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75%?

If you look at the euro or 3k skew for the same time its surface temp is within 1 degree. The problem is the gfs cannot see the warm layer at 750mb. It’s not capable of it. This is a known problem. In cases where there is WAA and a mid level warm layer you have to adjust the snow/sleet line NW on the gfs. You can figure out where it should be a number of ways. Least technical is to look at the 3k or euro and say ok now if their Synoptics were identical to the gfs where would they have the snow/sleet line? Then make the adjustment. If you use the GFS snow line in wAA situations you’ll be wrong EVERY SINGLE TIME. It won’t ever see the mid level warming. Caveat…the only way we overcome the mid levels is if the precip is so heavy (death banded) that dynamic cooling can overcome a bit and the heavy precip can mix out the admittedly small warm layer all the better guidance has for our area. That’s not impossible but it wouldn’t be the gfs being correct it would a similar result for different reasons. like if you call a crossing route on 4th and goal from the 5 and the receiver falls down and the QB scrambles and breaks 2 tackles and dives into the end zone. Sure it ended up with a TD, same results, but when breaking it down in film study you wouldn’t say the play worked.

Yep just expect 6-12 for the metro. Still a good storm . Once again the mid levels are ruining it for us. It all depends how fast the sleet comes in. The later the better. Who knows , maybe it will the models will be wrong and never turns to sleet. It has happen before.

Snowman - Totally agree. I am following the RDPS closely as that is another good Meso.

Just saw it and laugh......that 5" is a killer! I'd typically be thrilled with what we're getting......but when there's so much opportunity a mere 50-75 miles south, it's disappointing. I'll give 12z or 18z to show a tease of moving north. I think it's pretty locked at this point though.

6z AI GFS has a Monster Winter Storm next weekend

so the storm is over by Sunday night? seems quick

Once it gets under 48hrs we'll pay attention. Even so it still has the 6-8" front end dump before any changeover. That's pretty much the floor with this.

06z GFS

She's starting to come together.

Yeah GFS held or even ticked a bit colder. Rgem was colder, Icon too. Nam still drops 6-8" before any flip.

When the NAM shows a midlevel warm nose, definitely believe it. That’s literally the ONLY thing it’s good for and it has been schooling all the global models and the other meso models for years with it. It is a huge mistake to write off the NAM when it shows a warm nose. People have been burned time and time again when they ignore it

It gives me 15". I would be very happy if I received half of that total. The 06z NAM gives me no snow, but 1.5" of ZR. Who knows what's going to happen at this point.

Just catching up. So the gfs didn’t fully cave, but pretty much all guidance met in the middle. I’d cut gfs accums by 75% though to account for ip/zr. That gets us to 6-10 for dc/balt metros, with a foot being in play for NW suburbs (1-2 counties off from I-95 and north of 50)

Likewise. Yeah it's closer to its 18z solution. We can still benefit from ticks esp considering we're not escaping without ZR.

Mt Holly only mentions snow and freezing rain in the forecast for here- no mention of sleet. Maybe they are taking the Euro verbatim with its freezing rain output. GFS has more significant sleet and less amounts of zr.

0z euro also looks better. Still has us SE'rs pingin for a bit, but pops secondary a tad quicker. Theres not a model I wouldnt sign for. NMB's snow maps gotta look great right now.

A shit ton of that accumulation along 95 is sleet. Like 3” of sleet! 6z brings in this ridiculous band and dumps close to an inch of qpf midday Sunday most of which is sleet but hey that counts! It also did beef up the snow before the flip by 1-3”.

Looks pretty dang cold to me

Key takeaway…locking in

We are still in the flip flop stage. Every model outside the NAM has gotten a bit colder at 6z.

YES

Gfs has slowly shifted some towards other guidance if you account for the fact it can’t see mid level warm layers and adjust the snow/ice line 20-30 miles NW like you have to. Then it looks identical to the euro and rgem. The warmest guidance shifted colder. The coldest shifted warmer and they ended up converging on about what the euro has shown the last 24 hours. Shocking.

The RDPS is also holding serve. The RRFA-S is actually improved over its 0z run. The only bad boy from 06z so far has been the NAM.

We wait for Dr. No...but nice to be within 48 hours and things solidifying rather than rug pulling.