wdrag

Toying with a 5 day post Jan 6-10 five window to pick up widespread 2-7" of snow as now 10 to 1 ratio base amount ensembled by the 12z/28 CMCE and EPS, and 18z/28 GEFS. That would focus snowfall opportunity tracking for 1 or 2 events. I've not seen enough similar ensembled qpf-snow predictions to see how this can fail but I'm sure it can, so am holding off-thinking on it for at another day or two to see how the ensembles depart this baseline. Failure clue is the Total Snow Depth Change in that time frame which shows much of LI 1" or less. The NAEFS with the QPF axis well to our southeast, still is with about a 30% chance for 1" qpf in that time frame. That's pretty hefty considering its still 8+ days in advance of Jan 6. The chance for 0.4" qpf in that time frame is about 55-60%. Attached is an example from the 12z/28 version of the 50 member NAEFS for > 10 mm/ qpf in the time Fram 00z/6-00z/11. If this does fail, the ECMWF long range still allows opportunity after the 11th for several weeks though I need to limit enthusiasm (apply skepticism) on outlooks beyond 2 weeks. No new threads from myself for at least a day, possibly not at all if the ensembles slowly lower amounts.,

Thank you for unpinning. I've added a link for mPing past 2 hours showing sleet in nw CT, and still;l a little ice reports NNJ. https://mping.ou.edu/display/. That link should loop the past two hours of reports. Go to layers and change to top. You'll also notice the time in GMT upper right.

The following ASOS METARS nearby NYC reported Trace or slightly more icing overnight...I group (among those I checked) IJD-Willimantic CT POU-Poughkeepsie NY FWN-Sussex NJ CDW-Caldwell NJ

Very few reports for this event. NOT widespread ground truth but am sure in parts of the area, there were slips and falls. Of course ice midnight-6A is not what most winter enthusiasts like to check... especially sleep time. However, the interior advisory for contact icing on stone surfaces was probably a winner...may have saved a few ER visits-broken wrists etc.

I cant reach beyond ensemble modeling so am limited to Jan 11. Maybe Jan 10ish for a decent snowstorm but I dont know. Before then, I'm pretty sure we'll a little snow shower activity Jan 2-3 but no or negligble amounts in the city and then we watch Jan 6-11 time frame but what then?

Good Saturday morning everyone, it's Dec 28. I84 corridor through 930AM: Icy pavers and driveways where it's 32-33F will become ice free around 930AM. Treated roads are just fine and most decks-wires are ice free. Just be a little careful stepping outside early this.morning. Most of the icy conditions were in Warren-Sussex and Orange Counties here near the tristate corner of PA/NYS-NJ with spotty ice in ne PA and interior CT. Sunday-Monday I84 and OF: A mild and occasionally foggy snow melting rain will occur with temps into the 40s and maybe the 50s at times. Later Jan 1-3 I84 corridor mainly hilly terrain: Bands of snow showers will cause brief periods of scattered hazardous travel on untreated roads. Jan 6-11: I-84 corridor and possibly the I95 corridor from NC northward to Boston: One or two storms should deposit widespread hazardous amounts of snow and ice. The first storm around Jan 6-7 should be mainly limited to the I84 corridor northward. A second storm toward Jan 10ish could involve the I95 corridor from NC to MD NYC-BOS?

This thread should be unpinned at 9AM when the OKX advisory ends. Not much icing appeared to happen near the city. Truth is I'm unsure what happened (contact icing) except here in nw NJ with the above temp map.

Wantage NJ 8S of High Point NJ: 545A report. Freezing drizzle on contact with untreated pavers-driveway (ICY), but all other surfaces just wet at 32.4. Salting has been in progress up here since before 4A. Our early morning low has been 32.2. Dewpoint 31.8. 0.08 liquid since midnight. Walt Added a map of NJ Climate reported temps at about 540A... anywhere where 33 or lower, my guess is the untreated paver-driveway is icy (feet from under), but otherwise all other surfaces at 32.2 or higher are just wet. This is purely a contact with previously frozen ground problem... not trees and wires, at least not here.

Not sure if anyone is noticing the past 3 cycles of the GFS and one or 2 12 hr cycles of CMC, backside measurable snow down to I84 on Jan 1 as rapid intensification occurs with the neg tilt shortwave near LI. I see the latest GFS op has heavy snow Catskills on Jan 1. Gonna be a chilly rain in Time Sq NYE.

Attached is the NWS map for the winter weather advisory for icing tonight on untreated surfaces. Most of the icing should occur just northwest of I95 but spotty icing could occur even near NYC and on Long Island dependent on max temps this afternoon, and maybe a 2-3 hour window of radiating chill at sunset before clouds thicken and temps respond upward. Even if that occurs, wet bulbing and frozen ground could permit icing on rain contact with the frozen ground just a few miles away from NYC.. Canadian modeling and the SPC HREF have been leading the way as well as the HRRR. The ECMWF and GFS global models have been largely devoid of ice tonight. I've also added NWS probabilistic chance of .01 freezing rain and .10 (brown 5% chance).

Regarding threads: NWS PHI already is onto the probable ice via an advisory (frozen ground even if air temp at 5' is 33-34). I think the RGEM and WSSI-P are leading the way with support from the usually colder and sometimes too cold SPC HREF. I may start a thread on this tomorrow morning. It appears to me it will radiate a bit between 5P and 7P then temps level off as the lower-mid clouds arrive. It would not be impossible to see ice 5 or 10 Mi w-n of NYC and then spotty on the island with freezing rain-drizzle developing near midnight or whatever you think from the modeling. EC op devoid through the `2z cycle but it's ensemble has a little ice. I'd be careful about any warmup Saturday... only if the drizzle quits. There wont be much wind til Sat night or Sunday. My long shot of 5H undercutting a closed low to LI and backside sleet-snow arriving NY eve is probably a non player but still monitoring. For now, no thread on that. Rainfall: Solid 1.5-3" by NY day... the drought monitor finally ticked down a bit in NNJ...still moderate as of 12/24 Appended rainfall from CoCoRaHs since 11/20 which shows a general 6-9" over our area in 5 weeks.

I saw a couple of comments and I'm replying here. on NOHRSC snowfall... you may find a few discrepancies with your snowfall data but overall I trust the inputs are doing good job of servicing and commenting on model guidance results. I didn't take the time to check but maybe reviewing the output 12 hours later might have found that particular discrepancy was resolved. on WSSI-P... probabilistic slices that lower have probs than elsewhere could be for any number of reasons but the ensemble (60) does its best to integrate the base Blend of Models snowfall and ice data and go from there on WSSI-P. In this case, I did not check back...again, time limitations as I still part rime work and have plenty of daily activity going on, but it might have been land use. I'm leaving this link for you to review...it's 17 pages but gives you some background. https://www.wpc.ncep.noaa.gov/wwd/wssi/WSSI-P_user_guide.pdf As you may know, it tends to be too conservative inside of 3-4 days and can abruptly change at D6-7. Nevertheless, I think it's an important addition that needs to be incorporated into approach on winter events.

Added for Saturday morning concerns near and inland from I95. A bit of hazardous ice on all untreated surfaces due to the many days of frozen ground. Note this brings the ice risk pretty close to the big cities Philly-NY-BOS.

We'll see if the EPS trends same latitudinally or trends south the next 24 hours for the NY Day storm. For me, its getting interesting for marginal elevation snow and ice I84 as wet bulbs could cool if the 5H cools enough. fwiw...Canadian and now the EC have ice to near NYC Saturday morning the 28th. No threads on 12/28 or late 123/31, yet but monitoring (even if most folks dont care about ice).

Icing coming to I84 the 28th... it's a start to what may turn out to be an interesting NY eve. WSSI P- low prob minimal impact ice on the 28th (image) led by the RGEM (a typically warmer than USA model). EPS mean SD change has .1 to NYC NY eve. Might be a chilly rain to sleet? LONG shot. I'll watch how far se that second short wave digs across PA/MD (neg tilt) and how much low level marginally cool air is left behind on the 30th-31st.

NOHRSC snow depth this morning.

Wantage NJ. SD 10A. 3.5" solid.

Thank you for all your posts on the various threads the past 5 weeks! Glad to see CP had their first 1" snow cover Christmas since 2009. Ahead: I think caution. In my opinion, probably most disagree... I think we're going too see a lot of wintry mix Dec 29-Jan 2, which could include new snow or sleet amounts NYC before the end of the NY eve to get us to 3" in DEC. Definitely interesting on the EPS undercutting with the trough and already the Canadian with ice for the I84 corridor by the 29th-30th. Looks like a complicated evolution but blowtorch warmth in my opinion, if it lasts more than 12 hrs, lucky. I see secondaries south of LI. Merry Christmas all!

Thanks to all for participating and OKX CP for getting out the data promptly. That should put us at 2.8??? for Dec. We might get 0.2 sleet on the 28th???? Long shot. Walt

CoCoRaHs snowfalls for all who reported prior to 740AM.

Wantage NJ 1.5". snow almost over. I saw Blairstown CoCoRaHs 1"

fwiw..we have a separate obs thread for this mornings snowfall. this thread for the SD on 12/25.

Wantage NJ 0.8" at 635A. small - met sized densely filled fluff flakes. 20F SB around 515A. Snowing at a nice clip.

A burst of snow Tuesday morning will refresh area snow cover, helping many of us to a white Christmas (more than 1/2" of snow on the ground at 7AM Wednesday). There's a separate thread for the 7A Wed 12/25 snow depth. Snowfall may be impressive for short time, coating all untreated surfaces with slippery broom able fluff.

Probably starting an OBS NOW thread around 8P when I get time for a short duration- 2 hr light-met snow shower event 5A-10A and see if CP can get over the 2" mark.