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I think strong isentropic lift with sw jet at 7H/8H in the Virginia's with 8H trying to form a low in PA-NJ by 00z/7. The mesoscale models are holding onto the trough structure longer as we come toward T0 (Monday)... so presuming it has the upper low right in the OV, it wont disappear as fast as modeled-mushed by the globals. There wont be much northerly BL flow into the system prior to its arrival on the 6th so dry air advection I dont think is a player. It has basically what is out there now, a 15-20 degree T/Td spread. It will take awhile for snow aloft in any CSI Band to work down to the ground up here around I80. There may be some small ocean effect contribution along the NJ coast? I have to think the globals will drift north tomorrow... or I've interpreted wrong. First thing I have to see is there Canadian come way north. Just not what I expected from the Canadian (GDPS-RGEM). For now I think it the southerly outlier. That's it for me tonight. Thanks for the MDL NBM reply.

Watch the 18z EC and 00z/5 global models. Either the globals are too far south or you'll see a sudden shift north by 30-60 miles. I am seeing too many members trying to hook northeast at 5H up into NYS-CT. The 21z RAP continues its northward trend. Bothersome. Wouldn't take much for the confluence zone to shift north past I84. WPC and WFO's have all the guidance, more than what I'm seeing but something is going to eve to change south in the short term mesoscale models (ALA the oddly south Canadian) or the globals will be bleeding north in the next cycle or two. We'll know more by morning. Globals suppressed vs mesoscale modeling now. Compromise? I'll check the HSD and QPFPMD but I continue to think a little snow throughput NJ-LI til I see the mesoscale models move south from the 18z modeling.

I've notified Pivatol Weather via email regarding the qpf snowfall disconnect.

CTP and PHI hold the watch til at least one more forecast cycle. Guessing LWX will warn but unsure...still nothing from them at 346PM but they may be coordinating with partners, writing up whatever. No matter what happens Philly-DCA Monday, I think those cities and in-between I dont want to be trying to drive in a timely fashion and get to work that for most of us could easily hold off a day.

There's going to be a horrendous bust for the 18z NAM, 18z HRRR and 15z RAP, all having snow up here to varying degrees if the 12z/4 NAEFS nil prevails on I80. Still interesting and I'll leave it to you all and the WFO's to wrestle with final numbers. If I may add: looks a little ocean effect contribution possible Monmouth south Monday per model soundings of -7C over water plus 7C. GFS most variable for that with too much new flow on 12z/4 EC and CMC.

Regarding 1/10-11 potential event up here... I'm good with it NC/VA maybe Delmarva? I still have trouble with it getting up here. Could be wrong. I've attached 12z/4 5H ensemble picture for 1/7 00z and 1/11. Am staying away from any thread for 1/10-11 til we get 1/6 started. I kind of want to get through this first nearby event before trying to tackle another snow threat for CP and let a couple more days of modeling play. EPS still kind of dry here the next 10-14 days at our I80 latitude.

Hi everyone... I'm going to let the rest of this play out... we're fringe I80 north... how much I'll leave it to WFO Phi and OKX, as well as yourselves too decide. I may post some of the guidance one in a while. I have no stake... just that this is an event of sorts Monday and use D8 lead time errors help inform the future. I will track SREF, NAM, HRRR and RAP 51 hr trends and Banding links from WPC and FSU. This is just the start of a a wintry January... maybe more cold than snow with respect to normal? Watch the wind Tue and Thu and wind chill. I've got my propane heat on hold at 69 now to prevent pipe outside edge of the laundry room from freezing in continuously at or below 30F temps the next 7 days in Wantage NJ. This kind of cold can push infrastructure problems...its not extreme but water main breaks and fires are my concern.

I think so... If you go back to p1 and see the south shift since 12/30... it should inform those that plaster the page with D8 snowfall, how large an error can occur.

If it goes away on the se 12z/4 and 18z/4 runs...then I have to think its over. Overall pattern to me continues to shove north into our area at times 10A-10P. imo, think its best to keep projections stable til we KNOW for sure it wont happen and just wave it off and not worry anymore about the northern extent. I like the GFS banding signal. That will be something to watch these next 2 days. WPC also has a nice banding program but limited to 48 hours.

720A/4 edited the title to limit event to the 6th and dropped the ice pellet tag. The event has at least held onto the 6h for timing since the initial Dec 30 post, but the max axis in PA-NJ has shifted south about 150 miles since the post started 6 days ago. That is worthy of keeping in mind when posting threads 6 days in advance... limits confidence of occurrence. A positive note the accuracy of the D7 WPC chance of 1/4" frozen in the Ohio Valley!

General northeast USA PA NJ northward Tuesday the 7th through Thursday the 9th: WINDY! Scattered northwest wind gusts 40-50 MPH! Isolated power outages. NC-VA Fri Jan 10-Sat the 11th: A possible snow event of several inches? For now, if it makes up to NYC-I84 a dusting.

Basically: This is our only game in town for snowfall, possibly until the last two weeks of the month? I'm not big on the 10th-11th this far north and certainly no thread for that (Canadian is north for now). Back to the coming event (or non depending on where you live). I'll adjust the headlines slight at 745AM. nw NJ-nePA-Orange County NY and NYC-LI...right now a dusting to possibly 3" but we're on the fringe here with uncertainty. Best chance for 3" is along I80. Modeling differs saying I80-I84 basically nil including 07z/4 BOM, but for me.. I keep the door open. Basically there is going to be banding Monday and that will be a factor in generating snowfall. Just too early for me to discard, especially recent 00z-06z/4 cycles of the NAM/SREF/Canadian. If you put all your money on the EC/EPS...then its not favorable I80 north.

nw NJ-nePA-Orange County NY and NYC-LI...right now a dusting to possibly 3" but we're on the fringe here with uncertainty. Best chance for 3" is along I80. Modeling differs saying I84 and northward basically nil but for me.. I keep the door open for a dusting even in Orange County up to Danbury CT. Check back tomorrow at 7AM and seek other opinions. General northeast USA PA NJ northward Tuesday the 7th through Thursday the 9th: WINDY! Scattered northwest wind gusts 40-50 MPH! Isolated power outages. Temps I84 hills basically through the 18th: Continuously below freezing these next two weeks with the I95 cities and valleys occasionally just above freezing. This will develop safe pond ice, but also pushes the infrastructure into scattered problems... including outside wall pipes freezing if not enough house heat, especially these upcoming rather windy periods next week. It wont be extreme cold but persistent. NC-VA Fri Jan 10-Sat the 11th: A possible snow event of several inches? For now, if it makes up to NYC-I84 a dusting.

Here is the BOM qpf and snow at 07z/3 .. where zero qpf, should be no SNOW unless a BOM developer can explain. This needs a fix... cannot have both. I guess I can make it a reach on 0 qpf but snow, though makes no sense to me, is that one of the inputs is model snow but not that model qpf?? That is a reach on my part. Anyway, I have to go to work and will check back at 7P... I hope we're still in the fringe game at that time. One good think about all this BOM review.. the NWS wants us to use this as BASE and then adjust based on our model intelligent perceptions and collaborations. So they have us looking. Also good that all this is documented so we can look back Monday evening, at least I will. Good job on the part of all participants.

Basically I cant pretend to know all of NBM, nor do I think can anyone not directly tuned into what goes into it-certainly not me. Todays WPC 4AM products make more sense to me including prob 4", and the null qpf line give or take 30 mi. I do think the 06z models are too suppressed for the strength of the sw and confluence in my mind is lifting north. QPF did not respond. Not a strong northerly flow Monday morning helps as well... reducing influx of dry air.

What about dendrite-snow ratios in subfreezing airmass If qpf zero, then I say no snow. We just dont have it all... Also there is snow today s of I80.

I'll adjust the headline tomorrow---for now its good enough and I've no major changes in my own view of what is coming: 1/4-2" CP and north of I80 in NNJ with nil near or just north of I84 in NYS-CT. Main message and my own opinion-you take your chances but if I were going to Philly-DC Monday morning I'd plan for delays and probably many cancellations and prepare to get in and out of there Sunday or Tuesday, rather than slicing it too thin. Airports potentially a mess, especially getting aircraft in from Missouri to Ohio. Here's some NWS guidance that supports my contention. Again, do as you wish. Below is the NWS chance of 4+" through 7AM Monday, and the actual NWS snowfall forecast through 7PM Sunday, and the probabilstic map for moderate impact Monday (red and yellow 40-70% chance Monday).

Measurable snow showers brush I78 south this afternoon-evening impacting the extreme southern part of this NYC suforum but no thread since not widespread enough. Monitor radar and mPing. Should be highly variable - swiftly changing conditions near Philly later today--but that's out of our coverage domain. However, if you're planning to drive through that area mid afternoon into the evening, don't be surprised at delays.

Am negative Nelly on the ICON... I normally dont like to be negative on events except for perspective. Are we really going to see a 990MB low east of NJ Monday evening? Weaken it and therefore weaken the northward waa surge. I hope its right but I cant count on it. At east its this far north but that could all be Sfc Pres related. By the way a strip of watches are out now Plains to OV. My guess it may be hard to get aircraft out of some of these Watch areas into PHLLy-DCA Monday morning. If I was flying PHl-DCA ..I'd get on a flight Sunday or Tuesday to ensure destination nearly on time (ensure fewer cancels). Just my 2c. 12z/2 NAEFS 24 hr 5MM keeps edging north to near NYC now... it has some variability but so far so good. I don't want to see that ebb south the next couple of days. 5mm/25mm = 0.2" qpf... again it might still only be 0.01 but trend so far, is our friend... as many have oft said...northern fringe. New 19z/2 BOM qpf attached. Good sign but NOT a done deal... There is something WPC and local WFO's RE looking at that I have to respect on qpf being almost nil north of I80 on their graphic. In other words, BOM ICON NAEFS may be too bullish... me I'm steady good with 1/4-2" I80 north-NYC, maybe lucky 3" sw LI. Melting e LI. This could be wasted words... will check back tonight at 730P, and again tomorrow at 730A. Fingers crossed but hope doesn't do it... dynamics - confluences- short wave stronger and longer can.

May add a thread for 3p-9P tomorrow 1/4-1” south of I80. Need a recheck at 7P. This was on WSSI-P a few days ago and area of coverage of snow showers may be expanding. You may recall my questioning what it was trying to say. Now I think I know. Strong shortwave and secondary cold push with fairly large lapse rates.

Sure. You can do all the Severe. My fingers don’t work as quickly as yours and my severe detection is not up to snuff Keep me posted

I like that too.... if its shared with the public outside of an AFD. It needs to be in print-graphics. Not happening as well as it could be. I just think we do not help the public prepare as much as could with all the tools available as added here. We're behind. Tomorrow afternoon event also an example. My last on this as I need get back to the basics of what will happen or not up here next Monday.

Agree 100%. NWS general field office approach differs from NHC. It's definitely not my approach to well advertised multi modeling. NWS was pretty happy to see me go, at least at field level where I was generally pushing the envelope to get alerting going. I thought LWX was advanced in leading these winter situations as NHC in tropical. Automation will end this personal - institution conservative approach... it has to be coming as progress is made. These AMWX discussions will become moot I think in a few years, at least inside 7 days... presuming the monies are available for research, platform improvement and processing. Then I can sleep later. Right now, reliably accurate interpreting voices are needed to get planning considerations on the table, sooner than saying nothing. I

Regarding this AFD quote. Go back to 316PM yesterday... similar. Continuity. Conservative approach. 2" in rush hour Phill Monday morning is advisory imo despite criteria, even the conservative view. Doesn't snow much in Philly these days... big return to work day and GFS GGEM ECMWF all subfreezing. Using clusters: gotta make the right cluster call. For now, I wouldn't be downplaying PA-NJ and even NYC on the edge. Folks should be planning Philly south, maybe even up to I80. Right now, no change in my I80 Dr appt but monitoring,

Maybe so, but you haven't been sniffing much the past couple of years... at least there is an option on the table just ahead. Very little thereafter Jan 7-13. I'm counting on 1/4-2" CP until I see a decided ensemble shift south.