ORH_wxman

In the end, the 18z NAM did increase QPF for most of SE MA/S RI...esp PYM/Canal area and maybe back to EWB/UUU...prob owing to the better midlevels. It didn't change much over the interior.

I've had the water vapor loop up in the backround the entire day....I keep waiting for something to show a more obvious turn east and I can't find it. I've been keeping an eye to the east for convection....so far IMHO, the mesos have overdone convection east of NC but underdone it back inland. It's a good sign but doesn't mean much yet...the key will be like 6-8 hours from now. That's when I feel like the skill of water vapor loop v guidance is easier to parse. You need like under 10 hour lead time.....the whole thing reminds me of when we sniffed out the model failure of 1/27/11....the models were trying to shove it east too quickly and it rode up the coast and smoked us. Of course, 6-8 hours form now, we'll have a bunch more short term model guidance and actual OP model runs too....so the whole exercise is probably pointless. But it's still interesting to me personally. If I looked at that loop without looking at any model data, I'd be thinking how on earth that could miss or only scrape us.

Vorticity is more consolidated on the NAM thus far....that's a good thing. But so far, it's not quite enough to really consolidate the midlevels so this solution may still be dogshit.

Nah...take 'em up in BOS.

Sun angle is tossed during any meaningful snow. Might make the afternoon lighter stuff less impactful...esp on the roads and any blacktop/driveways/etc....but during anything resembling moderate to heavy snow, sun angle is tossed.

It's better for most of SNE...the best bandng is east of you, but you still want the more tucked look on the vort energy...that will give the best chance for good snow there too.

Def an improvement aloft on the 12z Euro....bucks the trend of the rest of the 12z suite. That is a good banding look.

Still quite solid in your 'hood....most of the 12z site is still a warning event in SE MA.

I'm not sure there's ever been a phase in this storm...it's really just a single shortwave...most of the question has been whats going on with the vort energy in this. It's weak and kind of diffuse.

Ukie is solidly east from last night as well...can't see the queen maps, but we don't need to...it will likely look like a lot of the ones weve seen already based on the sfc/500 charts.

That will depend on how much the midlevels close off...if you close them off, they will typically shove the fronto pretty far NW....but if they remain more open, then it kind of lingers barely north of the center. This isa hard storm to forecast...pretty big bust potential in all directions.

Probably time to retire for good on weather model watching if that's the case....

Midlevels are definitely still nice for SE MA on most of these solutions...prob inlcuding much of BOS area and RI.

Still a bigger hit than the mesos, but definitely E of 06z.

GFS def looks SE of 06z through 18 hours...seems like 12z is all headed the same direction.

The mesos are 12z are all in pretty decent agreement....advisory snow for interior SNE (less way out into NW MA) and maybe low end warning for SE MA/RI and perhaps parts of S CT. We saw this at 00z last night and then the globals went more robust (sans Euro)....then mesos came back at 06z only to go weaker at 12z again. We'll see what the globals do. The shunt east after it reaches the delmarva is still bothering me some though....not totally buying it.

Looks late again....

RPM is in the meso camp...no surprise since its a meso model....has a low end warning event for most of SE MA, RI, and S CT.

I'm not that concerned with the lakes shortwave....it's really how tucked in the system is against our main shortwave riding up through the TN valley and into the mid-atlantic. The lakes shortwave does interact with it some, and it will affect this system, but much more of the variance is due to how the vorticity is being handled....it's not strong which is giving the models fits on where to focus the conveyors.

The water vapor shot that jimmy posted is actually pretty impressive. Makes it hard to envision a mere scrape.

It definitely chases the convection once it gets going...it may have started off a tick east, but it gets exacerbated as we go into the run. You can actually see a couple little bullseye of vorticity south of the benchmark by 18 hours. Regardless, the lack of a compact vortmax is definitely an issue for a really wrapped up solution.

This is sort of a chicken/egg argument and both can feed on eachother...if the vortmax is stronger, it will help force the flow to buckle and you'll see this tugged back west...on the flip side, if the flow was already a bit more buckled, you'll see the vortmax curl up to the north easier....even if it's weaker. The problem is we are dealing with a relatively weak vortmax right now...it's not this intense ball of vorticity which would make this a really big storm. So smallish features like convection can wreak havoc on the eventual progression of the whole thing. The pros: The shortwave is already negatively tilted pretty good...so that is going to help a lot. It's why even on these really ugly strung out solutions, we're still somehow getting advisory snow from ASH to ORH and SE and warning snows over SE MA. Cons: Vortmax is weak and the shortwave is relatively "shallow"....meaning it is somewhat disconnected from the main shortwave over the western lakes. This will give a bit of tendency to try and slide the low east....but it can also work in our favor if we deform where that happens.

Yeah I think it's going to be almost impossible for this storm to be a total disaster (as in sub-advisory at this point) for at least the southeast half of SNE....but obviously the question is do we go more the 4-8" route or are we discussing 10-15"+?

Yeah it's running northeast with the convective blob....suspicious, but it doesn't mean its wrong. Convective interference can be real...it's just that often it's an illusion on model guidance.

Yeah looks worse than 06z...sliding further east.