wdrag

I84 corridor is in my mind ~25 either side of entire stretch I84. Scranton to Worcester (excluding CT coast where the 25 mi mark overlaps). Yes se NYS/ne PA. Hope that helps. Have a day.

Likewise, wishing everyone a Happy New Year and to add another topic later today for Jan 8-9. Just need time to think it through. Ensembles are timid despite 00z/1 GFS parallel, EC and GGEM on board. Will probably add the topic this afternoon but leave room for blocking forcing system too far south of us- ie a miss. I don't think it's a miss but I'm sure we can all envision how this might fail. Later, Walt

NY Day 2021 558AM quick update: Extended the event date to Jan 4. Ensembles suggesting a pretty good chance of 3+ inches for some the I84 corridor high terrain in possibly two long duration episodes. A short wave diving into the back side of the initial short wave trough may prolong the event considerably for the New England portion of the forum by forming a a very slow moving upper low along the New England coast. So it's complex but potent, especially if the 850-500 MB lows form in a favorable position for banding on the northwest side of this storm near I84. Just too early to overcommit but this could be a nice snow event for the I84 corridor and as previously proposed (modeled), can't rule out a touch of wet snow on the back side for NYC and especially eastern LI on the 4th. Just too early, especially with marginal thermal profiles and absolutely do not want to buy into any 8" amounts seen on some of the single member operational models for New England, at least not this early with so many differing solutions. If it's progressive and mainly afternoon of the 3rd into early 4th, then the 8" amounts won't happen and this would be an interior I84 standard climo modest event. Graphics is the 00z/1 GEFS prob of 2+ inches for this coming storm-- 10 to 1 ratio. Just an idea of primary risk area. Doubt if I'll comment again on this snowier looking Jan 3-4 event until today's is complete, which means I'll try to add some useful thoughts-graphics tomorrow morning - Jan 2. Have a good start to the New Year!

A routine wintry ice event, that will create some travel problems in high terrain above 1000 feet late today and early tonight, primarily along the I84 corridor.

Happy New Year! No significant change to yesterdays post. This event will focus it's main impact on ne PA, se NYS, nw corner CT into w HFD county and the Worcester Hills, in that order of priority, Valleys in pretty good shape s of I84. A little sleet possible at the start many areas but less chance of a few minutes ice pellets LI. the leading of qpf will increasingly grow sleet to an hour or two duration as it gets into far northern CT and maybe briefly mix snow there with snow on the leading edge along the MA Pike. Main risk of 1/4 inch glaze is ne PA high terrain, Catskills, and extreme nw HFD County into the northern Litchfield east facing slopes. graphics: Orange where best chance of problem icing in WPC ensemble, the second graphic is the SPC HREF ensemble FRAM icing potential=worst case scenario in my mind, showing ridge icing best but amounts may be a touch high? and finally the 06z/1 HRRR snow and sleet accumulator, which I think is a reasonable baseline for this event.

I don't like it either... probably good to wait it out a few runs. On that RGEM, notice the banding developing VT... if it occurs as portrayed... pretty darn good snow rates there. That's a nice signal... maybe it will edge down to I84? Till tomorrow.

I look at every model every cycle through 7 days. I just notice the HRDPS is slightly colder than the RGEM and consistently so. Once the HRDPS loses freezing, then I think the door shuts on new ice...even if there is a 1 or 2 hour delay from th HRDPS time. it has longer duration on western fringe of forum than many models are offering, With a grain of salt... HRRRX has quite a bit of sleet late NY Day...even LI will probably see at least spotty sleet during the first 2 hours of precip. Upshot of all this: a messy advisory cause most don't like ice.. and at night---it's impact is a little larger. I see model qpfs are increasing again. I definitely see whatever sleet-snow ice occurs, having a good chance for sunrise visuals Saturday, before melting increases. Someone noted big ice doesn't occur til we get down into the 20s. I don't have stats on that, but freezing is freezing and the northeast facing slopes will do well... even at 30F. Might even have enugh ice to break some small limbs (1/4")...Cats, Litchfield and Berks high terrain. 33 here at 746PM... wish there was better cold pool to our northeast.

Agreed 100% ... marginal but need to see FGEN mid level convergence near I84. Too early yet, i think. Gotta go. Thanks for the inputs.

agreed on all. Lets watch that HRDPS for ice and see how it goes.

Advisory package (blue) and warnings (pink)...nationally at 355PM.

A couple of graphics: SPC HREF icing potential... probably overdone.. but as fwiw worst case. and the WPC ensembles for .01 icing. That latter I like. Please use legend for pops. I won't comment again on this til tomorrow morning at which time I'll set up the wintry elements OBS page for our W and N suburbs folk. Happy New Year!

I think you're all on it...elevation dependent amounts..on the boards for potential of several inches high terrain snowfall...slushy 32-33F. Long ways to go. Not getting excited about NYC. I just know that everyone is primed about mid month potential... however, this one is the first decent snow attempt in a while along I84 and lets see if we can this one first. WPC latest 17z ensemble probs for 3" or more of snow. I won't comment again on his til tomorrow morning.

Have noted a few posts noting the blocky and possibly more favorable pattern the 8th-15th. No topic yet. Kind of want to clear the table of 1/1 and 1/3-4. I do see the potential... definitely would like a freshening of a colder boundary layer. If we can't deliver something decent in this pattern the next several weeks... At least there are some marginal wintry threats.

I agree with prior posts but also limiting my enthusiasm due to marginal thermal profiles. Sort of want to clear the interest for 1/1 night event. After review of the 00z/30 and 00z/31 cycle-no changes. Best to keep options open and look to the I84 corridor as most likely area to see some snow. Marginal thermal profiles the continuing concern. 00z/31 ensembles are growing qpf... but surface and upper lows may be too close to LI/se MA for much snow in the NYC subforum. This looks to me to be mainly an elevation I84 corridor wet snow concern. I cannot commit any further details - just too uncertain and that uncertainty may continue another day or 2. Far from an ideal snow event, but also the typical winter uncertainties for our area. Forward we go... worthy of monitoring. 515A/31.

12/31 5AM Update: Little change from 12/30 603AM. Timing the start probably closer to the end of the ranges listed below, and emphasis for event beyond 3 hours is for the terrain above 1000 feet. Snow, if any, is less than 1" far northern edge of the forum, but sleet a possibility at the start in many areas. Probably worth tracking wet bulbs for this mainly at night event... think it suggests longer duration than meets the eye but the model dew point forecast may be too low. mPING will be of value. Valleys, below 700 feet should have mainly wet roads after initial treatment and possibly the same higher up. Worthy of caution and best we can do for marginal thermal profiles. It should be noted that the NAM3K is trying to hold onto icing into the Saturday morning daylight hours highest elevations northern fringe of the NYC subforum - that may be an outlier but not impossible.

You're probably right. Yet, this may be getting tricky. 12z EPS starting to favor low pressure development along the SNE coast, with 1 L nr LI by 12z/2...and certainly baggy suggestion of a warm frontal wave going s of LI. Fortunately qpf should be less than 0.8" but the 12z V16 and 18z NAM look a little reluctant to warm up and I can see that due to very little sfc wind over I84 due to 850MB jet splitting N and S. 18z/31 NAM doesn't get temps out of the 30s prior 18z Sat... will have to presume that's wrong and too cool, but interesting. Even the 850MB wind near 06z/2 is lightening up and bending to s late at night., favoring a little better chance of CAD, already seen in the swwd ridged isobars across I84, Tomorrow's HPC HREF may be of interest for this probable light weight hazardous interior icing event. Blocking seems to be helping. Not a big deal, except for the unprepared stepping outside. Later, Walt

Not sure what the JB tweet was about??, but probably didn't cover an overlooked narrow band of 1/2"+ period of heavy rain Thursday, somewhere near I-195, to nr southern LI. Just don't think we can abandon adding up rain qpf the next 6 days in our area. It might yet have some minor impact on small streams. Have a day.

Good Wednesday morning nw suburbs: NWS has an advisory going for parts of the area tonight. from my perspective Tonight-early Thursday: I84 corridor high terrain only. A bit of ice possible in the Poconos se NYS high terrain above 1000 feet toward midnight that changes to maybe a slight covering of snow early Thursday: Less chance of this occurrence CT/MA high terrain but possible there above 1000 feet, mainly early Thursday.

12/30 603AM from the topic update: QPF down to .4-.8" for the forum for this event, and slowed a touch from yesterday. Otherwise my concerns have little change from yesterdays 12/29 reassessment. This event will be a problem for the Poconos, interior se NYS high terrain with less qpf and impacts for the CT River Valley, but otherwise I84 high terrain should do okay. Sleet or freezing rain develops ne PA/nw NJ (maybe even down to I78) between 2-5PM and probably changes to non freezing rain during the night all, except elevations above 1500 feet where it may be freezing rain throughout. Since temperatures will be briefly above freezing prior to the event - midday Friday, icing on treated roads, after initial treatment will probably be limited, but otherwise all untreated surfaces become icy, especially after sundown. Expect a slight glaze on untreated surfaces near I-78 (Easton PA, Warren County NJ) ranging up to about 2 tenths of inch above 1000 feet northern Sussex County NJ (northern Wantage-High Point-Vernon) and ne PA. Meanwhile, N CT and interior MA should see sleet and snow develop between 5-8PM Friday, with a possible 1-2 inches before a change to ice, and then probably non freezing rain after 2 AM Saturday. Glaze there a little less than ne PA. CT River Valley should see less impact due to near freezing temps. Boston: a little sleet/snow Friday evening then changes to rain or freezing rain during the night with much less certainty there on details. After sunrise Saturday, melting and improved weather! We'll start getting some short range ensemble guidance tomorrow morning that will help us detail impacts. Hopefully this is a reasonable assessment as presented above. I prefer not to comment again on this event til Thursday morning as model variations may skew me one way or the other, too soon. Have added one graphic- 00z/30 GEFS chance of 0.1" glaze.

After review of the 00z/30 cycle-no changes to the topic. Best to keep options open and look to the I84 corridor as most likely area to see some snow. Agreed with the prior member posts... I too am concerned about the latitude of the closed low aloft. One thought--- as many have probably noticed...models are trending a bit further south and slower for 1/1. Suggests to me blocking is playing a role. That should occur again 1/3 and force a slightly further south track of the 850-700 low than what we're seeing through the 06z/30 cycle. Lows aloft might develop too late to be significant for our subforum. However, for now, I do think the vertical 850-700 low development will occur in time, and if you use the 90L of 850MB low rule for max snowfall, I'm looking at I84 or even MA Pike (presuming thermal profiles allow for snow soon enough). I prefer not to reassess - comment on this storm again until Thursday morning, since models will have differing solutions and just want make small adjustments this far in advance. Plus 1/1 is the first order of concern.

As these systems for 1/1 and 1/3 head our way with variable solutions, at least they are wintry for the interior part of the forum. Here's maybe an eye opener ensemble look the 18z/29 GEFS 500MB for 18z/3. With above normal SST just s and e of LI... I now like our chances for an equally sizable event compared to 1/1 and bit colder... how much is snow (wet snow-elevation dependent?) is a question. I did see the 18z GEFS QPF ens come up similar to the 12z EPS. Unless the modeling fritters on this trough, I see this system as likely looking more robust in future ensembles and probably one of our routine late developing nor'easters, strongest winds e tipLI.

January 2, 2021 605AM Update: Am probably not commenting for our NYC forum on anything beyond 9AM January 4, which is about the still possible extension for eastern New England. That part of our oncoming light to moderate Nor'Easter snow event for the entire I84 corridor, will not happen for us. The remainder of the NY Day comments below seem reasonable. My anticipation is a widespread plowable 2-6" elevation dependent snow event from I95 northward through the I84 corridor and probably I90 eastern NYS and northern NJ/ne PA eastward through southern New England. I-84 valleys will manage this better because of marginal melting temps (32-34F) and the southeast edge near I95 will also be manageable, in part because a little rain/freezing rain/sleet is possible there. as well as the daytime temps near 33F. So, it's a mixed bag but the I84 corridor should enjoy this, with the primary event mainly Noon Sunday-6AM Monday. This storm will probably affect some of the return home holiday travel and also may force some Monday morning 2 hr cleanup delays, especially CT-MA portion where it still may be snowing a bit. NYC-LI should see a touch of snow/sleet but whether it measures or not and where, i don't know. My guess is eastern LI may do a little better and thats where there will probably be some wind gusts to 35 MPH but NYC might also see less than an inch?? There will be 1 or 2 brief periods of moderate snow with this event, but I'm not thinking of more than 10 to 1 snow ratios, possibly only 7 or 8 to 1 near I95. Will begin the OBS/NOWcast thread later tonight. Earliest part of snow/sleet/very brief ice arrival is around 8A-10AM Sunday for our NJ eastern PA membership. I don't anticipate adding any further potentially helpful information until maybe this evening. Noting the WPC ensembles for more than 2" are not very enthusiastic for this event, so we need to keep in mind failure. They also weren't as enthusiastic as they should have been for glaze this past night and the SPc SREF did much better. It already has 2-4" in ne PA by 7PM tomorrow night. Keep an eye on the SPC HREF MEAN snowfall after the 12z/2 cycle completes around 1030AM. The HRRRX was all over the place for this freezing rain/sleet/snow event that is wrapping up now and am not referencing it today. I as others here , like consistency in the modeling. One event at a time. NY Day 2021 558AM quick update: Extended the date to Jan 4. Ensembles suggesting a pretty good chance of 3+ inches for some the I84 corridor high terrain in possibly two long duration episodes. A short wave diving into the back side of the initial short wave trough may prolong the event considerably for the New England portion of the forum by forming a a very slow moving upper low along the New England coast. So it's complex but potent, especially if the 850-500 MB lows form in a favorable position for banding on the northwest side of this storm near I84. Just too early to overcommit but this could be a nice snow event for the I84 corridor and as previously proposed (modeled), can't rule out a touch of wet snow on the back side for NYC and especially eastern LI on the 4th. Just too early, especially with marginal thermal profiles and absolutely do not want to buy into any 8" amounts seen on some of the single member operational models for New England, at least not this early with so many differing solutions. If it's progressive and mainly afternoon of the 3rd into early 4th, then the 8" amounts won't happen and this would be an interior I84 standard climo modest event. Graphics is the 00z/1 GEFS prob of 2+ inches for this coming storm-- 10 to 1 ratio. Just an idea of primary risk area. --- Uncertainties exist including how much deepening and track for NYC subforum qpf, timing thermal profiles for phase change to wet snow. Looks like it will happen despite GFSV16 dropping it in recent cycles. EC has been on it for 3 successive cycles (prior to the 00z/30 cycle) and EPS now throwing out decent qpf (still does with the 00z/30 cycle) and a bit of snowfall all the way down to LI (questionable but could occur late in the storm and not be much...but??). 12z/29 NAEFS has it a little and the fact that the 12z/29 GGEM lit into it, also the 12z/29 UK, should be enough for us to give it a good chance to produce snow down to at least the I84 corridor. Others have been wanting a topic to track the models etc for this increasingly likely Sunday January 3 potential nor'easter. The initial precipitation (rain) from this initially weak Virginias low pressure system could begin after sundown Saturday Jan 2, as rain. As it intensifies and 500 MB heights lower, the combined lift, cooling thicknesses plus north-northeast wind advection of somewhat colder boundary layer temps southward, should change precipitation to snow along the I84 corridor by early Sunday, and possibly down to I95 west and north of NYC by nightfall Sunday? Rain over NYC and LI possibly ends as a bit of snow later Sunday or Monday morning? Probably too early for all this scenario detail but it's based on the 12z/29 NAEFS, EPS, GGEM, UKMET. No snow amount forecast though it appears that elevations should have highest accumulations, presuming it does snow. Snow looks to be slushy during the daytime and generally controllable for road crews, especially valleys, since daytime melting of any snowfall would occur during periods of lighter precipitation rates with marginal temps of 31-34F. LOW chance paragraph but reserve the option to increase IMPACTs of wet snow, add a small chance of gust 50MPH LI and minor flooding for a couple of NJ/PA rivers based upon the already anomalously wet December, plus future unknown qpf's from Jan 1 and 3...IF qpf up to I84 increases to 3/4" and mostly snow along I84? This is unlikely for now, but could happen, especially in the deformation zone if a closed low to 700MB develops near LI in this positive tilt trough. After review of the 00z/30 and 00z/31 cycle-no changes. Best to keep options open and look to the I84 corridor as most likely area to see some snow. Marginal thermal profiles the continuing concern. 00z/31 ensembles are growing qpf... but surface and upper lows may be too close to LI/se MA for much snow in the NYC subforum. This looks to me to be mainly an elevation I84 corridor wet snow concern. Definitely cannot commit any further details - just too uncertain and that uncertainty may continue another day or 2. Far from an ideal snow event, but also the typical winter uncertainties for our area.

Starting a topic by 3P for late Jan 2-early Jan 4. Just need a little time. Looks like it will happen despite GFSV16 dropping it in recent cycles. EC has been on it for 3 successive cycles and EPS now throwing out decent qpf and a bit of snowfall all the way down to LI (questionable but could occur late in the storm and not be much...but??). NAEFS has it a little and the fact that the 12z/29 GGEM lit into it, also the 12z/29 UK, should be enough for us to give it a good chance to produce snow down to at least the I84 corridor. Walt 220P/29

fwiw: This is probably sleet or ice mistakenly 10 to 1 snow ratio, but UK seemingly coming on board for Fri afternoon-night.

Yes... just hope it's consistent. will recheck everything at 4P and finally set up Jan 3 at that time GGEM and UKMET are now on abord. Hope the 12z GV16 comes back, and Euro stays on it. Thanks for all the posts. Suspect will favor I84 for primary now event but may allow for closer to I95 option. Need more thinking time.