Central PA Fall Discussions and Obs

[Blizzard of 93]

Great GFS run for CTP.

Warning snow potential gets down to Lancaster & York as well this run.

 

[Blizzard of 93]

0z GFS says we might have Another event to track next Friday.

This second late week chance looks to be gaining traction on recent model runs.

[Blizzard of 93]

13 minutes ago, Blizzard of 93 said:

0z GFS says we might have Another event to track next Friday.

This second late week chance looks to be gaining traction on recent model runs.

0z Canadian also has this second potential for next Friday night as well.

[Superstorm]

Euro bumping things up.




.

[MAG5035]

Overviewing all the model/ensemble stuff the last few runs I would think most if not all the subforum is looking good for the first widespread synoptic snowfall of the early winter season. I’m not really concerned about any P-type issues except for the LSV near the MD line, and even there I think there’s a good chance of advisory type snowfall or even a mostly snow event presuming we don’t trend the surface low NW much in the next 36 hrs. Think the ceiling  in our area is likely to be 5-6” but mostly a 3-5” type event. 

Main issues I see to sort out at the moment is axis and width of the swath of heaviest snowfall. The regular Euro suite has been a bit more disjointed upstream developing the shield of precip. It seems to be the most progressive of the major stuff to include the GFS and Canadian suites, as well as the AI Euro. This makes for a late blossom of the precip shield over the majority of C-PA and a more focused swath as the coastal low deepens and moves NE. Basically everyone still sees snow but it’s a lot more 1-2” or so with a tighter swath of 3-5” type amounts… which is the furthest SE with that getting a couple inches all the way into DC. It’s reflective in the associated ensembles too. Might as well show them all.

0z GEFS vs Euro EPS 24hr probs of 3”+

0z Canadian ensemble vs Euro AI ensemble for 24hr 3”+ probs, actually a pretty good match on swath axis

 

The other end of the spectrum is the 3 and 12km NAM being the furthest NW, most wound up solution (no surprise) still as of 6z this morning.  I’m sure thats the type of solution the MU guy is envisioning as the end game of what this system does in terms of the boundary being north. Which is certainly possible but I don’t see the amp in the pattern  to bend this up in a Chesapeake Bay to NYC to Southern New England trajectory as deep as it has the low developing. And honestly that’s about the only kind of track I would entertain detrimental p-type issues reaching far up into southern PA and the Sus Valley. Otherwise I think this pattern setup we’re in is plenty cold enough to overcome early season climo. Yea the ridge axis is just off the Pacific Coast, but the PV is also anchored over Hudson Bay. Look at the 500mb anomalies for storm time. The only detriment of a +NAO in this setup would be a progessive pattern. 

[Voyager]

3 hours ago, Superstorm said:

Euro bumping things up.

So did CTP. Last night they said 3-5 for my backyard on Tuesday, and now they added in overnight accumulations that take it to 4-10.

Monday Night

A chance of snow after 1am. Mostly cloudy, with a low around 23. Calm wind. Chance of precipitation is 50%. New snow accumulation of 1 to 3 inches possible.

Tuesday

Snow. The snow could be heavy at times. High near 37. Calm wind becoming northwest around 5 mph in the afternoon. Chance of precipitation is 90%. New snow accumulation of 3 to 7 inches possible.

[Voyager]

Graphical map of "expected" snowfall...