wdrag

Scattered snow squalls are likely to make it to near NYC midday Wednesday as a wind shift with steep lapse rates drives squalls out of NY state into the NYC metro area. Might have a few sprinkles at the beginning of any NYC squalls. Cant tell if it will be as dramatic as that of (Dec 18?). Probably not, but potential exists for rapidly changing road conditions in a couple of minutes in brief heavy squalls, especially northwest of NYC. Drier surface stabilizing cold air advection develops behind the squalls late in the day.

Good originating post: I'll drop my observations herein. I've added a statistical graphic from the NWS. It doesn't necessarily reflect ensembles issued after 0811z/8. NAM may be a little too strong but decent dendrite growth seen for an hour or 2 tonight in our NY metro area... am a little concerned about rain at the start, before being overcome top down with a change to wet snow, especially NYC. You'll see later model guidance after this post, which hopefully directs us to a reasonable expectation of reality. Right now, am thinking anywhere from 1-4" ne PA and nw NJ based on all the guidance i've seen so far. (event between ~6P-2A tonight). Enjoy the day, Walt

Thanks to those who've participated. I saw the general obs thread for NYC so I have an idea. 1.1" here in Wantage NJ. PHI LSR rep ~ 130AM. PRELIMINARY LOCAL STORM REPORT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 132 AM EST MON JAN 6 2020 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0117 AM SNOW 1 SSW GILBERTSVILLE 40.30N 75.62W 01/06/2020 M0.5 INCH MONTGOMERY PA TRAINED SPOTTER 1257 AM SNOW 4 SW WANTAGE 41.24N 74.65W 01/06/2020 M0.8 INCH SUSSEX NJ TRAINED SPOTTER 1250 AM SNOW SUCCASUNNA 40.87N 74.64W 01/06/2020 M1.0 INCH MORRIS NJ PUBLIC 0101 AM SNOW METUCHEN 40.54N 74.36W 01/06/2020 M0.5 INCH MIDDLESEX NJ PUBLIC Other impressive amounts in ne PA. I didn't see much if any for NYC-LI in CoCoRAHS but could have missed. Thanks again, may post new topic at 530P depending on 12z/6 evolution. Thinking 00z/6 modeling too far south but I could be wrong.

Wantage NJ 8 s High Point at 1.0" inches. I saw some images from NYC...wet roads and a touch on cars. Upstream in ne PA amounts 1-1.8". Roads are plowed here and only a few flakes now.

Wantage NJ or 8s High Point. 0.8" continuing to snow. All surfaces covered. 28.9F td 27.7. Last report probably til ~ 5A.1257A/6

Hi everyone, While much of this very very minor snowfall within NYC metro should melt on pavement, it looks as though there should be a slightest coating on cars/grass. Areas to the west-north-northeast of the city should accumulate a little better with the 1/2" or possible isolated near 1" accumulations in the higher terrain. This event should do a little better than that of this past Saturday night-early Sunday (1/4-5) which saw scattered dustings of snow and snow pellets in the northwest hills of NJ into ne PA. The best we can do right now. Walt

Wantage NJ 8s High Point had 0.8" yesterday 230P-1030P.

Wantage NJ 8 sHigh Point now at 0.7" for the day with steady snowfall after 730PM through 840PM. 20.7F and TD 12.4

Wantage NJ 8s High Point. Total today so far a solid 0.4" and flurries continue past 7PM this evening. Rural roads dusted and all home pavements well covered. 23.4 and dew point 16.4 so we probably have more snow coming this evening,

Wantage NJ 8 s High Point late report. Late report: 0.3" in a whiteout squall ~234PM with max gust 28MPH. Downtown Sussex NJ had about 0.2" ~ a couple of minutes later. Ice laden trees, grass etc continues though pavement wet (snow-covered in spots). Max T today Was 31.3. Yesterday it was 32.5 ~ 930PM.

This event is why I like to think down side and called it minor-moderate. Snowfall algorithms were a bust s of I-90 as many have noted, but still this storm brought an icy mess to the regions just a few miles outside of NYC that forced numerous travel delays, school closures/delays, power outages with over 10000 customers having no power in NJ as of late today. QPF in the freezing air was a little less than needed for more widespread power outages, and there wasn't a front end thump of snow. On school closings while roads were seemingly just wet... it differs when young adults are hanging out at hill town bus stops or walking to school in freezing rain, with sidewalks icy, especially rural areas. Lots of liability concerns. A little more freezing rain after they had gone to school, and trees/wires start closing roads and you're saying why did we risk it. Snow was overstated but in the end, model guidance FAR FAR in advance pegged a winter event from CO to New England, and certainly knew something was coming for our area as early as the 00z/9 run (in a daily blog). Modeling will continue to improve. I think it's magnificent compared to what we had in the 1960s. At 738PM/18 I've added the interpolated snowfall for this event. It includes some lake effect off the Great Lakes.

Wantage NJ 8 s High Point probably had 0.2" glaze on branches, grass blades and thicker ice on paved untreated surfaces this morning. Our max today is right now at 31. Under 100 customers were without power in Sussex Counties Sussex Rural Cooperative. 10,000 customers were without power in threat of NJ late this afternoon with most in Morris and Hunterdon Counties.

Wantage NJ 8 s HP: 29.1F. icing continues but only untreated. main roads just wet in Sussex County NJ.

Wantage NJ 8 s High Point. I see High Point Monument at 1800 feet and Mount Pocono at over 2000 feet ind the mid 20s and temps have dropped at both High point NJ and our home here in Wantage since 5AM as bands of heavier freezing rain roll in, here at the house 28.2F now.

Wantage NJ 8s High Point. Light Freezing rain-freezing drizzle. 28.6F. Glaze on all but also think if roads are salted, this will be manageable. Don't think I had any snow at the start but probably some ice pellets.

Hi David, We have a discussion thread for the storm and and an "OBS only" thread. That simplifies for users to find out what's going on, without all the model discussion slowing the review. I know I like to cut to the chase of what has occurred, including upstream. And If the media or NWS look at this, they may pick up on something they weren't;t already aware of. Example a NWS process; that would be Forecast Discussions (AFD) for one, and the Local Storm Report (LSR) or Public Information Statement (PNS) summaries for the other. I abbreviate observation(S) using OBS...to shorten the headline. Later, Walt

Good Monday morning everyone, It's Dec 16 and soon go-time for a widespread winter weather event that might not yield much snow-sleet in NYC but VERY close to the city there will be significant snow and ice, as noted by others previously. The city may see a period of flurries midday today? The event is tonight-Tuesday which is a delay from two days ago (initial snow thrust down to the Mason Dixon line this morning instead of I78-I80). Still while the modeling was ~60mi too far north, thats not too bad from two days ago. Added four graphics courtesy of Weather.US for the ECMWF, and one from the NWS experimental HREF glaze prediction, which better be wrong, or we've quite a few power outages tomorrow morning in the 1/4-1/2 inch glaze area from southern Ct to northwest NJ. NWS WPC glaze and snow predictions are less. So there is uncertainty on amounts of snow-sleet/ice but we know something wintry will impact travel in our area later tonight through Tuesday. Probably my last post on this, except post storm NOHRSC etc assessment of modeling.

VERY good point...

Good Sunday morning everyone, Having reviewed the guidance through 06z/15...my only uncertainty is start time Monday (is it midday or is it delayed til after 7PM Monday). Needs to be monitored for a return to an earlier start midday Monday than now generally modeled. Otherwise, quite a mess coming but still think a minor or moderate impact event depending on location. Too early for me to be sure about anything except quite slippery all untreated surfaces north and west of NYC early Tuesday morning. Added two graphics: One is the experimental prototype NWS Winter Storm Severity Index which is a result of NWS collaboration of all sorts of parameters including temps/winds/amounts of various precip phases (note the spotty difficult to see moderate impacts interior nw NJ which is the ice factor. and the other graphic is the 00z/15 ECMWF ensemble (EPS)chance of 1+ inches of snow (courtesy of Weather.US) 731A/15.

I try to understate, thinking downside. Agree with you..some areas minor but overall I think this will be a moderate mixed event. I'll post NWS WSSI stuff if its available in a day or so. Gotta run.

12z/14 EC looks quite good for a mess and a decent front end 2-3" 6 hour dump. Still lots of detail to be ironed out but the 12z GFS and GGEM were a little older. Am expect the NAM to trend colder but consensus on everything good shift back north... bottom line, a winter event is coming that will need to be considered for adjusting travel plans, especially near I80 north. Hopefully tomorrow it still looks halfway decent. (noticed 12z/14 Kuchera a little less than 10 to 1 and snow depth amounts though it might be my interp? Off line til tomorrow).

Good Saturday morning Dec 14, Since I didn't see a specific thread for this coming event, thought it would serve to get something started. It's probably worthy to debate, watch trends etc etc...have started it off with what I think are some helpful perspective graphics. These graphics, some of which are ensembles, act as a decent starting point for today, remembering that the greatest error generally occurs along the gradient edges. Credit goes to WEATHER.US and the ECMWF for the first two graphics, and to the NWS (WPC) for the freezing rain graphic. First: Is the EC operational estimate of what may occur Mon-Tue---a nice idea. 00z/14 version Second is the EPS (ECMWF ensemble chance of 1+ inches of snow). Legend suggests a 75% or greater probability of 1+ inch of snow I84 corridor and actually back to near STL/DEN. 00z/14 Third: Is the NWS ensemble probability of glaze... less than .10" ending 7AM Tuesday. There is a chance there will eventually be more than 0.10 and higher probabilities for .01 glaze somewhere within 50 mi of I84. 08z/14. If I missed a specific thread that had this started, I'll delete this. Just let me know. Thank you, Walt 1450z/14

Hi, This thread is for obs only, keeping it a swift read-check for anyone wanting to see how much has fallen, including any NWS/Media. Also, attached is a final NOHRSC snowfall analysis for our Dec 11 event, which now properly reflects the NYC reality of sub 1 inch. Thank you very much to all who have added data to the prior obs threads. Walt

Hi, Just letting you know they reanalyzed and her his the result. MUCH better. I also wrote NOHRSC when I criticized the post. They did not reply but here is their apparent final. I'll also open with this on a new topic shortly. Thanks for your review. Walt

Snowfall for this event interpolated-interpreted via NOHRSC. It see's more than 0.2" in CP. Something is wrong with NOHRSC analysis in and near NYC or with the obs. I'm moving forward.