psuhoffman

The nws map says 5-8” but my zone forecast says 3-7. I guess issuing multiple forecasts does increase your chances to verify!

Radar looks great

Clearly we live in a simulation and it’s not done Fng with you yet.

How will the plow companies calculate rates when they only have to plow half the parking lot?

Don’t you like to measure in the street?

Yea I want lots of things I’ll never get. Yea the northern max will be the better one. Could even see some isolated 8-10 totals in there. But it’s gone. The wave amplified and that shifted way to our north. We’re working with the southern max or nothing now.

That band they are focused on up there is long gone. That’s not ours. But the snow band for us is associated with the mid level fgen and better deep moisture transport. We just have to hope the CAMs are keying too much on that banding up in PA associated with the lift along the arctic boundary and are underdoing the southern max.

Maybe. 2010, 2014, 2015 would maybe indicate we can get hit pretty good with a favorable pdo still. And perhaps the wetter base state makes them more snowy. But small sample size. Howevwr there was another major temp spike post the 2016 super Nino. No telling how that’s changed the equation. Also the pdo has become increasingly hard to predict. The cycles have become more irregular so it’s impossible to say how much longer this lasts.

I didn't get your "donation" in time

Yes, there is usually a second snow max, an often its the better max, further north where the best moisture transport banks up against the arctic boundary. Higher ratios help here too. But honestly pinning that down is very difficult. Guidance has it a little south of where I placed it but I shifted both max zones north a little, just a gut call. I feel very confident in the 2-5 call but where within there are the 4-8 max zones is more guesswork in all honesty.

my thoughts

My thoughts

There is always the chance of a last minute curve ball, and there is so much guidance now you will always find something that shows either the solution you want or don't want. But I wouldn't worry about those two unless we were within 12 hours OR other more reliable guidance were to trend in its direction. The GFS did shift north some but it was south of the euro. The euro has been pretty much rock steady for 2 days now. I think this was just the GFS coming in line with it, and now the better guidance is all aligned. I am not saying NOT to worry at all but the RAP and HRRR are jumpy and unreliable and I wouldn't base my worries on them without any other support.

They have been a mess lately, never had me getting any snow with the last system, even as I already had a few inches on the ground!

I think PA south of 80 is in for a nice event here. Obviously know the local climo, ridges and higher elevation zones will do better as usual. Other than the typical upslope zones near the Laurels, I think there may be two max zones, one further north in Central PA with higher ratios where there is some enhanced lift along the arctic boundary where the moisture transport hits that brick wall...and one further south (south of 70) near the best FGEN and deeper moisture. These two zones I could see 4-6 with local 8" totals. In between probably a general 2-5" event.

Red Dot

They need to gerrymander the forecast zones to cut out his block as if he were some start up candidate in a primary against an entrenched party bulwark

You also rarely have a sounding that looks like this... The only issue there is the surface... seriously why is it 33 in the middle of the night under heavy precip north of the NS thermal boundary on February 17th? But that aside... the surface is important obviously if its actually 33 and thus the snow compacts and melts some as it hits the ground. But if it were to be say 31 at the surface instead of 33 and the rest of that sounding is accurate you very well could get 12 or 15-1 ratios. It's common for these NS waves to have fairly high ratios, what hasn't been common lately is for them to track south enough for it to do us any good. In this case what might ruin that for us is weirdly high surface temps given the situation.

Surface temps. Kuchera uses the warmest temp below h5 as a significant part of the calculation. Looking at soundings a lot of the area is right at 32 during the snowfall. First of all, that is a little warmer than I expected for a NS wave at night with the thermal boundary south of us! That said, so long as temps get below freezing so there isn't actually a lot of compaction as the snow hits the ground (at night there shouldn't be so long as temps are BELOW 32, gonna be close unfortunately) IMO the temps in the DGZ and through most of the column are more important. There is good saturation and lift in the DGZ so we should have near optimal snow growth. The column is cold until near the ground so there is nothing to ruin the integrity of the flakes. So long as the ground temps can be 30-31 and not 32-33 I think we will get higher ratios. 12-1 maybe. Places a little further north in the region that also get under good banding could see 15-1. But again this depends totally on ground temps not actually being 32-33. I was NOT expecting that...at night, north of the thermal boundary in a NS wave...under heavy precip, we should NOT have surface temp issues in mid February! But its going to be close...1 or 2 degrees as the surface will make all the difference here between getting low ratios due to ground compaction/melt and getting high ratios because every other level is good.

In a colder base state the nao was king. But a +pdo -nao could be cold/dry. So a lot of our snowiest years were -pdo -nao. A -pdo +nao was always a bad bad bad pattern though. Problem now imo, we’ve warmed too much for a -pdo -nao to work the same as it used too. The pac storms are coming in too amplified and dig the western trough more. The warmer gulf and atl pump the SER more. The SER links with the nao. Everything gets shifted north. It seems now the epo/pna have become more important. We’ve lost a -pdo -nao as a big snow producer combination.

When the nao block fell apart our hecs potential went with it. We’re fighting for table scraps now. Is what it is. But hey you still have a reasonable shot at climo. I have almost no chance. I need ~20” more just to get to “avg”.

Naw. That TPV lobe is really close by, which is why this wave is suppressed enough for us even despite less blocking than expected. It would have taken a really intricate complicated convoluted phased progression to get a big storm and have it be snow from this setup. It’s why I was never crazy about it. But having the blocking fall apart opened the door for the NS wave to ride the boundary and stripe us. This is about the best case scenario imo.

3k and 12k kuchera. But the ratios are being limited by the boundary temps. I think whoever gets under banding will do better than this thinks. Snow growth looks pretty optimal imo.

3k is nice too