RU848789

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...

I assume you meant Delaware County, which borders Philly, not New Castle, plus neighboring Camden Co. locations were all above 7", also making a 4" South Philly measurement unlikely, but particualrly the Philly measurements NW of South Philly, where one might think less snow fell as generally was the case from SE to NW in this storm. Thanks. Edit for @MGorse- now I'm confused, as the NWS just put up a new PNS, re-adding all the deleted, incomplete reports for Philadelphia County and elsewhere. Was that supposed to happen? Public Information Statement National Weather Service Mount Holly NJ 1150 AM EST Sun Jan 30 2022 ...Philadelphia County... 1 W Belmont 8.9 in 1230 PM 01/29 Trained Spotter Philadelphia Internati 7.5 in 0100 PM 01/29 ASOS Rittenhouse Square 6.2 in 0924 AM 01/29 Public Rockledge SE 6.1 in 0730 AM 01/29 COCORAHS Fox Chase 6.1 in 0730 AM 01/29 Trained Spotter Chestnut Hill 6.1 in 0207 PM 01/29 Public 1 SE Point Breeze 6.0 in 1000 AM 01/29 Trained Spotter Philadelphia 4.7 NE 5.0 in 0730 AM 01/29 COCORAHS Philadelphia 5.0 in 0830 AM 01/29 Broadcast Media Manayunk 4.5 in 0820 AM 01/29 Public South Philadelphia 4.5 in 1027 AM 01/29 Public 1 S Philadelphia 4.0 in 0730 AM 01/29 Trained Spotter

Mike - great to hear you're still there and posting here on occasion - and fantastic job on the forecast for this storm, as per what I just posted in this thread. You guys get enough grief, I'm sure, when forecasts don't pan out, especially from the public, who generally have zero clue how exquisitely difficult it is to get snowfall forecasts correct, given the complexities of most systems we deal with in this area, plus the limitations of NWP for chaotic, highly uncertain systems, like the weather; forecasts have gotten a lot better, but are still not capable of always getting these things correct. And I can't thank you enough on the insights on snow/liquid ratios, as I've asked that question more than a few times on weather boards and not gotten a response as helpful as this. Always thought you guys did the snowfall maps including in-house ratio adjustments, but couldn't be 100% sure. Also, thanks for confirming what I thought on the PNS reports on snowfall and how the final ones are determined and for the info on the measurements being done at the airport now. As an aside, would you think a 4" report from South Philly would likely be wrong? Seems like it would be or maybe a measurement error given blowing/drifting. Thanks again!!

Sorry if I missed it, but I think our forecasters at the NWS (and many of our posters, too, who did quite well) deserve some love for a bang on forecast for 95% of the Philly-NYC CWAs and where there were misses, they were typically at the edges of forecast swaths where one can't be too disappointed if ending up in the next lowest swath (not major busts). Here are the final forecasts from 4 pm Friday vs. actuals. Allsnow, NJwxguy78 and Jake302 like this

Apart from being just a tad low in the northern 2/3 of Somerset and eastern Morris, I thought the NWS did a superb job on this forecast with the vast majority of people being within their forecast ranges or very close to them (and people on the edge of a forecast swath shouldn't be surprised if they end up on the adjacent swath), as per the final forecast map, below vs. the actual above. On another note, if any Philly folks are reading this, any reports from Center City/South Philly? A guy I know is claiming he only got 4" in South Philly and that the forecast for Philly was a bust, despite reports from the airport, Fairmount Park and Chestnut Hill showing 6"+. There had been a preliminary report of 4.5" from South Phillly before the storm was over, but no final report from there or Center City. Again, @MGorse- if you weigh in on the above post, maybe you could here, too. Also always wondered whether the preliminary reports don't end up in the final PNS because somebody simply didn't update their report after the storm was over or do you guys weed out reports you think might not be credible?

MGorse in the house, thanks!! Are you still at Mt. Holly? Had been wondering if the NWS wasn't allowing employees to post on social media or something, since it's been a long time since I saw any NWS mets posting (or maybe I'm not paying enough attention). Two other questions if you don't mind. First, @JERSEYSNOWROBin a thread on this on 33 said he had been told that the ASOS station is at the airport, like you confirmed, but that the snowfall measurements for "Philadelphia Int'l Airport" are taken across the river in National Park NJ. Is that correct? Finally, yesterday, a met showed me how to find the forecast snow/liquid ratio in the point forecast matrices (which list QPF and snowfall, so one can easily do the math for snow ratios). For yesterday, it was showing 13.8:1 for NYC, while Kuchera was 15:1. Do you guys have some in-house ratio calculation and more importantly, do the NWS snowfall maps include a correction for ratios (vs. being 10:1 ratio maps)? Would love to know the answers to these questions. Thanks!!

Question: I know that Philadelphia International Airport is the climate site of record for Philadelphia County, but I also know that part of the airport is in Philadelphia County and part is in Delaware County - does anyone know if the actual weather station is in Philadelphia County or not? TIA.

Damn, radar didn't show it well, but we got some more light to moderate snow the past hour, so we got another 1/4", since my noon measurement, to get us to 7.5" as of 1 pm. Kept thinking the storm was over and it kept going, albeit at a mostly light clip. Had 4.75" at 4:30 am, mostly over about 7 hours (about 0.7" per hour, with only one hour at a 1" per hour clip) and then only got 1.5" over the next 4.5 hours (1/3"/hr) to get to 6.25", and the radar was looking really weak, so I was thinking we would not get to 7". But since 9 am, we went from 6.25" to 7.25" over 3 hours (still 1/3" per hour). Usually if we get a 7"+ storm, there would be some hours with 1" per hour and once it tailed off it would be over soon after that, but this one kept chugging, slowly. I kind of like the "slow" snowstorm more than I thought I would as it's been more hours seeing the snow falling, which I love. It is finally looking like it might be done though. Pretty good storm and, overall, very well forecast, with even the "busts" being maybe a couple of inches low or high vs. forecast, which is minor to me, given how complex this storm was. The NWS had a 9" forecast for my house before it started and I got 7.5", which is pretty good, IMO. One other meteorological comment is I've seen a couple of posters reporting snow:liquid ratios of about 12:1, which is what I was thinking it was this morning. This means the NWS was a little off (they were predicting 14-15:1) and Kuchera was off even more (15-16:1 for most locations and up to 20:1 NW). Have never liked the Kuchera maps, but yesterday was thinking they'd be reasonable, so I included them along with the 10:1 maps, but the 10:1 maps ended up being better predictors. Will likely go back to just showing 10:1 maps in the future, unless we have an unusual case. Plus 10:1 maps let you also know the QPF at a glance, whereas not knowing the Kuchera ratio easily, one has to work hard to get the QPF from Kuchera maps. Up to 15.3" for the season, over 50% of the seasonal average. Let's see if we can get to 30"...

Damn, radar didn't show it well, but we got some more light to moderate snow the past hour, so we got another 1/4", since my noon measurement, to get us to 7.5" as of 1 pm. Kept thinking the storm was over and it kept going, albeit at a mostly light clip. Had 4.75" at 4:30 am, mostly over about 7 hours (about 0.7" per hour, with only one hour at a 1" per hour clip) and then only got 1.5" over the next 4.5 hours (1/3"/hr) to get to 6.25", and the radar was looking really weak, so I was thinking we would not get to 7". But since 9 am, we went from 6.25" to 7.25" over 3 hours (still 1/3" per hour). Usually if we get a 7"+ storm, there would be some hours with 1" per hour and once it tailed off it would be over soon after that, but this one kept chugging, slowly. I kind of like the "slow" snowstorm more than I thought I would as it's been more hours seeing the snow falling, which I love. It is finally looking like it might be done though. Pretty good storm and, overall, very well forecast, with even the "busts" being maybe a couple of inches low or high vs. forecast, which is minor to me, given how complex this storm was. The NWS had a 9" forecast for my house before it started and I got 7.5", which is pretty good, IMO. One other meteorological comment is I've seen a couple of posters reporting snow:liquid ratios of about 12:1, which is what I was thinking it was this morning. This means the NWS was a little off (they were predicting 14-15:1) and Kuchera was off even more (15-16:1 for most locations and up to 20:1 NW). Have never liked the Kuchera maps, but yesterday was thinking they'd be reasonable, so I included them along with the 10:1 maps, but the 10:1 maps ended up being better predictors. Will likely go back to just showing 10:1 maps in the future, unless we have an unusual case. Plus 10:1 maps let you also know the QPF at a glance, whereas not knowing the Kuchera ratio easily, one has to work hard to get the QPF from Kuchera maps. Up to 15.3" for the season, over 50% of the seasonal average. Let's see if we can get to 30"...

Took a much needed nap and did some shoveling and walking around and as of 12:00 pm, we have 7.25" here in Metuchen, which was very, very hard to measure with the windblown snow, so it was probably an average of at least 20 measurements around the yard (the snowboard measurement seemed a touch high to me at 7.6") which is close to my 8.25" prediction - wasn't sure we'd get that close a few hours ago, but the mostly light snow still delivered 1/3" per hour for the last 3 hours. 19F now. Debating what to do with the 1/4" I got yesterday in the late morning - have seen some saying to include it - if so, I got 7.5". I'm inclined to not include it, as it was from the front/clipper and we had many hours of no snow after that. Don't think we'll get more than another 1/4", looking at the radar. 7.25" seems consistent with numbers I've seen reported near me in Middelsex County here and elsewhere, such as 8.5" in Carteret, 7" in P'way, 8" in Woodbridge, 8.5" in Staten Island, and 7.5" in New Brunswick. Haven't seen any reports from Edison/Metuchen, though. Anyone?

Took a much needed nap and did some shoveling and walking around and as of 12:00 pm, we have 7.25" here in Metuchen, which was very, very hard to measure with the windblown snow, so it was probably an average of at least 20 measurements around the yard (the snowboard measurement seemed a touch high to me at 7.6") which is close to my 8.25" prediction - wasn't sure we'd get that close a few hours ago, but the mostly light snow still delivered 1/3" per hour for the last 3 hours. 19F now. Debating what to do with the 1/4" I got yesterday in the late morning - have seen some saying to include it - if so, I got 7.5". I'm inclined to not include it, as it was from the front/clipper and we had many hours of no snow after that. Don't think we'll get more than another 1/4", looking at the radar. 7.25" seems consistent with numbers I've seen reported near me in Middelsex County here and elsewhere, such as 8.5" in Carteret, 7" in P'way, 8" in Woodbridge, 8.5" in Staten Island, and 7.5" in New Brunswick. Haven't seen any reports from Edison/Metuchen, though. Anyone?

Well, we got some light to moderate snow the past 2 hours and we're now up to 6.25", which is a nice storm, but very likely will fall a bit short of my 8.25" prediction. Part of that is because the NWS predicted 14:1 ratios, so I kind of figured that in, but DonCat in Staten Island reported a 12:1 ratio - if it had been 14:1, I'd be at 7.3" now. No biggie, just interesting to observe. It's still snowing and the radar looks like we might have another hour or two with a shot at a heavier band as the storm pivots and starts heading ENE. For hours I've been watching heavy bands about 10-15 miles east of me falling apart as they move west, but maybe we'll still get one. Oh well, still a fun storm. 20F.

Well, we got some light to moderate snow the past 2 hours and we're now up to 6.25", which is a nice storm, but very likely will fall a bit short of my 8.25" prediction. Part of that is because the NWS predicted 14:1 ratios, so I kind of figured that in, but DonCat in Staten Island reported a 12:1 ratio - if it had been 14:1, I'd be at 7.3" now. No biggie, just interesting to observe. It's still snowing and the radar looks like we might have another hour or two with a shot at a heavier band as the storm pivots and starts heading ENE. For hours I've been watching heavy bands about 10-15 miles east of me falling apart as they move west, but maybe we'll still get one. Oh well, still a fun storm. 20F.

That's a 12:1 ratio roughly. When I posted around 4 am I was speculating our ratios weren't nearly as good as predicted by the NWS (14:1) and guessed that I had probably gotten 12-13:1 ratios on a post on 33. And Kuchera was estimating about 15:1. Had 5.5" at 7 am and doubt I've had more than 1/2" since then, which would give me 6", but will measure shortly - that ~10 miles east of me really helped you get 1-2" more