wdrag

Posts on p38 (This one) are helpful for me and it is an interesting time. Not to go against anyone, but I'm thinking we are tending to expand the database with more extreme weather the past couple of decades here in our forum. I might be wrong on this and will listen to counter science. This could be related to the warming (cycle) planet. Have appended several graphics to ensure everyone has seen this and has an idea in advance what is ahead (flooding? but if we're lucky, some spring snowmelt for the reservoirs in April). Also, there is anecdotal evidence (unsure of the science research on this) that the southern edge of the snowpack tends to set up the warm fronts and future low pressure development (easier in warmer air with northward advance of warm fronts often slowed by the colder denser surface air associated with snow cover). Didn't add snow density because I don't understand the numbers and how they relate to impacts but I think it may have to do with difficulty passing through (walk, transportation)and/or removal. If there is a link--- please add on. Thank you.

Good Friday morning everyone, I hope this is a snow satiated group this morning. I think more snow is coming for NYC this December. I posted event options for the I84 area in our nw - ne suburbs thread. I am thinking of a storm thread for Christmas eve-Christmas morning- but think it best to wait until all the 12z/18 guidance (ensembles too) is in. Even the 21st looks interesting to me for NYC/CT. The thread for the 24th-25th would be along the model lines you see now. Big snowmelt (virtually all melted se of I84) by rain and a brief southerly flow warmup. Damaging wind potential e Li (already ~40% prob of 50 MPH gusts from the 00z/18 GEFS), then cap it off with a 1-4" backside CAA snow the morning of the 25th. These backside snows are not easy to attain and uncommon (long shot in the coastal plain). Temperatures will dictate remaining snowmelt on the 24th, but if it's rapid and we get 1" of rainfall on top of the 1" snowmelt water equivalent in 12 hours, we might have minor flood problem?? Again, a long shot per current guidance with so many variables to consider. The main thing, we continue in a highly amplified pattern with 'overall' near normal temps the rest of the month. Have a good day.

Just a tease: May have a topic started late today or tomorrow morning (Christmas eve). Sunday: A pretty good chance for a period of Trace-3" snow I84 high terrain. Monday the 21st: Right now models have a storm just offshore. This could end up closer, bringing a hazardous snow event of several inches for the I84 corridor, especially CT/MA. Christmas eve into Christmas morning: Definitely a storm coming. It could be mostly heavy rain melting our I84 snow pack Christmas eve with a quick coating of 1-4" in its wake Christmas morning. Monday the 28th: another opportunity for wintry precipitation. One event at a time. Have a good Friday.

You may be right... I don't know. What I do know is that anything beyond two weeks with reliability is not easy and I myself, while I look to our long rangers for hope (or lack of), I don't think we yet have a good handle on the multiple influences that carve out a season. So, I'll continue to pay attention but I'm not confident of anything beyond 11 days.

Unsure whether we return to La Nina base state before January at the earliest. Too much -NAO and hints at occasionally Positive PNA and from what I can see in the NAEFS, winter storm possibilities 21st-30th, special emphasis on the 24th-30th. Too much general blocking potential and jet modeled almost constantly south of our forum with a trough in the east. Doubt very much whether we can get something close to what just occurred the 16th-17th but I don't think we're done with snow this DEC in NYC. Since it looks like the sample size for LaNina behaviors has been expanded in Dec, what might we think about for JFM? Thanks, Walt

What am i to make of the continuously decreasing negative 3.4 Dec anomaly? and from what I can tell MJO influences may be weakening toward the end of the month? Any implications of both changes on winter snow here? GEFS seems to attempt a +PNA toward the end of the month and continues some sort of Greenland + anomaly. Just seems like wintry options may still be on the table? Is there a different read? Thank you very much for any reply, Walt

Will post two topics by 815 PM. Both shakey but there is so much interest in winter that I think there is enough model evidence to get something out there.

I just checked for myself. I don't want to waste forum time on a 1 inch gust 45 MPH routine event. However... I or yourselves can post a thread topic. I just need to build some confidence. It's been on my radar but I'm not willing to commit a thread this far out.... looking at marginality for the NYC forum-mainly I84 corridor, but certainly potential, any, date 16,18. My first interest lies in a possible (12z/8 GEFS 50% chance) first T snow (if ASOS sees it as snow), lower prob measurable (0.1") CP sometime between 10A-2P Wednesday 12/9. Normal first date of measurable in the entire CP (thread X) database is around 12/7. With hope... but not necessarily science yet.

Wantage NJ had a few flakes prior to 650A. Outlook: No snowstorms prior to the 16th. Wednesday 4AM to 2PM: A band of decent snow or snow showers lasting an hour or two will pass southeastward through the area with 1/2-2" Poconos but generally a Trace to 3/4" elsewhere. Might be a brief untreated hazard prior to 10AM. Wed-Sat 16th-19th: Might provide a small amount of marginally hazardous snowfall north of I84?? From two separate storms.

Yes but lapse rates were MUCH MUCH steeper and as i recall there was a decent surface trough.

Warmer than normal DEC here... i understand... Still, something not fitting all the negatives on snow. I could be wrong but this not last winter. Seems to me modeling is hanging on to weak blocking in the N Atlantic for many days, and I see a ridge in AK for awhile (7 more days) and an undercutting Pac Jet. This may provide for more opportunities beyond the 16th? I see the MJO indicies are trending weaker with time which may be a climo bias? I know the modeled MJO phase is not favorable for us, but I am interested in this pattern... I just dont see cold air ripping off to the east in southern Canada as easily in the GEFS dailies through D16 (laying in wait for something in the southern stream?). Again a GEFS blocking bias? And yes, it's nice to have cold air in place PRIOR to a precip event. Critical science is needed here to void my snow interest beyond the 16th. Have at it. fwiw...i checked CP first measurable snow date in xmacis... looks like Dec 7 (today) over the entire CP climate history. Monitoring Wednesday's 12z/7 3K NAM forenoon snow shower risk (probably melt on contact?, but of minor interest). Lapse rates don't look all that interesting... sort of surprised by the modeling of snow showers down to NYC at ~54 hrs.

From what I can sense through 00z/2 ensembling... it looks like there is going to be a cold intrusion next week into the northern tier with the next large scale storm toward the 14th (after this weekends). After that... no super warming immediately modeled prior to the 16th. However, it is LaNina with AGW. I might be seeing some sort of blocking trying to get going up by Greenland. Unsure if that is going to occur.

I'll post a new topic for Friday-Sunday dual event ~5P. Confidence is much much lower than the topics of 11/11-15, and 11/30-12/01. Ensembles are not as favorable for verifiable flood warning, wind advisory or greater, with maybe theist v reification possibilities - the I84 corridor having winter hazards (some ice or snow). Basically, if the 12z/1 EC op didn't do what it did today, I would have held off til tomorrow or beyond, to be more sure.

Hi! I want to think things through before probably posting a topic at 5PM, including check of 12z/1 ENS (GEFS/EPS/NAEFS) upper air patterns and the 850 wind flow. Modeling is favoring another storm of power outage potential (wind, perhaps 4+" wet snow extreme nw fringe of our forum with backside wind gusts 40+ MPH) and travel issues for late Friday into Sunday. Unsure how it evolves... NYC probably all rain til flurries at the end...I84 more complex. EC wind gusts 50+ now both front and back side for portions of our forum so power outages may not be much worse than yesterday but still a consideration. If the storm runs slower and max easterly inflow is midday Saturday, then a tidal flooding problem would develop. Thanks for your patience.. Walt 156P.

Yes, though I'm not quite sure if this intensifying trough will close fast enough (PA) before reaching our longitude (LI). BUT.... the backside wnw wind cold air advection(CAA) might provide at least 40-45 kt (wind advisory) gusts... possibly higher, depending on cloud cover and lapse rate... It's usually bit easier with 50-55kt 850MB winds to transfer in CAA during the day, whereas to have yesterdays southerly WAA wind, you tend to need 70+ knots at 850MB.

It's a member but I think its far too slo.

I corrected my prior RMOP post with adding the proper previous cycle forecast for 00z/7 as the 3rd frame. Now you can see the difference. Also put it in here... Finally...here is the 06z/1 500 MB GEFS. Pretty confident membership on something sizable PA or NYS (upper low) for 00z/7. Which is it? north of us...probably, but I think there will be a triple point low off NJ.

Of interest to me and for I84 northward winter weather interests. Note the side by side forecast for 00z/ 7 RMOP confidence (for Sunday evening). Two things... heights are 60 meters or more deeper on the 1/00 run than that of 00z/30. Two: vort max passage s of LI and likely triple point low s of LI... and position of the trough. This increases my confidence on a sizable event and winter weather down very close to I84. added the 3rd frame...the side by side of the previous 11/30 cycle for the second frame, same time. Now you can see.

Good Tuesday morning everyone, Dec 1. You may be in the mix for some ice or snow this weekend... marginal chance, but I think some ice or snow is possible. Please see details on the December topic 544A post. I'll shift everything here in the future, IF NYC is completely out of tail end trace snow and we are still in the mix. Probably won't happen til Thursdays posts.

Good morning everyone, Tuesday Dec 1! No topic yet... but the 5th-6th -possibly into early 7th, looks like a rain storm for most of the forum but may have a little ice for the nw edge of the forum I84 region, ending as an inch or two of snow, especially later Sunday the 6th. Overall a short wave dropping south in the Rockies this morning closes off and marches east this week, opening up a little over the Midwest then closing as it goes by LI Sunday with a surface low modeled-ensembled through PA-LI, intensifying as it moves to the northern New England coast late Sunday or Monday morning. NAEFS 52 member 500 MB heights are modeled to deepen 120 meters/24 hr period between the 5th-7th with the 500 MB vort max of the deepening 500MB system crossing NJ Sunday. The 00z/1 EPS does not have this, leaving too much of the lead short wave behind in the sw USA. It could be right but I don't think so. I expect the future EPS to gravitate to the GEFS/NAEFS solution at 500 MB. New 00z/1 RMOP not yet available to do a reality check. So, despite the 06z/1 GFS OP run, I think this deserves some monitoring - just can't topic it yet due to less severity, wind and storm totals wise, than what occurred yesterday-Nov30. Snowfall, mainly nw edge of the forum---IF that far south. I am looking at it carefully. As many will say, probably not much if anything wintry up there near I84 but I'm not so sure---certainly can see a period of hazardous minor ice or snow. 544A/1

Need to refire my engines Wednesday morning looking to between the 5th and 8th, seeing if there is any predictability, and.... close out the wind/rain topic (ending as snow Poconos).

We'll monitor with some interest the 5th-7th... especially hilly nw suburbs... as all have said, doesn't look good for this one in the city. One event at a time...

Adding one 00z/29 GEFS RMOP graphic on next weekend... door not closed. Confidence on trough axis but not the trough strength .. note confluent flow to our north. While it may be rain here, I'm looking for a decent storm to eventually re-evolve northward.

fwiw... EC starting to sit on a similar Monday-Tuesday event for this next weekend in our area, including similar event snowfalls... which if the EC is correct will offer spotty 2 feet in a part of west or northwest OHIO. One event at a time... I want to see how this works out here on Monday before starting something for next weekend.

First, I want to thank all the posters insights on modeling from LR to climate stats. Very helpful perspectives and I learn from this. Thank you! On Dec 4-6: No topic since considerable uncertainty ranges from 00z-06z OP runs of major snowstorms from the the Missouri Valley to the northeast USA and/or all rain. And the 850MB inflow is not as strong as that of this coming Monday, but broader and longer-which serves well for heavy precip event. I root for the 06z GFS op... but... its D9-10, not in my window of confidence. GEFS RMOP has a positive tilt trough over the eastern USA with uncertainty, while it is categorically confident of the 500MB ridge axised n-s ~115W. The one change in my thinking from previous days... a decent storm event is coming between Dec 4-6. What it is?