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Different than the refresher powdery event of Sat Feb 17, and this past Tuesdays Feb 13 wetter snowstorm, it still has possibilities for adding to our winter snow totals with modeled "potential" for half a foot or more for the I84 corridor inclusive of the Poconos-extreme nw NJ interior sections se NYS-CT. Possibilities even exist for an inch or four down to I95 and NYC though for now, odds are less. This could be one warmer more rainy event the 22nd and then a following rapidly intensifying coastal storm Fri-Sat the 23rd-24th. As generally usual higher terrain-inland best chance for snow. A strong short wave in the eastern Pacific this weekend will move through the southwest USA early this coming week and probably be ingested into a series of northern stream Canadian short eaves that dive southeast into Midwest and form a sharp amplifying trough over the northeast USA by next weekend. Details tbd. This probably will be of NYC subforum interest for some of us the next few days as winter potential refuses to go away. Added 10 to 1 SLR, 24 hour 00z/17 global ensembles and the NWS 04z/17 very low chance 3+" snow D6-7, to look back upon when whatever transpires. Title tightening up and downgrade update at 537AM/20. Verification attached for a failed event- useless thread. Numerous traces of sleet -snow-rain mix I84 into NNJ 3P/22-9A/23 but modeled short waves remained separate with one tracking across se Canada and the other actually trailed and dropped down through the Carolines. Was over early per the poster comments.

Hi everyone! Just wanted to get everyone's opinion on whether we could see wind speeds meeting Wind Advisory OR High Wind Warning criteria in portions of SE KY starting Monday night or Tuesday.

The downward slide into winter begins. Post your Obs/Discussions here.

Since we do have a variety of forum posters in areas that will see snow/sleet/ZR - at least initially and on the backend, plus there is a flood threat, along with some potential advisory-level winds and possibly record breaking cold, decided to go ahead and make an obs thread. Currently misty and mostly virga and 36 with dp 32 here in NW Philly.

Well, we are just one season away from winter. Nice to have a respite from the heat this week as the remnants of Ida depart the area. Thoughts and prayers for all of those affected by the hurricane along the Gulf Coast. Rainfall along the far eastern valley has been steady but reasonable - more as you go west I am nearly certain. This morning features light rain/drizzle and very low cloud decks. Lows in the northern valley are supposed to get into the 50s during the next few nights, and that is welcome news! Saw the first evidence of maples beginning to change color this morning. There is this one maple in our neighborhood which always changes first. Some of the dogwoods are beginning to show red in their leaves. Sycamores along the river are showing some yellow. For sure, some of that could be heat stress. Well, it is the first day of meteorological fall. I suspect this season will feature a quick snap to winter time temps late in the season. I am thinking warm early-mid fall, and then a sudden flip to cold. Somebody please fire-up an obs thread and also a banter thread for fall.

I’ve seen discussion in multiple threads, so here’s one for the storm. Should be a good widespread rain across a lot of the area. Tropical storm wind gusts working up the coast. Should be some gusty winds with whatever remains of the core as it moves through the Carolinas and into Virginia. Tomorrow afternoon could feature a tornado threat from the SC low country in NC coastal plain

Low pressure in the Virginia's late Wednesday will get picked up by an intensifying short wave moving east across the Mid Atlantic states Thursday and become a pretty good sized nor'easter as it departs the mid Atlantic coast Thursday afternoon. Does development occur fast enough to bring significant wind driven snow to a part of the NYC forum (rain or snow LI/NJ coast?)? 12z/23 GEFS is fairly robust on qpf, but further south than it's 00z/23 version, while 12z/23 EPS and GEPS are indicating too little too late. One small caveat: the low levels should remain fairly moist after the Tuesday - Tuesday night ( 26th) event (whatever it is) and there may be some advance snow or snow grains/freezing drizzle/drizzle late Wednesday or Wednesday night, in part related to leftover moisture and some sfc convergence. That too is an unknown. Added the WPC day shift forecast qpf and chance of 3+" of snow (darker green). Will update Monday the 25th, when some of the nor'easter threat to our area has resolved itself. Also added the NAEFS qpf... seems a little high near and north of I80 but it could happen. Also added the 12z/23 GEFS 500MB spaghetti for 12z/Thursday.

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.

With La Nina conditions forecast to develop, will be interesting to see the range of observations from the beginning of this thread to the last. An incredibly stormy night has come to an end. The sun is out. Please reference the severe thread regarding the powerful tornado that swept through middle TN overnight. Our thoughts and prayers are with the people in that region. If you are a new poster and not comfortable in posting in the pattern discussion thread, this is a great place to start. Give it a shot!

Hi! Please can somebody explain to me why the falling wind of the Chinook is warmer than the rest of the air near the ground East of the Rockies? I get that it warms back up as it falls from the top of the mountains and does so quicker when dry than moist as it rises on the west side. But how can it warm to higher temperatures than air that is already there? Does it start off that much warmer when it comes from the Pacific? Is there arctic influence East of the Rockies that there isn't West of the Rockies? Please if you know, share your wisdom. I must have read everything on google thank you!

My next post is about the potential snows from Saturday evening through Thursday morning. Models are in general agreement that the potentials for Ocean Effect Snow from Sunday through Tuesday and then storm produced snows from Wednesday through Thursday due to a coastal storm is on the table. However, this post will solely focus on the Ocean Effect Snow potentials. First is the event Sunday through Monday. Mesoscale WRF-NMM and WRF-ARW both support a single band of ocean effect snowfall impacting the region of Cape Cod from Hyannis to Chatham and Provincetown on Northerly winds from 900mb to the surface, which means a single convergence band is more likely than multiple bands of snow which are less intense. These two models keep the band over this region from about 12z Sunday to 00z Monday or later, that is at least 12 hours or more of heavy snowfall over this area of the outer cape, this could produce more than 6" of snow, we will have to see the next few runs until the event starts and then diagnose the real short range models and what they produce. For now the potential exists of a few inches to as much as 6" or more over the Outer Cape Cod area. Stay tuned!

Latest NAM run 00z shows a strong potential for ocean effect snow event from the Cape Cod Canal eastward to Provincetown on northerly winds, also unidirectional wind flow from 900mb to the surface indicates a single band event is probable along with a strong instability burst from 850mb to surface ocean temperature differential (Delta Ts) of 18-20C which is sufficient enough to produce heavy snows over the Cape and Islands. Also the flow is stronger than 10mph which should be sufficient enough for consistent band developing as we transition into a clipper low for the next few days. Big storm potential if the clipper low slows down its movement like the latest 12z guidance suggests at H5 with the low developing and closing off the H5 flow over the Northeast US. This will prolong the snow chances from Sunday morning to Wednesday afternoon for overall snow chances. Stay tuned!