wdrag

Anyone with a Central Park report from NWS? Wantage NJ...after a 45 min lull... snowflakes increasing in size and density. Still only 19F here... think we may not be above 22F at 7P here in nw Nj high terrain, if that. IPT is the next clue on change to IP.

Wantage NJ SB ~Noon, as of 1P 0.5" Was mostly small flake snow w some snow pellets. snow let up around 1P Temp 18F, dew point still only 11F. I see an SPS out of CTP for 1-2"/hr band crossing PA.

Quibble accepted... Thanks. All i think about is IMPACT... So i definitely define paved vs grass-trees-boards when I can/have time. In this case... shovel the walk or plow the road, it reaccumulates on untreated at these very cold air temp. Should that air temp during the day get close to 30...paved roads (darker surfaces) melt barring as you say the snowfall rates during the day.. After dark... then we lose that energy and easier to accumulate. In any case up here at 18F... roads all covered, but treated roads mixed wet-slight slush. 0.5" set 1P.

For what it's worth.... I've added the thermal profile for LGA from there 12z NAM. Some forecasters get concerned about Ice Pellets (IP) once the temp aloft nudges zero. In this case at about 22z, there is a modeled hint of IP before upward motion and wet bulbing may cool the sounding enough to permit snow til about 0030z. The sfc temp may not be cold enough to support much if any additional accumulation after 00z. Also RGEM from the 12z run is slightly warmer aloft and seems like less qpf in NJ. Hope am wrong about the warming aloft trends. I've added the Sparta NJ hourly type for any forum members in nw NJ. Hope it's right about only 1 hr IP. Walt 1530z/18

Good Saturday morning everyone (Jan 18). This is an mPING day. Should produce some accumulation for our entire forum area. I've added some ensemble products as self checks against big amounts... the questions I have...ultimate water equivalent QPF and does it sleet in a marginally thermal column late today, or does upward motion, compensate to produce 1/2S at 5-6PM. I've opted for the snow-sleet=trim amounts scenario for my own area of interest (I84 corridor of ne PA/nw NJ). The EC Kuchera is rather robust in the Poconos/nw NJ and as is the Experimental HRRR. I am definitely concerned about sleet...already sleeting (mPING) where one might have thought it be snowing in w MD. It will be hazardous at times this afternoon-evening on all surfaces up here nw NJ and se NYS. Ground too cold and air temps I do not think can rise as fast as modeled away from LI. So the first 3 graphics are NWS ensemble chances of 1+, 2+ and 4+ inches. Then the EPS prob courtesy Weather.US, for 3+ inches which continues uncertainty nw NJ but favors 3+ with its ~80% probs. Finally the 06z HRRRX variable density product and these amounts look a little too high to me.... I could see this would be possible if ALL snow. So my confidence in an all snow situation til 02z is below average for nw NJ and ne PA. Hope I'm wrong. 658A/18 at 502P/19 added the NOHRSC snowfall analysis to compare against NWS and EPS probabilities for various thresholds 2,3,4" This illustrates value of considering ensembles as limiters on extremes. One thing we know' HRRRX was terrible in northern PA where the sleet I think impacted this variable density product. Rest of the HRRX product looked decent. Later, Walt

Just trying too work with everyone... for good conversation but also a little learning about ensemble value (or lack of), as a self check. Thanks for your reply. There may be others...I'll check back. Later, Walt 1138z/18

Hello to all and the Moderators especially, I need a little guidance. Have checked forum coverage areas. Don't see a map (or I missed a link). In any case, can someone define the western and northern fringe counties of our coverage area. Can I presume north of I78 out to the Delaware River... do we extend into Pike, Monroe and Northampton Counties in PA? Also the north fringe...is that bounded by I84 or is that too far north? I presume no CT coverage but all of LI is covered. A little more clarity will help guide me on any topics. I also noticed some participants might not want to know of any NYC snow amount topics under 1". Is there any guideline for topic starter? Have started topics, when confident that there will be a wintry type hazard, even if I80 south including LI is out of it. Maybe thats too liberal and I should limit to when I think even NYC might get 1+"? Thank you kindly for American Weather Forum consensus advice. Walt Drag 351PM/17

Good Friday morning everyone, Jan 17. I wish my confidence was greater for Saturday. Concerned about qpf modeling... and as often mentioned by group members, southwest flow event, (especially 850MB)...just hard to get my hopes up. I expect 2 inch minimum just north and west of NYC. The city I think should still be snowing at 7PM but surface temps govern accums. FGEN embedded in the ridge well ahead of the short wave should develop a band or 2 of moderate snow for an hour or 2 Saturday afternoon-early evening. Modeling later today and tomorrow may help... anyway, with less than 3" so far in Central Park... if an inch falls....that would be noteworthy. I've added some ensemble graphics. The first two are courtesy NWS ensembling system for snowfall. The last is the ECMWF EPS chance for 3+ inches courtesy of Weather.US posted 718AM, data gathered around 5AM.

Good Thursday morning everyone (Jan 16). Here's a few graphics I used for a briefing this morning. NYC doesn't look good for an inch but for Morris and western Passaic Counties westward and northward including Orange County...even though it's not big, its a travel problem for ~ 5 hours during Saturday afternoon-evening due to temps hovering in the upper teens to mid 20's during the snowfall out there. NWS ensemble graphics are appended for 1"+ and 4"+. The EPS is courtesy of Weather.US and the ECMWF, and also is appended for the chance of 3+ inches. This differs from the NWS and I suspect is less detailed on terrain and its impact on qpf. I noticed the UK and EPS/GEFS all favor heaviest qpf in two stripes...one is I78 area southward and then well to our north. Surface temps and timing of snowfall will determine Central Park accumulation (if any). I wont be reposting til Friday morning...allowing models to fluctuate. 638A/16

Good Wednesday morning everyone, Yes... its a relatively snowless winter so far for NYC and maybe this is the way it goes the rest of the way but I think we need to work the science of ensembles for predictability and self checks against our own personal snow forecast processes. I've added again here, and I hope to add to the original post... the NWS ensemble chance of 3+" of snow and the EPS chance of 3+ inches of snow. The EPS is still pretty close to what its been for several days, but the NWS ensemble has decreased considerably s of I84. It doesn't look too good for NYC though I think a decent short burst of snow-sleet should occur during the early afternoon start---surface temperatures being a little on the warm side for much of a street problem. Looks a little dicier nw corner NJ into parts of se NYS with the bulk of this event there snow to ice before dribbling out to drizzle - showers later at night. I'm just not seeing much of a south wind in the interior, presuming it does snow-sleet 1+ inches. Snow growth at this distant forecast time for Saturday actually models okay for an hour to two Saturday afternoon. 733A/15

Good Tuesday morning the 14th. I added here and in the originating post the NWS ensemble forecast for 3+" of snow sleet (higher than yesterday and similar to the EPS). The EPS has also been added courtesy Weather.US and the ECMWF TOS. You can see a break down of confidence n of I84 in the EPS, til you get to the Adirondacks. In any case, the modeled chill via the 00z/14 GFS MOS and the ECMWF 2m temps appears to me to make it lock for hazardous travel on on all untreated surfaces Saturday afternoon when you get northwest of NYC tho it could be snow quickly to sleet-freezing rain with snow accumulation limited by duration of snow prior to the phase change. This system to me just doesn't have much chance for NYC being a big snow event, due to the track of the shortwave. Should it dig more, then there'd be a little more hope but I'd like to see southeast flow at 850 MB instead of strong southwest. Just not a good winter for us... but I'll take what little I can get. I only post ensemble guidance once/day since there are so many nuanced changes and I'd rather try to capture the essence of trends over several model cycles while still 3+ days from the event. 652A/14

Good Monday morning everyone, Have offered to focus the general discussion thread on next weekends storm into one single thread. It's been a terrible winter so far s of I80 and not much to boast about north of I80. I'm adding graphics daily at about this time, until the threat fails to materialize. No guarantees on anything. It does not look good for NYC south, so far. Contributions are from the NWS public domain and the Weather.US and the ECMWF. We'll see how this verifies for long range value. The first two graphics are the NWS ensemble chance of greater than .25" water equivalent of frozen precipitation. These are run off of late day ensembles and post, "prior" to the 00z cycle ensembles. The two graphics courtesy of the ECMWF are the chances of 3+" of snow for this event which are increasing a bit in the I84 area and are from the 00z ensembles. No LOCK on any of this coming to pass though I'm pretty confident the interior west and north of NYC will have some sort of winter hazards this weekend. Depends I think, in part on how strong the northern stream short wave is that crosses the Great Lakes. The stronger it is, then I think the storm tracks further north. At 633AM the 14th, I added the 00z/14 NWS ensemble and EPS chance of 3+ inches of snow so that it's easy to go back and compare to reality. The risk has increased a bit for the NWS ensemble system to something similar to the EPS. Certainly no lock for 3+ inches s of I-84. At 457PM/19 added the NOHRSC snowfall analysis. Gives a feel for value in the ensembles. Later, Walt

Decent snow showers here in Wantage NJ since ~120P, mixed pellets and medium sized flakes. I have a video but it doesn't compare to those I saw herein, ~ Dec 18.

Good afternoon this Wednesday January 8th. So, I'd like to add my own view on this minor or nonexistent event for most of us. Just to let you know how difficult the unusual results. Scranton had ~2.5" in 5 hours 5-10P, Baltimore ~1.5" 3P-7P yesterday but the snow evaporated once you got into Sussex and parts of Warren County NJ with only flurries from there into n CT/Ma Pike. The probabilistic guidance graphic yesterday showed no chance of 1" in Scranton. It's imperfect. Ensemble graphics are objective and serve as a check against what the forecaster is otherwise considering in the modeling. EC and NAM/HRRR were worst offenders 00z-12z/7 runs... RGEM/GGEM/GFS generally better and clearly noting the subsidence-evaporation far NNJ newd. I thought the hrrrX was pretty decent. No matter, it's done. (One thing I saw in the NAM 00z-06z/7 runs was an attempt to form an 850 low s of LI. I've seen that model attempt before, and fail with resultant qpf enhancement drained away. With regard to event specific threads... I recommend them to keep things organized and it might actually help a few readers, especially if there is interest to expand. I've added water equiv graphic to show the unusual reality for the 7th. I didn't have a decent snow map to add...but I do know that Carbon County high terrain had ~3" and also Dingmans in Pike County PA 0.9" Walt 08/1803z

Yes, I did mess up the date and thanks for the correction. Have been rather busy-active since those early 7th posts. So far, 0.2" in this part of Wantage NJ from a decent snow shower between 9A-10A. Had a brief snow pellet shower around 1220P.

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.