wdrag

Hi! I just saw the D10 comparison. Both 240's look similar to me... all you have to do is raise height a little on the GEFS to show the positive anomaly but 500 pattern looks similar to me. Regarding the upcoming: I am hoping my scenario below works out. Thinking we are going to see two upper lows come Friday the 23rd...one Great Lakes and one crossing PA/NJ before they merge north of us in Canada on the 24th. Some of the modeling may be putting too much stock on the lead short wave developing the midwest low. Expecting just like this last one... an upper low developing on the eastern flank of the 500 trough. Added this mornings analysis as an example of evolution except this one further south by 1-3 degxrees latitude. Suspect, the upcoming system is going to dig more than that of the 15th-16th. That doesn't mean Long Island will see much if any snow but it does allow for further east wintry weather just inland. I will be looking for future 12/18-19 cycles of the EPS and GEPS to start losing the intensity of the upper low attempting to bodily develop in the Ohio Valley--instead permit an eastward extension. IF all the marbles have been properly placed on big UA low in the Upper Ohio Valley Great Lakes, then I'll have to admit being wrong. All I know is we're still 5-6 days away and something will probably change in the lat-lon of the developing upper lows. I'll check back tomorrow. Raw verification for the elevation based wet snow of 12/16-17 is in the 12/16-17 thread. added the 12z/17 analysis at 658P that helped support secondary development

Well when I remotely read we were in trouble with snow, I am modestly encouraged coming home seeing both 12z EC and 18z/17 GFS both front and back end snow west of I95. Think we need to give this more time before we call it quits on the coast. Complex... I am pretty sure we're going to need advisories I84 corridor for either the front or back end. The front for your normal WAA transition snow. Thursday. Plenty of time to get this to a front end thump???? Back end for sharply falling temps causing transitioning rain to snow to freeze... never really sure what flash freeze is... don't think that is defined clearly but if we get a 30-35 degree 6 hour temp drop with precip changing to snow and lasting into the time it drops below freezing... I'd say road management would be difficult, at least in the elevations. It's not easy to attain this latter back end occurrence. I'd say if we dig this trough a little further se of the current 00z/24 position, it will get interesting for a a couple of hours on the back end---quite the 500MB vort max associated with the developing upper low. Could it cross NJ? And the wind driving it??? scattered gusts 45-55 MPH in NJ expected late Friday..cyclically consistently by the EC 00z/16 cycle-12z/17 cycle. I'll check back tomorrow.

Two day storm totals...CoCoRaHS offers rough idea of elevation based snowfall. Also added the NWS received LSR to supplement.

and now the guidance: Click the maps and note the further east trend in the last 12 hours and also greater consensus in the GEFS at 06z/17. Sunday morning call me wrong if the EPS warm wind south flow is still valid. I am definitely thinking GEFS/GFS are going to be more accurate with EC and CMC to follow: That doesn't mean I'm reading this correctly. I get leery of dismissing the GEFS.

I saw the huge change in the EC yesterday 12z cycle and associated EPS. EPS may start drifting closer to a GEFS solution. Below the 18z/16 and 06z/17 12z/23 GEFS 500MB. I am thinking that the EPS will eventually dig further east, reverting to its guidance prior to 12z/16. Just seems too far west. IF the GEFS is close, the ridge will build north, and the primary storm will redevelop to Delmarva and move NNE. There seems to be too much deference to the EPS. My guess is the very strong block to our north is going to result in a very intense low crossing the northeast late this week, with a following pair of accumulative snow opportunities between 12/26-1/3. 00z/17 GEFS and GEPS not nearly as warm at 360 hours.

Good Saturday morning everyone, Dec 17. I'll add on the two day snow event verification at about 4PM, for those that might be interested. What's next? Thursday afternoon-Friday Dec 22-23. Quite a range of solutions. Looks complex with the likelihood that the bulk of the snow and ice will occur west (inland) of the I-95 corridor from northwestern sections of NC and Virginia up to NYS-New England. The coastal cities from Washington to NYC and Boston could have a little snow at the start and end of the storm (an inch or 3?), with the better chance for higher impact wintry weather along and north of the I-84 corridor. Flurries or a slight covering of snow might even make it down to Atlanta Asheville and Raleigh? There is likely to be at least one short period of 50-60 MPH wind gusts with this rapidly intensifying strong storm. And, it still looks like the coldest air of the season so far, will arrive by Christmas Eve and linger Christmas Day. Two maps for this event were added this morning. Both of these are the NWS Blend of Models for snowfall by Friday night the 23rd... it's not gospel but does show that there might be a first little snowfall of the season for Washington-Baltimore-Philly-NYC? but the bulk of this wintry weather event should be from Pennsylvania NYS and interior New England northward. The last map is the Blend of Models low temperature for Christmas morning. I also saw the GEFS ens snowfall... MUCH closer to the coast and heavier than EPS/GEPS. I am not yet mourning and think it best to keep eyes wide open... til the GFS says, give it up Walt. To get there... the Great Lakes trough rolls through late this weekend...I could see flurries even down here in NYC. Then the colder air follows for the rest of the period Mon-Thu. Added blend of models from 00z/17 for snowfall and 7A Christmas temp.

WOW! I need to see if the EPS 500 looks like the 12z/16 op for 12/23?? offline for a day

If we get ourselves a persistent 24 hours onshore flow of 20-35KT, I see more flooding at high tide the 22nd or 23rd, than what occurred with todays high tides. New Moon coming on the 23rd I think. Worthy of monitoring for potential moderate or greater IF we can muster ne flow for about 24 hours prior to the high tides. I know there is potential for a period of much stronger wind but this storm for us is not a done deal, at least not yet.

Thanks... I hope folks noticed how good the GFS was on positive snow amount, at least in the gradient. Cyclically was VERY good. To me: this is winter as it should be ...we'll have some snow cover here in the elevations daily for awhile. Those who said Dec would be a colder snowier start (at least interior), looks like they will be correct. Overall: I think NWS snow amount numbers will work out well I81 N-S corridor eastward. Onto the next:

Finals will post tomorrow for this mainly elevation 3+" snow event.

Modeling (non 10-1) snowfall was constantly trying to highlight valleys throughout. Very difficult to get good snow in AVP, ditto also extensive big snow through Central Pa.

Snowfall analysis and amounts without LSR's in the 15-16 storm-ops thread.

Snow fall past 24 hours via CoCoRaHs and a sophisticated evaluation program (NOHRSC). LSR's not yet updated. May add late today?

Hi! I'll add a verification snowfall map around 9A today... for the first part of the storm and then do the two day tomorrow. Kudos to the long rangers for pushing the Canadian block potential impacts. Nothing a done deal but it does look interesting. For now, biggest wintry impacts here in the interior next Thu-Fri per first attached WPC graphic; BUT, in my opinion I can see coastal cities getting 2"+ of snow all along I95, before any change to rain. Why? Better cold air resource nearby to the northeast.... I think that plays. What I see see in two of the three ensembles (EPS and GEPS) is one heck of digging trough into the Great Lakes-Northeast that has a better chance of spawning a southern storm that can take over, but unfortunately probably move directly nne along the coast to merge with the upper low barreling sewd through the Great Lakes. That's my scenario...hopefully ballpark. ALL BETS OFF if the weaker GEFS prevails. Also, added EPS 2M temp for 12z Thu (6 days out), and the 850MB temp anomaly prior to yesterdays storm (12z/15 where GEFS and EPS initial analysis Wass identical, and the EPS modeled 12z/22 Thu 85-0 MB temp anomaly (due to change but by how much??). You can see projections start out a little better. Hopefully this ensemble D6 projection is reasonable.

One other note: I check GFS positive snow depth change and it did very well repeated cycles leading to this event for eastern PA/NJ and I think as well the rest of the I84 corridor. PLEase check it yourself on Tropical Tidbits. No matter: we can't be using 10-1 in this abnormally warm thickness situations where type is mixed and the models assign mixed as a 10-1 ratio.

Hi! I'll add a verification snowfall map around 9A today... for the first part of the storm and then do the two day tomorrow. Added below my thinking based on the op models. I like what is ahead and Kudos to the long rangers for pushing the Canadian block potential impacts. Nothing a done deal but it does look interesting. I may switch to the main Dec thread in couple of days if snow to the coast looks more likely. For now, biggest wintry impacts here in the interior. Big winter is here the next two weeks. I'll detail the wrapup elevation wet snow shortly. Ahead is a Rockies to the East Coast heavy duty dose of winter cold and snow events. Details to be determined. Plan on some sort of snow accumulation across basically the entire eastern half of the USA (excluding southern GA and FL) sometime between late next Thursday the 22nd and Wednesday the 28th. This will include the coldest air of the season so far arriving near Christmas. But let's not forget today. Today-tonight below: Poconos: Your winter storm warning continues. Expect an additional 2-5" of wet snow-sleet between 6AM and midnight. Power outages in your area should increase a bit today. Slippery at times, especially elevations. Sussex County NJ: Mainly near Montague, High Point, northern Wantage and possibly Vernon. Intermittent rain-wet snow-sleet-freezing on some surfaces above 1000 feet. Looks to me like an additional inch or 2 of wet snow possible, mainly elevations above 1000 feet near the Kittatinny ridge. Most roads just wet. w CT and western MA: Valleys may pick up 1-3" of manageable wet snow, mainly this afternoon-early tonight. However, northern Litchfield County CT and the Berkshires should receive anywhere from 3-9" of additional heavy wet snow between 6AM today and 2AM Saturday. Power outages may develop there. Ashford CT and Bostons northwest suburbs: Wind swept rain possibly mixed with wet snow at times but no accumulation today. However rain changes to wet snow tonight...with 1-3" likely between 10PM tonight and 8AM Saturday. Later Thursday through Friday Dec 22-23: A potentially high impact - much more extensive and stronger storm with heavier snowfall than what occurred yesterday from North Carolina northward to Canada. It could bring some snow to the big cities of Boston-NYC-Washington but just far too early to know details. There may be a short period of rain-ice? Wind may gust 50-60 MPH everywhere in the northeast USA for a few hours each day next Friday-Saturday. Ensemble probability map (click for clarity and see legend) attached for possible 3+" of snow. Dark green is favored but the coast is not excluded. Christmas (24th-27th): Blustery with the coldest temperatures so far this winter, for a couple of days. I had 3" in Wantage as of 250AM.

Wantage NJ 3.0" in this southern part topped by some drizzle. Might be slightly larger before rain/drizzle. 32.7F now. TD 32.5.

Also: NO cold air to the northeast to be drawn southwest into the system. ORH 36 is not what I look for in a pretty good snowstorm here in SC.

I try to comment to assist perspective on 10 to 1, positive snow depth and Kuchera. I'll continue. My guess is that this will end up best as a Kuchera-positive snow depth blend (Ferrier replace positive snow depth change on the 3KNAM). It's not over so I donate want to presuppose the HPC HREF is slightly overdone but I certainly don't see anything more than what isa on that 12z/15 24 hr prediction for 12z Friday. What we may need to watch for near sunrise Friday is little residual southward down the Hudson River marginal freezing air invading far NNJ??? This as presssure falls slip to our east. Cross isobaric CAD drainage. Still 1.8" here at 7 and just a mix of sleet/light snow near this time of post. Possibly my last of the night. Walt 759P

Wantage NJ 1.8" as of 520PM. Attached the 12z HREF amounts by 12z Friday. Very little snow after 2AM. Already modeling may be too snowy in southern Sussex County? Anyway, will let this play out. 32.2 and riding here in Wantage and all of the state above freezing except northern Sussex County NJ.

I just checked EC... I still feel okay on my SCX amounts. I don't have any members in se NYS so I don't forecast there. 12z EC gives you 6-8 western OC with heavier Sullivan. It could be that we get all we are going to get by 10PM down here in NJ...one more good shot late this afternoon-eve here. The the big lift passes by and low lvl mess begins again. Not tracking you as closely.

Wantage NJ 4SW 3PM 0.7" on everything except treated roads wet with slightly slushy shoulders. 30.6/29.7. Light north wind. Think I am too conservative on amounts up here in Sussex County.

Wantage NJ at 1249PM: 30.4F. light ice pellet showers nearby Frankford Township.

919AM update: Main snow-ice damage on this storm for ne PA/nwNJ is Noon-midnight. Not changing snow forecast but adding that I am now pretty sure it will be very slippery near the Kittatinny ridge in Sussex County NJ (both sides) and that's where I'd put the odds for best chance 4-5" of snow-sleet. That includes Sandyston-Montague, western and northern Wantage-High Point area for a period of very slippery travel all untreated surfaces between 2P-midnight. For southern Wantage---not sure of more than 3" and pretty sure the valley from below 600 feet elevation Newton south is less than 3".

Just letting you know that 11z HRRR temps seem absurdly warm at midday into western NJ... not sure what the problem is. If they are that warm... there won't be much accumulation in SC. That temp of 34 at KORH is bothersomely warm at 7AM. Lots of uncertainty in Sussex County NJ and probably up to POU in the modeled Kuchera snow gradient.