Jump to content
  • Member Statistics

    17,497
    Total Members
    7,904
    Most Online
    PhiEaglesfan712
    Newest Member
    PhiEaglesfan712
    Joined

2/13 Significant/Major Winter Storm Discussion & Observations


Northof78
 Share

Recommended Posts

I usually keep my thoughts for long range, but I figured since I'm a bit new at posting, I'll make one for this upcoming storm. As far as the threat for this storm goes, it is increasingly likely that there will be an at least a moderate-level storm for most of the region. What we would want to see more of is confluence pushing down, and separation of the northern stream and the southern stream. Ideally, if we had cold air in place, we would want a more amped solution and phasing between the northern stream and southern stream, but considering its a very warm weekend coming up, cold air will be scarce for this storm. Therefore, in order to get snow from the NYC-boston corridor, (where snow has been almost non-existent since Feb 2022), a further push of confluence would be the best scenario (as it's likely we see a last minute northwest trend anyway, as we almost always do).

  • Like 2
Link to comment
Share on other sites

19z/8 NBM 1.6" NYC,  12z/8 GEFS less than 1" NYC, 12z/8 CMCE less than 1"  and the EPS while around 2" NYC Positive snow depth growth, it busted pretty bad 1/28-29 on being too far south.  So, we'll see how this plays. WPC has all chances of 3" snow north of I80.  

D5-6 opportunity: will want to verify against these data that I'll append shortly and we'll see what might have been best at this distant time.  

 

These graphics added at 539PM.  All identified. Positive snow depth is my base amount that I use, then double in the axis, or even use Kuchera or 10 to 1 if cold enough thicknesses for TOP of the range.  For now, the positive snow depth change is good start for me. image.thumb.png.45463c51707cb20a0994ca73431f3c58.pngimage.thumb.png.a898d33003aef562b663db01e6bbedea.pngimage.thumb.png.d40ed818a4e9f1cfd309b96cb2dd22ef.pngimage.thumb.png.cde9c915d3e39ee335fb6327e2b4de2a.png

Screen Shot 2024-02-08 at 5.32.41 PM.png

 

Screen Shot 2024-02-14 at 7.01.33 PM.png

  • Like 1
Link to comment
Share on other sites

Too many moving pieces and still too far out but if you're near the NYC snow hole this is by far the best chance at this range I have seen this winter for anything remotely significant to happen.  That said, this easily could end up another Orange County bullseye or Philly bullseye.

  • Like 1
Link to comment
Share on other sites

New Disco from Upton: 

“LONG TERM /SUNDAY THROUGH THURSDAY/... * Models continue to see significant north-south shifts and changes in the timing of low pressure that is expected to impact the area Monday into Tuesday. Low track has shifted to the south the last 24h. Chance rain and/or snow. * Temperatures will trend down to normal levels by mid week. Models and their ensembles continue to lack continuity with the track and timing of a souther branch storm system that is expected to impact the area later Monday into Tuesday. Like we saw 24h ago, the ensembles continue to closely follow their operational, indicating an under dispersed solution. The players feature north Pacific jet energy diving down the coast of western Canada today and into a split flow of the polar jet across the west. This pattern has been causing much volatility in the NWP. Now that this energy is onshore, the hope is the continuity will improve heading into the weekend. In addition, the splitting of the energy into the two stream and their interaction across the CONUS is another major factor contributing to the run-to-run changes. As is stands now, once again with all the uncertainty in the forecast, have stayed closed to the NBM outside of some small changes. High pressure will builds across the area Sunday and then gives way to low pressure moving out of the Lower Mississippi Valley Sunday night and into the Ohio and Tennessee Valleys on Monday. The 12Z GFS is the slowest of the guidance and lags its ensemble mean (GEFS), but there is a good cluster of members that are in line with this slower track. The Canadian (and GEPS) and ECMWF are about 12h faster. The low is expected to track off the Mid Atlantic coast Monday night into Tuesday, passing south and east of the 40N...70W benchmark. That being the case, confidence is still not high on this track based on the lack of continuity. As for precipitation type, whatever gets in here Monday should be rain with the potential of a changeover on the backside of the system Monday night into Tuesday. The lack of a strong surface high to the north and ESE flow at the onset, will likely result in temperatures too warm for snow. There is more uncertainty of course for inland locations, being father removed from the maritime influence. Bottom line, it is way too early to be specific with details, but it is something to watch in coming days. High pressure builds in for the middle of the week with cold, dry conditions. Gusty NW winds will likely prevail on the backside of the system Wednesday into Thursday.“

 

https://forecast.weather.gov/product.php?site=OKX&issuedby=OKX&product=AFD&format=CI&version=1&glossary=1&highlight=off

  • Like 1
  • Weenie 2
Link to comment
Share on other sites

5 minutes ago, snowman19 said:

New Disco from Upton: 

“LONG TERM /SUNDAY THROUGH THURSDAY/... * Models continue to see significant north-south shifts and changes in the timing of low pressure that is expected to impact the area Monday into Tuesday. Low track has shifted to the south the last 24h. Chance rain and/or snow. * Temperatures will trend down to normal levels by mid week. Models and their ensembles continue to lack continuity with the track and timing of a souther branch storm system that is expected to impact the area later Monday into Tuesday. Like we saw 24h ago, the ensembles continue to closely follow their operational, indicating an under dispersed solution. The players feature north Pacific jet energy diving down the coast of western Canada today and into a split flow of the polar jet across the west. This pattern has been causing much volatility in the NWP. Now that this energy is onshore, the hope is the continuity will improve heading into the weekend. In addition, the splitting of the energy into the two stream and their interaction across the CONUS is another major factor contributing to the run-to-run changes. As is stands now, once again with all the uncertainty in the forecast, have stayed closed to the NBM outside of some small changes. High pressure will builds across the area Sunday and then gives way to low pressure moving out of the Lower Mississippi Valley Sunday night and into the Ohio and Tennessee Valleys on Monday. The 12Z GFS is the slowest of the guidance and lags its ensemble mean (GEFS), but there is a good cluster of members that are in line with this slower track. The Canadian (and GEPS) and ECMWF are about 12h faster. The low is expected to track off the Mid Atlantic coast Monday night into Tuesday, passing south and east of the 40N...70W benchmark. That being the case, confidence is still not high on this track based on the lack of continuity. As for precipitation type, whatever gets in here Monday should be rain with the potential of a changeover on the backside of the system Monday night into Tuesday. The lack of a strong surface high to the north and ESE flow at the onset, will likely result in temperatures too warm for snow. There is more uncertainty of course for inland locations, being father removed from the maritime influence. Bottom line, it is way too early to be specific with details, but it is something to watch in coming days. High pressure builds in for the middle of the week with cold, dry conditions. Gusty NW winds will likely prevail on the backside of the system Wednesday into Thursday.“

 

https://forecast.weather.gov/product.php?site=OKX&issuedby=OKX&product=AFD&format=CI&version=1&glossary=1&highlight=off

And Mt. Holly is much more optimistic than this morning, when they were only calling for a chance of snow well NW of 95; here's their latest...I like the part in bold...

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Unsettled weather on tap for the start of the new work week as
a developing storm system impacts the Northeast and Mid-
Atlantic. However, there are numerous inconsistencies among the
models that leads to a low confidence forecast.

A deep upper trough over the West Coast ejects into the
southern Plains, and the base of the trough pinches off into a
closed upper low over the Southern Plains and Gulf Coast states
Sunday night. Surface low pressure develops out ahead of it and
moves towards the Mid-Atlantic on Monday.

This is where the models go awry. The 12Z/08 ECMWF has the low
passing through southern New Jersey and Delmarva Monday night,
and then the low intensifies off the New Jersey coast as the H5
trough follows behind it Tuesday morning. This system then
departs Tuesday afternoon. In terms of sensible weather, the
predominant ptype will be rain on Monday, changing to snow over
the southern Poconos and northern New Jersey Monday night and
Tuesday as colder air filters into the region behind the
departing low. A plowable snow is possible for those areas, and
possibly even down to the Fall Line.

The surface low is faster in the 12Z/08 CMC, with rain moving
into the region earlier on Monday, and has the low over eastern
Long Island by Tuesday morning. The storm is then gone Tuesday
afternoon before the cold air filters into the region. This
results in minimal snow accumulation.

The outlier, though it has been a consistent outlier, is the
12Z/08 GFS. The storm is much slower, with the low still over
North Carolina and Virginia Tuesday morning, and then passes
through Delmarva during the day Tuesday before departing Tuesday
night. With high pressure building in from the north, cold air
advection will be underway, and temperatures drop to below
freezing across much of the region. This results in at least a
plowable snow across much of southern New Jersey and into
Delmarva.

The NBM snow probabilities have a less than 10 percent chance
for 4 inches of snow or more in 24 hours ending at 00Z Wednesday
for most areas south of the Fall Line, and up to 25 percent
chance for 4 inches of snow or more in the 24 hours ending at
00Z Wednesday for the southern Poconos and northern New Jersey.

Due to the low confidence in the forecast, opted to follow the
NBM guidance closely. This results in likely PoPs for Monday
afternoon and Monday night, and chance PoPs for Tuesday morning.
Opted to keep slight chance PoPs continuing into Tuesday
afternoon, mainly due to the GFS being slower.
  • Like 2
Link to comment
Share on other sites

Main issue again though is not sure we have the air mass to tap even if the GFS at 18Z happened precisely in that way...the old DT rule was if you wanna go rain to snow near the coast here you better be -10 at 700 nearby and its not even close to that really...the other way to do it is a slow moving vertically stacked bomb but thats not the case either.

  • Like 1
Link to comment
Share on other sites

24 minutes ago, RU848789 said:

And Mt. Holly is much more optimistic than this morning, when they were only calling for a chance of snow well NW of 95; here's their latest...I like the part in bold...

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Unsettled weather on tap for the start of the new work week as
a developing storm system impacts the Northeast and Mid-
Atlantic. However, there are numerous inconsistencies among the
models that leads to a low confidence forecast.

A deep upper trough over the West Coast ejects into the
southern Plains, and the base of the trough pinches off into a
closed upper low over the Southern Plains and Gulf Coast states
Sunday night. Surface low pressure develops out ahead of it and
moves towards the Mid-Atlantic on Monday.

This is where the models go awry. The 12Z/08 ECMWF has the low
passing through southern New Jersey and Delmarva Monday night,
and then the low intensifies off the New Jersey coast as the H5
trough follows behind it Tuesday morning. This system then
departs Tuesday afternoon. In terms of sensible weather, the
predominant ptype will be rain on Monday, changing to snow over
the southern Poconos and northern New Jersey Monday night and
Tuesday as colder air filters into the region behind the
departing low. A plowable snow is possible for those areas, and
possibly even down to the Fall Line.

The surface low is faster in the 12Z/08 CMC, with rain moving
into the region earlier on Monday, and has the low over eastern
Long Island by Tuesday morning. The storm is then gone Tuesday
afternoon before the cold air filters into the region. This
results in minimal snow accumulation.

The outlier, though it has been a consistent outlier, is the
12Z/08 GFS. The storm is much slower, with the low still over
North Carolina and Virginia Tuesday morning, and then passes
through Delmarva during the day Tuesday before departing Tuesday
night. With high pressure building in from the north, cold air
advection will be underway, and temperatures drop to below
freezing across much of the region. This results in at least a
plowable snow across much of southern New Jersey and into
Delmarva.

The NBM snow probabilities have a less than 10 percent chance
for 4 inches of snow or more in 24 hours ending at 00Z Wednesday
for most areas south of the Fall Line, and up to 25 percent
chance for 4 inches of snow or more in the 24 hours ending at
00Z Wednesday for the southern Poconos and northern New Jersey.

Due to the low confidence in the forecast, opted to follow the
NBM guidance closely. This results in likely PoPs for Monday
afternoon and Monday night, and chance PoPs for Tuesday morning.
Opted to keep slight chance PoPs continuing into Tuesday
afternoon, mainly due to the GFS being slower.

Interesting but what is the Fall Line?

 

Link to comment
Share on other sites

1 hour ago, LibertyBell said:

If it somehow does happen, no one will be criticizing this model for the rest of the season.

The fall line is the 95 corridor for the purposes of weather along the eastern seaboard and especially from DC to Boston.  More formally it's where the coastal plain meets the Piedmont and just NW of the fall line is where elevations start to increase and the fall line is often along rivers, like the Delaware in SNJ/SEPA.

https://en.wikipedia.org/wiki/Atlantic_Seaboard_Fall_Line

  • Like 1
  • Thanks 2
Link to comment
Share on other sites

47 minutes ago, MJO812 said:

That's what we need to continue 

I wouldn’t be excited at all until we’re under 72 hours with this. Countless times we’ve seen a late north bump especially with these southern stream lows. If the confluence isn’t really there to press this south this will be a lousy outcome for 80% of us or more. 

  • Like 2
Link to comment
Share on other sites

  • Northof78 changed the title to 2/13 Significant/Major Winter Storm Discussion & Observations
  • Rjay pinned this topic
  • BxEngine unpinned this topic

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...