WxMan1

MSLP error (KM) vs. lead time for our Mid Atlantic-Northeast blizzard. Notice that at 144 to 168 hours in advance the GFS was indeed KING! But overall, this graph shows once again that the skill (utility) with the AI models is in the medium range (after FH84). However notice that with this event, the AIGFS got much worse than the AIFS and a lot of other guidance between forecast hours 90-125.

I see what the EC Kuchera is showing. But as it's progged right now synoptically, this 'feels' more like your typical 2-4" with the front end snow, then some sleet, then some FZRA/DZ to end.

FV3 never verifies well. I'm more annoyed that the 00Z RGEM sucked for all of us. Never get into sustained mod-hvy rates for a while and the precip is gone before 12Z Mon. Looks to progressive with the coastal low.

Hey, we have an interesting analog! Feb 6-7, 1978. Very similar in terms of track and rate of deepening with the low along the coast. Certainly a top 10 storm for BOS... perhaps this will be one as well. Interesting to see the snow totals around our area during the storm. DCA 2.2" BWI 9.1" 3 NNW Upper Marlboro 6.5" Certainly a colder storm, but we could very well see sharp discrepancies in snow totals W-E with our storm tomorrow into Monday morning.

06Z RGEM Kuchera snow vs. 00Z totals. Still rather conservative (surface thermals) and mainly late afternoon into Sunday night. Areas in between the monster bands near the Atlantic Coast and the inverted trough band west could very well get sub-warning criteria snow given the weaker rates and marginal thermals.

Yeah, from what I see through 12Z Mon from the 06Z NAM is that the positive snow depth change is MUCH lower than the 00Z NAM. Ruh roh folks. What did the EC and ECAIFS pick up at 00Z that the other guidance didn't? Something was captured upstream, because I fear we're seeing a trend.

Yep, at least through 03Z Mon...

Ugh, just woke up after going down just before the GFS ran. Talk about swings. It's like watching a recorded game seeing your team up big at halftime, only to see it slipping away in the second half. Not jumping off the bandwagon yet, but gotta hope certain aspects of the ECMWF and AIFS aren't gonna become trends. That's is, um, where did the inverted trough go per the EC camp? That and a weaker surface low father offshore? It's like the EC runs of a couple days ago all over again. And I have to tell you, the CMC/GEM wasn't overly inspiring either, with the low farther offshore and much of our area in between the inverted trough band west and mega CCB band over the Eastern Shore. Lastly, the low over the VA Capes giving way to the new forming low off the NJ will need to be monitored. That can really screw with our totals. Remember a few winters back when Central Park had about 11" when they were supposed to get 2-3 feet (while areas east of them did)? That was the result of a similar quick transfer of energy. Not that 11" would be bad! But it was more than half less than what was anticipated. Damn this storm is littered with land mines. BTW 06Z HRRR Kuchera through 06Z Mon. Still snowing..

I will say though that those either within the Norlun trough band west of the Bay or over on the Eastern Shore closer to the low will likely see less disparity in projected Kutchera snowfall and positive snow depth change. That's all because of the rates. It really is gonna come down to that (...for the nth time mentioned, right?) Those areas likely closer to 8/9 or even 10-1 SLRs after 21Z Sun.

Just to throw some caution to the wind, which essentially becomes my low bar... NAM total snow depth change, considering the 33-34F surface temps, at least for most of us prior to 21-22Z. Note that both the NAM12 and NAM3 have the bulk of this after 21Z. The NAM3 particular, in my opinion, does a nice job with what looks like rain/snow mix until then, more rain or snow depending on the rates, again with the main show after 21Z. Again, what I would hope to be the absolute lowest bar. Even still, those east of the Bay still do quite well.

Hoping for the timing to be right. Ripping band will accumulate and bring down temps, even in the afternoon. Thus the widely used term "column cooling" because the entire sub-cloud column cools with the heavier rates. But again from a timing perspective, it would be great if that inverted trough/heavier rates would hold off until 20-22Z when we lose any solar effect. To play it safe IMBY (east of I95) I don't expect any accumulating snow until after 20Z. But when you look at the NAM, it snows all night. That's what we need!

Yep! I just remember holding at 32.5-33.0 with BIG dumping aggregate flakes! 11" or so for me in West Springfield VA, and even DCA did well. Less than 10-1 ratio certainly, so you'll want to look at Kuchera or cut the 10-1 by 20-30% to be safe. Hoping that the inverted trough banding would be mostly at night.

I actually lived in Japan as a youngster (age 9-13) when my Dad was assigned to Yokota Air Base. Went to a Boy Scout Jamboree in Zao, which I believe is north to northwest of Fukushima. Of course, that was in August. I recall it was quite beautiful! I hear Aomori, far northern Honshu, is the place to go for snow. Over 300" on average per year!

One of these days I want to experience this! I'm thinking Mammoth Lakes or Tahoe -- somewhere where there's some population and infrastructure. The guys at the Sierra Snow Lab in Soda Springs (west of Truckee) are in a pretty sparse location. Either way, You want to get your snow fixed, go to the Sierra. Or western/ northwestern Japan.

When temperatures are marginal, it's all about the rates as you all know. Strong ULL and higher rates leads to more diabatic cooling from both melting and evaporation, in the absence of the cold, drier air funneling in isallobarically at low levels like we see in good CAD setups. We get the band set up, we get the rates with those clumping aggregates, then we can accumulate at 7, 8, maybe 9-1 SLRs with surface temps of 32.3-33.0. The whole column cooling to the freezing point. However, you don't get those rates then you just get a lighter rain snow mix, 33-34F. It will be that drastic of a difference. Good luck with that forecast!