October 23-26, 2018 | Clipper | Rain & Snow Coastal Storm

[Phased Vort 1,074]

As a more trofy pattern starts to develop over the Northeastern CONUS and to some extent pver the Mid-Atlantic as well, the region becomes susceptable to precipitation, be it rain or snow, resultant from the so called Clippers. Some of these small weather makers, at times bring measurable precipitation and at other times can even develop into decent coastal storms for Long Island and New England.

It seems that a clipper may indeed try to at least grace the region, especially the northern portions of the area, with precipitation in the form of rain and even some snow, as the clipper enters the region coming from the Great Lakes into westen NY and tracks toward northern New Jersey and then may try to deepen just south of Long Island and then get stronger just off the New Englando coast. As a result, precipitation will fall across the area, and could be enhanced should a coastal forms. That could then,  allow some snowfall for some areas of New England.

 

Please the latest ECMWF depiction of the this possible event:

Spoiler

 

 

 

Please contribute to this discussion with your welcomed thoughts.

[UTSwiinii 1,883]

18 minutes ago, Phased Vort said:

As a more trofy pattern starts to develop over the Northeastern CONUS and to some extent pver the Mid-Atlantic as well, the region becomes susceptable to precipitation, be it rain or snow, resultant from the so called Clippers. Some of these small weather makers, at times bring measurable precipitation and at other times can even develop into decent coastal storms for Long Island and New England.

It seems that a clipper may indeed try to at least grace the region, especially the northern portions of the area, with precipitation in the form of rain and even some snow, as the clipper enters the region coming from the Great Lakes into westen NY and tracks toward northern New Jersey and then may try to deepen just south of Long Island and then get stronger just off the New Englando coast. As a result, precipitation will fall across the area, and could be enhanced should a coastal forms. That could then,  allownform some snowfall for some areas of New England.

 

Please the latest ECMWF depiction of the this possible event:

 

Please contribute to this discussion with your welcomed thoughts.

 

 There appear to be at least two, perhaps three, distinct cold fronts between now and then. Would not be surprised if more than the aforementioned "some areas of New England" see some type of frozen precip - as each front hammers down the "door" just a bit more with each one's passing. 

 

[MaineJay 2,062]

I'll outr the entire GYX long range disco here, as it mentions snow quite often.

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The extended will continue the trend of ridge building across
Wrn North America...which means trofing across the Ern CONUS.

Wed night could almost be a carbon copy of today...with a strong
cold front and gusty winds set to cross the area. Model guidance
however is in agreement that the trof will be more
anomalous...in the -2 to -3 standard deviation range...and that
the trailing air mass will be colder. First...temps are
generally a blend of a mixed down approach and raw 2 m temps
from model guidance...given the well mixed boundary layer after
the frontal passage. With H8 temps approaching -10C...mixed down
temps are generally in the 30s for the mtns and low to mid 40s
as you move towards the coast. Second...winds will become gusty
once again behind the front. While the core of the winds does
not look as strong or as low in the column as this
morning...there is around 40 kts at H8. We should be able to mix
down at least 30 kt gusts...and so I have bumped wind gusts up
from the multi-model consensus in the Thu morning and afternoon
time periods. Finally with the main trof passage there could be
some light precip. Wly flow should help with some downslope
drying SE of the mtns...but along and upstream will be aided by
orographic lift. Any trapped low level moisture will be wrung
out and given the very cold air mass arriving after the
front...fall in the form of snow after some initial rain
showers. Forecast Froude numbers look high...which makes sense
in the CAA regime and well mixed environment...so some snow
showers will likely cross the ridgelines and propagate
downstream. The higher elevations check a lot of boxes for an
upslope snow event...given the cyclonic flow...low level
moisture...and cold temps aloft supporting efficient snow
growth. So I have at least light accumulations in the lower
elevations of the North County...with higher amounts in the
mtns.

Beyond the end of the work week the extended looks to remain a
series of quick moving S/WV trofs and reinforcing cold shots.
Mean trofing over the Ern CONUS will support temps at or below
normal thru the period and thru next week. Notably...with
plenty of colder than normal air in place and the positive PNA
pattern supporting Nrn stream S/WVs potentially interacting with
the subtropics...the pattern is ripe for East Coast
cyclogenesis. Perhaps significant cyclogenesis. And if we are
going to dig a little deeper...ECMWF EPS individual members are
supporting low pressure late next week...and roughly 1 in 5
members has the first snowfall of the season for locations in
Nrn New England. Food for thought.

[Phased Vort 1,074]

06Z GFS :

[Phased Vort 1,074]

This event still looks possible as energy from the clipper may try to phase with energy ruuning northeastward along a cold front.

If that occurs, then NE US could get a decent storm, with even decent snows.

 

NOTE: Date has been fine tuned to better estabkish the event timing as we near the actual date.

[Phased Vort 1,074]

Gosh.... 

It seems the 12Z ECMWF decided to indeed do something dramatic with this event.

We get the clipper and its energy and energy from low pressure wave riding on the cold front interacting and coming together to create a potent coastal storn for the NE US.

Impressive run.

This should keep this event and time period interesting.

[TheDayAfterTommorow 349]

Very intriguing @Phased Vort. If only cold air were a little more abundant...good day to live in NH/VT, verbatim. ;)

[Phased Vort 1,074]

12Z ECMWF snow fall depth after this posible storm.

Of course, just for fun now.

[Uscg ast 1,088]

21 hours ago, Phased Vort said:

Gosh.... 

It seems the 12Z ECMWF decided to indeed do something dramatic with this event.

We get the clipper and its energy and energy from low pressure wave riding on the cold front interacting and coming together to create a potent coastal storn for the NE US.

Impressive run.

This should keep this event and time period interesting.

Looks like it bombs the storm out a bit late. If it were earlier, I believe this could be a colder event for many. There is an abundant amount of low level cold air just up North. 

[Phased Vort 1,074]

The latest 00Z ECMWF, has a big Maine snow special with this clipper turning into a coastal storm.

Getting closer to the event now. In a couple of days, we will have a better idea if this will let more areas of the region take part or if it will only be a Maine special, or maybe just a non event for the NE US at all.

[MaineJay 2,062]

Bit of an inverted trof look showing up in some modeling.  Temps would be marginal for they most part, but you can get dendrites to form just below 0°C.

GFS

NAM

[MaineJay 2,062]

Ukie is trying, this just seems like it blooms too late. 

[EstorilM 66]

So, I'm following this thread - but had a larger concern.  Long shot, but figured people in this thread would know. Not a "typical" IMBY post ;)

Sooo a few of us volunteers with the commemorative air force need to fly our wing's TBM Avenger to NAS Jacksonville from Northern VA on Thursday for an air show.  Weather here looks great, but does ANYONE know what's going on with the low pressure system in the gulf? It's looking like it'll rain, but I'm trying to get a general idea of the timing, and if ceilings will be acceptable (the rain isn't the end of the world).

If not, the plane goes Wed and I miss out on the experience of a lifetime - can't take three days off work this week.

[MaineJay 2,062]

GYX with a fun disco.

LONG TERM /TUESDAY THROUGH SUNDAY/...
Trend of high amplitude upper ridge building along 110w still
indicating strong bundles of energy digging southeast thru the
data sparse areas of Saskatchewan and Manitoba and then into the
Great Lakes. US models finally coming more in line with EURO
solution. For this reason using superblend which incorporates
Euro but once again going with higher POPs than guidance and
lowering temps. Redevelopment of coastal and mid level low
expected somewhere along the southern Maine or NH coast area.
1.5-2.0 degs north of this center will be strong UVV and
enhanced QPF. Ptype will be an issue as model temps much too
warm due to seasonality and had to adjust them lower, also due
to drainage cross isallobaric winds and damming cold air. Nice
conveyer belt may also set up. The ole 72-96 hr rule of thumb
for the proportional upstream/downstream development looking to
work out nicely with models playing catchup. Confidence rather
high mountains may get a decent accumulation of snowfall Tuesday
night into Wednesday with a mix in some inland areas especially
higher terrain. Also considering amount of latent/sensible heat
due to the seasonably warmer ocean off the coast, expect this
extra amount of energy to help enhance the system even further.
Some heavy QPF may develop well inland north of the mid level
track into the mountains but will only hedge for now to avoid
flip flopping.

[MaineJay 2,062]

NAM hits the Maine mountains pretty hard.

[JonSnow 211]

14 hours ago, EstorilM said:

So, I'm following this thread - but had a larger concern.  Long shot, but figured people in this thread would know. Not a "typical" IMBY post ;)

Sooo a few of us volunteers with the commemorative air force need to fly our wing's TBM Avenger to NAS Jacksonville from Northern VA on Thursday for an air show.  Weather here looks great, but does ANYONE know what's going on with the low pressure system in the gulf? It's looking like it'll rain, but I'm trying to get a general idea of the timing, and if ceilings will be acceptable (the rain isn't the end of the world).

If not, the plane goes Wed and I miss out on the experience of a lifetime - can't take three days off work this week.

If you have to turn that down due to work, I sure hope you earn some extra brownie points with your boss.  And if you do make the flight, take a low pass over Roanoke, I would love to look up and see that.

[MaineJay 2,062]

SREFs doing their thing...

Eustis, Maine.

[MaineJay 2,062]

GYX likely snowfall. 

[EstorilM 66]

4 hours ago, JonSnow said:

If you have to turn that down due to work, I sure hope you earn some extra brownie points with your boss.  And if you do make the flight, take a low pass over Roanoke, I would love to look up and see that.

I think we will be a little bit east of you, trying to track direct to the coast then hug it to JAX, probably around 8500' - it's pretty loud from the outside though!

I just started a thread in the southeast forum - looks like there could be significant severe wx Friday - hopefully we can get in before the rain starts Thurs afternoon though. Biggest issue is we don't have as much daylight this time of year.

[MaineJay 2,062]

59 minutes ago, EstorilM said:

I think we will be a little bit east of you, trying to track direct to the coast then hug it to JAX, probably around 8500' - it's pretty loud from the outside though!

I just started a thread in the southeast forum - looks like there could be significant severe wx Friday - hopefully we can get in before the rain starts Thurs afternoon though. Biggest issue is we don't have as much daylight this time of year.

Here's the euro forecast for cloud cover,I don't know the altitude of each level, sorry. All these are valid at 2pm.

High

Medium

Low

 

[MaineJay 2,062]

GYX, I don't expect to see snow IMBY.

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
In advance of the strong digging short wave thru the western
Great Lakes expect light WAA overrunning pcpn to gradually
develop as the baroclinic zone intensifies. Some areas over the
higher terrain and mtns may see a mix of snow and rain at times
while southern areas temps will be too warm.

By Tue night the digging short wave approaches and allows a sfc
low to redevelop along the NH/ME coast and then quickly develops
vertically as the s/wv becomes negatively tilted as it moves
thru central New England. EURO is model of choice and by far has
had best continuity of development due to the upstream high
amplitude upstream upper ridge at 110W. As the mid level low
passes on a track along the coast there should be an area
1.5-2.0 degs north of the axis where heavy qpf occurs as per
EURO. Meanwhile US models not wrapping offshore moisture into
system as they continue to play catchup with development of low.

Expecting a decent snowfall across the Maine mtns and portions
of northern NH with even potential for some accumulations across
the higher terrain above 1000ft in the foothills. For now opting
to hold off on any headlines since it will be a 24 hr event with
most of the QPF to be in the time frame of our 3rd-4th periods
Tue night into Wed. Across southern areas primarily light rain
expected as the low tracks overhead followed by downsloping on
the backside.

QPF totals were very close to RFC guidance and snowfall amounts
are figured to fall in a range of 3-7 inches across a stripe
from the western mountains of Maine into northern NH, this fits
in very well with WPC snowfall guidance.

Temps were once again lowered for Tue into Tue night. NAM DNG
temps actually didn`t look that bad.

[EstorilM 66]

17 minutes ago, MaineJay said:

Here's the euro forecast for cloud cover,I don't know the altitude of each level, sorry. All these are valid at 2pm.

High

Medium

Low

 

Thanks, not sure what they consider "low level" but we'll do what we need to to stay out of them.  

 

My eyes always invert those maps - doesn't matter how long I stare at them, I think the yellow is the cloud cover lol. 

[MaineJay 2,062]

28 minutes ago, EstorilM said:

Thanks, not sure what they consider "low level" but we'll do what we need to to stay out of them.  

 

My eyes always invert those maps - doesn't matter how long I stare at them, I think the yellow is the cloud cover lol. 

I do the same.

The GFS middle clouds looks very similar to the ECMWF, and these clouds are between roughly 12,000 to 25,000 feet.

[EstorilM 66]

1 hour ago, MaineJay said:

I do the same.

The GFS middle clouds looks very similar to the ECMWF, and these clouds are between roughly 12,000 to 25,000 feet.

Perfect thanks! Yeah the oxygen system was removed during restoration, so we'll probably be around 8500 the entire time. Still thinking there's a solid window as long as we get on the ground before 1-2pm.

[MaineJay 2,062]

Updated GYX snowfall map, the afternoon shift is more bullish.

Caribou