Re: Possible Snowstorm December 8th-9th

by **hyde345** Mon Dec 04, 2017 8:58 am

rb924119 wrote:Here come the EURO Ensembles for late week/this weekend......slow but steady, and I'm fine with that

I'm not sure what you're seeing but it looks like it's too far east for most of us.

by **Frank_Wx** Mon Dec 04, 2017 9:04 am

hyde345 wrote:
rb924119 wrote:Here come the EURO Ensembles for late week/this weekend......slow but steady, and I'm fine with that

I'm not sure what you're seeing but it looks like it's too far east for most of us.

The EURO Ensembles had a lot of members clustered near the BM. It gave I-95 and points east a couple inches of snow. We're inside 120 hours as of today, so model runs will become prudent. We'll see what happens Smile

by **hyde345** Mon Dec 04, 2017 9:09 am

Frank_Wx wrote:
hyde345 wrote:
rb924119 wrote:Here come the EURO Ensembles for late week/this weekend......slow but steady, and I'm fine with that

I'm not sure what you're seeing but it looks like it's too far east for most of us.

The EURO Ensembles had a lot of members clustered near the BM. It gave I-95 and points east a couple inches of snow. We're inside 120 hours as of today, so model runs will become prudent. We'll see what happens

OK, thanks. I don't get to see individual members.

by **Frank_Wx** Mon Dec 04, 2017 9:11 am

hyde345 wrote:
Frank_Wx wrote:
hyde345 wrote:
rb924119 wrote:Here come the EURO Ensembles for late week/this weekend......slow but steady, and I'm fine with that

I'm not sure what you're seeing but it looks like it's too far east for most of us.

The EURO Ensembles had a lot of members clustered near the BM. It gave I-95 and points east a couple inches of snow. We're inside 120 hours as of today, so model runs will become prudent. We'll see what happens

OK, thanks. I don't get to see individual members.

by **skinsfan1177** Mon Dec 04, 2017 9:19 am

One thing to note the sampling of that northern body is a few days away that's key

by **sroc4** Mon Dec 04, 2017 9:24 am

Frank_Wx wrote:
hyde345 wrote:
Frank_Wx wrote:
hyde345 wrote:
rb924119 wrote:Here come the EURO Ensembles for late week/this weekend......slow but steady, and I'm fine with that

I'm not sure what you're seeing but it looks like it's too far east for most of us.

The EURO Ensembles had a lot of members clustered near the BM. It gave I-95 and points east a couple inches of snow. We're inside 120 hours as of today, so model runs will become prudent. We'll see what happens

OK, thanks. I don't get to see individual members.

And here are the individual members current snow totals. Most of this on these members comes in for the 9th-10th. Like mentioned above we are in the MR where we can start looking to focus the details. The only thing to really look at with these images below is what percent show accumulation vs dry, and what are the trends over the next 3-4days. Do we see more and more members jumping on board the accumulation train or not? Etc...

Possible Snowstorm December 8th-9th - Page 2 Eps_sn10

Possible Snowstorm December 8th-9th - Page 2 Eps_sn10

Possible Snowstorm December 8th-9th - Page 2 Eps_sn11

by **amugs** Mon Dec 04, 2017 9:46 am

EPS MEAN - we'll see what is has at 12Z today

Flow maybe a bit to progressive and need this to dig a bit more SW not sow much SE or else we push this to far off the coast. We'll know more in teh next 24 - 36hours

by Guest Mon Dec 04, 2017 9:57 am

What possible effect(s) does the system in the Great Lakes have on the coastal system?

by **sroc4** Mon Dec 04, 2017 1:13 pm

TheAresian wrote:What possible effect(s) does the system in the Great Lakes have on the coastal system?

So I'm not sure if your looking at the cluster of LP on the EPS image Frank posted above but take a look at the 12z GFS from today. At about hr 114 you can see over the GL is a lobe of the PV that has a bunch of vorticity swirling around its center. In addition a strong s/w (shortwave) with its associated vorticity is also diving in on the back side of the polar jet and mean trough. On the surface this leads to weak areas of LP in and around the GL region out ahead of the vorticity in these locations. At the same time we have a progressive flow off the east coast which is leading to the vorticity along the main fontal boundary to remain elongated and strung out preventing the polar jet and STJ from phasing. With the progressive flow off the EC if the timing of a digging s/w into the back side of the trough is not perfect with energy in the STj then you cant raise hieghts out ahead which would bring the LP up the coast and stronger instead of weaker and strung out like we see currently modeled. In addition to the 500mb and the surface maps there are also the 200-300mb jet streak to account for in this set up. If we can get the fontal boundary to stall a little closer to the coast than was modeled on this run verbatim the upper level jet streak could allow the precip shield to expand further NW into the area than what we see here, but I don't have time to elaborate on these details now. Bottom line pattern suggests a progressive flow off the EC for this time frame meaning don't bet on a deepening coastal being the main idea here. There would likely be isolated areas of surface convergence between the GL and the coast due to so many areas of LP around the area such that the IVT snowfall could occur but this will be hard to predict. The best chance for a more wide spread mild to mod event will be related to how have south the frontal bourdary stalls and where the 300-200mb jet streak is positioned and a hopefully more expansive precip shiled related to those dynamics as well as some baroclinically enhanced lifting mechanisms.

Possible Snowstorm December 8th-9th - Page 2 Gfs_z512

Possible Snowstorm December 8th-9th - Page 2 Gfs_z512

Possible Snowstorm December 8th-9th - Page 2 Gfs_sl10

by **sroc4** Mon Dec 04, 2017 1:19 pm

Hypothetically speaking if we could get all the energy in the NE (all the yellow and reds) more consolidated further back S and W where I marked X and the timing of the back side s/w stayed the same then you would have a MUCH greater chance at a phase given the timing here which would raise heights out ahead of it and a much deeper LP would develop and head more NNE then remain strung out and head ENE. Timing and location is everything

Possible Snowstorm December 8th-9th - Page 2 Gfsss10

Possible Snowstorm December 8th-9th - Page 2 Gfsss10

by **Frank_Wx** Mon Dec 04, 2017 1:23 pm

EURO scrapes the coast on Friday. Tries to develop a 2nd storm but the lead energy from the 1st system shifts the baroclinic zone too far east.

by **Frank_Wx** Mon Dec 04, 2017 1:25 pm

Looks like 1 to 3 inches verbatim

by **weatherwatchermom** Mon Dec 04, 2017 1:32 pm

and so it begins.. Very Happy

..ps..the last time I hosted Christmas(2010)we had the boxing day storm...its my turn to host this year Wink

by **Frank_Wx** Mon Dec 04, 2017 1:53 pm

Here is that 2nd system the EURO shows for the 9th into the 10th. This is much larger than the first. A moderate event.

Possible Snowstorm December 8th-9th - Page 2 5a25931c8e1f1

Possible Snowstorm December 8th-9th - Page 2 5a25931c8e1f1

Possible Snowstorm December 8th-9th - Page 2 5a25934ac7e2f

Total snow from both waves

by **sroc4** Mon Dec 04, 2017 1:57 pm

sroc4 wrote:Hypothetically speaking if we could get all the energy in the NE (all the yellow and reds) more consolidated further back S and W where I marked X and the timing of the back side s/w stayed the same then you would have a MUCH greater chance at a phase given the timing here which would raise heights out ahead of it and a much deeper LP would develop and head more NNE then remain strung out and head ENE. Timing and location is everything

And like that the euro shows exactly what I was saying. Notice there is less energy over the NE and more in the base of the trough

Possible Snowstorm December 8th-9th - Page 2 Ecmwf_16

Possible Snowstorm December 8th-9th - Page 2 Ecmwf_16

Possible Snowstorm December 8th-9th - Page 2 Ecmwf_17

by **Frank_Wx** Tue Dec 05, 2017 6:04 am

Overnight models were not impressed. GFS has some light snow for NYC and LI late Friday while the EURO showed nothing. It looks like there are too many waves in the pattern and that is preventing an organized storm from developing. Doesn't help that the flow looks progressive too. Don't bank on much at the moment.

by **Radz** Tue Dec 05, 2017 6:57 am

Frank_Wx wrote:Overnight models were not impressed. GFS has some light snow for NYC and LI late Friday while the EURO showed nothing. It looks like there are too many waves in the pattern and that is preventing an organized storm from developing. Doesn't help that the flow looks progressive too. Don't bank on much at the moment.

Hoping for some mood flakes this weekend at least, if this threat doesn't pan out, maybe midweek will deliver...

by **skinsfan1177** Tue Dec 05, 2017 8:55 am

I still have hope in this system. We are days away anything can change. Hoping for positive trends today

by **Frank_Wx** Tue Dec 05, 2017 9:17 am

So much strung out energy ahead of a positively tilted trough. Not pretty, but the WAR (West Atlantic Ridge) is trying to keep the low pressure near the coast.

Possible Snowstorm December 8th-9th - Page 2 Gfs_z500_vort_namer_13

Possible Snowstorm December 8th-9th - Page 2 Gfs_z500_vort_namer_13

by **MattyICE** Tue Dec 05, 2017 9:39 am

Thanks, Frank. I have a question, for you, or anyone else. Completely understand that we have energy that is strung out and there's not enough consolidation or wave spacing. Is there any sort of teleconnection or other indicator that we should keep an eye on that sort of predicts WHEN energy consolidates itself better? I suspect the answer is no, and that it can happen organically as the pattern settles? No rush...thanks!

by **skinsfan1177** Tue Dec 05, 2017 9:42 am

Also one other thing to note the best sampling for the northern vort won't happen until late this week

by **rb924119** Tue Dec 05, 2017 9:47 am

skinsfan1177 wrote:I still have hope in this system. We are days away anything can change. Hoping for positive trends today

I am NOT giving up hope on this system AT ALL. I feel strongly that we, or at least some of us, will end up seeing an accumulating snowfall from this system. As you stated below, the northern stream energy will not be well-sampled until late-week, and if my memory serves me correctly, modeling tends to significantly under-represent the strength and speed of energy in setups where the PV is displaced so far south and the energy is truly coming directly from the Arctic. I could be wrong, but pattern recognition argues for an East Coast storm, and with guidance a mere 50 miles too far east right now, I see no reason to abandon my ship.....yet lol

by **rb924119** Tue Dec 05, 2017 9:48 am

MY GOD HERE COMES THE NAM

by **crippo84** Tue Dec 05, 2017 9:58 am

rb924119 wrote:MY GOD HERE COMES THE NAM

Please...do share the news lol.

by **sroc4** Tue Dec 05, 2017 10:23 am

rb924119 wrote:MY GOD HERE COMES THE NAM

Its so funny you say this because I just came home frm running errands and saw what time it was. I was like is it GFS time yet?? Nope but the NAM probably ran. Lts just take a gander at it. 500mb is very interesting to say the least. Of course its the NAM at the end of its run but interesting none the less.

Possible Snowstorm December 8th-9th - Page 2 Namconus_z500_vort_us_53

Possible Snowstorm December 8th-9th - Page 2 Namconus_z500_vort_us_53

by **rb924119** Tue Dec 05, 2017 10:33 am

crippo84 wrote:
rb924119 wrote:MY GOD HERE COMES THE NAM

Please...do share the news lol.

Take a look at the below two images both valid 00Z Saturday:

GFS:

Possible Snowstorm December 8th-9th - Page 2 Slide110

The northern stream energy diving down the southwestern flank of the mid-tropospheric PV is denoted by the red line through Minnesota. Note the extremely positive orientation of it compared to the much less positively tilted axis of the longer-wave trough centered through the eastern U.S., as well as the large amount of distance between the two. Also note the two blue ovals on either side of the larger-scale trough - they are there to highlight the wind barbs and forecasted strength/direction of the winds at this level. Notice how none of the barbs in the western oval are above 50 knots, while in the eastern one there are several well over 100 knots.

Compare that with the most recent NAM run valid for the same time:

Possible Snowstorm December 8th-9th - Page 2 Slide210

Possible Snowstorm December 8th-9th - Page 2 Slide210

Notice the significant differences in the northern stream energy with respect to both strength, location, and orientation. Also note the differences in the strength and orientation of the forecasted winds ahead of and behind the larger-scale trough. The reason why the GFS is so strung out is because the northern stream energy has no way of catching up to the energy in the larger trough. Why? The winds out ahead of it slow down markedly while the winds ahead of the larger trough are significantly faster, thus "dragging" the energy in the main trough out so fast that it can't organize at all. The NAM, however, does NOT decelerate the winds ahead of the northern stream nearly as much which would allow it to progress much more quickly around the base of the PV. It's orientation is also very important because the closer the two trough axes are in alignment, the closer to a phase they are. Secondly, because the winds ahead of the northern stream energy/behind the main trough are not decelerating nearly as much AND they are also directed from due north to south, or even slightly north-northeast to south-southwest in conjunction with the winds being noticeably slower ahead of the main trough compared to the GFS, this allows the energy in the main trough to continue to dig further south AND consolidate some. Why does this matter? It will slow the main energy down and allow the northern stream energy to begin to really close the gap. It will also the heights ahead of the whole system to begin rising more than the GFS, which would direct the steering flow toward a more south to north direction instead of a west-southwest direction.

Unfortunately I don't time to go much further, but hopefully that makes sense.

by **jake732** Tue Dec 05, 2017 11:02 am

12z gfs ots

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