wdrag

The 14th is a likely event I think, because there is not going to be much rain this weekend (less than a tenth or two) and we'll need a flushing of the mild air For Wednesday event). Therefore an event Monday takes advantage of some WAA leftover low lvl moisture (dew point 30+) from this weekend and wrings it out as short wave passes by, which should result in decent BL CAA Tuesday. (corrected PWAT reference at 822A to dewpoint).

Sferics: I remember interviewing with a Cincinnati private met around summer 1980 talking about the lightning triangulation., Yes..I remember both NYC names. Yes.... on 30 Rock--the gold walls... and back around 1962-63, US Weather Bureau Chief Gerald Shak (recently passed) allowed an in-person interview for my ~ 7th grade Elementary School science class in his office. Was pretty cool- it might have been there that I received copies of Weatherwise that highlighted the great Dec 1960, and Jan 1961 snowstorms (Kennedy Inaugural etc).

00z/11 cycle impressions: Will post the main show first: Wednesday-early Thursday 16-17. Caution: some models have had a southward trend. Something to think about. Continues to look good for a potential snow event. Water equiv as per WPC... am thinking 0.5 to 1" is a good start. Water temps in the 40s nearby LI will probably require an 850MB temp of -3 to -5C for snow not to change to rain in the +0C Boundary Layer for L:I (NYC too). That's a caution for LI, especially south shore and eastern tip as well as NJ coast. 00Z/11 ECMWF operational model pressure down to 984 MB is not likely. Look for a more reasonable 995-1000MB low s of LI with a 1030-35MB high over Quebec. Very nice set up...potentially a 40 MB difference (possible 40kt easterly flow near Montauk?). The 00z/11 ECMWF operational snowfall/depth has to be biased high because of the extreme with respect to multiple models and it's own EPS (which is closer to half foot or a bit more, along and n of I80). 00z/11 52 member NAEFS looks very good but with variability on qpf. The 00z/11 GEFS 850 low is weaker and develops later but develops. So it's game on (GGEM is back on board, more or less). The question is where will the max axis be? The track of the 850MB Low is close to LI... which to me favors I84 or northward for max snow axis. I think we need to be careful along the southern edge and there are still options for a further south track but for now...the WPC D6 probability of 3" or more of snow (1/4" or greater frozen water equivalent) looks good (30-49%). You would think this is too low, but what that tells me, is that there is a lot of variability on placement of colocated cold enough temps for snow and the 1/4" qpf. It also was generated without the benefit of the 00z model cycle. Tides: could be minor flood event either Wednesday or Thursday morning as the tides are astronomically very high. Duration of northeast flow, and pressure will determine. Fortunately...it looks like the worst of the inflow is at the lower high tide Wednesday evening with a wind turn to northerly probable Thursday morning. Meanwhile Monday the 14th: Don't toss this away. EC is coming north and so while the GEFS is locked south of us, the EC and 06z NAM suggests to me that there could be some snow in our forum Monday- minor and melting on roads except small chance of an SPS hazard income of the hills (Poconos -nw NJ?) Friday the 18th: this possible event will not arrive the 18th - instead warm air advection---probably delayed til the weekend sometime. Two graphics added: WPC D6--please see legend for your area of interest and the 00z/11 GEFS prob for 1" of snow Wednesday-early Thu. 551A

Let's enjoy the slippery slope greased with a little snow one of these days.

I used to listen to Don Kent-BZ, WCAU had a good met team in Phlegms, There was Denardo-McFarland in PIT, and WTIC Barbara Allen Buzz Bernard etc... they all helped get me psyched on events. WNYC used to have a 145PM radar report, right off the Weather Bureau Radar at Rockefeller Center. Anyway, better not digress any more. Gotta rest.

That's correct... Let's presume it will be back by Saturday... if it's not, then I'll be concerned. All these op runs are single members... even the EC op could lose it tomorrow but it might show the single member OP that represents only 10% of the ensemble. So--- my fingers are crossed. I like the setup... for a moderate event of 1/2-1" qpf... modeling can change my thinking but for now a conservative progressive approach. Any snow we can get now is nice to have. Most everyone on here is probably under age 60... I presume. Modelers-researchers-computerization and platforms for data have provided us with modeling that can be pretty accurate to D5 and alert us to a potential event D6-10 with some reliability. Back in 1960-65 I was reading the Farmers Almanac, and local long rangers (Gordon Barnes) for my hope... not a Weather "Bureau" D5-7 forecast (as the NWS referenced back then). Let's see what happens and keep the options open that there could be some sort of failure here.

Also, I've been away from guidance most of the afternoon and won't spend much time on it this evening, so I'm less appreciative-aware of the evolution. Stay on top of it. I'll probably be able to immerse myself in this early Friday.

I'm waiting this out ... no topic change til I'm sure Monday is a NO and Wednesday its big and south. I try to frame these topics so they're reasonable ballpark and will be helpful. If it looks like south will prevail, and/or many other guidance portend a big one, I'll reword the topic and try to be more accurate. This was written Tuesday evening. There is still time for many model adjustments and not necessarily favorable for us snow weenies. I just can't talk about this coming event as a done deal. Still somewhat a thread the needle-lucky timing- and will it develop. Tomorrow morning I'll use the 00z/11 guidance to reconsider everything. For now, best to be patient- wrap the holiday gifts, so you have more time closer to the event(s) to have fun with models and maybe shovel and appreciate those dendrites.

Sure... I've not seen significant QPF events of more than ~1 tenth inch not have the GGEM op on board. It doesn't necessarily have to be snow but we need it to give us decent qpf. I am aware as one of our posters indicated, that GGEM and RGEM were furnace and wayyyy too low on the snow idea (dynamic cooling) of this past Saturday the 5th. I also think the RGEM and GGEM, if I recollect correctly were more conservative regarding the western (extent) boundary of that event. Lots of folks deride the GGEM and statistically (500MB stuff) it doesn't compare with the EC/UK/GFS in that order... BUT it's a good basic starting point for me... and fwiw... I've lost confidence during 2020 in the UK operational being of much consistently reliable value. To test this GGEM hypothesis... please send me examples as we move forward in these synoptic storms where the GGEM was never on board and we got our selves a decent qpf event. That's the best way too refute my contention and reduce my use of the GGEM as a guide. I've never taken the time to document with stat analysis, just like my experience with the BL wind on the FOUS needing to exceed 26 KT to consider and verify a wind advisory. So... we're well in advance of the likely Wednesday-early Thursday storm event... If the GGEM doesn't climb on board by Sunday, I'm going to be losing hope and will be reluctant to commit to a big event. Regarding the topic: I have no plans to change the topic... I still think Monday the 14th is decent chance for 0.10 qpf or greater at LGA, along with some snow on the northern fringe in our area and I kind of think it will be needed to help draw colder BL air southward in it's wake and set up for Wednesday. That was a good question: Hope this helps a little and it's worthy to check GGEM for our area.

A little late and after the fact, but here is the CoCoRAHS snowfall report for Thursday December 9, 2020, NYC forum.

Hi! A few different things... just to try to keep perspective. I need op GGEM on board... i see some of it's ensembles are there but I need GGEM op on board. I don't think it will be much of a snow storm for us, if it isn't. 12z NAEFS has slightly warmer thickness than it's 00z/10 version...5540 cutting thru LI now 00z/17. That increases risk of mix or rain LI, for at least a time. Caution on buying in on the ratios til till we know for sure the sounding is all snow, and that the 1000-500 thickness is preferably ~5400m Thereafter it's the DGZ and Banding. WAYYYY too far off for me to count on anything except decent snow I84 north (heart of the ensemble axis). For now we in the NYS forum seem to be close to the gradient of snow and no snow. Gradient error's can be very large. I've added the WPC D7 GEFS forecast for 3" or greater of snow Or 1/4" water equivalent glaze or combo thereof. The prob is 30-49% in dark green. Will revisit tomorrow morning...

I wasn't there, but did CP not have any cover on grassy surfaces yesterday? They had .05" of melted snowfall... and moderate snow at times. I would ave thought a slimy wet snow covering of 0.1?

Good Thursday morning all, My morning update on this thread. I probably won't comment again til Friday. My primary dates of interest for wintry precip elements in the NYC forum are Monday the 14th, Wednesday the 16th and Friday the 18th. All dates have possibilities and I suspect will have qpf. The jet stream will be just to our south throughout. In addition there will be 3 southern stream short waves to monitor which should have qpf impact here and a NEAR 50/50 500 MB low will be developing mid and late week (actually closer to 55N, 50W). Thinking the primary date of concern for snow here is Wednesday the 16th, but let me begin with this coming Monday the 14th. When you look at the models, It doesn't look much qpf with the front on the 13th, at the expense of a trailing short wave in the lower Mississippi Valley, that currently is modeled mostly to our south. However, if it trends a little north, wintry precip could easily occur on it's northern fringe-just north of NYC. This would be a minor event, at worst, if my impression of what will happen is correct. This Monday event is my lowest confidence, but the GEFS is flagging decent qpf just to our south. NAEFS image attached. The 16th event to me is clearly cold enough for snow and ice, even down to NYC. BUT, given that it's at D7 and that modeling could be too cold (sfc pressure too low on the presented ensemble for 00z/17), I have to leave open the door for all rain NYC-LI and s of I80 in NJ. I've added a number of NAEFS graphics including small qpf, cold enough 1000-500 thickness, Surface pressure. Later the 18th is flagged as well. I think that one in part depends on what happens the 16th- If the 16th ends up as strong as the 00z/10 ECMWF op run, then the 18th probably is delayed or suppressed- however if we end up with a 1000MB surface low just to the south of LI next Wednesday evening, then the next southern steamer has a chance. Regarding the 00z/10 ECMWF op... I'm recommending tempering the amounts seen (especially the whopping Kuchera). Just too early and how often do those huge values verify at D7? I have added the 10 to 1 ratio EPS which looks like a reasonable start to me, realizing the southern edge amounts could fall as rain and make snowfall nil. I do not expect the EPS amounts to disappear I84 northward but what I expect and reality could be wrong.. Still, I have above average confidence that a wintry event of some sort is coming to the northeast USA the middle of next week, whether NYC/LI are involved is the most uncertain and could end up just wet and windy. Let's monitor. 542A/10

Timing timing timing... I'm no long ranger - no skill. I do look at basic (non MJO) patterns and it seems like we're running a bit different than Dec 2019.

I don't think you need as much cold air with respect to normal anymore. I am definitely interested in the 14th (weak wave of precip) and something more substantive 16-17 (wintry mix)... and with blocking in Greenland modeled by both the GEFS-EPS for the foreseeable 16 days... rainstorms are not a constant lock.Even seasonable temps give us a bit of a chance.

I see OKX afternoon prelim CLI for CP as T snowfall today.

I just checked the 12z/9 NAEFS... it's favorable for a light wintry weather event here, around Thursday the 17th. Plentyyyyy of time for things to go wrong or, get heavier. I am always keeping in mind the mild base state for our winter and many long rangers conservative snow forecast for this winter. Nevertheless, still something to watch for during this 5 day period and make the most of the marginal opportunities.

Wantage NJ, last band on its way in now for us out here. 0.8" solid. Thanks for adding your data. Will be curious what OKX does for CLI tonight--- 430CLI is prelim. The 130A Thursday will be the official. CP ASOS had moderate snow at a temp I think around 33F. Looks to me like first measurable snow must have occurred. Also note the moderate snow around 1P and the early morning NAM 3K image post on the DGZ lift. It doesn't take a lot of lift in the DGZ to make good sized flakes. NAM was pretty good for this event, I think. KNYC 091951Z AUTO VRB04KT 6SM HZ BKN016 BKN037 OVC070 01/M02 A2976 RMK AO2 SNE20 SLP070 P0000 T00111017 $ KNYC 091943Z AUTO 7SM SCT014 BKN037 OVC070 01/M02 A2976 RMK AO2 SNE20 P0000 T00111017 $ KNYC 091921Z AUTO 23007G15KT 200V270 3SM BR FEW010 BKN014 OVC034 01/M02 A2976 RMK AO2 SNE20 P0000 T00061017 $ KNYC 091915Z AUTO 22006G21KT 1 3/4SM -SN BR SCT010 BKN015 OVC036 01/M02 A2976 RMK AO2 P0000 T00061017 $ KNYC 091907Z AUTO 26007G16KT 210V010 1SM -SN BR BKN010 BKN015 OVC021 01/M02 A2976 RMK AO2 P0000 T00061017 $ KNYC 091851Z AUTO 24009G15KT 1/2SM -SN FG BKN009 OVC015 00/M02 A2977 RMK AO2 SLP074 P0004 T00001017 $ KNYC 091808Z AUTO VRB03G15KT 1/4SM SN FG BKN009 OVC016 01/M02 A2979 RMK AO2 P0001 T00061017 $ KNYC 091751Z AUTO VRB05KT 1/2SM -SN FG SCT008 OVC016 01/M02 A2979 RMK AO2 SNB09 SLP080 P0001 60001 T00061017 10033 20006 56021 $ KNYC 091731Z AUTO VRB06G15KT 1/2SM SN FEW009 BKN023 OVC031 01/M02 A2980 RMK AO2 SNB09 P0000 T00111022 $ KNYC 091723Z AUTO VRB06G18KT 1 1/4SM -SN FEW012 BKN031 OVC041 01/M03 A2980 RMK AO2 SNB09 P0000 T00111028 $ KNYC 091716Z AUTO 24011G18KT 2SM -SN BKN029 BKN043 OVC055 02/M03 A2980 RMK AO2 SNB09 P0000 T00171028 $ Snow reports so far by the NWS.

The 2" report just east of Scranton its probably closer to 3.5" .. solid event there. Here's some snow reports that are posted by the NWS.

Yea...NYC First trace of the season- unmistakeable at the KNYC ASOS!!

Wantage NJ (8 s High Point) 0.5" so far. Roads wet. Driveway mostly wet but some slight accumulation. Concrete and pavers accumulating. Nice small flake snow continues. 30.2F

Wantage 0.2" down to 30.4. TD 29.8 3/4-1mi S-. small flake but densely filled air. Hope the main precip clusters don't miss CP (splis right-left)

Sometimes this stuff acts like summer convection. Once it gets going, it lasts longer-further downstream than expected. Hope CP gets it's trace today and we can get that out of the way. I have followed up with the OKX web team.

Impact NYC metro probably nil except folks exclaiming 'It's snowing' (maybe mixed with sprinkles at the start). It could still fade, but i am pretty sure NYC will see some snow at CP sometime between 1230-2P. Doubt if it can measure... just too warm .. melt on contact except some of the roofs/carts/grass nearby the city. My daytime 1030AM ish greeting card - wish it were deeper. Soon it will be.

Mt Cobb on exit 8 I84 just east of Scranton with ~2" in less than 2 hours. Doing. We here in Wantage are down to 3/4mi or so. Ground whitening...still T. pavement wet. 32.2.