Stormchaserchuck1

DC-Annapolis, most of Delaware, 15-18" snow depth on 6z Hrr. Anyone know why it's so extreme?

6z Hrr has 12" snow depth for DC by hr33. Could be a 15"'er. Anyone know why the RAP and HRR are on this page, 12-15" snow depth is pretty significant - although the mesoscale of those models beyond shorter ranges isn't good, I might expect other models to juice up a little in the morning.

I think the problem is that the cold air might be getting cut off in Canada. The -NAO block is lifting out, and the +WPO ridge may extend south. The hope is that cold air from before holds, but usually when something is 7-8 days out those kind of things don't hold with a changing Pacific pattern..

That +WPO is underestimated at this time.. It usually trends warmer, unless that 3-contour trough over the Bering Strait backs off. I see the 11th as a rainstorm threat for NYC.

In the Pacific you have a ridge under a trough. Hard to get trough to dig too far in the SE with that pattern. It seems the cold air is becoming "stale" at that point, and usually in future runs the whole pattern catches up to what's happening in now time.

Kind of hoping that the cold air from before stays in place for the storm.. -NAO block is gone now, neutral, with some lingering ridging over Canada. I've seen this play before, it evolves toward the upper latitude pattern in the coming days. The +WPO Canadian ridge is going to extend south and kind of cutoff the cold air, unless it evolves away from +WPO in the coming days..

Pacific pattern has really evolved in the last few days to now a -PNA/+WPO look for the storm. The pacific pattern takes precedence as effect over the Atlantic, as the last 10+ years have shown clearly. Beyond that, it evolves to an Aleutian ridge. That's a -PNA pattern, with now a trough digging into the NW in the long range. Will be interesting to see if this favorable Pacific only lasts a few more days like what is being modeled. Models were super cold for the time period a short time ago, it was a question of if the 11th storm would merge with the Polar Vortex lol

My call is it's a rainstorm for Jan 11th.

Watch out for the +WPO trend on recent ensemble modeling for the 11th storm.. that pattern trends warmer as we get closer, if it holds.

New CPC 3-4 week has below average temps and above average precip for the coldest time of the year. I was thinking a -PNA would start to get going at that time, as the La Nina is really strengthening right now, but that's not what these maps show..

0z Hrr has 1" for me.. a nice 5-6 hour snowfall.

Hopefully I'm not too late. January 2025 DCA _ NYC _ BOS __ ORD _ ATL _ IAH __ DEN _ PHX _ SEA -5.3 -4.4 -3.6 -7 -5 0 +5.7 +6.2 +4.2

Seems like you guys forgot the first one is still 7 days out lol

Watch this timing.. it's not going to phase here, but it could on future runs with some slight adjustments.. lots of potential showing on todays models around Day 10.

I feel like a more probable trend going forward is to juice this thing up a little, vs stringing it out like before. Energy seems to be consolidating on a main vort.

Some similarities to Dec 18, 2009 in the NAO and 50/50 low region Although we did have a low in the gulf and El Nino STJ.. it was leading a colder wintery pattern to follow though, I like that similarity. H5 is pretty close over North America and the Atlantic.

blizzard map

On 0z GFS ensembles, mid atlantic is below average at 500mb every frame from 24hr to 384hr

I don't think rain will be an issue for Jan 6th.. upper latitude pattern is too favorable for cold. Question is does the storm get sheared out or not. LR GFS ensembles look good still at 384hr! No signs of -PNA that it seemed to be trending toward at the end last night, -EPO, sustained -NAO, West coast ridge.. -AO is going really strong 6-10 day shows the CPC thinks this coming storm has a chance..

Models are trying to handle the continuously building -NAO.. they may be a little too dry right now, just doing what the index typically favors from the medium range. I love that 50/50 low.

Yeah, that's what I like to see. Look at that 50/50 Low. This storm actually has a lot of upside potential NE of DC.

PNA has been positive every day this Winter so far (since Dec 1), and it looks to stay that way through Jan 15th, with nothing lower than +0.5 being modeled.

We haven't had much upper latitude support for the last 8 years.. maybe a handful of months honestly. NAO has been positive 41/46 Winter months since 2013. RNA broke it's 7-year consecutive record by 175% (going back to 1948). Now the GFS is showing >+400dm -NAO for the next 15 days. I'm stressing this because the global pattern is more consistent than when models just show a trough over the area. Last year and the last few years it would show a trough and snow when we were in -PNA! It's different this time, meaning it would take a much greater shift to erase the "cold enough for snow" pattern that right now has global support. My only fear is that the -NAO is being over modeled. But it's pretty legit. If we get waves, some should be snow. Of course too, +PNA/-NAO correlates with dry, so it's nice to see an active pattern on these models. I'd rather them show several waves cutters right now with a major -NAO block being modeled and no -PNA.

Individual ensemble members all over the place, but I'm surprised how many show cutters.. it's not an unfavorable upper latitude pattern. Maybe just be happy that they are showing so many storms in the medium range!

Thanks! I did better than I thought I would this month. Looks like you did pretty good too.