ORH_wxman

The dreaded 33 and rain obs here. We'll see if we start mixing with sleet in the next few hours as the cold push strengthens.

Yeah I am not gung ho on big ice because we waste some precip. Some of the highest spots of ORH county and Berks though may not waste as much. You really wanted to see dews still in the low to mid 20s at this hour for overnight good icing.

I doubt it...you're pretty far north. Warm layer up there is thinner with a defined cold layer in the 875-975mb range through 09z. So prob pellets most of the time. Maybe some snow early on if you get a good burst of omega.

If you aren't icing in the first few hours overnight, it prob won't happen until tomorrow morning. Drain doesn't really get going until about 09z and the secondary push is prob like 4-6 hours after that into midday. Could start as a period of sleet for the pike region as the warm layer is initially pretty shallow even though the cold layer early on is kind of weak. Could go either way though...if it does start as sleet in metrowest, it would prob flip to rain before too long...and then we see what happens with the cold drain later on.

Clown maps cause more grief than they are worth when it comes to transition events. They really should just be religated to the trash heap except maybe on pure snow events...but even then we start getting those weenie kuchera maps that think 15F at the surface will always produce 20 to 1.

Yeah. Initially the temps could be pretty diffuse across the region because the antecedent airmass kind of sucks...but as we get that push into S ME and S NH there should definitely be a gradient setting up. Im expecting it to be more defined than models show and also push further SW. The big question is by how much though. Does it drain into just N middlesex and N ORH county? Or does it go further and how intense is it?

Yeah you're getting a scalper there. Not sure about his area near 495 belt out to ORH. I could see some pingers for a time and then it's close for ZR. ORH will def be below freezing once it get going for a few hours, but a bit lower down is a bigger question. I'm still very leery of model guidance not handling that secondary push of cold on Monday morning/midday very well at all. Could be a situation where some areas like Bedford over to my hood are actually cold rain (after some sleet) but then fall back below freezing and flip to ZR with that secondary push...then maybe even go back to pellets if that cold layer at 900mb is strong enough. It will be interesting to track. The biggest problem I have with model guidance is that they will tend to have the surface too geostrophic to the west of the CF....they will kind of broadbrush this ENE sfc flow when in reality it ends up ENE to the east of the CF but the west side of the CF might be backed 30 degrees. The models in this case aren't even really showing much of a CF which is kind of weird...it's like they are evaporationally cooling the air on the coast with that lower dew feed and just extrapolating that same air into the interior which doesn't make that much sense to me...BOS isn't going to be 33-34F while ORH is 31-32F.

I could see ORH getting IP/ZR in enough of a split to minimize the impact. Like they end up with quarter inch or less of accretion with an inch of sleet...and maybe even some cold rain for a while early on.

Yeah I remember seeing big damage from Berkshires. But as you said, much higher in elevation. I think even MPM at 1000 feet didn't get much ice but at 300 feet in Leominster off to the east side of the ORH hills had catastrophic damage. You had to go much higher off to the west to see the equivalent damage.

Yeah it's hard to refreeze pure water but if the cold layer is deep then it's possible...and -6 can produce ice nuclei...esp around here on a NE flow. Not sure I've ever seen like a +5 warm layer right on top of a -6 cold layer though. One of them is probably overdone. Wouldn't surprise me it ends up more like +3 aloft if it's going -6 at 875-900mb or if it hits +5 aloft, it's verified more like -3 or -4 below it.

ORH is an interesting forecast. They have a pretty high max temp in the warm layer...which usually tells me to go ZR...but the cold layer below it is deep and gets to around -6. That's clear sleet there. So which method do we give more weight to? Typically when the warm layer gets higher than 3C, you're gonna go ZR...but when the cold layer goes to -6C or colder, it's sleet. But in this case a lot of guidance has both occurring around the ORH area.

He's learning well from lavarock..throw enough tantrums and get it to trend your way.

Yeah the issue with this is once that air gets moving southwest from southern Maine, it becomes really hard to stop it. We need some good WAA to stop it but where do we get it? We'd get some right near the water but that would just set up a boundary right near the water on the easterly flow there but that's just going to probably accelerate it southwest on the west side of that boundary. It will be like going through a tunnel between the boundary and the hills/monadnocks to the west. Topography is really the most effective way to slow it on that setup. It's hard not to see a huge push southwest into SNE (at least back to S ORH hills and N RI) unless the entire setup weakens (I.e the high ends up further north and/or weaker). I'm trying to think of other reasons....but those areas I just mentioned are really the first topography it will encounter.

They are modeled to rise into the low 30s tomorrow night. If dews are in the mid-20s still at this time (and esp toward midnight) tomorrow night in CT, then ice is going to be a big deal I think. The big secondary push though occurs between 12z and 18z Monday. Dews drop into the low to mid teens in southern Maine...and that could reinforce into SNE but a lot of models don't want to show it that far southwest....but experience says to hedge further southwest.

Yeah active drain scenarios almost always favor the elevations which is why it seems the higher end threats seem to have an elevation component. Basically anytime we have a stubborn high in Quebec. The in-situ (esp on SE flow) is where the valleys seem hang on the longest.

Not a terrible guess. He could be too far west for the big sleet.

He's trying to make up for missing '08. Lol. This one won't be as bad though...not nearly the QPF. But there's potential for someone to get over a half inch of ice for sure. Maybe isolated spots getting over 3 quarters of an inch accretion.

And the models may not have the lower dews advecting southwest far enough. They typically can't resolve the lowest 1000-2000 feet on such a sloped airmass. Still about 24 hours to see any late trends though. The whole thing could still bump north or south...weaker or stronger.

You are correct.

No. Latent heat release is an issue in a lot of events because we don't have advection of fresh lower dews...that is definitely not an issue in this event. There is a steady feed of low dewpoint Arctic air from the northeast. That's why some areas could actually get several hours of 34-35F rain and actually fall below freezing during the event and change to ZR. This isn't an antecedent airmass trying to hold on...it's actually bullying it's way in from the northeast.

Yeah it could stop in S ORH county. "Stop" is probably the wrong word...but rather it could moderate enough above freezing by the time it reaches kevin. If the euro was showing that 18z solution tomorrow night, I'd forecast ZR for him though. Models are probably going to be too warm at the sfc...the question though is whether we trend warmer for a couple runs before go time. If we got a solution a few degrees warmer by tomorrow night, then the ice maybe only makes it to ORH.

Euro continues to warm aloft...AWT. Sell snow in SNE.

I'd keep an eye on it. You aren't out of the woods by any stretch though the better chance is east of you or up in the Litchfield hills.

That real strong pulse that starts on Monday morning into Monday afternoon is pretty interesting. It's very strong...you have the analogy of a BDF...and I think I mentioned the same analogy a couple days ago. It is acting more like a spring time backdoor front rather than a winter CAD setup...except that we're dealing with a wintertime boundary layer with ocean being warmer than land in this case.

Yes. Hard to say where the sfc cold really stops pressing. It could get into central CT or it could have trouble getting past the south ORH hills/Union CT area. The cold looks pretty deep though...as evidence by that 850-925mb layer going crazy during the event getting pushed way southwest....so that tells me that the sfc will prob go further SW than models think. You have like low to mid 20s in NH and ME with pressures that are having a real problem lowering. Those are going to fly southwest...where do they stop though? That's the tough part. They'll make it to ORH...maybe to Kevin too?