JAN 12th-13th 2019 Snow threat

Keep in mind that the energy that will be our system is still well out in the Pac. and the energy that is the steering mechanism aka creates the confluence/N Trough is just now into N Canada.  




Here is the energy that will be our system in 36hrs....still just coming ashore.




A few other comments.  1st the GFS although has shifted back to a more strung out system at 06z it has also been the most inconsistent with many of these features from run to run so for now I trust the least.  While the GFS may have shifted to a more sheared out system at 500mb the NAM has not.  It still shows a stronger more consolidated system over the heartland of the nation at 500mb.  

GFS vs NAM




Recall the discussion yest morning when I compared 00z Jan 8th to 12z Jan 7th.  Specifically regarding the strength and positioning of the N Trough and the strength and positioning of the S energy and how far N it can make it.  While it still has a ways to go for a "significant event, the euro conts to slow and steady tick more positive.  The 3 images below are valid for the same time frame 12z Jan 13th.  Pay attention to the trend for the N Trough to shift N&W with successive runs and the S energy to be a tad stronger, more consolidated, and allowed to trend N along the coast.  Again its subtle but steady.  Remember subtle shift at this level in the atmosphere can pay big dividends at the surface.  






Here is the snow map for the euro at a 15:1 ratio.  This will be a high ratio event.  As high as 15:1-25:1 even in central to southern NJ.  925-850mb temps look to be -5 to -9 across the board and surface temps in the twenties while any precip moves in.  Those ratios would only go down if the storm track makes a significant shift towards the BM, but if that happens the amt of QPF significantly goes up as well which would easily compensate for a shift down in ratio.  CP if your reading you are absolutely correct in keeping of the mind set of having to deal with virga and no snow but it aint ova for you boys and gals yet either to the N.  Honestly even NYC and N should at least consider that.  CNJ on south looks like they could be in for a decent high ratio event to kick this winter off.  

Also here is the latest GFS vs its own supposed "upgrade" FV3-GFS where FV3 is still a more consolidated system and significantly further N.

Well all we can do is wait and see. Hi all. Work and life is taking much of my time so I do not get to check in or comment often. Not feeling too hopeful but we will see.

Get me to .25” qpf with 15:1 before I get excited

Northern energy looks noticeably more north on FV3...that's a big part too, right? getting the northern piece out of the way, so the storm can come up coast?

By looks of that map I see a coating to an inch, lovely...

Hello guys and gals nice to meet everyone i been following since accuweather blogs. And finally decided to join.quick ? Shouldn't the nam be more reliable at this stage then the bigger models

Since the man with one eye is king in the land of the blind, I'm our block's resident wx 'expert'. Here's what I told all the folks at the bus stop just now (remember we are Shore folk down here, Very south and very east): "A third, A third, A third. One-third chance that the 2-3" hits, one-third chance it busts low and a one third chance it busts high. We'll know more by Friday" That's the way I see it as of now...

Welcome Carvin, I think maybe another 24-36 hours before we are really in the NAM's zone, but def like that it's picking up on things already.

Carvin wrote:Hello guys and gals nice to meet everyone i been following since accuweather blogs. And finally decided to join.quick ? Shouldn't the nam be more reliable at this stage then the bigger models

Welcome Carvin!  You really never can make a definitive statement about one model over another.  While models like say the euro consistently out perform other global models one always has to look at any model forecast with an objective eye because models like the GFS will occasionally score the coup.  When we get powerful systems I think the NAM has been one of the better models at sniffing these things out in recent yrs.  For now that is all we can say.  Like I posted earlier the southern energy is still off shore.  Today and tonight we will hopefully get a better handle as to how  the N energy/steering energy will behave as it is on land.  There may be some who say it doesn't matter but I disagree adamantly as time and time again models will under or over estimate the intensity of key pieces of energy only to correct as it comes on shore which has big down stream effects on the final outcome.  Again time and time again under 72hrs the "zeroing" in on the details occurs often.  We shall see.  Cautious optimism conts to be the phrase of the day.  Cheers and again welcome!!

Carvin wrote:Hello guys and gals nice to meet everyone i been following since accuweather blogs. And finally decided to join.quick ? Shouldn't the nam be more reliable at this stage then the bigger models

Welcome aboard, matey, to our weather-weary fanatical crew!!! Nice to see another name tag in the forum while the NAM has been remarkably good since its last upgrade a few years ago, it is still outside of its useful range (for us) right now. It only runs out to 84 hours, which does not give us a good view of the entire evolution of the system at hand. Some of the more brave (or foolish, depends on which side of the fence you’re standing lmao) weenies (as many of us can be at times lol) will try to extrapolate what it would show. While amicable in the honest attempt, this is usually a fool’s errand. By the same token, it’s also a higher resolution model, which means that it tries to account for smaller processes that occur in the atmosphere that the other “bigger” models (think you are referring to one’s like the GFS, EURO, etc., which are called “global” models) are not built to try to resolve. Therefore, by adding in all of these additional calculations to the NAM, the errors toward the last 12-24 hours can be quite large, and limits the “trustable” window to generally within 60-72 hours. That is not a fixed window, though, and can change from storm to storm given the complexity of the situation. Make sense?

Fantastic writeup this morning, Scott, and to Frank’s yesterday! Dunzoo (and Greslig), I sincerely apologize if my remark the other day came across as nasty - that was not the intent, AT ALL. It was meant to be read in more a “firm, but fair” type of tone, to drill in the point. I was tired of repeating myself st that point amongst other forums, to be honest. As for my sources: Ryan Maue, an acquaintance on another forum who spoke to friends he knows in the NWS, and I had a direct source also in the NWS tell me that he knew nothing about any data issues.

rb924119 wrote:Fantastic writeup this morning, Scott, and to Frank’s yesterday! Dunzoo (and Greslig), I sincerely apologize if my remark the other day came across as nasty - that was not the intent, AT ALL. It was meant to be read in more a “firm, but fair” type of tone, to drill in the point. I was tired of repeating myself st that point amongst other forums, to be honest. As for my sources: Ryan Maue, an acquaintance on another forum who spoke to friends he knows in the NWS, and I had a direct source also in the NWS tell me that he knew nothing about any data issues.

No offense taken. You are always classy and give great info.

The phrase wave spacing will likely be used in the next 24-48hrs. ie: NAM coming in and I like the wave spacing at the moment

Scott, it’s flatter than 06z to me so far - look at your thickness contours. Those are your shear vectors/steering flow (in a sense).

From what I could tell, the SREFs were flat too, but cannot concretely confirm this.

Flat as in good or badd

Carvin wrote:Flat as in good or badd

Bad if you want more snow :/ ICON not currently looking good either, although I trust that model about as much as I trust the FV3.......I don’t lmao

rb924119 wrote:From what I could tell, the SREFs were flat too, but cannot concretely confirm this.

Boy you REALLY want your forecast to verify. LOL. A blip flatter yes

sroc4 wrote:

rb924119 wrote:From what I could tell, the SREFs were flat too, but cannot concretely confirm this.

Boy you REALLY want your forecast to verify.  LOL.  A blip flatter yes

Well duhhhh lmao every forecaster does!! Haha but I said that because I saw the indies posted elsewhere, but I’m honestly too exhausted to look intently aha even if I wasn’t, being awake for 24 hours can start messing with your mind ahaha

rb924119 wrote:

sroc4 wrote:

rb924119 wrote:From what I could tell, the SREFs were flat too, but cannot concretely confirm this.

Boy you REALLY want your forecast to verify.  LOL.  A blip flatter yes

Well duhhhh lmao every forecaster does!! Haha but I said that because I saw the indies posted elsewhere, but I’m honestly too exhausted to look intently aha even if I wasn’t, being awake for 24 hours can start messing with your mind ahaha

Haha - I can always tell which direction things are trending based on who's adding the most comments, which in turn stems from an initial forecast of a potential upcoming event.

Always enjoy everyone's insight - the suspense is killing me! I'm obviously pulling for trends toward a more snowy outcome.

When no one's posting the 12z yet, it's because it aint good. And it aint...hugs the coast to about Va Bch and then Bon Voyage.

And 2 runs in a row now that low kicks out at SC and not NC. That's too far south even for south folks to cash in. Time to wiper back to the north...

GEFS wiper effect

0Z


6Z


12Z - th pendulum swinging back??



From JB
The GFS is likely getting into its handoff to quick to the northern branch mode it likes to get into 4 days out, So we see it collapsing heights over the lakes and Ohio Valley at 84 hours.) or handing off to the northern branch) This looks to be an error to me, but perhaps this is the time it is right, But there are no changes in my thinking right now I think the Euro/NAM blend will be the best way to proceed going forward and there is no change in our ideas on the storm this weekend, I don't think this is a big deal for NYC ( 2-4) and think its 4-8 around DC for instance. Quite frankly this map shows what I think is coming, more or less, Euro 72 hour snow totals ending Monday morning There are some edge considerations but I dont expect a shift north to the experimental GFS at 06z But I dont think there is that much suppression either

GFY 12z EURO!!! I will not be roped back in!!!

SoulSingMG wrote:GFY 12z EURO!!! I will not be roped back in!!!

Umm euro was a miss...

Light amount of qpf and even knock some off that due to dry arctic air. That was c-2” at best

aiannone wrote:

SoulSingMG wrote:GFY 12z EURO!!! I will not be roped back in!!!

Umm euro was a miss...

Light amount of qpf and even knock some off that due to dry arctic air. That was c-2” at best

Compared to its previous run? Well north.