Watching November 9th to 12th - First Snow?

jmanley32 wrote:

rb924119 wrote:Regarding next week threat:

“Just my .02 here, based on very coarse and quick peeks, but I my early incling is that’s this will end up as either an I-95 special or a coastal scraper. Reasons being are the following, and they include the ideas presented heretofore by @33andrain, @CCB!, @Allsnow, @Armando S, and @PB GFI. There is an overwhelming number of factors that I like to look at when trying diagnose the most likely storm track/evolution, as those of you who have read my thoughts regularly last winter will probably remember. In this case, we would have the following: 70N/70E ridge, -EPO, -WPO, +PNA triplet, favorable downturn of >1°C in Niño 1.2 at an appropriate lead time of 2-3 weeks, AND favorable downturn in the SOI at an appropriate lead time of 5-7 days. These are only counterveiled by positive SST anomalies in the Western Atlantic/Gulf, MJO entering P6-7, and lack of a -NAO. Therefore, there is a clear bias towards an overall significantly colder/suppressed evolution.

However, the positioning of the Western North American ridge axis is a bit far back, and so will work to shift the storm track given the general wavelengths. That being said, the restructuring of this ridge is important because as it restructures, a piece folds over into the prime-time region with a (what I’ll call) a pseudo axis over Boise, Idaho. That should prevent a coastal hugger/inland runner scenario in conjunction with the other indices. As Geoff said, I am concerned with a miss wide-right, but I think the initial ridge axis placement saves us from that, while the restructuring of it and the other indices lead to a favorable evolution for the coastal plain in the long run. If I have time, I’d like to dig deeper, but that’s what I saw in approximately five minutes lol”

So what I got from this was it will be a coastal snowstorm or nothing but you are leaning away from suppressed? Are those temps mugs posted even close to possible? Thats gotta be some kind of record at least for the coast. Do you think it could be a lot of snow or just a moderate snow? I could see how that severe cold could suppress though, wouldnt be the first stime we seen cold mess up our snow storms.

Correct, Jman. I can see how a completely suppressed evolution occurs here, and am worried about it, but in terms of probabilities, I think it’s relatively low compared to the other two options (I-95 special or coastal scraper). I haven’t been able to look closely enough to establish my best guess on track between the I-95 special or coastal scraper, though, which is why I say it could be either or. If you made me pick one right now, based on my previous analysis, I’d probably favor the I-95 special storm truck, which would be good for 90% of this forum (including you lol). In terms of accumulations, I think a moderate event (3-6/4-8”) is a reasonable guess right now. I don’t see much option for more than that, but I do see how it turns into a 1-3/2-4” event, which would be my other option right now (lean lower instead of higher if you’re assessing possible risks). Lastly, yes, I do think the cold is possible, especially if we manage to get some fresh snow. It’s not everyday you seen sub 510 thicknesses in November, and with Canada bathing in white gold, there’s very little time for airmass moderation.

skinsfan1177 wrote:

Euro Ensemble mean is about 400 miles east of the Op. Major red flag there.

Consistent among models:
1) the trough will be positively tilted.  This means it acts as the steering rather than a major part of the storm dvelopment
2) The pattern to the N&E is not on or side for a big storm
3) -EPO ridge
4) +PNA ridge that is flattening out as the energy reaches the coast dude to Pac energy crashing the WC.  


The N energy is going to act as a steering mechanism rather than a major part of the storm.  Non consolidated energy/vorticity being released down the Southern branch compliments of a closed ULL in the SW; will lead to possible weak LP development along a frontal boundary.  Baroclinically enhanced lift may lead to precip totals higher than what global models can pick up on.  

There are still big differences between GFS and Euro regarding the details of the N piece and Southern piece in placement timing and strength but we are getting closer.

sroc4 wrote:Consistent among models:
1) the trough will be positively tilted.  This means it acts as the steering rather than a major part of the storm dvelopment
2) The pattern to the N&E is not on or side for a big storm
3) -EPO ridge
4) +PNA ridge that is flattening out as the energy reaches the coast dude to Pac energy crashing the WC.  


The N energy is going to act as a steering mechanism rather than a major part of the storm.  Non consolidated energy/vorticity being released down the Southern branch compliments of a closed ULL in the SW; will lead to possible weak LP development along a frontal boundary.  Baroclinically enhanced lift may lead to precip totals higher than what global models can pick up on.  

There are still big differences between GFS and Euro regarding the details of the N piece and Southern piece in placement timing and strength but we are getting closer.

I was wondering when I’d see you lol what are your current thoughts regarding track/impacts (if any)?

Frank_Wx wrote:GFS is a nice snowy November day while EURO tracks the low inside the coast to cause warm air to intrude. To Scott's point the positively tilted trough and +NAO does not help matters.



The EURO intensifies the trough so much 500mb closes off over the Great Lakes. Can't have that. We'll see if that is a trend started by the EURO or just an off run.

Respectfully disagree about the +NAO/positive trough, Frank. You want some progressiveness/resistance to the cold here. If you had a -NAO this would very likely end up entirely suppressed as it sheared out along the fast flow at the base of the broader-based trough OR a trough split would occur with one piece fading southwestward and the other shortening its wavelength and wrapping up to our west, IMHO. Similarly, the progressiveness allows for this to be a quick mover and deamplified long enough so that it winds up somewhere between suppressed and inland, again, in my opinion. The initial ridge axis argues for the inland track but thanks to the pseudo progressiveness in the Western North American domain as the ridge reshuffles and a piece rolls forward, the lack of blocking in the Atlantic allows the system to gain longitude before amplifying while running along the SW-NE baroclinic zone. If the Atlantic was blocked up, this would not happen. In all honesty, I think we may end up with a great balance of factors here; however, this is also based on my analysis from yesterday’s quick glance.

rb924119 wrote:

sroc4 wrote:Consistent among models:
1) the trough will be positively tilted.  This means it acts as the steering rather than a major part of the storm dvelopment
2) The pattern to the N&E is not on or side for a big storm
3) -EPO ridge
4) +PNA ridge that is flattening out as the energy reaches the coast dude to Pac energy crashing the WC.  


The N energy is going to act as a steering mechanism rather than a major part of the storm.  Non consolidated energy/vorticity being released down the Southern branch compliments of a closed ULL in the SW; will lead to possible weak LP development along a frontal boundary.  Baroclinically enhanced lift may lead to precip totals higher than what global models can pick up on.  

There are still big differences between GFS and Euro regarding the details of the N piece and Southern piece in placement timing and strength but we are getting closer.

I was wondering when I’d see you lol what are your current thoughts regarding track/impacts (if any)?

Dont have much to say about specifics yet but excited to track

There are two parts to this set up. First is the weak LP forming along the frontal boundary compliments of the disorganized weak vorticity/energy ejected from the ULL in the SW labeled 1. Second is a deepening low that reforms as a result of stronger more consolidated energy rounding the base of the mean trough originating from up in Canada labeled 2 which leads to the mean trough axis shifting from a positive tilt to neutral and even slight neg. I think for us to have a shot at snow we need to rely on a frontal boundary passing far enough south such that the initial weak wave of LP can develop and be enhanced by a few factors (ie: baroclinic forcing, as well as a possibly favorably positioned jet streak enhancement).

Unfort it looks like the configuration of the bigger picture items looks to be lined up too far to the west preventing this from happening.

You have the -EPO domain pressing arctic and polar air mass south into the CONUS. You have the +PNA ridge domain aiding this; however, simply stated the main ridge axis in the west is aligned over the western GL which is also too far west. The result is a frontal boundary that does not press far enough south such that when the energy coming out of the SW labeled 1 arrives to the coast the weak LP forms to far west putting us in the warm sector.

The other factor Im seeing is is as the main trough digs into the N CONUS there is a massive amount of energy crashing the WC of NA such that it is knocking down the PNA ridge at the same time. This also inhibits the mean trough and therefore frontal boundary from pressing further south. The mean trough does try to close off and does begin to tilt neutral and maybe even slt neg but it does so too far N and eventually east leading to the new deepeing deepening low developing too far N&E of our area. Great for Northern NE though.

Time for trends still but the main players are starting to alighn on both GFS and Euro