wdrag

Very icy here in Wantage NJ...post is in NW suburbs thread.

Wantage NJ 8 S High Point NJ Icy all surfaces... soft ice on asphalt but this will surprise some folks. 0.05" of freezing rain since it began around 10P. 31.1F here. Dewpoint about 30. Thanks Walt Wed morning Dec 22 1246AM.

No sure if anyone is seeing mping reports to our southwest PHL area to near DC with spotty freezing drizzle, ice pellets and snow? Not sure about the snow but an interesting night for ice is coming I think for nw NJ.

fwiw... I think we're going to see an ice problem tonight in spots vcnty ABE-12N-BAF, cities excluded but rural areas not. Already 32.4/23.8 at 515PM here at my house in Wantage and have noticed models trending toward more ice. Presuming it -precipitates here between 05z-15z... then I think the RGEM is on it. daytime cycles HRRRX, HRRR, EC/GFS all slightly colder. Just a matter of qpf occurring. No thread: all the ice obs can be placed into the nw suburbs thread.

No thread for tonight or Christmas eve early morning... but may eventually begin OBS thread if anything looks more certain for near NYC, otherwise suggest the freezing-frozen are tucked into the NW-NE suburbs thread. This is my take upon looking at multiple model output: Best chance tonight for ice is interior MA, if precip occurs there. HRRR, SPC HREF, HRRR X favor up there. However, some other modeling allows for spotty icing all the way down to near I95 in NJ. RGEM being one of them. Because of this I add the NWS 10z ensemble for chance of spotty icing tonight---LOW chance but not zero. The period of light snow risk (less than 1") continues for Thursday night-early Friday but it too may be a non player in NYC. That's not much winter, but something. My last on this til after 5P. Have a day!

fwiw: 18 EC has spotty zr now expanded west to extreme nw NJ early Wed, and then this attached graphic is a sampler for early Christmas Eve morning... ie colder solution than the 12z counterpart and more in line with the GFS/GGEM. Whether this holds or not??? Will monitor for flurries or a period of S- into NYC around daybreak Friday (melt on contact NYC, mood snow nw of I95).

So, if I review this correctly, the southern stream is INACTIVE, lighter than normal flow along roughly 25-35N in the Pac through to the ATLC, but above normal speed Aleutians to the Canadian USA border. IF that's a correct read, I want to be looking for a strengthening of the jet near 30N, which if this were to eventually occur with a WAVE breaking ridge off the west coast, our chances for something in the southern stream would increase with eventual -NAO cold air damming (CAD) benefits. For now as I see it, we just cant tone down the strength of the short wave jet stream energy packets (500MB vorticity centers) in the northern USA. Fingers crossed that there is so much we don't know, that this pattern will eventually evolve-respond to permit at least 10" of seasonal snow in NYC and 25" out here in nw NJ. Those are my goals now... which I hope we can achieve by March 15 2022.

Thanks Don... !

Positive snow depth change all related to the 24th-25th... one cycle GFS change... just aint easy to rely on single member guidance beyond a few days. This is about 6-8 days away and big snow on 06z cycle for MA has shifted north on this 12z/19 GFS cycle.

I've seen a lot of references to the fast Pacific flow. Can someone point me to a chart that shows the previous 4 weeks of anomaly that is referenced. 200MB? 500MB? Thank you.

Probably a good time for me to chime in.. I originally, when it first came out, was favorable to the CFS but in the last year or so, I do not see any value in relying on the CFS for any range in winter. If someone has stats that oppose my impression, let ir rip. Thanks, Walt

No thread at this time for sleet down to I80... if need one, will add in the on-going 6am time frame. Models have generally warmed a bit since this time yesterday.

Good Friday morning everyone (Dec 17). Focus I84 corridor high terrain Poconos through northern Sussex County NJ into the hills of CT and much of MA. A period of hazardous ice on UNTREATED surfaces is likely Saturday, mainly elevations above 700 feet, and possibly restricted to elevations above 1000 feet. That leaves out the valley region along I80 (Warren County and Easton PA). Other elevation details to be determined. A sleet-rain mix will develop by dawn Saturday in the Poconos, nw NJ and se NYS then quickly spread across CT and MA as a sleet-snow mix. It all gradually changes to freezing rain for the elevations during the day and plain rain valleys. Most treated surfaces should be okay, but be cautious early in the day, especially elevations. Snow sleet totals, less than 1" MA (Turnpike) and extreme northern CT with maybe a tenth or two of sleet possible down into the Poconos - extreme northwest NJ. Icing totals in the highest elevations above 1500 feet should be less than 2 tenths inch. Attached a NWS ensemble chance of icing issued just before 5AM this morning...see the legend for your area of interest. As you can see...this is marginal and the best we can do for this slow start to wintry precip here. 622A/17

Depending on future modeling I may begin an OBS-NOWCAST thread for I80 north Friday evening: for a little mixed freezing precip starting Saturday morning trending to freezing rain high terrain north of I84. Maybe extreme n CT gets lucky and picks up an inch or 2 of snow-sleet Saturday, but I 84 itself should be 1/2" or less of any frozen, even if it ends as light snow Sunday morning. If the models drop extreme nw NJ and even LI from the icing mix at the start, then I'll refrain from a thread and all the obs can be tucked into the nw suburbs. Just a late start to winter.

Good Thursday morning everyone, It is Dec 16. I'll follow up this post Friday morning...for hazardous high terrain ice Saturday, especially the morning along and north of I84 from the Poconos through extreme northern Sussexn County NJ to the hills of CT and much of Massachusetts. The attached graphic shows the chance of icing-see the legend for your area. It's just a heads up for some 'possible' untreated surfaces slippery travel for a few hours. Maybe a scenario of mixed sleet/snow to start, changing to freezing rain for a while. Most of the snow threat is extreme northern CT northward. Have a good day. Walt

So attention is on the Plains-Midwest. Understandably. Locally, not threading the coming weekend event along or just n of I84 due to membership being fewer up there but may start posting on nw suburbs thread tomorrow or Friday. EC keeps chilly air along the I84 corridor while all other models much less so. Could be a winter wx advisory event up there Saturday afternoon into early Sunday for sleet/zr- maybe even a little snow, possibly ending as rain (hilly terrain especially). Again, I do have some concern about the EC being too cool. 09z/15 SREF is not as cool and more like the somewhat milder GFS. So the 11/28 and 12/8 threads while minimalist snow, at least were something, compared to what winter elements we've had since, and sort of what it looks like for a while longer (to me: no future multi model agreed snow dates for the NYC area, at least not yet). I like the -NAO but not sure it will be enough to give us much more than what we enjoyed 11/28 (-NAO) and 12/8 (neutral NAO). What i want to see is some southern streamers get drawn newd into the -NAO pattern. So far, seems difficult.

The following locations experienced 40 knot or greater winds generally near or after squall line passage. HPN 41 POU 40 EWR 41 Below: Anemometer heights may not meet NWS criteria in NJ Brick IN NY Bayville 50 Eatons Neck 62 Great Gull 44 Bannerman Inland 41 (Hud Rvr) Jones Beach 46 Great S Bay 44 Fire Island 40 East Moriches 41` Shinnecock Light 45

Adding on: I expect that more data verification will have to be added to local storm reports today. I just saw two reports of 50 knots nw LI via Weatherflow, also lower Hudson Valley a number of reports around 40 knots. Staffing may be a reason why the data has yet to post. I can list the stations if needed. 544A/12

While not all the data is in as of this 536 AM Dec 12 writing, our area basically didn't have advisory criteria. Squall line was less focused than I would have wanted (narrower line with spotty high reflectivity), possibly cut off by the Delmarva line that had developed earlier around 6P. There is some spotty power outages in our area, most of it northern and western fringe near I84. Definitely not the magnitude of a couple of early Dec events. Meanwhile north of I90... good luck with the recovery, especially northern NYS. Ditto our tornado ravaged mid Miss Valley-lower Ohio Valley region.

Everyone has noticed the spotty lightning from the Catskills to NNJ since 830AM.?

I am dropping the following on the forum: Let's see what happens. This includes a new tool I will reference in the future... Imperfect but it coalesces some of the finer high resolution guidance into a general solution for forecaster applications (Neural Networks). 1) 12z/11 3K NAM position of the squall line at 10PM. 2-3) Neural Network (NN) info 4) NN prob of severe today 5) NN prob of 50 KT gust 6) NN timing of event within 2 hours. 7) 12z HRRR 2-5K max updraft helicity. Suggests my earlier concern for TOR was too far north. Overall I may be an hour fast on the more ing timing. Nothing else to share.

So OKX and BOX joined the wind advisory previously issued a day ago by Mt Holly. SPC has no change from yesterday in it's outlook. A squall -fine line of briefly heavy showers is continuing to be modeled by the HRRR as of 5AM this morning with the primary time frames for passage roughly 7-830PM ne PA, 8P-930P NJ/se NYS, 9-11P CT-NYC, 11P-1A BOS-E LI. Modeling continues as posted yesterday... This is the same system that has caused all the fatalities upstream in the Ohio Valley, but in lesser severity here. Not impossible to see a TOR central NJ approaching NYC this eve, per HRRR 2-5KM helicity but probability quite low as of early this morning. There are some parameters that will need to monitored for increasing their values in future modeling for this to become a greater risk. I will probably be off line at times today, though I'll monitor-especially this evening to see what occurs.

Good Friday morning everyone, A consistently modeled 970s MB low moving into southeast Canada later Saturday will develop a strong low level 55-70 knot 850MB southwest jet ahead of it and a period of 50 knot west-northwest dry cold advection 850 MB winds behind it. A dying squall line is possible with the cold frontal passage Saturday evening. SPC has a D2 marginal risk for severe. Much of the guidance has near 45 MPH wind gusts for a fairly large portion of our area along the front with potential for pockets of 50-65 MPH gusts accompanying the squall line (could be just heavy showers and no thunder). This event should be a little more widespread than the previous two early December events. Mount Holly already has a wind advisory posted from 1PM Sat-1AM Sun. In advance, there could be isolated gusts 45+MPH during the afternoon in rather warm southwest flow but the main show should be with and just after the cold frontal passage-gust front during the early night, beginning over the Poconos around 6PM and sweeping east of the Twin Forks by around midnight. At least spotty tree-powerline damage should occur. Courtesy to the the NWS and Pivatol Weather for their graphics (SPC D2 outlook) and the (ECMWF sounding near LGA at squall line passage - a bit isothermal in the boundary layer which is a possible hindrance to transfer). Title: added OBS-NOWCAST in front of the previous title at 636AM 12/11/21.

I'm counting on all our long range specialists to not bury ourselves in short term ugliness and be unable to extricate later during the winter. I'm seeing the gamut of no winter, to more favorable winter opportunities after Christmas or January. I don't know, except we'll probably need something to jar the pattern into something that will be a broader snowy impact along and north of I80. Meanwhile, am holding off on a wind thread for Saturday afternoon-early night. Will check SPC D2 tomorrow morning, as well as HRRR/NAM. Many models have near or greater 64kt at 850MB in the Saturday afternoon WAA and 50+kt in the evening CAA. Both a little stronger wind fields aloft than what has occurred in our last two minimal wind events of early Dec. I'll want to be a little more certain of momentem transfer, so will try and figure it out early Friday.

The gist of the snowfall yesterday is in this CoCoRaHs map. Not shown are the icy conditions that followed after clearing set in during the night with subfreezing temps. Just about everyone had measurable melted w.e. as per the latter two maps. Click each for clarity. CP 0.04 includes T wet snow. You be the judge of the modeling and results of the original modeling prompt. Not a whiff but less qpf/snowfall than desired but the general idea was there well in advance. Best short term modeling was the HRRR and HRRRX followed by RGEM/SPC HREF, NAM 12k (NAM 3k was far too conservative). Not sure what the GFS was thinking from start to finish.