RU848789

Radar really blowing up now in CNJ - those NWS guys know what they're doing, lol - this could easily put down another 1/2"-1" if it holds together - beautiful big dendrites fallkng moderately right now.

As of 9:00 am, we have 2.6" of snow (only 1/10th of an inch the last hour) and I just cleared the snowboard (every 6 hours), so let's see if we get much more or not. I'm guessing another 1/2" given that we have some snow bands incoming from the SW. It's 32F here and will stay around 32F for the next several hours before dropping into the 20s this evening. Just shoveled as we have enough on the driveway/sidewalks that won't melt before this evening and I don't want frozen slush for the next 2 days. Also, the NWS update just said it looks like accumulating snow in NWNJ (esp Warren/Sussex) and the Lehigh Valley, which overperformed with 3-5" of snow, so far, is over, but that they're seeing snow bands blossoming over SWNJ/SEPA (clear on the radar), which should impact the 95 corridor and much of SNJ and the coast for the next several hours with another inch or so possible, although that snow will very likely only accumulate on colder surfaces now that the sun is up and stronger and temps are at or slightly above 32F. Area Forecast Discussion National Weather Service Mount Holly NJ 912 AM EST Sun Feb 13 2022 NEAR TERM /THROUGH TONIGHT/... There was a bit of a lull in the snowfall rates this morning. However, another band of snow was beginning to develop and advect northeastward along the Interstate 95 Corridor and vicinity around 9:00 AM. That should continue to be the trend during the balance of the morning with the band drifting eastward and off the coast late this afternoon. With temperatures at or just above freezing, additional snowfall amounts in those area should be no more than an inch or two. Meanwhile, for the areas to the northwest of the Interstate 95 Corridor where the overnight snow over-performed, the current trends suggest little additional snow accumulation, with the snow mostly coming to an end by afternoon. The Winter Weather Advisories will be left in place and may need to be adjusted around midday.

As of 8:00 am we're up to 2.25" OTG with 1/2" the last hour. 31F. Here's a pretty picture... worth a walk outside y'all. Also, you can see from the pic that the lightly traveled road across the street is still fully snow-covered, while the busier street right in front of our house is only partly slush-covered, as traffic has warmed things up a bit and melted some of the snow.

Really nice band just popped up for Southern Somerset through most of Middlesex/Union - coming down nicely now with decent sized dendrites.

As of 7:00 am, up to 1.75" with fairly light intensity most of the last hour, but picking back up again now. Temp down to 31F. HRRR shows another inch or so for most through about noon, but at fairly light rates of 1/4" per hour, I doubt we'll see that much more accumulate with the indirect sunlight becoming more of an issue for melting by 9-10 am. Guessing we'll end up with 2-2.5" here.

As of 6:00 am, we're up to 1.50" OTG, as intensity as definitely lighter the last hour (1/4" fell). Intensity picked back up the last 10 minutes and flakes are now more dendritic/drier, presumably due to better growth up in the DGZ and a colder column. 32F here.

As of 5:00 am, we're up to 1.25" OTG, as intensity was a bit less the last 20 minutes or so. Temp down to 32F, so melting should no longer be an issue, at least not until 9-10 am when the sun is up in the sky a bit. Very pretty out there and it's great snowball snow...

Woke up at 3:30 am and it was snowing moderately with a dusting on the colder surfaces; went outside at 4:30 am and it's still snowing moderately (close to heavily) and we have 1.0" on the ground, including 1/4-1/2" on paved surfaces, already - as expected, the snowfall rate is greater than the melting rate and now that we have a snow foothold on paved surfaces, the rest of the falling snow should accumulate on those surfaces, as it's down to 33F. The snow is kind of like icy granules in a water ice. Looks like 2-3" should verify easily if this kind of rate keeps up.

Agree with everything, except for one caveat. Remember, if we get decent rates before 8 am, which is forecast, we'll get some accumulation on untreated paved surfaces and once snow gains a foothold on the paved surface, subsequent snow is falling on high albedo snow at 32F, where it will accumulate much easier than on actual blacktop.

Nice to see the first run in 3 days of the UK showing a decent snowfall. Man has that model just fallen off the wagon or what? I could definitely see the NBM being the forecast after looking at the models (assuming the Euro doesn't do something unexpected - I'd love to see ~2" along the 95 corridor from Philly to NYC.

The 12km and 3km NAMs have been wildly divergent in their snowfall maps for a couple of days. Seems like the 12km is having trouble resolving convection at its larger grid scale or at least I hope so - will take the 3km please.

Thought the Channel 7 (Lee Goldberg/Jeff Smith) map was pretty good, although several of the 18Z models look even a bit snowier than that. Will be interesting to see if 18Z was a blip or a trend. Will start to see shortly, I guess. Would be nice to get an overperformer for a change.

12Z suite (every model; Euro still to come) has been horrible for snow for the big cities/95 corridor: at best maybe an inch in some snow showers (and 1-2" at the coast) and at worst nada, with that inch just along the coast and maybe not even there. NBM seems to capture this well...

Yes, but it was mostly far less precip causing less snow: 0.2" vs. up to 0.7" at 6Z

And no...way less precip/snow at 12Z, although a stronger looking coastal forms later in the 12Z NAM run, but might be too far offshore...still, there's potential for a minor to moderate event, I think...

Asleep at the wheel, lol...let's see waht the 12Z says shortly...

It's been freezing rain for the last 30 minutes or so and we now have a glaze of ice on everything, including driveways and sidewalks, which are treacherous - our road was treated, so that's ok. 31F here with precip ending for now. WWA certainly verified for us.

Just got a nice little dusting of snow...

Well, about an hour ago it finally reached 32F here in Metuchen (and N or the Raritan in general) and we did get a very light glaze of freezing rain on colder surfaces (unpaved), like the grass and our deck and any metal, which means the NWS advisory verified for us. Also had a short burst of sleet. Looks like another burst of freezing rain or sleet is on our doorstep. Nice to at least see something...

Yep, GFS was always an outlier and I'm glad I didn't go for it in my communications to others - have been very skeptical of much ZR for CNJ south of 78 here, on 33 and elsewhere and it looks like we're going to get little to no ice, as precip is shutting off before we get to 32F. The NYC thing was fascinating though, seeing NYC and NENJ east of the TPK (all close to the Hudson) get below 32F well before places 10-20 miles west, which is the opposite of what we usually see.

Sorry, but temps of 30-32F will not lead to icing on any well traveled paved surface (especially treated ones, which will be most of them) during daylight and even after sunset. Yes, there could be a glaze on lightly traveled neighborhood roads, driveways, and sidewalks, but there will very likely not be any widespread icing event on the secondary and major roads in NYC, LI, CNJ and NENJ (south of 80).

Do you happen to know what the FRAM alogrithm does? When I learned how simplisitic and scientifically questionable the Kuchera ratio algorithm was a few years back I was kind of taken aback, so was wondering whether the FRAM algorithm assumptions/calcs made sense. They appear to be quite close for light ZR amounts, but pretty far apart for heavier amounts, with FRAM showing about half of the standard ZR - wondering if the key is precip rate and FRAM assumes much more of the rain doesn't accrete in heavy rainfall. Thanks.

My 0Z summary of ice, since I don't think anyone cares as much about an inch or two of sleet/snow (need to be north of 84 for that, probably) vs ZR. Euro next. One other thing, taking the NAM verbatim, is that almost all of the ZR for the NYC metro (inside of 287) falls from 7 am to 4 pm, when temps are just barely below 32F and when there should be enough indirect sunlight to prevent much ice accretion on most paved surfaces. Timing may really help us here. The GFS goes much colder, much faster and would likely be more impactful. 0Z NAM icier than 18Z with significant (>0.1") ice down to 195/276 OZ RDPS/RGEM similar to 18Z with significant ice only N of 80 0Z GFS icier than 18Z with significant (>0.1") ice down to Philly to LBI 0Z CMC less icy than 18Z (and 100+ miles NW of GFS) with significant ice only N of 80 0Z UK less icy than 18Z (presumably, as the snow shield moved NW, but I don't see ZR maps for the UK; snow is similar to 18Z Euro, so if ice is similar it would be down to the Raritan/202). 0Z Euro is slightly less icy than 18Z with significant (>0.1") ice down to about 78. Good luck making a forecast with that model spread, lol. Fortunately, we're still 54-60 hours from changeover time, so we have some time to figure this out.

Reminder...if one is going to use precip maps in a mixed event like this could be, IMO, one has to use three maps to get a sense of what's actually going to happen, as per below for the 6Z GFS (or use the accumulated precip types maps at the bottom of this post, at least for the GFS/NAM). For pure snowfall, use the Pivotal snowfall map For pure freezing rain accretion, use the Pivotal freezing rain map (understanding that that is converting all rain falling at <32F as accreting freezing rain, which is a wost case) For sleet, take the Tidbits "snowfall" map (which includes sleet as 10:1 snow), and kind of manually subtract out the pure snowfall from Pivotal and then divide that resulting "snowfall" (sleet) by 3 to get the sleet accumulation (given the roughly 3:1 frozen/liquid ratio for sleet vs. 10:1 for snow). Actual sleet maps would be nice, since clearly that TT "snowfall" map is mostly sleet at a much lower ratio. Alternatively, for the GFS/NAM, at least, I know there are these precip type accumulation maps from cool.wx, below, which are nice, but not zoomed enough for me. I know these offer the ability to get very detailed precip type accumulations for specific stations, like Newark and Central Park, but I can't seem to figure out how to get these from the site any more. Anyone else use these? http://coolwx.com/cgi-bin/getptype.cgi?region=ne&model=gfs&run=06&fhr=29&field=acctype

Thanks! How much did you get during the day on Friday - looks like people are including that...