Dec 17-18 Front End Snow/Ice/Rain Event

[UlsterCountySnowZ]

euro has 1-2" on the ground by 8am for most

[Allsnow]

euro on sv has about .10+ for the area as all snow by 15z the rain snow line is north of nyc

 

1-2 for the area and 2-4 extreme nw nj 

[ag3]

1 minute ago, UlsterCountySnowZ said:

euro has 1-2" on the ground by 8am for most

7am. 12z is 7am

[Animal]

7 minutes ago, Allsnow said:

euro on sv has about .10+ for the area as all snow by 15z the rain snow line is north of nyc

 

1-2 for the area and 2-4 extreme nw nj 

As others have noted.  The euro has basically sucked dong for a long time and has a known dry bias.

 

[BxEngine]

11 minutes ago, UlsterCountySnowZ said:

Actually it's not... ESDT 12z is 8am during daylight saving time

 

You don't need to comment on everyone of my posts attempting to correct me.. especially when your wrong.. we get it, you don't like me lol

 

http://www.noaanews.noaa.gov/hurricanes/zulu-utc.html

Think about this post a minute...

[ag3]

14 minutes ago, UlsterCountySnowZ said:

Actually it's not... ESDT 12z is 8am during daylight saving time

 

You don't need to comment on everyone of my posts attempting to correct me.. especially when your wrong.. we get it, you don't like me lol

 

http://www.noaanews.noaa.gov/hurricanes/zulu-utc.html

I wasn't saying it in a bad way.

And 12z is 7am.

8am is during DST.

[dmillz25]

Nothing anafrontal on the euro correct?

[pazzo83]

Right now we are UTC -5h, so 12z or 1200 UTC is 1200 - 500 = 700h EST.

In DST we are UTC - 4h, so 12z or 1200 UTC is 1200 - 400 = 800h EDT.

Math shouldn't be hard for people on a science board.

[ag3]

Just now, pazzo83 said:

Right now we are UTC -5h, so 12z or 1200 UTC is 1200 - 500 = 700h EST.

In DST we are UTC - 4h, so 12z or 1200 UTC is 1200 - 400 = 800h EDT.

Math shouldn't be hard for people on a science board.

Thank you. Wasn't even posting it in a bad way.

Just correcting the error.

 

12z is 7am

18z is 1pm

0z is 7pm

6z is 1am

 

During DST add 1 hour to each.

[pazzo83]

1 minute ago, ag3 said:

Thank you. Wasn't even posting it in a bad way.

Just correcting the error.

 

12z is 7am

18z is 1pm

0z is 7pm

6z is 1am

 

During DST add 1 hour to each.

Yep.  Working often with Brits has it almost on auto for me - although we'd argue in the summer about GMT because technically London is in BST (British Summer Time) so they are GMT +1hr (GMT doesn't have daylight savings time).

[Ralph Wiggum]

This thread is a trainwreck. "NAM says I get 2.8" but the GFS says 2.7".....and the GGEM says changeover at 8:15 ESDT(?) but the Euro says changeover at 8:20am....and a tenth of a mile to my East always reports sleet but a tenth mile to my West always reports snow". The model nitpicking is laughable. We get it....its a crap event for most much like last weekend. You guys are killing yourselves debating a hundredth of an inch difference in precip etc.

[WeatherFeen2000]

Edit: this is going to be a big storm. 

Much better Ana frontal Sunday night on the GFS para 12z

And the ukmet looks like a decent Friday night 2-3 inches of snow with heavy rain during the day Saturday.

[NorthShoreWx]

3 hours ago, psv88 said:

ha true. of course not every event. But snowfall averages over time. NorthshoreWX has some maps over the years showing the annual snowfall. 

I'm about 5 miles east of the 3" NAM blob, but that level of precision is pretty useless at this time.  As good as the resolution is on the NAM, it's not enough to make reasonable snow maps for LI.

 

We've been in a rut of sorts where I am snow-wise.  Very roughly speaking (no statistical rigorousness to this at all) we've been in the top 20% of the island for annual snowfall and in the bottom 20% for just about every big storm (15"+).  Some are obvious because you can see where the best banding was east or west of here, and some are unexplainable (which annoys those who measured more).  One possible answer is the wind we get here on an east facing hill a couple of miles from the sound beating down the accumulations, but I am not convinced that is it.

[rgwp96]

Ok here is the eurowx snownmap . Usually it's always less than wxbell , I  now it's way higher .  Anyone know much about that site ?

[Allsnow]

Nam continues with less qpf to start. 1-2 less by the city and coast 

[NJwx85]

Changeover on the 18z NAM between 13-14z. Should go over to plain rain in the city and immediate coast fairly quickly but it looks like sleet and snow could hang around North and West for a few hours after that. I see some potential for around a quarter of an inch of ice for the far interior and NE PA on Saturday afternoon. All areas of this subforum should flip to plain rain by 16-17z with perhaps the exception of Sullivan County and Western Orange County. A 2-3 hour period of moderate to locally heavy rain then looks likely for most of NJ, NYC and LI before a dry slot moves in after 19z. 

Rain then moves back in pre-dawn on Sunday and persists most of the day, perhaps flipping over to some wet snow North and West before tapering off.

[SnowBlitzkrieg]

4K and 3K NAM still look ok. Upton cut totals for LI but still have 3-4" for NYC and 2-3" for northern Nassau/NW Suffolk.

[Animal]

Latest from Mt Holy NWS.

Sorta looks like game, set match south of i 78 for snow.

Talk of an I 80 special in terms of max snowfall.

 

Timing...Precipitation will overspread the region Friday night, but
with departing high pressure nearby, it will have to overcome a dry
air mass in place near the surface. By midnight Friday night, precip
should be reaching the ground northwest of I-95, but may struggle
to reach further east of here until late. The heavier precipitation
is expected to commence after midnight, northward of the I-195 and
PA Turnpike corridors, where deeper moisture is co-located with
stronger isentropic ascent. In fact, the heaviest precip is
favored in the late Friday night into Saturday morning period,
with the bulls eye between the I-80 and I-195>PA Turnpike
corridors. Overall, moderate confidence.
Almost time to spike the football for my area.

Amounts...In terms of snowfall, the highest amounts are expected
close to I-80. The snow is expected to be generally light, with a
heavier burst a few hours either side of sunrise Saturday, just
prior to the change-over. There is a narrow window in this period,
where upward vertical motion is maximized within the optimal Snow
Growth Zone (SGZ) region. In addition, the NAM also indicates some
frontogensis. However, model snow-liquid ratio (SLR) values are
expected to decrease rapidly during this time frame, while heavier
QPF may also be shifting southward with the stronger isentropic
lift. Thus, we have decreased snowfall amounts from the previous
forecast south of I-80. While sleet is expected to be minimal, a
longer period of freezing rain is expected Saturday morning, with
measurable ice glaze as far south as the I-195 to PA Turnpike
corridors. The amount of ice is dependent on how quickly 2-meter
temps warm Saturday morning, as well as the placement of the
heavier precip during this period. The greatest ice glaze is
likely between the I-80 and I-195>PA Turnpike corridors, where
some locations may receive up to around 0.10" with isolated 0.2"
amounts. Overall, moderate confidence in snow amounts and low
confidence in ice amounts.

[JerseyWx]

Nice write up by them.  They seem to like the I-80 area for snow.

[winterwx21]

RGEM continues to look better than most other models. We really thump for a few hours before the changeover, and this 18z run gives 3 to 4 inches for much of the area. 

[UlsterCountySnowZ]

RGEM 

[Allsnow]

gfs continues to delay the start and less qpf. Coating to a inch for NYC and 1-2 nw 

[wthrmn654]

46 minutes ago, SnowBlitzkrieg said:

4K and 3K NAM still look ok. Upton cut totals for LI but still have 3-4" for NYC and 2-3" for northern Nassau/NW Suffolk.

Upton actually raised my amounts plum island,NY expecting 3 inches ironically. Lol not sure how they came up with that.

[snowman19]

24 minutes ago, Allsnow said:

gfs continues to delay the start and less qpf. Coating to a inch for NYC and 1-2 nw 

Allsnow, Looks like the RGEM is on its own now, forecasting the most snow accumulations for the metro area. GFS, NAM, CMC, UKMET and the Euro have all dropped snow totals and qpf since 0Z and have also sped up the warming and changeover to all rain

[Ralph Wiggum]

Allsnow, Looks like the RGEM is on its own now, forecasting the most snow accumulations for the metro area. GFS, NAM, CMC, UKMET and the Euro have all dropped snow totals and qpf since 0Z and have also sped up the warming and changeover to all rain

Higher resolution guidance slower with the upper air warming fwiw (12k nam/rgem) at least down my way vs former runs. Probably wont make a huge difference anyway tho.

[snowman19]

12 minutes ago, Ralph Wiggum said:

Higher resolution guidance slower with the upper air warming fwiw (12k nam/rgem) at least down my way vs former runs. Probably wont make a huge difference anyway tho.

Right off the bat, early this week I thought the setup looked bad for snow, bad surface high position, bad Atlantic setup, bad low track and unimpressive moisture advection early on with the overrunning

[CPcantmeasuresnow]

Not loving the trend. AGAIN!!!

[Allsnow]

32 minutes ago, snowman19 said:

Allsnow, Looks like the RGEM is on its own now, forecasting the most snow accumulations for the metro area. GFS, NAM, CMC, UKMET and the Euro have all dropped snow totals and qpf since 0Z and have also sped up the warming and changeover to all rain

It's was to cold with the last event. I doubt it's correct 

[UlsterCountySnowZ]

27 minutes ago, CPcantmeasuresnow said:

Not loving the trend. AGAIN!!!

You should see atleast 3". . Take it and run, I'll be happy with my 3" 

[jm1220]

I'm thinking 1-2" around the city and most coastal areas (maybe less than 1" right on the shore). 3-5" once you get to northern Westchester, Rockland and I-287 and west. Far northwest near I-84 locally 6" or more. I'm not liking this near the coast and city, we really needed the heavy onset of snow. Looks like dry air will eat up the start of precip and make it choppy, allowing the increasing south wind to rocket up the temps.