RU848789

12Z Euro and later HRRR runs (13-16Z) are similar through 1 am with much less precip SW of about NYC to the Sussex/Warren border (~0.3") and both have temps above 32F for NYC and points SW and S of there by 1 am. Can't say I like the idea of getting light rain and maybe some freezing rain after that time. On the other hadn, I was quite happy to see the NAM largely cave and the RGEM, UK and AIFS look snowier SW of NYC, so it's still a bit of a crapshoot on what's going to happen, especially on the SW side of the storm where lots of sleet is possible to likely.

Kuchera doesn't count sleet either, at least not on Pivotal. Kuchera is a terrible algorithm only based on max column temp, not taking into account crystal formation, which governs snow bulk density/ratio on the ground, as long as melting doesn't occur while falling, so Kuchera helps when the column is over 32F somewhere and can give some hint at ratios where the column is cold, but much of that depends on the crystal habit being formed in the DGZ, which is dependent on lift and supersaturation, none of which has anything to do with Kuchera. 10:1 is best IMO because it also gives an easy estimate of QPF (10:1, duh), whereas one has no idea how much QPF went into the Kuchera calculation. The sleet question is separate. Some services show sleet separately but most don't. We have the Pivotal approach of only showing snow, so sleet is missed completely, which is bad, since sleet is as impactful as snow (same mass) on road conditions and removal/shoveling (but it's not as pretty), while we also have the TT approach which counts sleet as 10:1 snow, so one at least gets an impact assessment, but it's also very misleading on the snow/sleet depth and many like to know the depth too. I type something like this every storm. I should just save it somewhere and copy/paste, lol.

Nice improvements for most in snowfall over the last 4 runs on the NBM, even if the Euro has me a little worried over its light QPF, lol.

I think Lee Goldberg's is my favorite map so far, so I'll post it as my forecast, lol. I like that it's a little bit more aggressive than the NWS, which is now probably the low end of the predictions, but it's also below several others who have large 6-10"+ swaths which I think are too high. Lastly, time for my usual guess: I'll go with 6.1" vs. my NWS point and click of 5.7" and our advisory of only 3-5", which ought to be at least 3-6" for Middlesex County since there's a small 6"+ swath right near me in NE Middlesex Co.

NWS finally updated their map, below, which shows Metuchen just about on the 6" line which kind of is within the 3-5" range for us in the advisory, but is also within the 4-8" range on my point and click. This snowfall map also makes sense with the warnings for ~6" for Morris/Warren and Sussex. They really need to issue their updates across all products at the same time or close to it, not over 2+ hours (their advisories/warnings were issued around 1 pm).

NWS finally updated their map, below, which shows Metuchen just about on the 6" line which kind of is within the 3-5" range for us in the advisory, but is also within the 4-8" range on my point and click. This snowfall map also makes sense with the warnings for ~6" for Morris/Warren and Sussex. They really need to issue their updates across all products at the same time or close to it, not over 2+ hours (their advisories/warnings were issued around 1 pm).

My NWS point/click for Metuchen is a general 4-8" (plus maybe another inch at the end), while my hourly weather graphic gives me 7.1", but the new advisory says 3-5" of snow/sleet and a glaze of ice and the snowmaps haven't actually been updated (people keep posting the same map from 4 am with new time stamps on them). I have no idea what to think.

TWC backed off some, obviously...

Significant trimming back of snowfall for areas south of 78 in PA and W NJ and near/south of 276/195 is what I was expecting to see at 4 am - not sure why it took them a couple more hours to do so. I do like the single map showing NWS-Philly and NWS-NYC together (although it does miss the northern edge of the NYC office counties), better, though, so here it is.

Door #3 - The NWS offices in Philly and NYC punted, lol, keeping all of the watches up and not really reducing snowfall forecasts much in the updated map vs. yesterday afternoon's map, other than trimming back a bit near 276/195, but they also bumped snowfall up a bit in EPA and on LI, although their discussion talks about reduced snowfall due to more sleet in the W/SW counties that have watches and due to more rain possible for the SNJ counties that have watches. Hard to blame them for simply keeping the watches, as there's still almost 36 hours before the event starts and this way they don't have to change twice.

Not 100% sure on that unless all of NYC suffers from the HIE, as everywhere was 35-36F 32F with the outlier being Teterboro at 33F; we were 32F at 7 am 25 miles SW of NYC. Would need to see LI/CT being colder than NYC to be convinced and I don't know the temps to the east. New York City Metropolitan Area Weather Roundup National Weather Service New York NY 700 AM EST TUE DEC 23 2025 CITY SKY/WX TMP DP RH WIND PRES REMARKS Central Park LGT SNOW 36 30 79 SW6 30.33F WCI 31 LaGuardia Arpt LGT SNOW 35 26 69 S10 30.32S WCI 27 Kennedy Intl FLURRIES 36 33 89 SW15 30.34F WCI 27 Newark Liberty FLURRIES 36 30 79 S8 30.31F WCI 30 Teterboro Arpt LGT SNOW 33 29 85 S9 30.31S FOG WCI 25 Bronx Lehman C N/A 37 32 81 SW12 N/A WCI 30 Queens College N/A 34 32 93 S8 N/A WCI 27 Breezy Point N/A 36 N/A N/A SW9G16 N/A WCI 29 Brooklyn Coll N/A 36 32 87 S9 N/A WCI 29 Staten Island N/A 36 32 87 S8 N/A WCI 29

7 inches to 5 inches wouldn't bother me at all, but 7" to 2" would suck.

Bridgeport and Brentwood went down a little, while Waterbury and Norwalk went up a little, so eastern sections of the CWA were a wash, IMO, whereas everywhere else throughout the NWS-NYC area, amounts went down 1-2", which is a much bigger drop, plus this decrease extended throughout the NWS-Philly counties.

After mostly minor fluctuations in the NBM, the latest 19Z took a decent hit in snowfall amounts for most, so I'd expect to see the NWS back off amounts at 4am by at least 1" or so for most if we see similar at 0Z, as they rely pretty heavily on the NBM.

Yep, I like Lee a lot; here's his updated map (from 3-6" to 4-8" for most). Pretty consistent with the NWS...

You are correct sir. Was guessing a bit, since the AFD wasn't out when I wrote that. Here's what they said: "There is greater uncertainty further east due to the interaction with the lingering surface ridging/dry air and overall lower liquid equivalents."

I did this for folks elsewhere so thought folks might like this summary of all the watches for NWS-Philly and NWS-NYC, as well as the map of watches and the new snowfall map. Getting officially excited as my point-and-click is up to 6.9"... Winter storm watches up for most of the region (counties in grey), so the forecast is obviously gaining in confidence, but still some uncertainty in how far north/northeast the warm air aloft makes it, turning snow to sleet for some of the storm (outright plain rain is looking unlikely for any part of CNJ). Watches are up for the following areas for the snow/sleet and ice amounts listed with some comments from looking at the point/click forecasts which are not explicitly listed in the watches. For 4-6" for Camden, Coastal Ocean, Northwestern Burlington, Ocean, and Southeastern Burlington Counties; for this area, the NWS is expecting some of that to be sleet, which could keep accumulation depth down For 4-6" and up to 0.2" ice glaze for Carbon-Berks-Lehigh-Northampton-Philadelphia-Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks Counties; obviously the NWS feels there's more chance of sleet and then freezing rain here For 5-8" for Sussex-Warren-Morris-Hunterdon-Somerset-Middlesex-WesternMonmouth-Eastern Monmouth-Mercer-Monroe; NWS is basically calling for all snow for these counties For areas SW of the Philly/Camden/Burlco counties, the NWS-Philly is still predicting a few inches of snow, then sleet, then rain as those areas will be closer to the warmer air aloft from the storm; these areas will likely get advisories tomorrow. For 4-8" for almost the entire NWS-NYC area, i.e., Northern Fairfield-Southern Fairfield-Western Passaic-Eastern Passaic-Hudson-Western Bergen-Eastern Bergen-Western Essex-Eastern Essex-Western Union-Eastern Union-Orange-Putnam-Rockland-Northern Westchester-Southern Westchester-New York (Manhattan)-Bronx-Richmond (Staten Island)-Kings (Brooklyn)-Northwest Suffolk-Southwest Suffolk-Northern Queens-Northern Nassau-Southern Queens-Southern Nassau; the only exception is eastern Suffolk, where they expect sleet to keep accumulations down. All of the watches are in this link: https://forecast.weather.gov/wwamap/wwatxtget.php?cwa=PHI&wwa=winter storm watch

Not sure what your point is. The NBM and NWS maps for yesterday were quite good, except for NYC proper, where it was slightly warmer and little accumulation occurred. I'm 25 miles SW of CPK along 95 and got 0.8" vs. a 0.5" prediction - the only reason I can think of why NYC didn't get accumulation was the heat island effect.

Great NWS graphic on their thinking on that; 6Z models, overall, seem like they'd push that transition zone to the NE...

No, riding the NBM, as per their discussion.

There are always things to worry about 3+ days out, but this is about as good as it gets for the EPA-NJ-NYC-LI region with regard to model consensus (at the surface). 2-4" shown by all the major globals (Euro, AIFS, GFS, CMC, and UK at least) with potential for 4-7" shown by the AIFS, and GFS (and the others in spots) seems like a good guess right now. I do worry a little about the possibility of a changeover to rain as seen on the CMC up through Philly and SNJ keeping accumulations way down and that possibly even moving further north into CNJ, but that's quibbling...

Probably a final measurement of 0.8", since temp is up to 34F and we're seeing melting/compaction so even though it's still snowing, it's not really accumulating much anymore. Still pretty happy with this little overperformer (forecast was for 0.5" and my prediction was 1.0"). 7.8" for the season so far and hopefully several more on Friday night.

Some huge flakes the last 20 minutes (almost 1") and the street is mostly covered again - intensity matters, lol.

Up to 3/4" as of 9:00 am, so might get to my 1" prediction, although with it being 33F and slowly rising, I don't think we'll get accumulating snow for more than another hour. Snowing pretty good right now though...

As of 8 am, it's snowing moderately with 0.5" on the ground and it's 33F, but still accumulating with decent rates, even on the driveway and sidewalks - not as much on the roads in front of the house.