idea of a light to moderate snowfall for the NYC area (including the suburbs, NJ, and Long Island) than the GFS outcome. That the NAM and RGEM, even beyond their useful range, suggested some accumulation hints that the higher-resolution ECMWF's solution still remains more likely to verify than the 12z GFS idea. Let's see what the 12z ECMWF and EPS show.

[SnowGoose69]

UKMET doesn’t look bad at 72 to the west but it may dampen significantly thereafter.  Can’t see past 72 yet

[MJO812]

 

Looks like a 1-3 inch deal

[SnoSki14]

Gfs is bone dry and now has that Miller A missing to the east. Looks cold & dry for the entire stretch until the pattern breaks down well in the LR.

CMC has been trending drier as I suspect all the models will. It has a Miller A but that model is garbage beyond a few days and I suspect it'll get more suppressed over time. 

We're not going to get anything in this airmass, it's going to overwhelm any system that tries to develop. I don't think we see any precip until the pattern breaks down, but by then it may just be a rainstorm or mixed event.

[dmillz25]

3 minutes ago, SnoSki14 said:

Gfs is bone dry and now has that Miller A missing to the east. Looks cold & dry for the entire stretch until the pattern breaks down well in the LR.

Oh yeah? That sucks.

[Brian5671]

With the extreme cold and PV so far south-definitely have to consider a cold and dry outcome as a possibility.

[SnoSki14]

2 minutes ago, Brian5671 said:

With the extreme cold and PV so far south-definitely have to consider a cold and dry outcome as a possibility.

It's happened many times in the past, so it's not shocking, we've just been so spoiled that it's a shock to weenies. 

We will probably see some unusual snows well to the south in this pattern, so I'm curious to see how that will turn out. The cold stretch is also interesting from a historical perspective.

[Brian5671]

3 minutes ago, SnoSki14 said:

It's happened many times in the past, so it's not shocking, we've just been so spoiled that it's a shock to weenies. 

We will probably see some unusual snows well to the south in this pattern, so I'm curious to see how that will turn out. The cold stretch is also interesting from a historical perspective.

I think our best bet is as the cold relaxes....some of our biggest storms come out of these patterns...

[MJO812]

15 minutes ago, SnoSki14 said:

Gfs is bone dry and now has that Miller A missing to the east. Looks cold & dry for the entire stretch until the pattern breaks down well in the LR.

CMC has been trending drier as I suspect all the models will. It has a Miller A but that model is garbage beyond a few days and I suspect it'll get more suppressed over time. 

We're not going to get anything in this airmass, it's going to overwhelm any system that tries to develop. I don't think we see any precip until the pattern breaks down, but by then it may just be a rainstorm or mixed event.

You do realize that we dont need alot of precip for a few inches of snow ?

Ukie and cmc gives the city 2-4.

Gfs is coming around.

[ILoveWinter]

Yes a cold pattern can be suppressive but this is not always the case.  I remember several past MECS with temps in the upper teens to lower 20s, so just saying its cold and that's that is not constructive. 

[SnowGoose69]

5 minutes ago, SnoSki14 said:

It's happened many times in the past, so it's not shocking, we've just been so spoiled that it's a shock to weenies. 

We will probably see some unusual snows well to the south in this pattern, so I'm curious to see how that will turn out. The cold stretch is also interesting from a historical perspective.

Maybe.  Right now a good amount of the guidance suggests that even the cold may be too overwhelming for snows for places like AL GA SC TN.  I’m inclined to believe though that as is often the case the Day 6-8 cold down there is overdone and they may get hit by something ejecting out of the western Gulf 

[North and West]

I think cold and dry with no snow is good and interesting from a weather hobbyist perspective, as well as controlling insect populations around my yard for the spring.


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