Hurricane Agnes

We're at nowcasting time (vs wishcasting) and will soon be doing obs. If this were a classic "Miller A" or a clipper, it would be easier to model. It's be more of a PITA because it starts at night.

They may do an update later tonight at say 8 pm-ish. Mike posted earlier in this thread about how much of a mess it was to try to communicate to the public about what may happen and I agree. I posted earlier about anything "looking like" a "Miller B" is always a PITA to try to nail down. And we all have experienced the "dry slots" that happen with that type of storm just before any coastal starts revving up.

I don't think that is a "final map". It would be their latest version based on the current guidance and input from the latest model runs that they use to do the snow forecasts. They may revise later tonight and tomorrow depending on when any changeover happens.

Adding those maps. And I did notice it was adding some inches for a few hours more - at least to places well west of us. Apple has this for their description of the app and sources (seems like they claim to use a lot of foreign sources although those might be tweaked for use for people who live in those countries) - https://support.apple.com/en-us/105038 One of my sisters and a niece have been using that app and sending screenshots of the snow forecast calamity!

What I heard on the radio yesterday was that the city hadn't expected the November snow so they cut into their stocks for that, and then used up some for the last 2-day storm. But they said they had enough for this upcoming storm. I think the bigger issue was the salt for consumers (e.g., ice melt), which has disappeared out of the stores, and from some posts I saw on Nextdoor, some smaller hardware stores were price gouging what they had.

I remember some sleet storm since I moved to my current location, which was 2016 (but after any winter weather, so something 2017+). I know the threads are here for that. 2017 - 2019 (notably 2017 - 2018) were significant "recent" years.

Was looking at some cool temp animations that I generated from the 12z 3k NAM for 2m & 700mb temps. You can see what the NAM thinks is the issue...

Your wish is my command!

What popped in my mind is a "clash of the titans". If it snows hard enough and the cold air clashes with the warm nose, it could get convective and maybe even produce "thundersnow". It seems all these signals for a big "thump to sleet" suggests some high in/hr before a changeover. ETA - 12z 3k NAM running...

The GFS 6z just for completeness although we are obviously in the mesos/short term ranges.

6zs - 3k NAM & EC -

Haven't had chance to deep dive into weather.us's stuff but here is the 0z NAM p-type from that.

No 0z for that yet (at least that I have access to). Last was 18z.

0z NAM + the temps from it at 700 mb. You can see why it's doing what it's doing with what it thinks is gonna happen.

Waiting for some more frames on it but it definitely has a dividing line there.

My dewpoint just went negative (-1) so this PV means business. Temp is down to 21. If that kind of dry air hangs around for long enough, I can imagine a period of virga. 0z 3k NAM is running.

The ocean is a laggard for seasonal change in temps and doesn't chill completely until like February, which is why our springs can get strung out into May and sometimes June, with a number of bouts of March snow (the kind of snow people wanted the December before )!

Surface map is showing the front has crossed the area and my dp dropped down to 6F within the past hour. Am currently at 30 after getting up to 37 as a high with 18 dp.

it's that "line". Have been listening to Accuwx this afternoon as they slowly drop the totals.

19z NBM still bullish.

18z Canadian.

3k NAMs. All Philly schools closed. City has a "snow emergency". Gov. of NJ declared "state of emergency" (her presser is going on right now).

Randy might have found it during that Tug Hill blizzard fest.

AmWx WAS EasternWx until 2010 when they re-did the site. I remember the years of the routine of "changing the snow tires" in spring and fall (on 2 different station wagons over the years in the '60s - late-'70s) and keeping a set of chains in the back of the station wagon. Except for the '66 storm, none of that was really needed. The snow drought literally "broke" the year my mom bought a brand new Mercury Zephyr after getting rid of the old station wagon and then a few months later, having some cop car doing a chase on the snowy street, and T-boneing it while it was parked in front of the house. Thank goodness for "all-weather tires" (at least around these parts - the snow zones in the northern U.S. still have those snow tires as I understand).

I think the blizzard criteria is for sustained 35 mph or greater. Traction! It was also the days of chains and spiked tires.