December 3-4, 2023 | Winter Storm

[Penn State]

30 minutes ago, MaineJay said:

Can't unsee that ECMWF run

GFS was good to me at 12z.. I like the low placement. Just needs to rev-up a little bit faster. 

[Pghsnow]

[JDClapper]

2 hours ago, MaineJay said:

Can't unsee that ECMWF run

Hows your EPS members looking?

Kinda something in the 6/7 timeframe down here, but very luke warm and minor at best. Pretty much flat-lines prior to that.

[MaineJay]

1 hour ago, JDClapper said:

Hows your EPS members looking?

Kinda something in the 6/7 timeframe down here, but very luke warm and minor at best. Pretty much flat-lines prior to that.

Not bad.  Moderate effect, with some upside potential with a favorable track and deepening.

 

Here's this morning 0z

12z

[JDClapper]

22 minutes ago, MaineJay said:

Not bad.  Moderate effect, with some upside potential with a favorable track and deepening.

 

Here's this morning 0z

12z

Looking better! Cant wait to see my first run like that this season. I swear every yr I become more impatient. It's Nov30, still 3.5 months left!

[MaineJay]

GYX

Quote

Evolution of the surface low and strength of the surface high
to the north will play heavily into precip types across the
area. Guidance continues with a broad spread of low centers amid
ensemble guidance and deterministic runs holding in their
camps. Of greater confidence is the high pres locking in cool
air NW of the mountains due to strong high pres slowly eroding
north. This cooler air could be overcome should parent low pres
continue to track up the St Lawrence Valley as suggested by the
GFS. Its ensemble however pauses a lot of these running
outcomes, transferring energy to an offshore low. This transfer
is most represented by the ECMWF and EPS, with only a handful of
members taking a surface low north of the VT/Canadian border.
The rest, are widely spread throughout the Gulf of Maine to east
of Nova Scotia. This represents a lot of variability that will
play on temperature advection throughout the CWA, especially the
interior and foothills. To accommodate this spread, have kept a
generous spread of rain/snow mentioned during this time period.
As this system heads into the medium term forecast, will keep
an eye on guidance that typically performs CAD well, namely the
NAM, and sometimes overly so, the HRRR.

 

[TheRex]

BTV's forecast discussion about the event.  I'm pulling for the Euro. Boo GFS!!!

Quote

LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 327 PM EST Thursday...A shortwave trough will pass through the
North Country Sunday night into Monday and a low pressure looks to
develop along it. There is still high model uncertainty with this
event, but there is decent agreement that there will be heavier
precipitation than in the previous storms. Therefore, continued to
forecast a period of likely PopS Sunday night.

The GFS has a warmer setup with the primary low over the Great Lakes
remaining stronger and pushing the North Country into the warm
sector. The Euro continues to have the primary low transfer its
energy to a secondary low off the New England Coast quicker and keep
a cold enough airmass for snow accumulations to occur over much of
the region. Currently about 30-40 percent of the EPS members give a
large area of Vermont over 6 inches of snow while less than 10
percent of the GEFS members do the same. The Canadian ensembles are
split between the GEFS and EPS. Despite the differences, the
atmospheric temperature profiles show that this would likley be a
rain or snow event without much of a freezing rain threat. It also
looks like if the EPS solutions end up occurring, snowfall would be
less elevation dependent than the previous storms with temperatures
in the Champlain Valley cold enough for snow. After the storm moves
out, there will be consistent northwest flow for much of the week
under a broad trough. This should lead to mostly cloudy conditions,
below average temperatures, and some upslope snow showers.

 

[so_whats_happening]

On 11/29/2023 at 7:23 PM, so_whats_happening said:

Those hot ribbons are just eddies overall we are doing much much better than last year at this time. We saw the rather drastic change over the summer of less ridging in the east and more tropical activity between the US and Bermuda that helped churn the waters up. Im sure we will still have bouts where the ridge pops up but shouldn't be anything too crazy.

Just to add onto this briefly. When temps are not sitting at 45-50 degrees just offshore and are now upper 30's low 40's that makes an enormous difference when we are talking boundary conditions. This holds the warmth more along the coastal region instead of flooding areas inland. It also promotes a more coastal track due to baroclinicity being offshore and allowing cold to actually make it to the coast before modifying too much.

As for this system and timeframe, unfortunately, my thoughts really haven't changed too much. Interior New England snows while coastal plain gets a cold rain 4th-5th. The trailing energy around the 6th-7th could spark some snow showers with the upper levels a bit favorable what looks to be more in the Mid Atlantic now instead of going up to SNE as well but can't rule out a potential light snow in places up that way.

Euro has a solid storm up that way, while it looks like GFS is playing a bit of catchup. 

[MaineJay]

NAM opting for the robust inverted trof.

[MaineJay]

FV3 is pretty warm.

[StretchCT]

Some energy coming through after the storm I think this is referencing does this on the 12z GFS.

But there's a huge diff with Kuchera

 

[telejunkie]

Nice to see 12z GFS take a huge step towards Euro, although 12z Euro went warmer...but not as warm as CMC or Ukie. Burlington office still keeping forecast vague saying guidance is still all over the place.  Will remain in wait and see mode...but if some of the events this nascent winter season has taught me, it's that the colder scenario seems to be winning more times than losing.

[jbrumberg]

The NWS/B-N Office is leaning towards a rain event for this pending weather event:

Spoiler

Confidence in the forecast has increased as deterministic guidance
has come to more of a consensus. There are still some details to
hash out with the exact track of the low and its intensity as it
will determine where the heaviest precip falls. Fortunately things
are fairly progressive, so am not anticipating a whole lot of impact
to the region other than it being soggy Sun into Mon. Will note the
latest NAM depicts essentially a dry solution with no SW/W low level
jet over the south coast. This is an outlier from the rest of the
deterministic guidance, so am throwing it out at this point, but it
bears worth keeping an eye on. Right now looks like the heaviest
precip would fall later on Sun into early Mon. Best shot for 24 hr
QPF AOA 0.50 inches is during that late Sun early Mon timeframe with
probs of 40-90 percent with the best shot across the interior per
the EPS/GEFS and GEPS. There are even some low probs (10-20 percent)
of 24 hr QPF AOA 1 inch across the interior. The NAEFS indicates
PWATs of 1.5-2.5 STD above model climo Sun into early Mon with
values increasing to 0.75-1.25 inches. At this point it looks like
an all rain event with 925-700 hPa layer max temps of 3 or greater,
but there are still a few ensemble members filtering in colder air
and bringing some snow. Will need to see how things trend with
guidance as we get a bit closer.

Given there still is some spread in guidance have stuck with the NBM
at this point.

 

[TheRex]

BTV's latest on the storm Sunday into Monday.  Looks like the higher elevations will be getting heavy wet snow and valleys mostly rain.  However, I agree with @telejunkie that the systems have trended colder so far this season.  Our biggest snowfall was from a system we were only supposed to get rain.  I hope that trend continues.

Quote

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 403 PM EST Friday...The active weather pattern continues Sunday
afternoon into Monday as the next system bringing widespread
precipitation moves into the region. Current guidance is depicting a
primary surface low from the Great Lakes and a secondary surface low
off the New England Coast. Widespread QPF amounts between of 0.7 to
1.25 inches are currently expected during this time frame. Strong
flow aloft should keep the system fairly progressive, moving out of
the region by Monday afternoon.

While confidence is increasing regarding the potential impacts,
there is still some uncertainty, especially in regards to snowfall
amounts and snow ratios. Thermal profiles continue to be tricky,
with very marginal temperatures. The general idea continues to
be cold rain with a possible dusting of snow in the broad
valleys, while wet and heavy snowfall occurs across the higher
terrain and across portions of eastern Vermont with a fairly
sharp gradient. With these marginal profiles, snow ratios have
been tricky, as they will be very elevational dependent.
Snowfall amounts this forecast package were similar to the
previous forecast, with summits possibly seeing 6 to 8 inches,
with 2 to 6 inches midslopes, and nothing to 2 inches 1000-1500
feet. One change was to slightly increase potential amounts
across eastern Vermont with slightly higher snow ratios. WPC`s
experimental Winter Storm Outlook continues to highlight a 10-
30% chance of reaching warning criteria across portions of
northern Vermont, with pockets of the northern Adirondacks
having a 30-50% chance of reaching criteria. There are
currently no winter headlines, but confidence is increasing that
they will be needed. The potential for heavy, wet snow
continues in the HWO and the forecast will continue to be
monitored as we get into the hi-res guidance time frame.

 

[Wayuphere]

NOAA Caribou, early map.

[MaineJay]

GYX with a nice write up.

Quote

LONG TERM /SUNDAY THROUGH FRIDAY/...
Overview: Low pressure will bring accumulating snow for the
mountains and foothills, rain to the coast and southern NH.
Uncertainty exists between these regions, as a rain or snow line
will fluctuate over time. Precipitation may be heavy at times
Sunday night, with a slick Monday morning commute possible.
Departure of the low may be slow, with lighter precipitation
lingering through the day Monday. High pressure will attempt to
nose into the region midweek, with drier and cool conditions.

Details: Potential impacts for late weekend storm should be
fairly consolidated to winter hazards, due to snow accumulation,
and perhaps a period of gusty winds. No flooding, strong winds,
or coastal flooding is currently forecast.

Initial disturbance has entered off the west coast this
afternoon, and will travel across the Inter Mountain West
tonight. The disturbance will be picked up in the Central Plains
via a rapidly strengthening jet from TX to southern New England.

Model consensus has improved from this time yesterday in regards
to general low handling and transition. This brings the center
of sfc low up the Eastern Great Lakes Sunday with a transfer to
a coastal low overnight into Monday morning. This period is also
when precipitation is expected to be the most widespread with
increased rates for our CWA.

Should this track and handoff continue, precip types should be
fairly straightforward in regards to a rain/snow system. The
cool column doen`t show too many warm hints that would cause a
period of accumulating sleet or ice. What will continue to need
refinement is where this transition line will lie. For this
forecast cycle, opted to continue to blend cooler sfc temps in
during the event. This is a reaction to cool drainage from north
high pres across the area Sat night. This flow largely remains
in place through Sun morning, and perhaps even a bulk of the
event considering the high`s strength. As mentioned above,
little in the way of a warm layer appears likely aloft, so
surface temps will play a large role in accumulation. The NAM is
by and far the coolest the longest for the area, with cold air
damming keeping much of the area 32 or lower outside of the
immediate coast. CAD signal can be seen in other global models
as well, and this gives confidence in this mechanism being quite
strong.

At this time range, it is enough to keep a slimmer rain/snow
line favoring all snow for the mountains, foothills, and into
portions of the interior. Amounts come in heavy, with up to a
foot possible in the higher elevations. With lighter winds,
upslope/downslope may be hard to define, and it will be more
temp/ratio based for elevation amt differences. The bulk of this
falls during Sunday night, picking up for the Sunday evening
commute.

The uncertainty rain/snow zone, wrapping from Lake
Winnipesaukee through much of interior ME towards the Midcoast
and ME Capitol region, will harbor much of the going debate over
the next forecast cycles. Areal coverage of surface
temperatures that remain A) supportive for snow and B) cool
enough to accumulate is tricky designate. A clearer picture will
come with additional hires guidance. Currently weighed towards
a cooler solution, but there remains a solid 8 to 10 degree temp
spread for some locations in the band outlined above. Thus
confidence is still low here. Towards the immediate coast, rain
will tend to be the primary precip type, but consideration will
be needed for the Monday morning period where wrap around,
ongoing precip may be mainly snow as rates being to taper off. A
safe bet would be to be on alert Mon morning for potential
slick travel conditions throughout the CWA.

The trough that lingers overhead w/ exiting low should keep some
snow showers in the region through the day Monday. These
features can sometimes harbor a thin region of enhanced rates,
and will need to keep an eye out for the formation of this.
Otherwise, high pressure will look to nose into the region
overnight through the middle of next week. This will generally
favor cooler temps and offshore wind directions.

 

[MaineJay]

NAM 3 and FV3 are not on the same page. I'm certainly leaning towards the colder solutions given the setup.

 

[MaineJay]

I made the post above before reading this AFD, as they also noted the hi res discrepancies.

GYX

Quote

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Generally quiet tonight...and with cloud cover and continued WAA
aloft temps will be mild overnight. Only a slow drop in temps is
anticipated...and most of that as precip approaches near
daybreak and there is a little evaporational cooling.

As the next S/WV trof approaches...and precip shield will get
better organized to our southwest and lift into the area during
the first half of the day. Initially temps will be above
freezing and rain is likely. Over time a gradual cooling is
anticipated as precip keeps falling thru the column. Eventually
I have readings wetbulbing down to around 32 to 34
degrees...which should be cold enough for some snow to mix in or
dominate even near the coast. As it will take time to occur very
little accumulation is expected outside of the higher elevations
thru Sun afternoon.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Active winter weather will be ongoing to start the long term period
Sunday night into Monday as waves of low pressure bring accumulating
snow across the interior. While the 00Z guidance is in relatively
good agreement, there is enough spread in ensembles with respect to
the rain/snow line south of the foothills leading to low confidence
in snowfall accumulations here and potential impacts to the Monday
morning commute. From the foothills northward, snow will likely
dominate with several inches of accumulation through Monday. The
primary low pressure system exits Monday evening while lingering
upper disturbances could keep snow showers going through Monday
night. There will be a general drying trend Tuesday into Wednesday
while an upper trough passes well south of New England with high
pressure building in Thursday.

The synoptic setup Sunday night into Monday will feature a potent
upper jet stretching from the TX Gulf Coast into the Gulf of Maine
with northern New England in the left exit region. At 500 mb there
will be short waves embedded in SW flow that lead to one wave of low
pressure tracking into the eastern Great Lakes with a secondary low
forming in the vicinity of coastal southern New England. The 00Z
model suite generally agrees that high pressure anchored over Quebec
will force the low over the eastern Great Lakes to transfer
eastward. This aligns well with previous the previous forecast cycle
leading to increased confidence that snow will be the dominant p-
type from the foothills northward. BUFKIT profiles do not show much
in the way of a warm nose that could lead to a prolonged period of
sleet or freezing rain and have continued with rain or snow wording
in the forecast.

The main point of uncertainty continues to be the rain/snow line
south of the foothills. There are some ensemble members, mainly the
EPS, that bring accumulating snow to the NH/MA border and the coast.
Granted this is a minority of members with majority of ensembles
highlighting the foothills northward where there is the potential
for greater than 6 inches of snow. Unfortunately, things are also
unclear looking into the tail end of hi res guidance with the NAM3K
showing accumulating snow across the south while the FV3 brings
mostly rain into the foothills with only accumulating snow in the
higher terrain. Therefore, this forecast does not deviate much from
the previous forecast cycle and will await better clarity from hi
res guidance with respect to the potential for Winter Storm Watches
for the Sunday night into Monday timeframe.

Low pressure will be pulling away from New England Monday afternoon
while a short wave will cross the region Monday night. This short
wave will keep chances for snow showers going Monday night with
light accumulations possible, mainly in the mountains towards
central Maine. This short wave exits Tuesday morning while a second
short wave dives into the Great Lakes. Tuesday looks mostly dry
while the proximity of short waves at this time range suggests that
showery weather may be possible. The short wave diving across the
Great lakes looks to pass well south of New England Wednesday with
high pressure building in for Thursday.

 

[MaineJay]

They certainly trimmed back the amounts. 

Previous

RGEM now has me right on the R/S line.  Worst case scenario is 6-8" of paste that brings trees down.  I did fire up the generator yesterday, just to make sure it's running fine.

[TheRex]

BTV's latest forecast discussion on the event.  Those getting snow will see low-ratio heavy wet snow and elevation will play a key role in who gets snow or not.

Quote

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
As of 335 AM EST Saturday...A double-barrel low situation is on track
Sunday afternoon into Monday. There has been little change to
overall forecast and the level of confidence with the forecast. The
degree of spread remains large due to marginal temperatures, an
aggressive dry slot, and forecast guidance not relenting from their
position with little clustering. For the sake of messaging likely
utility impacts from heavy, wet snow which will not be as reliant on
surface temperatures, the forecast leans towards the 75th
percentile. Yet, this is still not enough to place snowfall amounts
towards watch/warning criteria (7" for an event). Users are reminded
that 10:1 ratio model forecasts will have a high bias due to ratios
likely ranging between 5 and 8:1.

Below are some key messages:
*Moderate to heavy snow will be possible in the Adirondacks and
along the Green Mountains into eastern Vermont. The time frame for
travel impacts is most likely between Sunday evening and Sunday
night. Snowfall rates are likely to decrease Monday morning with
temperatures warming above freezing.

*Snow will be wet and heavy. Scattered power outages will be
possible across northern New York and along the Greens into eastern
Vermont. The time frame for utility impacts is most likely between
Sunday night into Monday morning.

*Temperatures are expected to warm above freezing on Monday before
falling below freezing Monday night. Any snowmelt on roadways may
result in black ice Monday night.

The main reason for potential concerns is the QPF associated with
the system. With liquid equivalents ranging between 0.66-1.25",
there is potential for some higher snow totals depending on snowfall
rates, but there are several caveats that also point to some bust
potential. Due to warm surface conditions, it will be highly
elevation depending. Winds aloft are mainly 35 to 40 knots, and not
anticipating strong gusts. There will be some terrain influence, but
not as notable as can occur with these type of events. Broader
regions of the St. Lawrence Valley and the Champlain Valley are more
likely to receive a dusting to 3 inches of snow. Across the
Adirondacks, northern St. Lawrence County, and the foothills of
either side of the Greens and eastern Vermont are likely to receive
2 to 6 inches of snow. Then as you climb above 2500 ft elevation,
amounts are likely to range between 6 to 10 inches, locally up to a
foot. When exactly precipitation ends will depend a bit on how
quickly low pressure slides east against broad high pressure in
eastern Quebec Province with the EC lingering precipitation longest.
Again, the forecast is a bit on the higher side running with a more
stretched out time frame for potential snow accumulations.
Nevertheless, as northwest flow develops, we should observe a
transition to orographic snow favoring our western slopes, and down
to the Champlain and St. Lawrence Valleys as flow remains very light
and likely blocked. As temperatures fall below freezing behind the
departing system, any snowmelt or standing water could transition to
some black ice on roadways.

 

 

Edited December 2, 2023 by TheRex

[TheRex]

BTV's latest snowfall map

[jbrumberg]

NWS/B-N Office "snowfall" graphic for this timeframe 😭:

[NHSparky]

Looks like I'm going to get a nice cold rain here. Seen a lot of guys with there plows on for some reason but I believe that is just wishful thinking.

[jbrumberg]

32 minutes ago, NHSparky said:

Looks like I'm going to get a nice cold rain here. Seen a lot of guys with there plows on for some reason but I believe that is just wishful thinking.

I did fire up the tractor this afternoon............  just in case 🤣

[TheRex]

3 hours ago, jbrumberg said:

NWS/B-N Office "snowfall" graphic for this timeframe 😭:

This won't be the snowmap the local news will be leading with tonight. 

To spin they could go with "National Weather Service says there is a chance some of us may be seeing snow the next couple of days".