Kevin Reilly

Light snow picking up was almost flurries here for about 15 minutes now back to light snow picking up a bit 27.1f humidity 96% dewpoint 26 pressure 29.77 wind NE 11 Total Snow so far just measured 1.2" (Looks like Kamu and I on the same pace as we should be he is immediately downstream from me looking at this radar.)

Light Snow 26.4f humidity 99% dewpoint 26f pressure 29.79 wind NE 9 Total Snow so far 1.1" Looking at radar looks like there is a focus with banding just north of the Mason Dixon line down towards Baltimore and west side edging towards DC moving ENE. South of Washington kind of Meh. See how this develops over the next few hours looks like the band is more of a SW to NE orientation at the moment.

Light Snow 26.4f humidity 99% dewpoint 26f pressure 29.79 wind NE 9 Total Snow so far 1.1" Looking at radar looks like there is a focus with banding just north of the Mason Dixon line moving ENE. South towards Baltimore and Washington kind of Meh and well north.

or not LOL. I would expect a lot of wiggling around by this band either side of the Mason Dixon Line 15-25 miles north and 15-25 miles south of it either way. I am telling of the Heaviest Axis of snow should there be one.

Yep a tick SSW LOL

Yep got 7" here in Media Delaware County. Longwood Gardens in Kennett Square 16 miles away got barely 1" and 15 miles north also got 1" the band started in Lancaster and exited the coast just north of ACY. If I recall the only models that had this was the NAM, RAP, ETA models back then all of them were about to be put on moth balls so no one believed them and went with the global models which showed light snow and flurries quickly ending.

wow stark difference from Media to Cape May 28f here bit of a gradient setting up there.

Anyone have a snow map of the 18z Euro? Looks like it ticked south again with the main INVT trough.

I am out see you for Hurricane Tracking in August! Before I go 29.7f humidity 39% dewpoint 9f pressure 29.92 steady cloudy snowfall so far 0.00" My bar for tomorrow is 4.3" here in Media Delaware County. Start time 4:57 am.

These guys knew the snow was coming!! They also told me the Norlun Trough will set up from East Natmeal Twp Chester County to Coatesville east to Delaware County to Swedesboro NJ then towards Southern Ocean County.

Also you will be injecting true arctic air on a NE wind colliding with the Norlun trough squeezing everything out. The most intense Norluns troughs can produce 1"+ hour rates and have thunder. I am not saying that will happen here with this Norlun trough I am sure there are all kinds of different orientaitons and set ups and intensities. This Norlun trough is set up in a west to east or west-southwest to east-northeast orientation hence the models wiggling around with this.

I mean seriously this will wiggle back and forth like every hour on the HRRR.

I agree with MGorse: The best way to go is 3" or so with a max of 5" where ever the norlun sets up. Maybe some lucky soul picks up 6-7" but that will be an isolated area or two somewhere in southern pa over to the Jersey Coast north of ACY.

I mean come on lol just call it 2-4" let someone complain about the 0.8" This whole set up is not an exact science. Good Luck nailing down the Norlun trough its like pinpointing exact location of a strong thunderstorm when there is a 20-30% chance of them in the first place.

Well we will know exactly who uses mesoscale models and who does not LOL. I am going with mesoscale models too I learned my lesson on February 6-7th 2016 when I laughed at the NAM.... but maybe the prudent thing to do is go with 2-4" a blend of the all the models.

FWIW probably a quick 1-3" then a flip to rain in SE PA.

Agree the only thing that GFS and others will do is smooth things out for a general 1-3" the greatest potential to this event is to follow the dynamic models and meso models which hone in on the banding and lift over the inverted trough that will lie east to west across southern PA into Central NJ it will act as a conveyor belt for the moisture to track over almost like traning thudnerstorms in the summer. The railroad track is being laid down as we speak with this weak disturbance pulling through.

razor sharp cut off about 35 miles away if you are like me in extreme SE pa. This has a classic Norlun trough look. I would put more stock into dynamic short range dynamic models instead of Icon, GFS, and Euro they are just going to smooth things out. While the NAM's of the world will hone in on more local dynamic features like lift along the norlun trough to wring out all available moisture to efficiently mix with cold air feeding down from the NNE and NE.

I think the Icon and Euro smoothing things out while the mesoscale models NAM is picking up on individual dynamic possibilities like ascent over a norlun trough Mason Dixon Line points ENE. Looks like 1-3" Dc to Baltimore then 5+ where the convergence is taking place somewhere between Mason Dixon Line to Trenton NJ to the Jersey Coast.

Yep we are on the conveyor belt of cold to the north of the trough squeezing out all the moisture with pretty cold temps so higher snow ratios. We lift off!! I mean a lifting mechanism. It is uncanny how similar this set up looks to February 6th into 7th 2016 with the inverted Norlun trough this one here on Friday is just over a much larger area.

That's it!

Nashville, TN I saw -3 I don't remember the last time they went below zero that far south?

Ratings my friend ratings. Check back at 11 please!

Love Norlun troughs (not) they are very difficult to predict. If I recall the NAM and dynamic models did best with the set up way back. The NAM showed like 7" for Delaware County all other models showed literally nothing. Results: Media 7" Colwyn Delaware County just SW of the Airport 10" Swedesboro NJ over to Mulica Hill NJ and Pittman NJ 12" some thunder and lightning. Lancaster 4" western most part of the norlun trough also had some thunder and lightning. Wilmington De 1.6" Southern Chester County 0.5" Bensalem Bucks County a few pixie flurries with moon shine. I am not sure of the year think John Bolaris was calling for left over light snow and flurries then quickly moving out by 6 pm. Our reality in Media Delaware County 7" of moderate to heavy snow for 6 hours. Not sure of the year 2005? 2007?

Wherever the Norlun Trough sets up will be where you have a sweet spot 4-6" most likely east to west I would think through Chester, Delaware County, then move ENE from there south of the Mason Dixon Line is drops off for now. The Vort to our south cruising just south of Baltimore or DC needs to drop just a bit more to affect more people with the moderate snow band. Also, I would think to see these changes at 0z tonight and see if we can increase the ascent of warm air up and over the top as this clipper like system glides to our south and hands off to a developing coastal moving out to sea. This is a tricky situation, but for now I favor Extreme SE Pa over to Central New Jersey over to Ocean County.