MANDA

Would kind of agree with this as the Euro tends to leave too much energy over the SW in phasing situations. It is a known bias. Once you factor that into a forecast and the EURO catches on it does better than the GFS in that it will stick to a solution that is closer to reality. Even if the GFS latches onto the phase first it still swings wildly with the track, at least most of the time. GFS has known bias of being too far east initially with major coastal storms only to trend then back to the west in the days leading up to the event. Sometimes may have to wait until 48 hours for GFS to latch onto a hit. If the GFS has no other model support I tend to take it with a very large grain of salt. As is the case with the event slated for later this coming week.

Like I said several days back the GFS is a follower, not a leader. Can't remember last time it was first to the party in forecasting a significant weather event. It flips and flops from one run to the next. Its ensembles are the better way to go beyond day 3-4 but even they can have big swings. No matter there is significant potential later in the coming week. As I said yesterday I'm leaning more towards freezing and/or frozen precip especially inland areas. If some of the ensembles are on the right track could be a significant Arctic shot in the days centered around Christmas.

Been a signature for this on a few runs now but yes impossible to pinpoint from this far out. Most of the time they are over modeled.

Evolving pattern has potential. Ensembles (MMU attached) look promising. Bigger question for me is do the positive temperature departures we've racked up so far this month (+4 to +5 degrees) get completely wiped out by the end of the month. Don't think we quite make it but it is possible. Places along and north of Rt. 80 and west of 287 still look like they could pickup C-2" amounts, especially highest elevations with the Sunday night - Monday morning event. Then we move onto the potential late this coming week. Way to early for those details but in my mind colder and more frozen precip is the way to lean right now, especially inland.

Nice look and closing in on -10 days for a change. Lets see if the general theme holds in the days ahead. Perhaps start date is just before the 12/20 I've been thinking. I believe Monday system has potential for N & W of NYC. Likely not the extreme of 00Z GGEM but something on the order of C-2 or maybe 1-3 north of Rt. 80 and west of 287 in NJ. That is my early thinking. Any POSSIBLE accumulation for the coast will have to depend on 500 trending very favorably and rapid sfc intensification. Not expecting this to pull off the extreme solution but worth watching for N & W.

Will be interesting to watch the model progression of this over the next few days. Certainly the last several cycles have trended more favorable. Let's see if those trends continue. Will be most interested to see if 12Z CMC can hold onto something similar and if the EURO looks similar or better.

Useless. Above or below by how much 1 degree? 10 degrees? I don't disagree with the poster though. The -NAO and -AO will not cut it alone. Been saying that for the better part of 10 days now. So yes it is possible the PNA stays negative and EPO stays positive and S.E. Ridge links up with the block and we get ugatz. However the target period at least in my mind has always been 12/20 to 12/31 and that is right after time stamp on both these maps. I agree the 6-10 and 8-14 are going to be above normal. How much? My estimate is that the period 12/1 to 12/19 runs about +3. It is the period after that that still has the potential to deliver some snow and a modest chance to beat the +3 back down so the month finishes close to normal or a tad below. Should have much better idea once we get to next Monday where this pattern is going. By that time we'll be within 10 days of 12/20 to the rubber is going to have to start hitting the road.

Just absolutely 100% useless. Serves no purpose.

Every 6 hours!

GFS is always a follower and never a leader so I agree.

Nice signal, especially inside of 10 days instead of 15. In my mind any freezing or frozen precipitation prior to 12/18 is gravy on the biscuit. My target dates for something of substance remains 12/20 - 12/31. We SEEM to be edging slowly in that direction. Confidence remains guarded however. At least for another week or so and we see how things look at that point.

If this is real, and I suspect it is then this is going to help the cause. Neutral or weak positive is better than a -1 or greater.

Moral of all of this is: -Not all -NAO / - AO's are created equal and with a -PNA may not deliver the desired results. EPO is also a factor but I believe PNA is more crucial. By the end of this coming week we'll have a rather clear view to 12/18 or so. If December is going to be "saved" in terms of BN temperatures and at least normal snow if will be in the period 12/20 - 12/31. It always has been that period but originally the period starting 12/7 was supposed to start trending at least colder. That is now delayed. Don't want any additional delays beyond 12/18. At least there is no blow torch in the cards. Next 7-10 days look to average modestly above normal, on the order of about +2. That will leave the first half of December above. I think if things fall into place we could beat the positives back to normal or a little below for the month but until things become clearer that is not a given. Leaning toward a solid period of BN temps last 1/3 of the month but confidence only about 60% as of now.

Just some quick and dirty ensemble data to be taken with a grain of salt. All three LR models rather similar with snowfall over the next 2 weeks or so. These can and will change especially once to day 7 and beyond. EURO members pretty weak though in terms of notable (4"+) snow for NYC. Pattern is forecast rather wet so it is not that qpf will be lacking just not looking to be in the form of snow. EURO also not bullish on any notable cold over next 2 weeks. Again, will likely be some adjustments once to day 7 and beyond. Just pointing out that at least based on 12Z run of ensemble means pattern does not look overly cold or snowy through 12/17. Did not have time to dive into 500 mb. charts so this is just a snapshot based on the means. We're hoping for the period after this to deliver the goods as far as cold and storminess so we'll see where all this heads. I'm still favoring an active 12/20 to 12/30 period.

I'd take the CMC over the GFS though. Skill scores confirm that. GFS I find essentially useless beyond 4-5 days. It has huge swings run to run. We'll see if the newly released version does any better????

Totally agree. If anything of substance - notable cold and snow threat(s) are going to happen it will be from roughly 12/20 to 12/30. There does remain the risk of not much during that period depending on how things evolve. I'm leaning toward an interesting period but there are risks that the pattern does not setup and deliver the goods. At least interesting to watch.

Great post !

Of all of those the EPS looks best as far as cold and storminess potential in the east. If I had to pick one to be in my court I'd want the EPS. We're still looking at day 10+ and maybe day 15+ before this potential pattern can maybe start to deliver. Don't see much next 7-10 days to get that excited about. Do have to watch for the dreaded constant push forward in time model solutions in the coming days. Block is coming of that I'm sure but what the effect is on sensible weather in the east is uncertain. The block on its own is not going to do it as far as cold and snow for this forum.

Anyone got the Kuchera

I believe the GFS was upgraded and put into op mode today, GFSV16.3. Was supposed to go operational yesterday but held off until today due to the severe weather. We'll see how it performs. My expectations are low. The upcoming high latitude blocking seems like a given at this point. Model consistency across the board has been good and it has not been getting pushed out in time like last year. What fruit it yields is yet to be determined. Do not underestimate the possibility that it is just cold and dry with perhaps something as the block retrogrades and decays in the week or so before Christmas. As mentioned in a prior post by jm1220.

Thank goodness for the "cold" period after the very warm opening or it might have been a top 3 or warmer November. The colder than normal middle of the month did a decent job at knocking back the opening very positive departures. Months with negative temperature departures (even against the warmest normals we've ever had) are pretty rare these days. We'll see what December can produce but the opening of the month is certainly going to start off on the milder side. December does look to have the POTENTIAL to finish BN but caution is advised since much will depend on the -NAO blocking and were / how it actually positions itself. If the SE ridge (which seems to be a semi-permanent feature of late) hangs on, even only modestly then temperatures will finish at or above normal levels. Pattern overall though looks to favor much colder air masses from the center of the country at least oozing into the eastern 1/3 of the nation.

Ugly

IF, and it is a BIG IF this far out, that over the top ridge bridge works out then we could see winter weather of note. I'll add that it is the GFS and it is WAY out in time. If this vanishes or keeps getting pushed out in time, i.e. it is always two weeks away then it is not likely to evolve. Right now my expectations are muted.

I know this if off topic for this forum but not much else going on in the near term so I'm posting totals from around Buffalo. Best totals clearly south of the city. Forecast max totals were realized but they were just further to the south and not in the city proper. Such is the nature of LE bands.