February 12-13, 2024 | Winter Storm

[Undertakerson2.0]

3 hours ago, Cdfarabaugh said:

That's what I thought...................................before my wife said NO!   

In all seriousness feels wierd to get smoked with a foot of snow by the goofs while likely being outside in a t shirt tomorrow 

Don't get me started. I'll have to break out my story of Easter 1970. 

[Undertakerson2.0]

The latest from the modeling world

 

[Undertakerson2.0]

Pretty solid signal all things considered. 

 

 

Edited February 9 by Undertakerson2.0

[Undertakerson2.0]

AI Overlords have this

 

[Undertakerson2.0]

Overview and Weather/Hazards Highlights... The low pressure system crossing the Mid-Atlantic Monday night into early Tuesday will likely have enough moisture to fuel an axis of heavy rainfall in the warm sector of the low across the eastern Carolinas. There has been a slight increase in model QPF during the new Day 4 period across eastern NC and central/eastern SC, and therefore the Marginal Risk area inherited from the previous Day 5 was extended north to the NC/VA border. Farther to the north, there is an increasing potential for the spread of wrap-around accumulating snows and windy conditions across the marginally cool Appalachians/interior Northeast Monday night and into Tuesday before the whole system exits the coast as a continued maritime hazard. - WPC

[Undertakerson2.0]

Wake and Bake

Last 3 GFS Op runs

Seems a tick north with snow, but same overall? 

 

 

Edited February 9 by Undertakerson2.0

[Undertakerson2.0]

Let's be honest here - these two are the only ones we really care about

 

[Sentinel]

I do think Long Island could take a hard hit here, given the confluence pressing down and the avaliable moisture and energy combined. 

[Anthonyweather]

11 minutes ago, Undertakerson2.0 said:

Let's be honest here - these two are the only ones we really care about

 

a pasty during the day special. Heavy wet pushing 

[Undertakerson2.0]

1 minute ago, Anthonyweather said:

a pasty during the day special. Heavy wet pushing 

Yes, this should not be super impressive accumulation on paved. Some north sloping woodlots may see those numbers. (here in PA) 

Probably not much accumulation on paved even this side of C NY

[Wtkidz]

Well only rain for my backyard. Not complaining.  Just a fact.  If the model is correct.

 

 

[TLChip]

Skew-t shows nice cold air above with a quick turn to 32/34 degrees at the sfc. Snowfall maps are going to be over done for this event in the southern half.

[Wtkidz]

The latest book from Sterling.

 

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Early next week, attention will turn to a system approaching the
area from the southwest. To set the stage, a very strong area of low
pressure is currently located over the Aleutians. As this storm has
intensified over the last 48 hours, it has acted to amplify the
downstream waveguide, building a diabatically driven ridge over the
Gulf of Alaska, which in response has acted to reinforce troughing
downstream along the West Coast. Over the next 48-72 hours, the
aforementioned ridge will build overtop the West Coast trough,
eventually resulting in an anticyclonic wavebreaking event that will
produce either a closed upper low in the vicinity of the Southern
Plains, or a narrow, positively tilted trough that extends from the
Great Lakes to Southern Plains. Then, the closed low or shortwave
trough will lift northeastward toward the area from the Southern
Plains Monday into Monday night, resulting in what could be our next
impactful storm.

Model guidance still exhibits a fair amount of spread with respect
to the eventual track and timing of this system. Ensemble
sensitivity analysis suggests that much of the uncertainty
associated with this system stems from the building ridge over the
Gulf of Alaska, which will eventually have downstream implications
with respect to whether we get a closed upper low or a more
progressive open wave that forms over the Southern Plains. As has
been the case for several model cycles now, the 00z GFS and GEFS
favor the closed upper low solution, which tracks further south and
is a bit slower. The 00z Canadian maintains a more progressive open
wave. Then, the 00z Euro splits the difference and has a weaker,
slightly faster and further north tracking closed low than the GFS.
From a more probabilistic perspective, the respective ensembles are
similar, with the GEPS showing the furthest north track, the GEFS
the furthest south, and the EPS falling in-between. There had been a
notable shift southward in the EPS over the last few cycles, but
that trend appears to have stopped between the 12z and 00z runs,
with both showing similar solutions. It is worth noting that the
GEFS did start to trend slightly further north toward the Euro, even
though the deterministic GFS run stayed further south.

With no surface high to speak of to our north, there won`t be any
cold air in place ahead of this system. As a result, precipitation
should start as rain for all during the day Monday. Then as the
closed upper low or upper trough axis (depending on the model you
believe) works overhead, we get dynamical cooling in response to the
strong vertical lift, which then drops temperatures within the
column. The extent to which this occurs varies by model. As you
might expect, the strongest dynamical cooling response occurs with
the more southern, stronger closed low solutions like the GFS. In
this scenario, locations roughly along and north of US-50/I-66
change over to snow for a time Monday night into Tuesday morning,
and this snow could come down heavily for a time. However, boundary
layer temperatures would potentially limit accumulations even in
this coolest scenario, with the GFS showing surface temperatures of
33-35 degrees while the snow is occurring. The solution as depicted
by the Euro would produce lesser snow to the north of I-66/US-50,
with most of the accumulation remaining close to the PA border. The
solution as depicted by the Canadian would be an all rain scenario.

So to summarize, a wide range of solutions remain on the table with
this upcoming system, with locations further north having greater
chances for snow. And in the event that it does snow, all of the
cold air will be generated in-situ by dynamical cooling, which will
make preceding warm boundary layer temperatures difficult to
overcome at lower elevations. We`ll continue to monitor this storm
system over the upcoming days.

Low pressure will intensify offshore on Tuesday, with gusty
northwest winds and colder air filtering into the region in its
wake. Upslope snow showers may continue through at least part of the
day in the mountains. Behind the system, another shortwave trough
will descend down in northwesterly flow for later Wednesday into
Wednesday night. This system may potentially produce some snow
showers in the mountains, as well as a reinforcing shot of cold air
in its wake for Thursday.

 

[Undertakerson2.0]

6 minutes ago, TLChip said:

Skew-t shows nice cold air above with a quick turn to 32/34 degrees at the sfc. Snowfall maps are going to be over done for this event in the southern half.

 

5 minutes ago, Wtkidz said:

The latest book from Sterling.

 

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Early next week, attention will turn to a system approaching the
area from the southwest. To set the stage, a very strong area of low
pressure is currently located over the Aleutians. As this storm has
intensified over the last 48 hours, it has acted to amplify the
downstream waveguide, building a diabatically driven ridge over the
Gulf of Alaska, which in response has acted to reinforce troughing
downstream along the West Coast. Over the next 48-72 hours, the
aforementioned ridge will build overtop the West Coast trough,
eventually resulting in an anticyclonic wavebreaking event that will
produce either a closed upper low in the vicinity of the Southern
Plains, or a narrow, positively tilted trough that extends from the
Great Lakes to Southern Plains. Then, the closed low or shortwave
trough will lift northeastward toward the area from the Southern
Plains Monday into Monday night, resulting in what could be our next
impactful storm.

Model guidance still exhibits a fair amount of spread with respect
to the eventual track and timing of this system. Ensemble
sensitivity analysis suggests that much of the uncertainty
associated with this system stems from the building ridge over the
Gulf of Alaska, which will eventually have downstream implications
with respect to whether we get a closed upper low or a more
progressive open wave that forms over the Southern Plains. As has
been the case for several model cycles now, the 00z GFS and GEFS
favor the closed upper low solution, which tracks further south and
is a bit slower. The 00z Canadian maintains a more progressive open
wave. Then, the 00z Euro splits the difference and has a weaker,
slightly faster and further north tracking closed low than the GFS.
From a more probabilistic perspective, the respective ensembles are
similar, with the GEPS showing the furthest north track, the GEFS
the furthest south, and the EPS falling in-between. There had been a
notable shift southward in the EPS over the last few cycles, but
that trend appears to have stopped between the 12z and 00z runs,
with both showing similar solutions. It is worth noting that the
GEFS did start to trend slightly further north toward the Euro, even
though the deterministic GFS run stayed further south.

With no surface high to speak of to our north, there won`t be any
cold air in place ahead of this system. As a result, precipitation
should start as rain for all during the day Monday. Then as the
closed upper low or upper trough axis (depending on the model you
believe) works overhead, we get dynamical cooling in response to the
strong vertical lift, which then drops temperatures within the
column. The extent to which this occurs varies by model. As you
might expect, the strongest dynamical cooling response occurs with
the more southern, stronger closed low solutions like the GFS. In
this scenario, locations roughly along and north of US-50/I-66
change over to snow for a time Monday night into Tuesday morning,
and this snow could come down heavily for a time. However, boundary
layer temperatures would potentially limit accumulations even in
this coolest scenario, with the GFS showing surface temperatures of
33-35 degrees while the snow is occurring. The solution as depicted
by the Euro would produce lesser snow to the north of I-66/US-50,
with most of the accumulation remaining close to the PA border. The
solution as depicted by the Canadian would be an all rain scenario.

So to summarize, a wide range of solutions remain on the table with
this upcoming system, with locations further north having greater
chances for snow. And in the event that it does snow, all of the
cold air will be generated in-situ by dynamical cooling, which will
make preceding warm boundary layer temperatures difficult to
overcome at lower elevations. We`ll continue to monitor this storm
system over the upcoming days.

Low pressure will intensify offshore on Tuesday, with gusty
northwest winds and colder air filtering into the region in its
wake. Upslope snow showers may continue through at least part of the
day in the mountains. Behind the system, another shortwave trough
will descend down in northwesterly flow for later Wednesday into
Wednesday night. This system may potentially produce some snow
showers in the mountains, as well as a reinforcing shot of cold air
in its wake for Thursday.

 

These two posts fit nicely together. They both make reference to the dynamic cooling available - and that can translate to overcome the surface and overcome those thermals providing that it's not too deep into the daylight hours. Even IF that happens, I would suspect that warmth surrounding the event will make for rapid melt scenario regardless. I don't mean a total melt (yet that is possible inside the northwest "ring" of coldest air) - more as if it's a "mostly slush" deal. 

[Undertakerson2.0]

The best part of this in two images

 

Spare me the clean up 

 

[Wtkidz]

1 minute ago, Undertakerson2.0 said:

The best part of this in two images

 

Spare me the clean up 

 

Which perfectly shows the anti snow dome in Virginia ❄️

[Undertakerson2.0]

 

 

Edited February 9 by Undertakerson2.0

[bigben89]

I vote "bring on Spring."

[MaineJay]

Just now, bigben89 said:

I vote "bring on Spring."

This is more of a storm thread, posts like this belong in the monthly threads.  TIA

[TLChip]

1 hour ago, Undertakerson2.0 said:

 

These two posts fit nicely together. They both make reference to the dynamic cooling available - and that can translate to overcome the surface and overcome those thermals providing that it's not too deep into the daylight hours. Even IF that happens, I would suspect that warmth surrounding the event will make for rapid melt scenario regardless. I don't mean a total melt (yet that is possible inside the northwest "ring" of coldest air) - more as if it's a "mostly slush" deal. 

I was going to post the record warmth leading up to this event but didn’t want to crush dreams.

[Anthonyweather]

Realistically, it’s Friday. If we can get this to move in later towards nightfall, that’d greatly help accumulation

[JDClapper]

1 minute ago, Anthonyweather said:

Realistically, it’s Friday. If we can get this to move in later towards nightfall, that’d greatly help accumulation

Definitely, thats one good thing going for this, a nighttime start.

[Anthonyweather]

3 minutes ago, JDClapper said:

Definitely, thats one good thing going for this, a nighttime start.

Euro is definitely better as far as timing

[JDClapper]

1 minute ago, Anthonyweather said:

Euro is definitely better as far as timing

I always assume the start time will speed up an hour or two. Seems to always come in a little faster than its modelled, even on the short rangers

[JDClapper]

I wasnt paying too much attn to the time stamp, in my head thought Mon Night into Tues. I see GFS is like a 7amish Tue start here in CPA, but yeah, it will prob speed up a little.