Hurricane Agnes

I know Ralph likes to sometimes post the RAP and since it is in range, I noticed that (well...since it updates hourly) it was hugging that same Florida low and then suddenly loses it and that continues to suggest how these models are dealing with that and the low that forms off the Carolinas. I am in the camp of not to completely discount the GFS but to perhaps weight to towards the others because if some kind of dry slot appears with any banding, some might get a bigger thump initially and they are done but others might have to wait to make up for it if they get under a band as it pivots over them when the storm moves away to the NE. This will be a fast mover so that might be a factor too.

12z GFS is still a bit further east from the others but not as much and has a "weaker" low (in relative terms because it is still pretty strong)than the 12z NAM.

I'm gonna posit a guess - and we have to see how it pans out - but right now it is 26 where I am with dp of 8. So the air is very very dry. And what has been mentioned on and off for the past week is that there is supposed to be an arctic intrusion of cold air for this (meaning some high ratio snow as a result). SO I think maybe the GFS is thinking subsidence and atmospheric drying (or over-thinking it - like the opposite "convective feedback" that happens with some model runs of the NAM). I don't know how many storms some of us have been through where returns were directly overhead but resulted in nothing but virga. The last event is exactly what happened to me where I registered "Trace" (as just some flurries) and didn't get anything "measurable" until later that night, and even then, it was just a dusting. The 12z GFS is just starting so will see where it goes...

The HRW WRF-ARW is reflecting that earlier small event. Kinda cool.

12z NBM (looks like what the current forecast seems to go with).

Well interestingly enough, between 12z on Jan. 28 to 12z on Jan 29, there is a 33 mb change (deepening) on the NAM, so at least that model appears to be having it "bomb" as it comes past here.

Looks almost like a cold front. Waiting for the 12z to finish.

6z Euro and its snow map.

It's all calculus! I had to take 3 semesters in college as a chem major and in the case of these models, it's all multi-variable calculus (and then they add the statistics piece in).

In this forum, people are sometimes afraid to do it lest they jinx it! I know Paul did the last couple. You could go ahead and start one since we are a bit more then 2 days out from start time.

Thanks! What that basically does is get into the weeds about how "mother nature" "must come into equilibrium" and shows the mechanisms (and equations) to explain how that happens with "weather". Adjacent high pressure and low pressure will "move" to try to equalize and come to some sort of "steady state". Same goes for differing temperatures and humidity. I kind of compare that (as the "macro" application) with what goes on with the ideal gas law too - PV=nRT.

The Euro and NAM were also doing that "hot potato" move of the low from one place to another earlier and it seems it might have to do with some "double-barrel" / pair of lows that were in play. The earliest depictions had some weak low strolling along the southern U.S. moving due east, and off the coast of FL, and then "something happens" and that low fades and a new low forms off the coast of the Carolinas... And somewhere along the line, there is this far-away interaction in the atmosphere between the remnants of the old low and the newly-formed one and then that whole mess gets dragged up the coast along the jetstream. You then see what I call a "sloppy" system of convection slapping around a core and periodically stretching and contracting and undulating just off the coast. I know that description probably sounds silly. But that is exactly what it "looks like" after running the animations over the past few days.

Battle of the cutoffs for the 6zs. And as a quick obs, my low may end up being 13 (it's been wavering around that). Currently 14 with dp 8.

0z Euro pretty much stayed put compared to the earlier 18z.

NAM did the opposite of the GFS by speeding up the low in the 6z.

The 6z GFS brought the low a bit west compared to the 0z and slowed it down.

Mt. Holly's latest hot off the press - I thought the below tweet was hilarious!

At least the low in this latest depiction isn't slapping around itself like a zombie.

There you are... Figured you were cookin' up quite a storm at work today. You can't discount the NAO trend though... and meanwhile, the 18Z GFS looks like it sped up and but continues the precip scrape trend (although it's just the 18z). And as a quick obs, I did make it up to 28 today with a low of 19 and it's currently 24 with dp 7.

Mt. Holly's and WPC's updates -

The Euro has had the low looking like this -

No comment.

18z NAM looks to be moving to the GFS without all the junky feedback (but then it's the 18z).

I was looking more closely at the 12z Euro and 12 NAM and they both have the double-barrel lows that sortof become like a Pushi-pullyu. Am wondering if there's something like convective feedback going on considering it seems there was a consensus that the storm would undergo bombogenesis at some point.